revista de odonto rsbo - v. 11 – n. 2 – april/june 2014

v. 11 – n. 2 – Apri l/June 2014

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RSBO Joinville–SC v.11 n.2 102p. 2014

ISSN:Electronicversion:1984-5685

RectorSandra Aparecida Furlan

Vice-RectorAlexandre Cidral

Dean for EducationSirlei de Souza

Dean for Research and Post-GraduationDenise Abatti Kasper Silva

Dean for Extension and Community AffairsClaiton Emilio do Amaral

Dean for AdministrationCleiton Vaz

Editorial ProductionEditora UNIVILLELuciana Lourenço Ribeiro Vitor – Text revision and translatione-mail: [email protected] Schmitz – Graphic designMarisa Kanzler Aguayo – Diagramming

EDITORIAL BOARDEditor-in-chief Flares Baratto-Filho – Univille and UP, Brazil

Administration Editors Fabricio Scaini – Univille, Brazil Luiz Carlos Machado Miguel – Univille, BrazilCarla Castiglia Gonzaga – UP, Brazil Tatiana Miranda Deliberador – UP, Brazil

Associate Editors Edson Alves de Campos – Unesp, BrazilSandra Rivera Fidel – Uerj, BrazilGisele Maria Correr Nolasco – UP, BrazilLuiz Fernando Fariniuk – PUC/PR, BrazilKathleen Neiva – University of Florida, USAClaudia Brizuela – University of Andes, ChileJohannes Ebert – University of Erlangen, GermanyNicolas Castrillon – University São Francisco of Quito, Ecuador

Editorial BoardAlessandro Leite Cavalcanti – UEPB, Brazil Carlos Estrela – UFG, Brazil Christoph Kaaden – University of Munich, GermanyFernanda Pappen – UFPel, BrazilFernando Branco Barletta – Ulbra, BrazilFernando Goldberg – University of Salvador, ArgentineFrank Lippert – Indiana University, USAGuilherme Carpena Lopes – UFSC, BrazilJesus Djalma Pécora – Forp/USP, BrazilJosé Antônio Poli de Figueiredo – PUC/RS, BrazilJosé Carlos Laborde – Catholic University of Uruguay, UruguayJosé Luiz Lage-Marques – USP, BrazilJosé Mondelli – FOB/USP, BrazilJuan Carlos Pontons-Melo – Sao Marcos University, PeruLourenço Correr Sobrinho – FOP/Unicamp, Brazil Lúcia Helena Cevidanes – University of North Carolyn at Chapel Hill, USALuciana Shaddox – University of Florida, USALuis Sensi – University of Florida, USALuiz Narciso Baratieri – UFSC, BrazilManoel Damião Sousa-Neto – Forp/USP, Brazil Marco C. Bottino – Indiana University, USAMaría Mercedes Azuer – Javeriana Universit y, Colombia Mário Tanomaru Filho – Unesp, Brazil Miguel González Rodríguez – Odonthos Institute, Dominican RepublicMuhanad Hatamleh – University of Manchester, EnglandOsmir Batista de Oliveira Júnior – Unesp, BrazilPedro Bullon Fernandez – University of Sevilha, SpainRegina M. Puppin-Rontani – FOP/Unicamp, BrazilRichard L. Gregory – Indiana University, USARivail Antônio Sérgio Fidel – Uerj, BrazilRodrigo Neiva – University of Florida, USASandra Milena Brinez Rodriguez – Javeriana University, ColombiaSaulo Geraldeli – University of Florida, USAUlrich Lohbauer – University of Erlangen, GermanyValentina Ulver de Beluatti – University of Maimonides, ArgentineValeria Gordan – University of Florida, USAYara Teresinha Corrêa Silva Sousa – Unaerp, Brazil

The content of the articles is of sole responsibility of the authors.

Table of Contents

Guesteditorial................................................................................................................................. 111

Original Research Articles

Histologicalanalysisofcleaningcapacityinapicalthirdofflattenedrootcanalswithpassiveultrasonicirrigation......................................................................................................................... 113Tiago Luís Boff, Caroline Zamin, Deborah Meirelles Cogo, José Roberto Vanni, Mateus Silveira Martins Hartmann, Volmir João Fornari

A7-yearretrospectivestudyofbiopsiedorallesionsin460Iranianpatients....................................118Shila Ghasemi Moridani, Fatemeh Shaahsavari, Mohammad Bagher Adeli

Informationandcommunicationtechnologiesindentaleducation:students’perceptions................125Alessandra Martins Ferreira Warmling, Cláudio José Amante, Ana Lúcia Schaefer Ferreira de Mello

Prevalenceoforallesionsin25yearsofOralCancerPreventioncampaignsinParanáState,Brazil,1988to2013........................................................................................................................134Laurindo Moacir Sassi, Gyl Henrique A. Ramos, Jose Luís Dissenha, Juliana Lucena Schussel, Maria Isabela Guebur, Cleverson Patussi

Students’perceptionsondiagnosisandtreatmentofocclusalsurfaceoffirstmolars.......................138Beatriz Vieira de Paiva, Fernanda Ladico Miura, Silvana de Andrade Silvestre de Lima, Danielly Cunha Araújo Ferreira, Alessandra Maia de Castro, Fabiana Sodré de Oliveira

KnowledgeofHumanGenomeProjectamongDentistryundergraduates......................................... 148Daniela Peressoni Vieira, Thaisa Cezária Triches, Marcos Ximenes Filho, Ana Paula Silveira Caldeira de Andrada Beltrame, Leila Posenato Garcia, Mabel Mariela Rodríguez Cordeiro

Comparativeanalysisoffourcleaningmethodsofendodonticfiles..................................................154Bárbara Guandalini, Ivana Vendramini, Denise Piotto Leonardi, Flávia Sens Fagundes Tomazinho, Paulo Henrique Tomazinho

Evaluationoforalhygieneindex,monitoringandoralhygieneinstructioninvisuallyimpairedpeople...............................................................................................................................159Jackyeli Windmuller, Rafaela Araujo Mendes, Sheila de Carvalho Stroppa, Juliana Yassue Barbosa da Silva

Bacterialinfiltrationcomparisonoftworootcanalfillingtechniques............................................... 166Gislaine Pontarollo, Raphael Hamerschmitt, Beatriz Coelho, Denise Piotto Leonardi, Flávia Sens Fagundes Tomazinho

Invitrostudyofthemorphologyofinternallowersecondmolars....................................................172Humberto Ramah Meneses de Matos, Luanni Belmino Mastroianni, Aldo Angelim Dias

Literature Review Articles

PhotoelasticityinDentistry:aliteraturereview.................................................................................178Cássia Bellotto Corrêa, Ana Lúcia Roselino Ribeiro, José Maurício dos Santos Nunes Reis, Luís Geraldo Vaz

Conservativeestheticsolutionwithceramiclaminates:literaturereview...........................................185Gisely Naura Venâncio, Rosceline Rodrigues Guimarães Júnior, Sybilla Torres Dias

Reliningofremovabledentures:aliteraturereview..........................................................................192Cinthia Sawamura Kubo, Fabrício Reskalla Amaral, Edson Alves de Campos

Case Report Articles

Hypochlorite-inducedseverecellulitisduringendodontictreatment:casereport............................. 199Bernardo Almeida Aguiar, Fábio Almeida Gomes, Cláudio Maniglia Ferreira, Bruno Carvalho de Sousa, Fábio Wildson Gurgel Costa

Aestheticmanagementofmolar-incisorhypomineralization............................................................ 204Juliana Feltrin de Souza, Camila Maria Bullio Fragelli, Manuel Restrepo, Amanda Mahammad Mushashe, Estela Maris Losso, Leonardo Fernandes da Cunha

Guest editorial

Dental amalgam “prohibition”: what the dentist should know

Many and different nongovernmental organizations (NGOs), scientists, professors, dentists, physicians, activists and attorneys have tirelessly worked and legislated on the prohibition of amalgam as restorative dental material, whose articles and opinions contribute for encouraging the “third war” against amalgam. Most of us have read and known the literature cited by them. Unfortunately, even dental professionals and professors from Brazil and other countries have defended and supported these manifestations. The analysis, even superficially of the presented arguments, seems little commendable. For example, they have argued about the number of mercury that would evaporate from the oclusal surface of an amalgam restoration during function. Also, they have discussed concurrent increases of mercury in the blood and urine when amalgam restorations are inserted, followed by the reduction of this level when amalgam restorations are removed. Notwithstanding, after reading many of these documents and manuscripts on hazard potential of the amalgam, I concluded that none published good-faith, authentic, scientific research demonstrated some valid relationship between amalgam inside oral cavity and any systemic disease. However, even with its historical context, the amalgam unfortunately becomes more a victim of the archaic teaching, undervaluation, and dental esthetics than of the science.

The advent of an esthetic material of fast application compromised dental amalgam image, but it is wrong to say that this latter should not be used simply due to its silver, dark color or even to meet the population’s demand for metal-free restorations because, in fact, dental amalgam assures excellent performance in maintaining the occlusal-functional, marginal or interfacial integrity.

The dentist should always remember that three mercury forms exist: inorganic, organic and elementary. The mercury inside amalgam is inorganic (or metallic), that is, it is poorly absorbed by the intestine, and when eventually absorbed, mostly tends to keep this state up to urine excretion; therefore, it is nontoxic. This is totally different from organic mercury, which is highly toxic and present in fishes and shellfishes from contaminated water and in some pesticides and herbicides. This is fast absorbed by the organism. On the other hand, elementary mercury results from the vapor inhalation when inorganic mercury is heated at high temperatures (work accident).

The mercury may penetrate in the organism in its elementary, inorganic, or organic form. The elementary form has high vapor pressure and is classified as a manufacturing, not environmental contaminant. Its main absorption route is the respiratory tract. Inorganic mercury is the oxidized form of elementary mercury and it is little absorbed by animals or plants. On the other hand, organic mercury is highly toxic, considered as an environmental contaminant and pollutant, and 95% are absorbed by the gastrointestinal tract.

The organism is not capable of transforming large inorganic mercury amounts from amalgam, which is toxic. The mercury amount absorbed by the organism from amalgam is very small compared with that absorbed from food [1, 2].

Recently the United Nations Environment Programme, (UNEP) concluded the discussion on an international agreement, so-called the Minamata Convention on Mercury, which aims to reduce the significant environmental impacts on health due to mercury atmospheric pollution and includes guidelines on many products containing this chemical element. Some of these products should be banned as of 2020. These include batteries, except those used in watches, mobile phones and implantable medical devices; switches and relays; soaps and cosmetics; certain types of compact fluorescent lamps; mercury in cold cathode fluorescent lamps and external electrode fluorescent lamps; certain non-electronic medical devices, such as thermometers and sphygmomanometers. Some exceptions were approved, as follows: non-electronic measuring devices installed in large-scale equipment or those used for high precision measurement, where no suitable mercury-free alternative is available; and vaccines in which mercury is employed as preservative. Although Minamata Convention has cited dental amalgam restorations, suggesting a voluntary decrease of its use and commitment regarding to proper measurements of its application, it does not demand obligatory or prohibitive guidelines to reach these goals or banishment deadline.

According to the recent UNEP publication from 2013, the most anthropogenic (human activities) sources of mercury environmental contamination have been associated to the artisanal gold mining, coal burning in power stations to produce electricity, and the production of cement, ferrous and non-ferrous metals. The amount of vapor released by amalgam restorations to atmosphere due to burning per year at worldwide rate does not reach 1% of the total released by the other sectors accounting for pollution. Concerning to possible vapors from amalgam residues, there are no data monitored or recorded until 2013 by UNEP.

The most toxic mercury form, methylmercury or inorganic mercury, is found in water systems, which is accumulated in fishes and marine mammals consumed by humans; moreover, in this environment, nontoxic inorganic mercury and less toxic elementary mercury can be transformed into methylmercury. Most part of the human exposure to health risks occur due to the food consumption of foods such as marine and/or freshwater fishes.

According to Leinfelder [3], dental amalgam will be available for dentists for many years. Readily admitted or not, dental amalgam has served exceptionally to dental demands of the population for many years because of its forgiving nature. Although a good number of dentists is capable of using resin composite as amalgam substitute, this figure is far from 100%. For those not believing in this fact, they should question the endodontists who have observed the inappropriate use of resin composites accounting for an increasing of endodontic demands. The number of restoration replacements associated to secondary caries undoubtedly will continue to occur at an alarming rate until the dentists reach the competence required for using resin composite. Considering that rubber dam is recommended for the insertion or condensation of amalgam, its use is obligatory for resin composites; notwithstanding, many dentists have not employed it, regardless of the material to be inserted, condensed, or cemented [3].

Think about it. If amalgam is banned as restorative material, in each and every moment, dental profession will experience severe problems, mainly in poorer, underdeveloped or emerging countries. Thus, despite all its detectable failures and defects, our old friend amalgam will be with us for a long time, since we manage responsibly its use and discard.

In conclusion, in the name of modernity, one cannot enable that words and studies far from scientific evidences but closer from market interests, NOGs or political organizations give the final verdict on a dental material, unless international organizations (ADA, FDA, FDI), Brazilian official dental organizations (CFO and CROs), Brazilian dental organizations (ABO and ABCD) and Brazilian scientific organizations (ABENO, GBMD and GBPD) accounting for the qualification and teaching of dental products demonstrated which should be used, taught and discarded. Until now, with all due prudence and within the knowledge and relevant studies, we can continue to use dental amalgam without the fear on a possible hazard effect of one of its components – the mercury. Therefore, with all due prudence, common sense and within the knowledge and relevant studies, we can continue to teach and use dental amalgam in cases which esthetics is not mandatory, without fearing a possible systemic side effect.

References

1. American Dental Association. Council on Scientific Affairs. Dental amalgam: update on safety concerns. J Am Dent Assoc. 1998;129(4):494-503.

2. Food and Drug Administration (FDA). Center for Devices and Radiological Health. Class II special controls guidance document: dental amalgam, mercury, and amalgam alloy – guidance for Industry and FDA staff. Silver Spring: FDA; 2011. Available in: http://www.fda.gov/.../guidancedocuments/ucm073311.htm.

3. Leinfelder K. The enigma of dental amalgam. J Esthet Restor Dent. 2004;16(1):3-5.

José MondelliSenior Full Professor of the Department of Operative Dentistry,

Endodontics and Dental Materials of School of Dentistry of Bauru, University of São Paulo, Bauru, SP, Brazil

Keywords: endodontics; root canal therapy; ultrasonic therapy.

ISSN:Electronicversion:1984-5685RSBO.2014Apr-Jun;11(2):113-7

Original Research Article

Histological analysis of cleaning capacity in apical third of flattened root canals with passive ultrasonic irrigation

Tiago Luís Boff1

Caroline Zamin1, 2

Deborah Meirelles Cogo1

José Roberto Vanni1, 3

Mateus Silveira Martins Hartmann1, 3

Volmir João Fornari1, 3

Corresponding author:Volmir João FornariCentro de Estudos Odontológicos Meridional (CEOM)Rua Senador Pinheiro, n. 224 – RodriguesCEP 99070-220 – Passo Fundo – RS – BrasilE-mail: [email protected]

1 Department of Endodontics, CEOM Dental School – Passo Fundo – RS – Brazil.2 Community University of Chapecó Region – Chapecó – SC – Brazil. 3 IMED Dental School – Passo Fundo – RS – Brazil.

Received for publication: November 25, 2013. Accepted for publication: December 20, 2013.

Abstract

Introduction and Objective: The aim of this study was to evaluate histologically the passive use of ultrasound for cleaning the apical portion of flattened root canal systems. Material and methods: The sample consisted of 20 extracted human mandibular incisors which were divided into two groups after being prepared with the rotary system Hero 642 up to size #45 surgical diameter: Group A – final irrigation with 4 ml of 2.5% sodium hypochlorite by the conventional technique using a syringe, and Group B – final irrigation with 4 ml of 2.5%, sodium hypochlorite divided into 1 ml amounts which were activated with the passive use of ultrasound for 15 seconds each time, generating a total activation period of 1 minute. Following, the teeth were subjected to morphometric analysis to evaluate the cleaning ability promoted in both groups. Results and Conclusion: Statistical analysis showed significant difference (p < 0.05) between the groups, with the passive ultrasonic irrigation resulting in cleaner canals.

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Boffet al.–Histologicalanalysisofcleaningcapacityinapicalthirdofflattenedrootcanalswithpassiveultrasonicirrigation

Introduction

One of the goals of endodontic treatment is tooth preservation within the mouth, keeping it integrated into the masticatory system, thereby providing conditions for its repair allowing it to return to perform its functions normally. By knowing the relationship between the cleaning of the root canals system and the success of the endodontic treatment, the dentist must target on the highest possible cleaning when performing it [11, 18].

Since the early 90s, the pattern has been automating the biomechanical preparation of the root canal system to reduce the time spent at this stage, keeping it more centered, increasing the chances of actually touching all the walls, avoiding risks of major defects in the apical region [14].

By achieving these requirements, the rotary Ni-Ti instrument is widely used in the treatment of root canals today, and it was the type of instrument selected for this study, although many scientific studies show that with the biomechanical preparation using Ni-Ti instruments it is not possible fully eliminate dentinal debris present inside the root canal system [12, 13].

The anatomy complexity of root canal system is directly related to the quality of cleaning it. The root canals of lower incisors are often flattened at mesial-distal direction, and even with the use of Ni-Ti instruments, it is difficult to thorough cleaning the labial and lingual portions of these teeth [8].

To compensate for these cleaning failures, more resources are needed to improve the prognosis of endodontic treatment. In addition to the chemical action of the irrigant solutions and the physical action of the process of irrigation / aspiration that are part of the process of cleaning the root canal system [12], a passive irrigation using ultrasound can also be used.

The combination of conventional irrigation along with ultrasonic irrigation improves the elimination of bacteria and the smear layer around the root canal system, thereby contributing to higher rates of endodontic treatment success [1, 11].

This study aimed to evaluate the effectiveness of using passive ultrasound irrigation after root canal instrumentation performed with rotary instruments Ni-Ti.

material and methods

This quantitative experimental study consisted of a sample of 20 extracted human incisors selected according to the following criteria: presence of only one root canal, flattening of the proximal portion

of root, intact root and fully formed apex. For this selection, the sample was previously imaged to exclude specimens that had more than one root canal, internal resorption and calcification. All teeth in the sample were obtained through donation after the signing of the Free and Clarified Consent Form, and the project was submitted and approved by the Ethics Committee in Research of the University Inga-UNINGÁ under protocol number #0002/10.

The teeth were stored into 10% formaldehyde solution until the time of use when they were washed in running water.

The X-ray was performed with Agfa Gevaert M2 3 x 4 cm film (Heraueus Kulzer, Hanau, Germany) with an exposure time of 0.5 seconds and object-film distance of 10 cm. For this purpose, it was used the x-ray machine Odontomax 70/7P (Astex Dental Equipment, São Paulo, SP, Brazil), with power of 70 kVp, current of 10 mA, open-locating cylinder of 20 cm and a total filtration of 5 mm aluminum. The films were processed manually and analyzed with X-ray light box and subsequently digitized.

The surgical access to the pulp chamber of the selected teeth, as well as wear and compensatory form of convenience were performed with diamond burs (KG Sorensen, São Paulo, SP, Brazil) at high-speed (Kavo Brazil, Joinville , SC, Brazil), and air / water cooling, aiming at a free and direct access to root canal. After the opening, the content of the pulp cavity was removed with size #15 K-files (Dentsply Maillefer, Ballaigues, Switzerland) and the apical foramen cleared with the same instrument. The canals were irrigated with disposable plastic syringe (Ultradent Products Inc., South Jordan, Utah, USA), using a Navitip needle (Ultradent Products Inc., South Jordan, Utah, USA) with a solution of 2.5% sodium hypochlorite (2.5% NaOCl, Pharmaceutical Rioquímica, Sao Jose do Rio Preto, São Paulo, Brazil), and its contents aspirated with siliconized Capillary tips (Ultradent Products Inc., South Jordan, Utah, USA), and then the complete drying was performed with absorbent paper points (Dentsply Maillefer, Ballaigues, Switzerland).

To perform the root canal preparation, X-Smart motor (Dentisply Maillefer, Ballaigues, Switzerland) set at a constant speed of 350 rpm, at clockwise direction and torque of 2 Newtons was used. The cervical roots were prepared with Protaper System size S1 and Sx instruments (Dentsply Maillefer, Ballaigues, Switzerland). To determine the working length, a K-file was carefully introduced into the root canal until its tip exceeded the apical foramen. This limit was analyzed on the operating microscope (M900; D.F. Vasconcellos S.A., São Paulo, SP, Brazil) with x10 magnification.

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All root canals were prepared with size 642 Hero System (MicroMega, Besançon, France) in the following sequence: 20/.02 Hero at working length (WL), 25/.02 at WL, 25/.04 until resistance is encountered, 30/.02 at WL, 35/.02 at WL, 30/.06 until resistance is encountered, 40/.02 at n WL, and 45/.02 at WT. After every instrument change, the root canals were irrigated with 1 ml of 2.5% NaOCl and 1 ml of 17% EDTA (Pharmaceutical Industry Rioquímica, São José do Rio Preto, São Paulo, Brazil), used interchangeably, with disposable plastic syringe and Navitip needle for irrigation.

The prepared specimens were randomly divided into two groups: Group A – final irrigation with 4 ml of 2.5% NaOCl using the conventional technique with a syringe, and Group B – final irrigation with 4 ml of 2.5% NaOCl divided into 1 ml amounts that were ultrasonic passive activated (U.S. Jetsonic – GNATUS) using a size #15 K-file coupled to ultrasound device (A120 insert, GNATUS) at working length for 15 seconds each, resulting a total time of 1 minute of activation.

After preparation, the specimens were placed into properly identified individual flasks, containing 10% formalin solution for a period of 48 hours. After this period, the specimens were washed in running water and immersed in a solution of 10% trichloroacetic acid, renewed every 24 hours for a period of 15 days for decalcification. Completed this phase, the specimens were cut at 5 mm short of the apex, and these fragments were placed into plastic copings, marked their labial surface and properly identified, and washed in running water for 2 hours to remove acid residues before histological preparation.

The specimens were then subjected to histological processes and observed in an optical microscope (Nilkon®, Eclipse E 600, Japan) with x4 eyepiece 0:13 and x10/25 objective magnification was used yielding a final magnification of x40. Images were captured using Adobe Photoshop 5.1 software.

After, these images were released in Microsoft Power Point software, where, previously, the size of the slides was standardized so that the captured image adapted to the same extent (28.9 mm x 21.68 mm). The image was appropriate in its labial-lingual direction in a square measuring 10 mm x 10 mm and divided into quadrants, and then the counting of debris of each histological section (figure 1) could be realized and classified into scores. The scores were nominated and determined as follows:Score zero: t he absence of debr is i n a l l quadrants;Score one: one quadrant w ith the debr is presence;

Score two: two quadrants with the debris presence;Score three: three quadrants w ith debris presence;Score four: four quadrants with the debris presence.

figure 1 –Imageadaptedinitslabial-lingualdirectioninasquaremeasuring10cmx10cmanddividedintoquadrants

Results

Preliminary tests were performed in order to determine the dust data from the two groups of teeth. The data presented normal distribution (p > 0.05), according to the Kolmogorov-Smirnov test. The variances were homogeneous (p > 0.05), according to the test of homogeneity of variances of Levene.

The analysis of the results obtained in these preliminary tests led to the conclusion that the sample distribution was normal, which led to perform the parametric analysis, and analysis of variance showed that there was a statistically significant difference between groups (p < 0.05).

Discussion

Because of the anatomical complexity found in the root canal system, i.e. the lower central incisors with a single root canal, which are often due to oval flattened mesial-distal root, adjuvant methods for cleaning are required to be used in endodontic treatment [11, 18]. In these cases, the instruments used in biomechanical preparation do not touch and remove the dentinal debris from various points of the inner portion of root canal, especially at the buccal and lingual walls [8]. Wu

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and Wesselink [19] demonstrated the difficulty of instrumentation in oval canals, showing that in 40% of their sample there were areas not instrumented and incompletely filled.

Likely to other authors [10, 13], this study was conducted with extracted human teeth. Although the use of natural samples makes difficult to control the variables of length, shape and diameter of root canals, the results may have greater clinical significance than those made in simulated canals in resin blocks. The surface of the simulated root canals is very different from that of natural dentin surface, which ultimately affect the bottom line. The natural sample reached a result more similar to the in vivo study, unlikely to the study of Townsend and Maki [17], who used simulated canals in resin blocks for your study. Lee et al. [7] considered that the porous nature of the dentin could set a different behavior of a synthetic material, such as those found in simulated root canals in glass or resin.

In order to standardize the sample, according to the study of Mancini et al. [9], we used only lower incisors with one root canal, f lattening in the proximal root region, with fully formed apices and intact roots. The selection of teeth was performed with previous radiographs and ocular examination.

Similarly to the study of Gu et al. [3], the biomechanical preparation of the sample was carried out with rotary instrumentation system with Ni-Ti instruments to resemble everyday clinical practice. The use of Ni-Ti instruments is increasingly common in endodontic treatment because it reduces the time spent during the biomechanical preparation. The instrument works more centered in the canal maintaining its original format, increasing the chances of actually touching all the walls, decreasing major defects in the apical foramen as foramen transport. According Hülsmann et al. [5], the Ni-Ti rotary systems comply with the curvature of the root canal during the preparation, but fail to remove debris and smear layer in most cases.

In this study, ultrasound was used in order to stir the solution existing inside the root canal as well as made by Tasdemir et al. [16], not being provided directly by the tip of the ultrasound as in the studies of Gutarts et al. [4]. Consideration should be given for the impossibility of using NaOCl inside the ultrasound device, which could damage it by doing so. As evidenced in the study of Zeltner et al. [20], and Kuah et al. [6], ultrasound increases the capacity for action of the irrigating solution used in endodontic treatment. This study used teeth with flattened root canals just to evaluate the effectiveness of ultrasound in removing the

debris of the places where the instruments used in the biomechanical preparation are ineffective in cleaning the root canal walls.

After the biomechanical preparation of root canals, the methodology applied in this study was, the microscopic evaluation of the presence of debris remaining inside the root canal system. As in the study of Tanomaru-Filho et al. [15], histological sections of the apical third of roots were analyzed in an optical microscope. Images were captured using Adobe Photoshop 5.1 software. After these images were released in Microsoft Power Point and divided into quadrants, the counting of debris of each histological section could be performed and then classified into scores. The scores were nominated for the results of each section analyzed.

The results of this present study agree with those of Rödig et al. [13], who also used the ultrasound in a passive mode in the final irrigation with NaOCl. The studies have shown that the use of passive ultrasonic irrigation cleaned better the inner walls of the root canal. There was a statistically significant difference between groups, but in all groups, the debris still remained on the inner walls of root canals, as well as the study of Castagna et al. [2].

One must consider that in vitro scientific studies should approach the maximum that can be performed in the clinical treatment. For this, this study used only 4 ml of 2.5% NaOCl for irrigating root canals, unlikely to Passarinho-Neto et al. [12] who used 100 ml of sodium hypochlorite, which would be virtually unfeasible.

As shown by Wu and Wesselink [19], this study confirms that it is very difficult to remove all dirt from oval root canals, despite the passive aid of the ultrasound at their final irrigation. Although this method is efficient in cleaning the root canal system with flattened proximal surfaces, it still does not completely remove the debris from the root canal.

Conclusion

Through the results obta ined from the methodology used in this study, it can be concluded that:• The use of passive ultrasonic irrigation cleaned better the apical portion of root canals of the specimens used in this study;• The instrumentation sequence associated with the technique and time of passive ultrasonic irrigation can be used clinically;• Regardless of the techniques used in the study, debris remained inside the root canal system.

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References

1. Cachovan G, Schiffner U, Altenhof S, Guentsch A, Pfister W, Eick S. Comparative antibacterial efficacies of hydrodynamic and ultrasonic irrigation systems in vitro. J Endod. 2013 Sep;39(9):1171-5.

2. Castagna F, Rizzon P, da Rosa RA, Santini MF, Barreto MS, Duarte MA et al. Effect of passiveEffect of passive ultrassonic instrumentation as a final irrigation protocol on debris and smear layer removal – a SEM analysis. Microsc Res Tech. 2013 May;76(5):496-502.

3. Gu X, Mau C, Kern M. Effect of different irrigation on smear layer removal after post space preparation. J Endod. 2009;35:583-6.

4. Gutarts R, Nusstein J, Reader A, Beck M. In vivo debridment efficacy of ultrasonic irrigation following hand-rotary instrumentation in human mandibular molars. J Endod. 2005;31:166-70.

5. Hülsmann M, Gressmann G, Schäfers F. A comparative study of root canal preparation using FlexMaster and Hero 642 rotary NiTi. Int Endod J. 2003;36:358-66.

6. Kuah HG, Lui JN, Tseng PS, Chen NN. The effect of EDTA with and without ultrasonics on removal of the smear layer. J Endod. 2009;35:393-6.

7. Lee SJ, Wu MK, Wesselink PR. The effectiveness of syringe irrigation and ultrasonics to remove debris from simulated irregularities within prepared root canal walls. Int Endod J. 2004;37:672-8.

8. Malki M, Verhaagen B, Jiang LM, Nehme W, Naaman A, Versluis M et al. Irrigant flow beyond the insertion depth of an ultrasonically oscillating file in straight and curved root canals: visualization and cleaning efficacy. J Endod. 2012;38:657-61.

9. Mancini M, Armellin E, Casaglia A, Cerroni L, Cianconi L. A comparative study of smear layer removal and erosion in apical intraradicular dentine with three irrigating solutions: a scanning electron microscopy evaluation. J Endod. 2009;35:900-3.

10. Mayer BE, Peters OA, Barbakow F. Effects of rotary instruments and ultrasonic irrigation on debris and smear layer scores: a scanning electron microscopic study. Int Endod J. 2002;35:582-9.

11. Mozo S, Llena C, Forner L. Review of ultrasonic irrigation in endodontics: increasing action of irrigating solutions. Med Oral Patol Oral Cir Bucal. 2012;17:512-6.

12. Passarinho-Neto JG, Marchesan MA, Ferreira RB, Silva RG, Silva-Sousa YT, Sousa-Neto MD. In vitroIn vitro evaluation of endodontic debris removal as obtained by rotary instrumentation coupled with ultrasonic irrigation. Aust Endod J. 2006;32:123-8.

13. Rödig T, Sedghi M, Konietschke F, Lange K, Ziebolz D, Hülsmann M. Efficacy of syringe irrigation, RinsEndo and passive ultrasonic irrigation in removing debris from irregularities in root canals with different apical sizes. Int EndodInt Endod J. 2010;43:581-9.

14. Souza RA. Endodontia clínica. São Paulo: Santos; 2003.

15. Tanomaru-Filho M, Tanomaru JM, Leonardo MR, da Silva LA. Periapical repair after root canalPeriapical repair after root canal filling with different root canal sealers. Braz Dent J. 2009;20:389-95.

16. Tasdemir T, Er K, Celik D, Yildirim T. Effect of passive ultrasonic irrigation on apical extrusion of irrigating solution. Eur J Dent. 2008;2:198-203.

17. Townsend C, Maki J. An in vitro comparison of new irrigation and agitation techniques to ultrasonic agitation in removing bacteria from a simulated root canal. J Endod. 2009;35:1040-3.

18. Van der Sluis LW, Versluis M, Wu MK, Wesselink PR. Passive ultrasonic irrigation of the root canal: a review of the literature. Int Endod J. 2007;40:415-26.

19. Wu MK, Wesselink PR. A primary observation on the preparation and obturation of oval canals. Int Endod J. 2001;34:137-41.

20. Zeltner M, Peters OA, Paqué F. Temperature changes during ultrasonic irrigation with different inserts and modes of activation. J Endod. 2009;35:573-7.


A 7-year retrospective study of biopsied oral lesions in 460 Iranian patients

Shila Ghasemi Moridani1

Fatemeh Shaahsavari1

Mohammad Bagher Adeli2

Corresponding author:Shila Ghasemi MoridaniPostal Address: No 2 – Kashani pour st.Opposite of Barghe – Alestom – Satarkhan st. – Tehran – IranE-mail: [email protected]

1 Oral Pathology Department, Islamic Azad University, Dental Branch – Tehran – Iran.2 Private practice – Tehran – Iran.

Received for publication: August 21, 2013. Accepted for publication: November 26, 2013.

Keywords: oral lesion; retrospective study.

Abstract

Introduction: Frequency of oral lesions is varied in different population and knowledge of diseases prevalence in a geographic location will improve preventive measures. Objective: The objective of this study was to determine the prevalence of oral biopsied lesions in a major oral pathology laboratory center of city of Tehran. Material and methods: A retrospective study was done on data obtained from the archive of oral and maxillofacial pathology department of Islamic Azad University, dental branch of Tehran, from 2005 to 2011. Following variables were analyzed: age, gender, anatomic location, and the histological results obtained. Lesions were classified to 18 different categories. Data were analyzed using the SPSS version 12.0 for windows Xp. All the data were recorded in Microsoft Office Excel for further evaluation and making a data bank to easy access. Results: Of the 460 patients studied, the mean age was 38 years. The most frequent lesions were in the group of reactive lesions (22.51%), followed by odontogenic cysts. The most frequent lesion was radicular cyst and odontogenic keratocyst (keratocystic odontogenic tumor). Malignant lesions constituted 2.38%, of which squamous cell carcinoma was the most common malignancy (1.52%). Mandible was the most common location for occurrence of lesions (32.6%) followed by gingiva (11.95%). Conclusion: Our study provides helpful


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Moridaniet al.–A 7-year retrospective study of biopsied oral lesions in 460 Iranian patientsA7-yearretrospectivestudyofbiopsiedorallesionsin460Iranianpatients

information of oral lesion’s distribution in an Iranian population. The results showed high frequency of odontogenic keratocyst (keratocystic odontogenic tumor) which is not in agreement with other studies and need more evaluation of etiological factors.

Introduction

When comparing the frequency of oral lesions in different population, major and minor differences regarding to age, gender and geographic distributions would be found. Better control of diseases and improvement of preventive measures will be achieved considering the relative frequency of oral lesions in a geographic location. Many studies focusing on the prevalence of oral and maxillofacial lesions have been conducted around the world [1, 2, 4, 5, 11, 16, 24-27]. But to our knowledge, few studies on Iranian population were reported [2, 8, 9, 19, 21, 22]. Surprisingly, we found few reports on the frequency of histologically confirmed oral lesions in Iran [19, 21-23]. The purpose of this study was to investigate the relative prevalence of different types of oral and maxillofacial biopsied lesions received by the Oral and Maxillofacial Pathology

Department of Islamic Azad University and to review the literature on this subject.


This retrospective descriptive study was carried out on the biopsied specimen of the archives of the Oral and Maxillofacial Pathology Department of Islamic Azad University, which is one of the major oral pathology departments of Tehran. The department mainly receives specimen from general and specialized dental practitioners in the North-East of Tehran and affiliated hospital (BouAli hospital) which is located in the East of Tehran. All the specimens from 2005 to 2011 were surveyed and following data were retrieved: patient’s age, sex, clinical manifestations and diagnosis and the histopathological results. Lesions were classified in 18 different categories, as detailed in table I.

Table I –Classificationofdiagnoses

Reactive lesions

Irritation fibrosis, epulis fissuratum, pyogenic granuloma, peripheral giant cell granuloma, epulis granulomatosa,

inflammatory papillary hyperplasia, traumatic neuroma, giant cell fibroma

Odontogenic cystsdentigerous cyst , odontogenic keratocyst (keratocystic

odontogenic tumor), paradental cyst, calcifying odontogenic cyst, orthokeratinized odontogenic cyst

Pulp & periapical lesions Periapical cyst, periapical granuloma, residual cyst, periapical abscess, osteomyelitis

Immunologically mediated lesions Lichen planus, pemphigus vulgaris, pemphigoid

Bone pathologyCentral giant cell granuloma, traumatic bone cyst, cemento-

osseous dysplasia, focal osteoporotic bone marrow defect, central ossifying fibroma

Odontogenic tumors Ameloblastoma, odontoma, odontogenic myxoma

Epithelial lesions Benign hyperkeratosis, verrucous hyperplasia, carcinoma in situ, squamous papilloma, keratoacanthoma

Salivary gland diseases Mucocele, mucus retention cyst, sialolothiasis

Malignant epithelial tumors SCC

Benign mesenchymal tumors Lipoma, arteriovenous malformation, neurofibroma

Pigmented lesions Nevus, amalgam tattoo, oral melanotic macule

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Non-odontogenic cysts Nasopalatine duct cyst, epidermoid cyst, nasolabial cyst

Malignant salivary tumors Adenoid cystic carcinoma, mucoepidermoid carcinoma

Benign bone tumors Osteoma, juvenile ossifying fibroma

Benign salivary gland tumors Pleomorphic adenoma

Physical and chemical injuries Surgical ciliated cyst

Periodontal diseases Juvenile periodontitis

Miscellaneous Nonspecific ulcer, normal bone, nonspecific inflammatory process, fibrotic dental follicle

Table I (continued)

Based on the new WHO classification, odntogenic keratocyst is now considered as an odontogenic tumor, “keratocystic odontogenic tumor” [18]. Because most of the previous studies are according to earlier classification system which included the odontogenic keratocyst in odontogenic cyst’s group, to comparing the data and better evaluation, we have used the previous classification system [14].

All the results were subjected to statistical analysis, using the SPSS version 12.0 for windows Xp. The data also were recorded in Microsoft Office Excel, as a data bank.

Results

The number of patients studied was 460, excluding patients with incomplete records or those who had more than one biopsy at the same time. The age range of the patients was 3-89 years and the mean age was 38 years. Most of the lesions (62%) were found in the third to fifth decades of life. Females constituted 53.26% (n = 245) of the cases and 46.73% (n = 215) of the lesions found in males. The most affected anatomic location was the mandible (32.6%), followed by gingiva (11.95%) and buccal mucosa (10.86%). The distribution of lesions according to location is shown in figure 1. The prevalence of the most common different diagnoses is shown in table II.

figure 1– Distribution of lesions according to locationDistributionoflesionsaccordingtolocation

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Table II – Three most common diagnoses in eachcategory

Reactive lesions irritation fibromaepulis fissuratum pyogenic granuloma

Odontogenic cystsOdontogenic keratocyst (keratocystic

odontogenic tumor) Dentigerous cystParadental cyst

Pulp & periapical lesionRadicular cystPeriapical granulomaResidual cyst

Immunologically mediated lesionsLichen planusPemphigus vulgarispemphigoid

Bone pathologyCGCGTBCCOF

Odontogenic tumorsAmeloblastomaOdontomaMyxoma

Epithelial lesionsBenign keratosis Hyperkeratosis with mild dysplasia Papilloma

Salivary gland diseaseMucoceleMucous retention cyst Sialolithiasis

Malignant epithelial tumorsSCC

Benign mesenchymal tumorsNeurofibromaCavernous hemangiomaLipoma

Pigmented lesionsExogenous pigmentation Amalgam tattooIntradermal nevus

NO99291915

8034

254

72342510

25

2041

23533

231462

1843211

9117

77

7321

7321

Percent21.526.304.133.26

17.397.39

5.430.86

15.627.395.432.17

5.43

4.340.860.21

51.080.650.65

53.041.300.43

3.910.860.650.432.39

1.950.210.211.52

1.521.52

1.520.650.430.21

1.520.650.430.21

Non-odontogenic cystsNasolabial cyst Epidermoid cyst Nasopalatine duct cyst

Malignant salivary gland tumorsMucoepidermoid carcinoma Adenoid cystic carcinoma Malignant salivary gland tumor

Benign salivary gland tumorsPlemorphic adenoma

Physical and chemical injuriesSurgical ciliated cyst

Periodontal diseasesJuvenile periodontitis

Unclassified tumorBenign spindle cell tumor

Non-diagnostic MiscellaneousGranulation tissue Perifollicular fibrosis Non specific ulcer

5311

4

211

22

2

2

11

11

4033422

1.080.650.210.21

0.86

0.430.210.21

0.430.43

0.43

0.43

0.210.21

0.210.21

8.697.170.860.430.43

CGCG = Central giant cell granulomaTBC = Traumatic bone cystCOF = Central ossifying fibromaSCC = Squamous cell carcinoma

Intra-osseous lesions constituted 56.4% and extra-osseous lesions 43.6%. The most frequent lesions were in the group of reactive lesions (21.52%), followed by odontogenic cysts (17.39%). The most frequent lesion was radicular cyst and odontogenic keratocyst (7.39% each). Malignant lesions constituted 2.38%, of which squamous cell carcinoma was the most common malignancy (1.52%).

Discussion

In this study, we analyzed the prevalence of oral lesions, biopsied during seven years in an academic oral pathology laboratory and found 460 specimens. The mean age of the patients was 38 years and 62% of the lesions were discovered during the third to fifth decades of life. The mean age in similar studies, reported by Fierro-Garibay et al. [4] and Sixto-Requeijo et al. [25] were 54 and 51.8 years respectively. In addition, the mean age in the survey of Kniest et al. [11] was 47.2 years.

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It seems that oral lesions in our study revealed in lower age range in comparison with other surveys which may be related to younger population in our country. Although, Al-Khateeb [1] reported the mean age of 33 years for the patients, but their study was conducted only on benign oral masses excluding intra-osseous lesions. Luqman and Al Shabab [15] recorded 31 years for mean age in their study which is much similar to our results. Shahsavari et al. [23] analyzed oral mucosal lesions in an Iranian population and found that 90% of lesions were in 30-58 years old. Likely to most of the other studies [4, 6, 11, 25], we found slightly more frequency of lesions in women, which may reflect attitude of women about their oral health. However, in a similar study conducted on a small population of Saudi patients, the majority of lesions were discovered in males [15]. In addition, Jahanbani et al. [9] in a clinical based study on an Iranian population, revealed more frequency of lesions among men that may be a sign of different type of study design.

Concerning the anatomical location, about one third (32.6%) of lesions in our study were located in the mandible with statistical significant difference with other locations (p < 0.001). It was followed by gingiva (11.95%) pulp and periapical tissue (11.08%) and buccal mucosa (10.86%). In the study of Fierro-Garibay et al. [4], and Ibnerasa [7], mandible was also the most frequent location. On the other hand, Pour et al. [19] reported the gingiva as the most common location.

Similar to report of Fierro-Garibay et al. [4], intraosseous lesions were more frequent than peripheral lesions in the present study (56.4% Vs 43.6%). It may be interpreted by high frequency of cysts and odontogenic lesions in the present study. In addition, it shows that patients with more advanced and aggressive treatment plans are more referred to our academic oral pathology laboratory. However, in the other report of the Iranian population, peripheral lesions were more common than intraosseous lesions [6].

The most frequent category in this study was reactive lesions (21.52%), followed by odontogenic cysts (17.39%), similar to results of Jones and Franklin [10]. However, we accounted the radicular cysts and residual cysts in the pulp and periapical lesion’s category. Considering them in the odontogenic lesion’s category will show odontogenic cysts as the most prevalent lesions and the results would be different.

Consistent with new WHO classification, odontogenic keratocyst is now considered as an odontogenic tumor named “keratocystic odontogenic

tumor” [18]. Considering the fact that most of the previous reports and data are according to former classification of WHO, we have used the earlier classification system for better comparison and assessment [14].

The most prevalent odontogenic cyst was radicular cyst and odontogenic keratocyst (keratocystic odontogenic tumor) (7.39% each one), followed by dentigerous cyst (5.43%). These results were different from the same studies which showed radicular cyst as the most prevalent odontogenic cyst. Daley et al. [3], Nakamura et al. [17] and Fierro-Garibay et al. [4], reported the radicular cyst as the most common cyst, followed by dentigerous cyst and odontogenic keratocyst (keratocystic odontogenic tumor). However, in the study of Ramachandra et al. [20] odontogenic keratocyst was the second most common odntogenic cyst after radicular cyst which was in agreement with the report of Koseoglu et al. [12]. The high frequency of odontogenic keratocyst in the present study may be due to more recurrence of the cyst which leads to referral of the patients to academic centers. Notwithstanding, the etiological factors should be evaluated in other researches.

Considering the irritation fibroma as the most common lesion among reactive lesions (29.2%), findings are similar to the results of Pour et al. [19]. The total frequency of fibromas in the other surveys was 10% [4], 11.4% [25], 5.5% [11] and 3.16% [16]. Jones and Franklin [10] recorded a low percentage of fibromas and a high rate of squamous papillomas. These contradictory results are probably because of different classification systems and histopathological criteria used in different studies.

Malignant lesions constituted 2.38% of the lesions in the present study similar to report of Kniest et al. [11] which accounted 2.4%. Malignant lesions were composed of 7 cases (1.52%) of SCC and 4 cases (0.86%) of salivary gland malignancies. Sixto-Requeijo et al. [25], found the frequency of malignant lesions 3.9% and SCC 3.4% which is higher than our study as in the report of Jones and Franklin [10] which accounted malignant lesions 5.4%. On the other hand, malignant tumors were observed in 1.9% of cases studied by Mendez et al. [16]. The total frequency of SCC in the reports of Fierro-Garibay et al. [4] and Franklin and Jones [5] were 0.4% and 0.1%, which are much lower than our assessment.

Conclusion

In general, the prevalence of oral lesions diagnosed in our oral pathology laboratory was

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relatively similar to other studies. However, odontogenic keratocyst (keratocystic odontogenic tumor) showed high frequency which needs further evaluation and assessment of etiological factors. Likewise, it is important to put emphasis on the specimen sources that vary significantly among oral pathology laboratories. For instance, 80% of specimens in the study conducted by Weir et al. [27] were obtained from a private office, which could shape the occurrence of oral lesions according to the favorite treatment plans of the clinicians. Moreover, diagnostic criteria and classification of lesions are considerably various in different studies which may hinder precise comparison with other studies.

References

1. Al-Khateeb TH. Benign oral masses in a Northern Jordanian population – a retrospective study. The Open Dent J. 2009;3:147-53.

2. Carvalho MV, Iglesias DP, do Nascimento GJ, Sobral A. P. Epidemiological study of 534 biopsies of oral mucosal lesions in elderly Brazilian patients. Gerodont. 2011;28(2):111-5.

3. Daley TD, Wysocki GP, Pringle GA. Relative incidence of odontogenic tumors and oral and jaw cysts in a Canadian population. Oral Surg Oral Med Oral Pathol. 1994;77( 3):276-80.

4. Fierro-Garibay C, Almendros-Marqués N, Berini-Aytés L, Gay-Escoda C. Prevalence of biopsied oral lesions in a Department of Oral Surgery. J Clin Exp Dent. 2011;3(2):e73-7.

5. Franklin CD, Jones AV. A survey of oral and maxillofacial pathology specimens submitted by general dental practitioners over a 30-year period. Brit Dent J. 2006;200(8):447-50.

6. Ghasemi Moridani S, Mohtasham Z, Sazesh SF. Correlation between clinical and histopathological diagnosis of oral lesions surgery in the city of Rasht (2000-2002). J Islam Dent Assoc Ir. 2005;17(2):95-9.

7. Ibnerasa S. Retrospective study of variations in the microscopic morphology of dental biopsy specimens received in Pathology Department of Lahore. Pak J Medical Health Sci. 2011;5(3):497-500.

8. Jahanbani J, Morse DE, Alinejad H. Prevalence of oral lesions and normal variants of the oral mucosa in 12 to 15-year-old students in Tehran, Iran. Arch Iran Med. 2012;15(3):142-5.

9. Jahanbani J, Sandvik L, Lyberg T, Ahlfors E. Evaluation of oral mucosal lesions in 598 referred Iranian patients. Open Dent J. 2009;(3):42-7.

10. Jones AV, Franklin CD. An analysis of oral and maxillofacial pathology found in adults over a 30-year period. J Oral Pathol & Med. 2006;35(7):392-401.

11. Kniest G, Stramandinoli RT, Avila LFDC, Izidoro AC. Frequency of oral lesions diagnosedFrequency of oral lesions diagnosed at the Dental Specialties Center of Tubarao (SC). RSBO. 2011;8(1):13-8.

12. Koseoglu BG, Atalay B, Erdem MA. OdontogenicOdontogenic cysts: a clinical study of 90 cases. J Oral Sci. 2004;46(4):253-7.

13. Kramer IR, Pindborg JJ, Shear M. Histological typing of odontogenic tumors. 2. ed. Geneva: WHO; 1992.

14. Kramer IR, Pindborg Jr. J, Shear M. Histological typing of odontogenic tumours. Springer; 1992.

15. Luqman M, Al Shabab AZ. A 3 year study on the clinico-pathological attributes of oral lesions in Saudi patients. Inter J Contemp Dent. 2012;3(1):73-6.

16. Mendez M, Carrard VC, Haas AN, Lauxen IDS, Barbachan, Rados PV. A 10-year study of specimens submitted to oral pathology laboratory analysis: lesion occurrence and demographic features. Braz Oral Res. 2012;26(3):235-41.

17. Nakamura T, Ishida J, Nakano Y, Ishii T, Fukumoto M, Izumi H et al. A study of cysts in the oral region. Cysts of the jaw. J Nihon Univ Sch Dent. 1995;37(1):33-40.

18. Philipsen HP. Keratocystic odontogenic tumor. In: Barnes L, Eveson JW, Reichart PA, Sidransky D (eds). WHO classification of tumors; pathology and genetics of head and neck tumors. Lyon: IARC Press; 2005.

19. Pour MAH, Rad M, Mojtahedi A. A survey of soft tissue tumor-like lesions of oral cavity: a clinicopathological study. Iran J Pathol. 2008;3(2):81-7.

20. Ramachandra P, Maligi P, Raghuveer HP. A cumulative analysis of odontogenic cysts from major dental institutions of Bangalore city: ay: a study of 252 cases. J Oral Maxillofac Pathol. 2011;15(1):1-5.

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2 1 . S e y e d m a j i d i M , H a m z e h p o o r M , Bagherimoghaddam S. Localized lesions of oral cavity: a clinicopathologic study of 107 cases. Res J Med Scie. 2011;5(2):67-72.

22. Shahsavari F, Fereidouni F, Farzane Nejad R. The prevalence of oral mucosal lesions and associated factors in Pathology Department of Tehran Cancer Institute of Imam Khomeini Hospital since 2000 to 2010. J Res Dent Sci. 2012;9(2):111-5.

23. Shahsavari F, Khourkiaee SS, Ghasemi Moridani S. Epidemiologic study of benign soft tissue tumors of oral cavity in an Iranian population. J Dentomaxillofac Radiol Pathol Surg. 2012;1(1):10-4.

24. Shulman JD, Beach MM, Rivera-Hidalgo F. The prevalence of oral mucosal lesions in US adults

data from the Third National Health and Nutrition Examination Survey, 1988-1994. J Am Dent Assoc. 2004;135(9):1279-86.

25. Sixto-Requeijo R, Diniz-Freitas M, Torreira-Lorenzo JC, Garcia-Garcia A, Gandara-Rey JM. An analysis of oral biopsies extracted from 1995 to 2009, in an oral medicine and surgery unit in Galicia (Spain). Med Oral Patol Oral Cir Bucal. 2012;17(1):e16-22.

26. Splieth CH, Sumnig W, Bessel F, John U, Kocher T. Prevalence of oral mucosal lesions in a representative population. Quintessence Int. 2007;38(1):23-9.

27. Weir JC, Davenport WD, Skinner RL. A diagnostic and epidemiologic survey of 15,783 oral lesions. J Am Dent Assoc. 1987;115(3):439-42.


Information and communication technologies in dental education: students’ perceptions

Alessandra Martins Ferreira Warmling1

Cláudio José Amante1

Ana Lúcia Schaefer Ferreira de Mello1

Corresponding author:Alessandra Martins Ferreira WarmlingRua Lauro Linhares, 2.123 – 605B – TrindadeCEP 88036-002 – Florianópolis – SC – BrasilE-mail: [email protected]

1 Department of Dentistry, Federal University of Santa Catarina – Florianópolis – SC – Brazil.

Received for publication: September 24, 2013. Accepted for publication: November 26, 2013.

Abstract

Introduction: Among teaching and learning methods, those using Information and Communication Technologies as new dental education possibilities are based on the student’s knowledge construction and the development of new capabilities such as innovation, creativity, autonomy and communication. Objective: To demonstrate the use of information and communication technologies (ICTs) as support tools for teaching-learning process in Dentistry by using an application that manages dental caries determinants. Material and methods: An application was used by students from a Dentistry Undergraduate Program from a public university in southern Brazil. Data collection comprised a qualitative study with Dentistry undergraduates, through focus group technique. Data analysis was performed according to Bardin’s content analysis. Results and Discussion: Results are presented in categories: 1. Use of ICTs in Dentistry teaching; 2. Students’ perceptions on the application; 3. The application as a teaching-learning tool in Dentistry. Data analysis showed advantages of using ICTs in dental teaching as key tools and process facilitators. The application is a decision-taking and action-planning tool, guiding students’ clinical reasoning towards recognition of local reality. Conclusion: Relevance and potential use of ICTs in Dentistry teaching was detected, making them auxiliary tools in students’ education in the face of their need to adapt to the current context of technological advances and the rapid expansion of scientific knowledge.

Keywords: dental computer science; dental caries; dental education.


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Warmlinget al.–Information and communication technologies in dental education: students’ perceptionsInformationandcommunicationtechnologiesindentaleducation:students’perceptions

Introduction

Dentistry education should harmoniously follow the development of the health care system and attend to its needs. In Brazil the current educational model proposed by the National Curricular Guidelines (NCG) seeks a balance between technical excellence and social relevance and has a resolutive role towards the health demands of the population. Other elements have been added to this model such as curriculum integration as the use of interactive teaching-learning methodologies [4].

Among the teaching-learning methodologies, some are based on information and communication technologies (ICTs), seen as a new possibility in dental education, supported by the student’s knowledge construction and by the development of new abilities such as innovation, creativity, autonomy and communication [7, 10, 14].

ICTs are tools of growing importance in Dentistry as well as in other health areas, as they allow the use of new educational media that provide students with the practice of seeking and selecting information, leaning independently and more autonomously and solving problems. The dentists are thus expected to be able to use these tools to look for the required information. Also, they should also be able to select these pieces of information as best as possible, and apply them to their professional practice routine whether as a clinician, researcher or professor. The addition of information and communication technologies to the curricula is a way of stimulating, potentiating and improving their use [6].

Although there has been a continuous debate over the efficacy of virtual learning applications, ICTs add value to traditional teaching methods and function as a complement to more traditional approaches [12].

An application used to study dental caries determinants, was used for this research. This study aimed to demonstrate the use of information and communication technologies as a support tool in the teaching-learning process in Dentistry through the use of this application from the point of view of undergraduate Dentistry students.


The software was developed by means of an interdisciplinary study conducted by Dentistry, Information System and Design professionals, together with undergraduate students from a

public university in southern Brazil. Dentistry researchers provided the theoretical framework on which the necessary rules for the development of the software were established based on dental caries health-disease process determinants and identified by a systematic literature review. The Scientific Electronic Library Online (SciELO) and The United States National Library of Medicine (PubMed) databases were consulted by using the key words “Dental caries”, “Epidemiology” and “Susceptibility” without the use of filters. Full-text articles were chosen whose topics were related to the Brazilian social and oral healthcare focusing on self-reported dental caries health-disease process determinants. Articles published in the last 5 years (2007-2011) were selected from SciELO database and articles published in the previous year (2011) were selected from PubMed database.

Books, theses and dissertations dealing with the dental caries disease issue with a focus on Cariology and Epidemiology and publications by the Brazilian Ministry of Health on Dental Public Health were also researched.

The In format ion Systems a nd Desi gn professionals encoded the system by structurally developing HTML pages with CSS (Hyper Text Markup Language) and Java (Java Server Faces) as well as interactivities in Java Script. The database was developed and managed in MySQL (My Structured Query Language). These tools were primarily chosen due to their independent platforms, that is, systems that can be used by any other operational systems (Windows or others) without the need of prior download. MySQL database was selected by using SQL, the most widespread language for web systems, thus facilitating the system operational support, besides being a free access tool. The Design professionals created an intuitive aesthetically pleasant layout consistent with the software theme.

The application can receive, store and analyze data related to dental caries health-disease process determinants.

Softwareoperationalcharacteristics

System access is done through an Internet password from the Federal University of Santa Catarina provider. Accesses were divided into user and administrator logins with personal passwords. The main differences from other access profiles are the tools available for registration, data collection and storage, as well as stored data queries and

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analyses, the latter being restricted to the system administrator (figure 1).

The software consists of a Self-reported Individual Questionnaire, which seeks to understand the individual profile, general and oral health condition, in addition to his habits and lifestyle, and includes a Professional Perception Form (figure 2) including an oral physical examination and the dentist’s subjective perceptions related to the respondent’s interests and response consistency.

The fact that the software results can be shown either on an individual or group basis is worth mentioning, that is, the software allows the individual’s data to be grouped by family, classroom,

school, street, neighborhood, city, county, state or country. The most relevant information on tooth decay health-disease process determinants can also be viewed for each group; additionally, it allows comparisons between groups to be made.

The application also includes the dental caries disease spatial expression, which is a helping tool for the identification of territorial influence on the health-disease process in oral health. Other relevant features are its greater coverage due to its online availability, its ability to act as a database for the dentist, and the possibility of generating data and statistical analysis for the planning and management of dental services.

figure 1–Theuseraccesswithpersonalpassword

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figure 2 – The software consists of a Self-reported Individual Questionnaire, which seeks to understand theindividualprofile,oralandgeneralhealthcondition,habitsandlifestyle.IncludesaProfessionalPerceptionForm

The use of the application as a teaching-leaning process support tool was developed by means of a qualitative study whose investigation process was based on the focus group technique. The data obtained through this technique resulted from carefully planned discussions. During these, the participants expressed their perceptions, beliefs, values and attitudes on the information and communication technologies issue as a support tool for the teaching-learning process in Dentistry. This aimed to capture the participants’ collective thinking during the dynamic interaction process when speech unveils opinions and emotions, whether convergent or conflicting, as well as to debate problems, conflicts and proposals so that solutions could be reached within the application scope [2, 16].

The research subject universe comprised the 3rd year Dentistry undergraduates from a public university in southern Brazil who carried out different activities at Health Care Centers of the municipal school network. These activities were extended to the other public schools located within the coverage area of the health care centers.

The research project was submitted to the Ethical Committee in Research of the Human Being of the Federal University of (UFSC), the Institutional Review Board (IRB) of Santa Catarina, and approved by regulation no. 2100/12. All participants were asked to sign an Informed Consent Form.

Data collection was divided into two phases:Phase 1 – Use of the application as a support

tool in the teaching-learning process in Dentistry: the application was presented to a team of four

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students from a Dentistry Undergraduate Program so that they could become familiar with its operation and thus be able to use it fully. Afterwards these students used the application with 40 teenage students from two public schools where activities referring to Dentistry in Public Health contents within specific courses were developed between October and November 2011 (figure 3).

figure 3 – The dental students used the applicationwith 40 teenage students of two public schools,whereactivitiesreferringtoDentalPublicHealthweredeveloped

Phase 2 – Report on the use of the application as a support tool in the Dentistry teaching-learning process: the report on the application use was made by means of the focus group technique [2, 16]. This second phase aimed to know the students’ perceptions towards the application use and to discuss its teaching and dental care potentials. The analysis of the transcribed data was done according to Bardin’s Content Analysis assumptions [3].

Results

The results were grouped into three categories referring to students’ perceptions on the use of information and communication technologies in Dentistry teaching, in addition to perceptions on the application use itself and the ways this tool can be used in the teaching-learning process in Dentistry.

Theuseof informationandcommunicationtechnologies inDentistry teaching

The students evidenced the advantages of using information and communication technologies (ICTs) in Dentistry teaching.

The use of technologies make it much easier, they are fundamental to everything that is related to education, mainly because nowadays everything is linked to the question of the speed of information transmission, and in Dentistry the use of these technologies are also critical for teaching (A.M.).

According to them, these tools played a fundamental role in teaching by being closely related to the teaching-learning process, acting as facilitators of this process and increasing the information transmission rate. The students also pondered that ICTs had been present throughout their undergraduate program, which was shown by the fact that they thought of themselves as belonging to a young adult generation that tried to search for contents by using these tools. The use of the computer as an important teaching tool is emphasized, once it is, according to them, often used in carrying out research and papers, consulting materials provided by professors, as books and papers; it also enables access to Moodle® virtual learning environment, individual email accounts, and social networking sites. The students also believe that the computer facilitates the teaching-learning process because they can access contents far from the university, as from home.

Students gave several examples of the use of ICTs along their academic education, reporting the use of social networks as being an important teaching-learning tool for case and doubt discussions. Interestingly, students have reported the existence of virtual study groups on Facebook® through which they study collectively, exchange experiences, clear each other’s doubts, and share materials, mainly before tests. Another tool highlighted by students was Google® website where they search for information related to Dentistry as well as for news sites through which they can also come across related contents.

According to students, information and communication technologies have great potential for the teaching of Dentistry and could be better exploited during the program; as to copyright and intellectual property, the present literature discussion refers to it as a new unsolved worldwide

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issue of artistic, scientific and literary property control brought about by the use of ICTs. From the students’ point of view, the incorporation of ICTs to course methodologies neither necessarily change the pedagogical relationship nor does it replace the professor but rather changes some of his roles. Students understand that the professor must be a stimulator of the student’s curiosity so that the latter develops an interest in learning, researching and searching for relevant information. The professor develops a new approach in the construction of the student’s knowledge.

Students’perceptionson theapplication

The use of the application was deemed valid by the students.

They were pleased and interested on it, mainly because it was thought to be simple and easy to keep. The students reported that, after the first explanation, they already had an idea on the application purposes; with reference to its operational characteristics, the students highlighted the mere fact of having to use the computer made it a much more interesting activity. The use of the tool was facilitated by its availability on the Internet, which allowed it to be used at different locations by different computers simultaneously, thus making it possible for its users to interact.

It was a lso reported that the software characteristics made the work much easier, mainly due to the application speed as compared to paper questionnaires, even when there were several blank items to be filled in; because of these characteristics, the application could also arouse a higher respondent interest.

I noticed something very interesting is that when I finished using the application, when I finished asking, and before the physical examination, before I examine the child’s mouth, it seems that I already knew what I would find, I was able to “predict” the oral health condition of the child, based on the answers she gave (A.M.).

Students stated that they were able to identify some issues related to the health-disease oral process in the school environment more directly, speeding up the identification of dental caries determinants during the application use. The application questions were directed towards clinical reasoning so that they knew what to expect in oral condition terms and based on the answers given

by the patients before the physical examination was performed. The students also considered the questions as guiding tools that supported the oral-related instructions passed on to the teenage students. What the students perceived upon physical examination corresponded to what they expected to find regarding each individual’s oral health.

Theapplicationasa teaching-learning toolinDentistry

The questions of the application served as a tool to guide some issues related to oral health. I asked about oral habits and, according to which it replied, I was giving guidelines for oral hygiene and healthy eating. I know this was not the purpose of the work, but as we were there with them, and they are children, if it was an adult I may not speak, but sometimes parents do not say to their children that they have to brush their teeth (B.M.).

The students believed that the contact with schoolchildren would be the most appropriate moment and that the use of the application served to mediate their contact. Before its use, the students believed that the application would bring confidence to the teenage students, acting as a bond-building tool, which was in fact observed; from the students’ viewpoint, the teenage students felt more comfortable with the use of the computer. Health guidelines were given according to the teenagers’ responses to each question. Although it was not initially meant, the students passed on instructions simultaneously with the interview.

During the face-to-face interview the students had already initially identified determinants related to the dental caries health-disease process in the teenagers, such as the presence of tooth plaque, halitosis or a high candy intake. With the application use, they were able to identify the most common determinants which were related to the dental caries health-disease process in the school environment at this age group, as poor toothbrushing, high candy intake, and health service underuse. They concluded that the application helped in the identification of the school reality, developing a collective overview by the use of all available data for planning action within the school environment.

The data obtained by this activity guided collective actions to be taken within that environment. The students were able to plan activities, especially

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those related to health education, based on what had been identified by the application use; they were also capable of identifying those teenage students who had the worst oral health condition so that future interventions, as topical fluoride applications, ART and other educational activities in oral health could be performed.

Discussion

The findings of this present study agree with those reported in literature which show ICTs as new paths towards teaching-learning methodologies and new possibilities in Dentistry education, which is supported by the construction of knowledge by the student and the development of abilities such as innovation, creativity, self-esteem and communication [7, 10, 14].

The literature has evidenced that the use of ICTs is an increasingly important tool, not only for Dentistry but also for other fields of knowledge. These tools enable the use of new educational media, provide the ability of searching and selecting information, and result in independent learning and problem solving skills. Dentistry programs must offer activities that involve the use of ICTs in their syllabuses so that iniquities among professionals from different countries do not grow bigger, insofar as a critical factor in the use of these tools currently is the great skill variability of professors and students in the use of computers [6].

Examples of these tools have been mentioned in literature, such as Case Studies for Dentistry®, a computer case simulator software that allows students to learn in an interactive and self-directed way [1], Tooth Atlas 3D® version 6.3.0, developed for the teaching of dental anatomy containing three-dimensional models of teeth and support structures and including the anatomy and morphology of these structures, a dental radiograph database, besides practical tests for evaluation purposes [13]. Still, others are 3D viewing software for teaching radiology as a helping tool in radiographic interpretation learning [18], virtual reality software for Dentistry teaching [9, 17] and virtual learning courses of the Atraumatic Restorative Treatment (ART) technique [5].

The importance of understanding ICTs as new communication, educational and learning practice structures is necessary, and that includes the formulation and implementation of public policies aiming to re-democratize their access. Thus the professor’s permanent education would be required to enter this expanding and changing universe of higher education [15]. The relevance of giving attention

to the teaching-learning process at the university in connection with new technologies expands towards a teaching performance improvement in higher education with reference to the use of these technologies aiming to improve the student’s education. A systematic reflection on the best ways to achieve an integrated view of contents and the role of computer tools in this process is needed, calling the university professor to rethink from the new aiming to introduce competent professionals into the labor market who can both interact with and benefit from new technologies [11].

Generally the participating students showed good acceptability as to the application use. According to literature, students react positively towards the use of ICTs as a teaching tool [8].

The use of ICTs would be a way to achieve an important goal in Dentistry education: the ability to access, evaluate and apply new knowledge to the patients’ benefit; it is necessary, however, to promote a greater integration of these tools in teaching and learning, as well as evaluation, activities [7]. The professor still needs to pay close attention to the condition under which new professionals graduate by taking into account the social appropriation of new methodologies and technologies that will enable to bring individuals from different cultures and backgrounds close together in favor of health care improvement, thus leading to improved learning in higher education [11].

The study has been limited to the students’ educational experiences at Health Care Centers of the municipal school network. Results cannot be extended to other undergraduate Dentistry student contexts, as their educational backgrounds may differ.

This study is based on the first-year experi-ences in the use of information and communication technologies as support tools in the Dentistry teaching-learning process through the use of an application to analyze dental caries determinants by Dentistry undergraduates who carried out different activities at Health Care Centers of the municipal school network. A report at this early stage is important for three different reasons:- First, the application provides a potentially

useful tool for service management and the teaching of Dentistry. It was developed aiming to expand the dentist’s horizons towards a new approach on the caries health-disease process so as to reach the correct diagnosis and intervene appropriately based on scientific evidence;

- Second, this study can benefit subsequent public oral health classes. The software can

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be a helping tool in oral health daily clinical practice; it also serves as an instrument for data collection as well as a management and planning tool for various organizations such as private oral health clinics, dental offices, and health insurance and public services. Also, it can be an important tool in the planning of educational and preventive actions for caries control both at individual and collective levels. Information and Communication Technologies are increasingly necessary tools that can be used for electronic health data capture and analysis improvement;

- Third, the results of this study will benefit dental education, insofar as it introduces a new support tool to the teaching and learning process in dental clinics and oral health services where training activities occur, assisting in the training of professionals and students alike, who will develop the ability to scientifically and critically understand dental caries related to actual conditions and needs, both at an individual or a specific population level. The encouragement to use Information and

Communication Technologies as new possibilities in dental education, supported by students’ knowledge building and development of new capabilities, such as innovation, creativity, autonomy and communication, is reinforced. In addition, this study provides contemporary information on professional socialization to use Information and Communication Technologies as new possibilities in dental education, because the number of studies on this topic is limited.

Conclusion

This study has provided a deeper knowledge on the use of information and communication technologies in dental education. It is worth emphasizing the importance and potential of using these tools, which play a fundamental role in supporting the students’ academic education in the face of the need to adapt to constant technological advances and the rapid expansion of scientific knowledge.

The obtained results point out to a positive attitude of the Dentistry students towards to ICTs use as teaching tools. However, the professor’s new attitude is needed so as this new Dentistry practice can be built. The professors ceases being a mere information transmitter to become a mediator and a facilitator in the knowledge construction

process, able to adapt to daily challenges that a new generation of students brings into the Dentistry undergraduate program.

The use of ICTs is emphasized as a complement to traditional educational processes. In addition, the use of these instruments enables a new outlook and a new involvement with the school by means of an opening that brings out the possibility of students and teachers alike having access to knowledge by means of research and experience exchange among other students and professors from different institutions, thus contributing to the formulation and dissemination of new knowledge.

References

1. Abbey LM. Case studies for Dentistry®: development of a tool to author interactive, multimedia, computer-based patient simulations. J Dent Educ. 2003;67(12):1345-54.

2. Barbour R. Doing focus groups. London: Sage; 2008. 168 p.

3. Bardin L. L’analyse de contenu. Paris: Presses Universitaires France; 2007. 280 p.

4. Brasil. Ministério da Educação. CNE. Resolução CNE/CES 3/2002. Diário Oficial da União, Brasília, 4 de março de 2002. Seção 1, p. 10. Institui Diretrizes Curriculares Nacionais do Curso de Graduação em Odontologia. Available from:Available from: URL:http://portal.mec.gov.br/cne/arquivos/pdf/CES032002.pdf.

5. Camargo LB, Aldrigui JM, Pettorossi JC, Mendes FM, Wen CL, Bönecker M et al. E-learning used in a training course on a traumatic restorative treatment (ART) for Brazilian dentists. J Dent Educ. 2011;75(1):1396-401.

6. Fontanella VRC, Schardosim M, Lara MC. Tecnologias de informação e comunicação no ensino da Odontologia. Rev ABENO. 2007;7(1):67-81.Rev ABENO. 2007;7(1):67-81.

7. Ford JP, Foxlee N, Green W. Developing information literacy with first year oral health students. Eur J Dent Educ. 2009;13(1):46-51.

8. Foster L, Knox K, Rung A, Matheos N. Dental students’ attitudes toward the design of a computer-based treatment planning tool. J Dent Educ. 2011;75(1):1434-42.

9. Gottlieb R, Lanning SK, Gunsolley JC, Buchanan JA. Faculty impressions of dental students’ performance with and without virtual reality simulation. J Dent Educ. 2011;75(1):1443-51.

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10. Levine AE, Bebermeyer RD, Chin JW.0. Levine AE, Bebermeyer RD, Chin JW. Development of an interdisciplinary course in information resources and evidence-based Dentistry. J Dent Educ. 2008;72(9):1067-76.

11. Marchiori LLM, Melo JJ, Melo WJ. Avaliação docente em relação às novas tecnologias para a didática e atenção no ensino superior. Avaliação. 2011;16(2):433-43.

12. Mattheos N, Stefanovic N, Apse P, Attstrom R, Buchanan J, Brown P. Potential of information technology in dental education. Eur J Dent Educ. 2008;12(1):85-91.

13. Mowery D, Clayton M, Lu J, Schleyer T. Software review tooth Atlas 3D, version 6.3.0. J Dent Educ. 2010;74(11):1261-4.

14. Pahinis K, Stokes CW, Walsh TF, Tsitrou E, Cannavina G. A blended learning course taught to different groups of learners in a dental

school: follow-up evaluation. J Dent Educ. 2008;72(9):1048-57.

15. Pretto NL, Ricio NCR. A formação continuada de professores universitários e as tecnologias digitais. Educ Rev. 2010;37(5):153-69.

16. Ressel LB, Beck CLC, Gualda DMR, Hoffmann IC, Silva RM, Sehnem GD. The use of the focus group in qualitative researching. Texto Contexto Enferm. 2008;17(4):779-86.

17. Urbankova A, Engebretson SP. Computer-assisted dental simulation as a predictor of preclinical operative Dentistry performance. J Dent Educ. 2011;75(1):1249-55.

18. Vuchkova J, Maybury TS, Farah CS. Testing the educational potential of 3D visualization software in oral radiographic interpretation. J Dent Educ. 2011;75(1):1417-25.


Prevalence of oral lesions in 25 years of Oral Cancer Prevention campaigns in Paraná State, Brazil, 1988 to 2013

Laurindo Moacir Sassi1

Gyl Henrique A. Ramos2

Jose Luís Dissenha1

Juliana Lucena Schussel1

Maria Isabela Guebur1

Cleverson Patussi1

Corresponding author: Cleverson PatussiDepartamento de Cirurgia Oral e Maxilofacial, Hospital Erasto Gaertner Rua Dr. Ovande do Amaral, n. 20CEP 81520-060 – Curitiba – PR – BrasilE-mail: [email protected]

1 Department of Oral and Maxillofacial Surgery, Erasto Gaertner Hospital – Curitiba – PR – Brazil. 2 Department of Head and Neck Surgery, Erasto Gaertner Hospital – Curitiba – PR – Brazil.

Received for publication: December 12, 2013. Accepted for publication: January 9, 2014.

Keywords: oral cancer; prevalence; prevention. adhesives.


Abstract

Introduction: Epidemiological studies add up as a large area of scientific research and play an important role revealing the prevalence of the several diseases in the place where they applied. Public and health professionals have become more aware of the importance of oral mucosal lesions. Objective: To determine the frequency of the oral lesions and determinate the epidemiological profile of patients attending the prevention of oral cancer campaigns in the state of Paraná, Brazil, between 1988 and 2013. Material and methods: A prospective study was conducted evaluating 25 years of oral cancer prevention campaigns in the state of Paraná, Brazil, between 1988 and 2013. All patients were evaluated in a systematic way and were older than 30 years, answering one questionnaire with data relating to harmful health habits, family history of cancer, family income, frequency of visits to dentists and knowledge on the subject. Results: A total of 22,300 patients were evaluated during the 25 years of projects and 3,731 had oral lesions, while 18,569 patients had no oral alterations during the evaluation. Among those patients,

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Sassiet al.–Prevalence of oral lesions in 25 years of Oral Cancer Prevention campaigns in Paraná State, Brazil, 1988 to 2013Prevalenceoforallesionsin25yearsofOralCancerPreventioncampaignsinParanáState,Brazil,1988to2013

13779 (61.78%) were female and 8521 (38.78%) were male, 843 (22.59%) were smokers, 578 (15.49%) used alcohol and in 1386 (37.14%) had the habit of using yerba mate. The prevalence of lesions occurred as follows: 533 (14.28%) cases of lesions with aspect of leukoplakia, 1095 (29.34%) inflammatory lesions, 1934 (51.83%) of traumatic origin and 169 (4 5%) classified as other. Conclusion: The campaigns have brought benefits to the health of the elderly population but it is still not enough to make up for low levels of oral lesions appearance. Education of the population should in this way be approached more seriously and effectively.

Introduction

Epidemiological studies add up as a large area of scientific research and play an important role, because they reveal the prevalence and incidence of several diseases and particularize their distribution according to specific characteristics of the environment where they are being analyzed [6].

In recent years, public and health professionals have become more aware of the importance of oral mucosal lesions. Apart from evaluation of oral health for dental caries and periodontal diseases, the need for epidemiologic study of oral cancer and other oral mucosal conditions, especially related to human immunodeficiency virus (HIV) or hepatitis-B virus (HBV) infections is also being emphasized [2].

Several authors have published epidemiological studies of oral lesions in several reference centers, and the most frequent lesions were: nonspecific chronic inflammation, inflammatory fibroepithelial hyperplasia, fibroma, mucocele, hemangioma, pyogenic granuloma, radicular cysts and odontogenic squamous cell carcinoma [3, 7, 8, 10-12].

The oral mucosa serves as a protective barrier against trauma, pathogens, and carcinogenic agents. It can be affected by a wide variety of lesions and conditions, some of which are harmless while others may have serious complications, as cancer. Identification and treatment of these pathologies are an important part of total oral health care. Hence, oral soft tissue examination is crucial, and it should be done in a systematic manner to include all parts of the oral cavity [1].

In this way, the aim of this study is to evaluate the epidemiological profile of patients attended in 25 years of campaigns oral cancer prevention in the state of Paraná, Brazil, between 1988 and 2013, assess the frequency of the most common lesions founded, and compare them with world literature.


Volunteer patients were evaluated during 25 years of oral cancer prevention campaigns in the state of Paraná, Brazil, between 1988 and 2013 and approximately 400 municipalities in the state received the campaign team.

All patients were evaluated in a systematic way with inspection of all intra-oral areas, with wooden spatulas and appropriated lighting.

Among patients, the majorities were older than 30 years, due to the epidemiological profile of the prevalence of oral cancer in Brazil being of patients with above referred ages.

A questionnaire with data relating to harmful health habits, family history of cancer, family income, frequency of visits to dentists and knowledge on the subject was applied.

Results

After the analysis of the database of patients assisted by the campaign, it was found that a total of 22300 patients were attended during the 25 years of projects. Of these, 3731 had oral lesions and 18569 patients had no oral alterations during the dentist evaluation.

Regarding gender, 13779 (61.78%) were female and 8521 patients (38.78%) were male, over the age of 30 years in 99% of cases.

Among the patients evaluated 20129 (90.26%) were Caucasians and others belong to others ethnics groups.

The analysis of the harmful health habits showed that 843 (22.59%) were smokers, 578 (15.49%) used alcohol and 1386 (37.14%) used yerba mate.

The lesions were classified into groups, and the prevalence of lesions occurred as follows: 533 (14.28%) cases of lesions with aspect of leukoplakia, 1095 (29.34%) inflammatory lesions, 1934 (51.83%) of traumatic origin and 169 (4 5%) classified as other.

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The final diagnosis of the lesions found in patients referred to the reference hospitals in the region cannot be assessed because they had been not followed-up.

The classification of groups can be visualized in table I.

Table I–Lesionsfoundineachgroup

Leukoplakias Oral lichen planusCandidiasisActinic keratosisOral leukoplakia

Inflammatory CandidiasisMedian rhomboid glossitisBlack hairy tongue MucositisPapillomaParacoccidioidomycosis

Traumatic Denture hyperplasiaOral FibromaTraumatic ulcersTorus palatinus and torusmandibularis MucoceleRanula

Other HemangiomasLymphangiomasPyogenic granulomasAmalgam tattooHyposalivation

Discussion

Epidemiological studies add up a large area of scientific research and play an important role because they reveal the prevalence and incidence of several diseases and particularize their distribution according to specific characteristics of the environment where they are being analyzed. Several studies have been conducted in order to determine the frequency of oral lesions in different geographic regions in the world [1-5, 7, 9, 12]. In comparative analysis of the aforementioned studies observed markedly different prevalences, ranging from more to less expressive, which can be explained due to different culture, social and political characteristics of each region, especially internationally, such as the number of dental schools in the country, socioeconomic level of the region and the profile of the examined patient.

Our results showed a high prevalence of oral mucosal lesions among older patients, which emphasizes the importance of routine examination of the oral mucosa, particularly in adults [1]. By comparing this data with others publications is it possible to see that exists a minor prevalence of oral lesions in world literature, explained by the age pattern of the others studies that carried out examinations at all ages. Moreover, Brazil is considered a developing world economy.

In contrast to the data mentioned above, it is possible to observe statistically significant epidemiological differences inside the national territory. Kniest et al. [6] showed a prevalence of approximately 85% of injuries among all patients examined. In this study, the examinations were performed at a referral center where patients are referred to diagnosis and treatments. In our study patients presented themselves voluntarily without prior referral from another health professional, leading to a minor number of lesions found which justifies this epidemiological divergence.

Regarding the gender variables, 61.78% were female and 38.78% were male, corroborating previous research, in which the female was also the most affected by oral lesions [3, 6, 8]. It is known that a series of oral lesions affects more women than men, but the statistical data of all injuries added together for each gender is not known. This shows the greatest concern of women with oral health and not necessarily females are most affected by oral lesions.

The total number of malignant lesions and benign cannot be proven because patients had been not followed-up. Notwithstanding, other Brazilian research showed that approximately 95% of the lesions were benign and 5% were malignant [6, 8]. Probably, the number of malignant lesions found during the 25 years would not reach to 5%, which is because the patients had been examined in the field and randomly selected in cities that received the campaigns of Oral Cancer Prevention.

Correlating the occurrence of benign lesions it can be seen 14.28% of leukoplakia, 29.34% of inflammatory lesions, 51.83% of traumatic origin and 4.5% were classified as other. This reinforces the profile of individuals assisted in the campaign of prevention of oral cancer for which much is evaluated in an attempt to diagnose or treat benign lesions, including candidiasis, inflammatory fibrous hyperplasia, mucocele, fibroma and hyposalivation. Similar results were found by other studies on the prevalence of oral lesions [3, 8, 13].

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Conclusion

Epidemiological research of oral lesions in a specific geographic region establishes the real needs of this population and provides information to develop treatment plans and preventive actions towards the lesions found. By analyzing 25 years of prevention campaigns on oral cancer, we conclude that there is a necessity for greater investment in research plans on prevention of these diseases, because a large number of patients requiring care and treatment of oral diseases is still found. Educating the population is of paramount importance because it helps not only the dental professional, but also the patients themselves who were unaware of the presence of lesions inside their oral cavity. The campaigns has brought benefits to the health of the elderly population, so that, such strategies could be extended to other age groups and other regions of the country and could even serve as a basis for the development of prevention of oral cancer in other countries, considering, of course, the peculiarities of different realities.

References

1. Ali M, Joseph B, Sundaram D. Prevalence of oral mucosal lesions in patients of the Kuwait University Dental Center. Saudi Dent J. 2013 Jul;25(3):111-8.

2. Bhatnagar P, Rai S, Bhatnagar G, Kaur M, Goel S, Prabhat M. Prevalence study of oral mucosal lesions, mucosal variants, and treatment required for patients reporting to a dental school in North India: in accordance with WHO guidelines. J Family Community Med. 2013 Jan;20(1):41-8.

3. Cavalcante ASR, Marsílio AL, Kühne SS, Carvalho YR. Lesões bucais de tecido mole e ósseo em crianças e adolescentes. Pós-Grad Rev Fac Odontol São José dos Campos. 1999;2(1):67-75.

4. Fortes TMV, Queiroz LMG, Piva MR, Silveira EJD. Estudo epidemiológico de lesões proliferativas não neoplásicas da mucosa oral – análise de 20 anos. Ciênc Odontol Bras. 2002;5(3):54-61.

5. Izidoro FA, Izidoro ACSA, Semprebom AM, Stramandinoli RT, Ávila LFC. Estudo epidemiológico de lesões bucais no ambulatório de estomatologia do Hospital Geral de Curitiba. Rev Dens. 2007 Nov-Dec;15(2):99.

6. Kniest G, Stramandinoli RT, Ávila LFC, Izidoro ACAS. Frequência das lesões bucais diagnosticadas no Centro de Especialidades Odontológicas de Tubarão (SC). RSBO. 2011 Jan-Mar;8(1):13-8.

7. Lima GS, Fontes ST, Araújo LMA, Etges A, Tarquínio SBC, Gomes APN. A survey of oral andA survey of oral and maxillofacial biopsies in children. A single-center retrospective study of 20 years in Pelotas-Brazil. J Appl Oral Sci. 2008;16(6):397-402.

8. Marin HJI, Silveira MMF, Souza GFM, Pereira JRD. Lesões bucais: concordância diagnóstica na Faculdade de Odontologia de Pernambuco. Odontol Clín Científ. 2007;6(4):315-8.

9. Martins JS, Abreu SC, Araújo ME, Bourget MM, Campos FL, Grigoletto MV et al. Strategies andStrategies and results of the oral cancer prevention campaign among the elderly in São Paulo, Brazil, 2001 to 2009. Rev Panam Salud Publica. 2012 Mar;31(3):246-52.

10. Miyachi S, Tommasi MHM, Zardo F, Sugita RK, Gevaerd S, Giuriatti WA et al. Oral cavity lesions diagnostic center: potential impact in oral cancer epidemiology in Curitiba. BCI. 2002;9(33):80-5.

11. Rocha DAP, Oliveira LMM, Souza LB. Neoplasias benignas da cavidade oral: estudo epidemiológico de 21 anos (1982-2002). Rev Odontol Univ São Paulo. 2006;18(1):53-60.

12. Sobral APV. Estudo epidemiológico de 2.147 casos de lesões bucomaxilofaciais. RBPO. 2007;2(4):70-81.

13. Vieira VG, Fernandes AM, Machado APB, Grossman SMC, Aguiar MCF. Prevalência das alterações da normalidade e lesões da mucosa bucal em pacientes atendidos nas Clínicas Integradas de Atenção Primária (Ciaps) da Faculdade de Odontologia / UFMG. Arq Odontol. 2007;43(1):13-8.


Students’ perceptions on diagnosis and treatment of occlusal surface of first molars

Beatriz Vieira de Paiva1

Fernanda Ladico Miura1

Silvana de Andrade Silvestre de Lima1

Danielly Cunha Araújo Ferreira2

Alessandra Maia de Castro3

Fabiana Sodré de Oliveira3

Corresponding author:Fabiana Sodré de OliveiraUniversidade Federal de UberlândiaAvenida Pará, 1.720 – Bloco 2G – sala 2 – Campus UmuaramaCEP 38400-902 – Uberlândia – MG – BrasilE-mail: [email protected]

1 School of Dentistry, Federal University of Uberlândia – Uberlândia – MG – Brazil.2 School of Dentistry of Ribeirão Preto, University of São Paulo – Ribeirão Preto – SP – Brazil.3 School of Dentistry, Federal University of Uberlândia – Uberlândia – MG – Brazil.

Received for publication: January 31, 2013. Accepted for publication: November 5, 2013.

Keywords: dental caries; preventive dentistry; dental education.


Abstract

Introduction: Accurate diagnosis of dental caries is a fundamental requirement in health care. Objective: The aim of this study was to evaluate the opinions of undergraduates concerning different conditions of the occlusal surface of permanent first molar. Material and methods: Two experienced and trained examiners, using visual and radiographic examinations, classified five occlusal surfaces of permanent first molars. The surfaces were photographed and presented to students with a questionnaire about classification of occlusal surfaces, methods used to aid caries diagnosis and type of treatment to be applied. The answers were classified as correct and incorrect and submitted to Chi-square test (p < 0.05). Results: The results showed a higher percentage of correct answers regarding to dentine caries (87.95%) and no caries (84.34%). For all surface conditions, the methods most commonly used to aid diagnose were professional prophylaxis, good lighting, drying and dental probe. Considering the treatment, a greater number of correct answers were obtained for the surface with dentine caries, with indication

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Paivaet al.–Students’ perceptions on diagnosis and treatment of occlusal surface of first molarsStudents’perceptionsondiagnosisandtreatmentofocclusalsurfaceoffirstmolars

of conventional (65.06%) and/or preventive restoration (33.73%) and no caries without treatment need or sealant (53.01%). For students at 6th, 7th and 8th semesters, the percentage of correct answers for classification and treatment was 72.31%, 58.33% and 62.94%, respectively, without statistically significant differences (p < 0.05). Conclusion: It was concluded that the opinion of students differed regarding to the diagnosis and treatment mainly when the occlusal surface showed early stages of dental caries.

Introduction

Despite the fact that the prevalence of dental caries has declined considerably, the reduction has not occurred uniformly for all dental surfaces. Occlusal surfaces are still the most likely sites for the development of lesions and occlusal caries account for most of the lesions in children aged 8-15 years [1, 8].

The diagnosis of occlusal caries has always been difficult [3, 5, 6, 19]. Every practitioner is aware of the problems inherent in determining the presence or absence of an early lesion in these sites, which because of their morphology cannot be directly visualized [6].

There are many different methods for detecting occlusal caries [4]. The ideal caries detection method should capture the whole continuum of the caries process, from the earliest to the cavitation stage [25].

The dental professional’s approach to the treatment of caries has been evolving in recent years. Changes in caries epidemiology, advances in materials and technology have all contributed to the emergence of a more proactive, tailored, preventive and conservative treatment philosophy characterized by greater attention to the individual and his or her disease [2].

Due to the high susceptibility to caries of occlusal surfaces and the difficulties of diagnosis, many studies were conducted to evaluate different diagnostic methods [1, 10, 13, 16, 22, 23] diagnosis variability and treatment decision for this surface [3, 5, 9, 17, 18].

Some studies were conducted among students [18], between students and teachers [5, 23], between students and dentists [3], and among dental professionals [13, 17]. A wide variability in the diagnosis of occlusal caries and treatment decision for this surface has been found [5, 17, 18]. Knowledge and experience of examiners influence on their ability to detect caries and affect inter-examiner reproducibility [23].

Accurate diagnosis of either the absence or presence of the disease is a fundamental requirement in health care [14] and the accurate diagnosis of the presence of disease is paramount for appropriate care [10]. The diagnosis of non-overt occlusal decay is challenging and can be highly subjective, and its inherent uncertainties can lead to widely differing treatment decisions [14]. Thus, the aim of this study was to evaluate the behavior of undergraduates regarding to different conditions of the occlusal surface of the permanent first molars. The specific aims included: (1) to investigate the ability of dental undergraduates to classify an occlusal surface and define a logical management for each clinical condition and (2) to identify the methods that students would use to aid the diagnosis of these surfaces.


Ethicalaspects

This study was approved by the Ethics Committee (protocol no. 050/07) of the Federal University of Uberlândia, Minas Gerais, Brazil.

Sampleselection

A convenience sample of undergraduates was chosen on the basis of availability for comparative study from the 6th, 7th and 8th semesters at the School of Dentistry of the Federal University of Uberlândia. The students were informed on the objectives of the study and signed the informed consent form. Eighty-three students participated in the study, 13 (15.66%), 36 (43.38%) and 34 (40.96%) enrolled at 6th, 7th and 8th semesters, respectively.

Studydesign

Five occlusal surfaces of permanent first molars of five patients underwent treatment at

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the Clinic of Pediatric Dentistry were selected by two experienced and trained examiners using visual and radiographic examinations. The clinical examination was performed according to the visual examination criteria established by Ekstrand et al. [7] (Table I). Visual examination was carried out using only a dental operating light and air-drying for 5 seconds. No dental explorer was used during the examination. Prior to the visual clinical examinations, the occlusal surface was cleaned with bicarbonate jet and water (Profident – Dabi-Atlante). Each occlusal surface was scored as presented in Table I. The tooth selection included scores 0–4. This examination was performed by each examiner separately and final scores were obtained by discussion and consensus. The occlusal surfaces of the teeth were photographed and printed in order to produce examination sheets generating 10cm x 15cm images. These photographs were randomly numbered from 0 to 5. Photography 1 = Cavity in enamel, Photography 2 = Cavity in dentine, Photography 3 = Visible white spot, Photography 4 = White spot difficult to visualize, Photography 5 = No caries.

The teeth were radiographed under standardized conditions. The same two experienced and trained examiners analyzed the bitewing radiographs using

the criteria established by Ekstrand et al. [9] (Table I). This examination was carried out by each examiner separately and final scores were obtained by discussion and consensus. Based on visual and radiographic examinations a logical management was established for each occlusal surface varying from no treatment to sealant, preventive restoration and conventional restoration.

The students were required to analyze the five photographs and to answer the questionnaire containing three questions about classification, methods used for aiding caries diagnosis and management for each one of the occlusal surfaces. The questionnaire was applied by two previously trained interviewers (Figure 1).

The students’ answers were compared with the condition, the methods of diagnostic and proposed management given for each occlusal surface by two experienced and trained examiners and classified as correct and incorrect based on the literature.

Statisticalanalysis

Descriptive statistics were used to analyze the quantitative data. The percentages of correct answers among the students at 6th, 7th and 8th semesters were compared using chi-square test (p < 0.05).

Table I –Criteriausedinvisualandradiographicexamination

Score Clinical appearance Radiographic examination

0 No or slight change in enamel translucency after prolonged air drying (> 5s)

No radiolucency visible

1 Opacity (white) hardly visible on the wet surface, but distinctly visible after air drying

Radiolucency visible in enamel

2 Opacity (white) distinctly visible without air drying

Radiolucency visible in dentine but restricted to the outer third of the dentine

3 Localized enamel breakdown in opaque or discolored enamel and/or grayish discoloration from the underlying dentine

Radiolucency extending to the middle third of dentine

4 Cavitation in opaque or discolored enamel exposing the dentine beneath

Radiolucency in the pulpal third of dentine

( ) 6th semester ( ) 7th semester ( ) 8th semesters1. According to visual clinical examination, the tooth can be classified into: a. Cavity in enamel b. Cavity in dentine c. Incipient lesion in enamel/ visible white spotd. Incipient lesion in enamel/ white spot difficult to visualizee. No caries

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2. To aid in the clinical diagnosis, which method (s) would you use?a. Dental probe;b. Periapical radiographyc. Bitewing radiographyd. Prophylaxis professional, good lighting and dryinge. All the methods described above3. Which treatment would you indicate according to the clinical classification?a. No treatmentb. Glass ionomer cement sealant c. Resin-based sealantd. Preventive restoratione. Conventional restoration

figure 1–Questionnaireappliedtoundergraduates

Results

Table II presents the frequency and percentage distribution of answers from the students at each semester for the condition classification of the occlusal surface per each photograph.

Concerning to photograph #1, in which caries in enamel was presented, the results showed that the percentage of correct answers for students at 6th, 7th and 8th semesters was respectively 38.46%, 36.11% and 50.00%.Within the sum of the responses of all students, the total number of correct responses was 42.7% (Table II and Figure 2).

The results from the occlusal surface having cavity in dentine (photograph #2) showed that the percentage of correct answers for students at 6th, 7th and 8th semesters was respectively 100.00%, 88.89% and 82.35%. Within the sum of the responses of all students, the total number of correct answers was 87.95% (Table II and Figure 2).

With regard to photograph #3, in which the occlusal surface had a visible white spot, the results showed that the percentage of correct answers for students at 6th, 7th and 8th semesters was respectively 84.62%, 72.22% and 79.41%. Within the sum of the responses of all students, the total number of correct answers was 77.11% (Table II and Figure 2).

The results of photograph #4 (occlusal surface with a white spot difficult to visualize) showed a percentage of correct answers for students at 6th, 7th and 8th semesters was respectively 38.46%, 11.11% and 23.53%. Within the sum of the responses of all students, the total number of correct answers was 20.48% (Table II and Figure 2).

The percentage of correct answers for students at 6th, 7th and 8th semesters was respectively 100.00%,

83.33% and 79.41% for photograph #5 (occlusal surface without caries). Within the sum of the responses of all students, the total number of correct answers was 87.95% (Table II and Figure 2).

Figure 2 displays the total number of correct and incorrect answers with respect to the condition classification of the occlusal surface considering the responses of all students.

Table III presents the distribution of frequencies and percentages of students’ responses at each semester comprising the methods used to aid in the diagnosis of the occlusal surface condition for each photograph.

For all clinical photographs, the most cited response was professional prophylaxis, followed by good lighting and drying, except for photograph #2 (dentine caries) with a lower percentage (65.06%). With regard this latter photograph, the method of choice was the use of dental probing and periapical radiograph (59.04%), On the other hand, bitewing radiographs was chosen for all conditions of the occlusal surface at a lower frequency ranging from 2.41% to 25.30%. The combination of methods for diagnosis of the surfaces was indicated in a lower frequency ranging from 1.20% to 7.23% (Table III).

With regard to the treatment indication, 53.01% and 63.61% of the students answered that they do not treat both occlusal surface without caries and cavities in enamel, respectively. The glass ionomer cement sealant was indicated for all surfaces, except for those with dentine caries, but greater than the indication for the surface with visible white spot. Resin-based sealant was chosen for all occlusal surfaces, including those with dentine caries, but at a smaller proportion. The preventive restoration was indicated for all occlusal surfaces

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and conventional restoration surfaces for white spot difficult to visualize, cavity in enamel and dentine caries at a higher frequency (Table IV).

Table V shows the distribution of frequencies and percentages of students who answered correctly the classification and treatment of occlusal surface. All students who correctly classified the condition indicated the occlusal surface treatment correctly. Concerning to the students at 6th, 7th and 8th semesters, the percentage of correct answers for classification and treatment was 72.31%, 58.33% and 62.94%, respectively (Table V). Chi-square

test (p < 0.05%) was applied and no statistically significant difference was found.

Figure 3 displays the distribution of the percentages of correct and incorrect answers of the students at each semester considering all the questions. According to the results, it was observed that students at 7th and 8th semesters showed a higher number of correct answers than those from the 6th semester. Chi-square test was applied (p < 0.05%) and no statistically significant increasing of correct answers among the percentages obtained by students at the three semesters was seen.

Table II–Distributionoffrequenciesandpercentagesofstudents'answersregardingtotheconditionclassificationoftheocclusalsurface

Classification AlternativesSemesters

Total6th 7th 8th

Cavity in enamel(Photograph #1)

a 05 (38.46%) 13 (36.11%) 17 (50.00%) 35 (42.17%)

b 0 04 (11.11%) 06 (17.65%) 10 (12.50%)

c 01 (7.69%) 0 01 (2.94%) 02 (2.41%)

d 03 (23.08%) 01 (2.78%) 07 (20.59%) 11 (13.25%)

e 0 0 0 0

Cavity in dentine(Photograph #2)

a 0 05 (13.89%) 07 (20.59%) 12 (14.46%)

b 13 (100.00%) 32 (88.89%) 28 (82.35%) 73 (87.95%)

c 0 0 0 0

d 02 (15.38%) 01 (2.78%) 0 03 (3.61%)

e 0 0 0 0

Visible white spot(Photograph #3)

a 06 (46.15%) 06 (16.67%) 02 (5.88%) 14 (16.87%)

b 0 0 0 0

c 11 (84.62%) 26 (72.22%) 27 (79.41%) 64 (77.11%)

d 01 (7.69%) 03 (8.33%) 01 (2.94%) 05 (6.02%)

e 0 01 (2.78%) 0 01 (1.20%)

White spot difficult to visualize

(Photograph #4)

a 01 (7.69%) 06 (16.67%) 02 (5.88%) 09 (10.84%)

b 0 0 0 0

c 0 07 (19.44%) 02 (5.88%) 09 (10.84%)

d 05 (38.46%) 04 (11.11%) 08 (23.53%) 17 (20.48%)

e 0 05 (13.89%) 06 (17.65%) 11 (13.25%)

No caries(Photography #5)

a 01 (7.69%) 06 (16.67%) 06 (17.65%) 13 (15.66%)

b 0 0 0 0

c 01 (7.69%) 03 (8.33%) 04 (11.76%) 08 (9.64%)

d 02 (15.38%) 28 (77.78%) 18 (52.94%) 48 (57.83%)

e 13 (100.00%) 30 (83.33%) 27 (79.41%) 70 (84.34%)

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Table III –Distributionoffrequenciesandpercentagesofstudents’answersregardingthemethodsusedinthediagnosisofocclusalsurface

Methods AlternativesSemesters

Total6th 7th 8th

Clinical probe

a 09 (69.23%) 31 (86.11%) 16 (47.06%) 56 (67.47%)b 05 (38.46%) 26 (72.22%) 20 (58.82%) 51 (61.45%)c 06 (46.15%) 23 (63.89%) 14 (41.16%) 43 (51.81%)d 10 (76.92%) 28 (77.78%) 8 (52.94%) 56 (67.47%)e 03 (23.08%) 27 (75.00%) 13 (38.24%) 43 (51.81%)

Periapicalradiograph

a 0 05 (13.89%) 08 (23.53%) 13 (15.66%)b 08 (61.54%) 21 (58.33%) 20 (58.82%) 49 (59.04%)c 0 01 (2.78%) 03 (8.82%) 04 (4.82%)d 0 02 (5.56%) 07 (20.59%) 09 (10.84%)e 0 01 (2.78%) 01 (2.94%) 02 (2.41%)

Bitewing radiograph

a 01 (7.69%) 02 (5.56%) 12 (35.29%) 15 (18.07%)b 02 (15.38%) 09 (25.00%) 10 (29.41%) 21 (25.30%)c 0 01 (2.78%) 01 (2.94%) 02 (2.41%)d 01 (7.69%) 03 (8.33%) 01 (2.94%) 05 (6.02%)e 0 03 (8.33%) 01 (2.94%) 04 (4.82%)

Professional prophylaxis, good

lighting and drying

a 10 (76.92%) 32 (88.89%) 26 (76.47%) 68 (81.93%)b 09 (69.23%) 21 (58.33%) 24 (70.59%) 54 (65.06%)c 13 (100.00%) 33 (91.67%) 33 (97.06%) 79 (95.18%)d 12 (92.31%) 29 (72.22%) 31 (91.18%) 72 (86.75%)e 11 (84.62%) 33 (91.67%) 33 (97.06%) 77 (92.77%)

Association of methods

a 0 01 (2.78%) 05 (14.71%) 06 (7.23%)b 01 (7.69%) 03 (8.33%) 02 (5.88%) 06 (7.23%)c 0 02 (5.56%) 0 02 (2.41%)d 0 01 (2.78%) 0 01 (1.20%)e 0 0 0 0

Table IV–Distributionoffrequenciesandpercentagesofstudents’responsesregardingthetypeoftreatmentoftheocclusalsurface

Treatment AlternativesSemesters

Total6th 7th 8th

No treatment

a 02 (15.38%) 01 (2.78%) 0 03 (63.31%)b 0 0 0 0c 03 (23.08%) 06 (16.67%) 04 (11.76%) 13 (15.66%)d 02 (15.38%) 12 (33.33%) 06 (17.65%) 20 (24.10%)e 12 (92.31%) 15 (41.67%) 17 (50.00%) 44 (53.01%)

Glass ionomer cement sealant

a 08 (61.54%) 16 (44.44%) 14 (41.18%) 38 (45.78%)b 0 0 0 0c 09 (69.23%) 18 (50.00%) 24 (70.59%) 51 (61.45%)d 06 (46.15%) 12 (33.33%) 21 (61.76%) 39 (46.99%)e 01 (7.69%) 11 (30.56%) 16 (47.06%) 28 (33.73%)

Resin-based sealant

a 01 (7.69%) 05 (13.89%) 07 (20.59%) 13 (15.66%)b 0 0 01 (2.94%) 01 (1.20%)c 0 08 (22.22%) 06 (17.65%) 14 (16.87%)d 03 (23.08%) 09 (25.00%) 04 (11.76%) 16 (19.28%)e 0 08 (22.22%) 01 (2.4%) 09 (10.84%)

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Preventive restoration

a 01 (7.69%) 08 (22.22%) 08 (23.53%) 17 (20.48%)b 03 (23.08%) 11 (30.56%) 14 (41.18%) 28 (33.73%)c 01 (7.69%) 03 (8.33%) 0 04 (4.82%)d 02 (15.38%) 02 (5.56%) 03 (8.82%) 07 (8.43%)e 0 02 (5.56%) 0 02 (2.41%)

ConventionalRestoration

a 01 (7.69%) 06 (16.67%) 05 (14.71%) 12 (14.46%)b 10 (76.92%) 25 (69.44%) 19 (55.88%) 54 (65.06%)c 0 0 0 0d 0 01 (2.78%) 0 01 (1.20%)e 0 0 0 0

Table V – Distribution of frequencies and percentages of students who answered correctly the condition andtreatmentoftheocclusalsurface

Classification and treatment of occlusal surface

SemestersTotal

6th 7th 8th

Cavity in enamel 0552.85%

1336.11%

1750.00%

3544.58%

Cavity in dentine 13100.00%

3261.11%

28 82.35%

7375.90%

Visible white spot 1184.62%

2672.22%

2779.41%

6477.11%

White spot difficult to visualize 0538.46%

0411.11%

0823.53%

1720.48%

No caries 13100.00%

3083.33%

2779.41%

7084.34%

Total 4772.31%

10558.33%

10762.94%

25962.41%

figure 2–Distributionofpercentagesofcorrectandincorrectanswerstotheclassificationoftheclinicalconditionofeachsurfaceofallstudents

Table IV (continued)

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figure 3–Distributionofpercentagesofcorrectandincorrectanswersofstudentsof6th,7thand8thsemestersconsideringallquestions

Discussion

Diagnosis is a fundamental step for making treatment decisions [4]. As far as carious lesions are concerned, diagnosis implies deciding whether demineralization is present, the depth of the lesion and whether it is progressing rapidly or slowly or whether it is already arrested. Thus, diagnosis is more than lesion detection: it should also consider lesion activity [8, 20].

In clinical practice, students are faced with many clinical situations in which they must diagnosis and decide which treatment is most appropriate. The occlusal surface of the first permanent molar is the site of greatest risk for the development of dental caries. This study was an attempt to investigate the ability of undergraduate students to classify occlusal surface and define a logical management for each clinical condition and to identify the methods that students have used to aid the diagnosis of these surfaces.

Most studies have been performed on extracted molars [1, 3, 16, 18, 22, 23] or indicated for extraction [9] to be later evaluated by macroscopic and microscopic examination. This study used a questionnaire and clinical photographs in order to simulate a similar clinical situation methodology to that used by other authors [5, 10].

Although the questionnaire did not contain data on the caries risk to the patient, the chosen photographs that had white spot lesions were classified as active [8].

The results agree with other authors who observed a wide variation in the diagnosis of the occlusal surface [5, 17, 18]. In this study, there were a higher percentage of correct responses when the surface showed no cavity and caries in dentine. The intermediate stages in which the surface presented with white spots difficult to visualize and the presence of cavity in enamel, the amount of correct answers were lower and highly variable (Table III; Figure 2).

Although there are different methods for the evaluation of occlusal caries in clinical routines during graduation, new technologies are not available and the visual method is the most used. It is known that this method of diagnosis gives sensitivities to the order of 60.0% and a specificity of 85.0% [6]. Nevertheless, the current diagnostic model of visual is qualitative, subject to operator interpretation, and consequently can produce varied diagnosis from dentists examining the same patient [19].

To conduct the clinical examination of caries it is necessary that the teeth are clean, dry and well lit. In this study, all photographs were taken by obeying these criteria. Thus, for all surfaces this alternative was considered correct for all clinical situations. The percentage of correct responses was high for all clinical situations ranging from 65.06% to 92.77% (Table IV). The detection of early signs of caries cannot be achieved unless the teeth are clean and dry [11].

The use of dental probing for occlusal caries detection causes enamel defects [12, 24]. This study

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did not evaluate how probing is being used whether appropriate or not. However, the results showed that probing was the second most appropriate method to aid in the diagnosis for all dental surfaces (Table III). In another study, the authors reported that the use of the probe is the main clinical diagnostic method used [10].

The difficulties in the accurate diagnosis of occlusal caries only by visual examination have been highlighted in the literature. Thus, bitewing radiographs should complement the diagnosis of clinical appearance. However, this is only valid whether cavities are found in dentine obviously. For the diagnosis of occlusal caries in enamel this method is inaccurate [15]. The results showed a low percentage of responses for this method in the diagnosis of all conditions of occlusal surface, including the healthy surfaces (Table III). However, it was observed a higher percentage of answers for periapical radiographs as a diagnostic method. A smaller percentage of students answered that associated methods assist in diagnosis (Table III).

Wit h rega rd to t he t y pe of t reat ment recommended for areas classified as healthy, a little over half of the students would not perform any treatment (53.01%), followed by glass ionomer cement (33.73%) or resin-based sealant (10.84%) of pits and fissures, or preventive restoration (2.41%). If the tooth belonged to a child at risk for dental caries, all the treatments mentioned, except performing preventive restoration were considered correct responses (Table IV).

Considering the surface that had white spots difficult to see, all treatments were considered and glass ionomer cement sealant was indicated (46.99%). On the other hand, for the surface with visible white spots, all treatments were cited, except for performing conventional restoration. In this clinical situation, sealing with glass ionomer cement was also the most appropriate treatment (61.45%). The use of glass ionomer cement sealant is justified by the fact that it has been recommended by the school of dentistry. All treatments were chosen for the occlusal surface with enamel caries, with the highest percentage (63.31%) for no treatment (Table IV). These results are in agreement with other study [5] in which the therapeutic method adopted in cases of clinical occlusal caries without cavitation, showed significant differences between the teacher and students.

A distinct stage in the caries process is the formation of the cavity. When a carious cavity is formed, it is much more difficult to control biofilm by oral hygiene procedures. Thus, the treatment of

choice usually involves surgical intervention in the form of restorations [21]. For the treatment options cited for cavity in dentine, performing conventional (65.06%) and conservative restoration (33.73%) (Table IV) were recommended.

The diagnosis of occlusal caries is highly subjective, with considerable variation in the ability and experience among clinicians to diagnose and treat occlusal caries appropriately [10]. However, the correct diagnosis of the condition of the occlusal surface allows adequate treatment. In this present study, all students who correctly classified the condition of occlusal surface indicated the correct treatment (Table V).

It seems that students of 6th period had a greater number of correct answers than those from 7th and 8th periods. Meanwhile, there were no statistically significant differences among the students (Table V). Methodological differences make difficult to compare these results with those of other studies.

According to the results, considering all answers, it was observed that students at 7th and 8th semesters showed a higher number of correct answers compared to those at 6th semester (Figure 3). There was no statistically significant increasing in correct answers, among the percentages obtained by students at the three semesters.

It was concluded that the opinion of students differed regarding the diagnosis and treatment mainly as the occlusal surface showed early stages of dental caries. According to Coelho et al. [5] there is a real need to reduce the divergences and disagreements of therapeutic diagnosis to benefit the patient. The implementation of teaching/learning strategies based on constant training/calibration process is needed to minimize these variations and to contribute to professional’s formation [18].

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Knowledge of Human Genome Project among Dentistry undergraduates

Daniela Peressoni Vieira1

Thaisa Cezária Triches1

Marcos Ximenes Filho1

Ana Paula Silveira Caldeira de Andrada Beltrame1

Leila Posenato Garcia2

Mabel Mariela Rodríguez Cordeiro3

Corresponding author: Mabel Mariela Rodríguez CordeiroDepartamento de Ciências Morfológicas, Centro de Ciências BiológicasUniversidade Federal de Santa Catarina, Campus Universitário – TrindadeCEP 88040-900 – Florianópolis – SC – BrasilE-mail: [email protected]

1 Department of Dentistry, Federal University of Santa Catarina – Florianópolis – SC – Brazil.2 Institute for Applied Economic Research – Brasília – DF – Brazil. 3 Department of Morphological Sciences, Federal University of Santa Catarina – Florianópolis – SC – Brazil.

Received for publication: February 18, 2013. Accepted for publication: December 9, 2013.

Abstract

Introduction: The Human Genome Project (HGP) has allowed for advances in diagnosis and prevention of diseases. Objective: The aim of this study was to investigate the knowledge of undergraduates from the Federal University of Santa Catarina, regarding HGP and its applicability. Material and methods: Thirty-one students were interviewed by using a questionnaire with open questions, followed by qualitative and quantitative analysis through answers’ grouping. Results: Only 4.5% did not know HGP, while most of them (83%) demonstrated knowledge gained from the media. Only 21% cited the undergraduate program as a source of information, 56% recognized advances in disease prevention and 81% reported applicability in Dentistry. 97% students would give blood samples for research, 28% reported concern about misuse of this information, while 31% did not report any disadvantage. Conclusion: It may be concluded that the students have some knowledge on HGP. However, it is not widely discussed during course, because the media was the main source of information.

Keywords: biotechnology; human genome; education; Dentistry.


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Vieiraet al.–Knowledge of Human Genome Project among Dentistry undergraduatesKnowledgeofHumanGenomeProjectamongDentistryundergraduates

Introduction

The Human Genome Project (HGP) started in the United States of America aiming at sequencing and mapping the human genetic code. Readily, it became a worldwide Project involving many countries, including Brazil. In 2003, the sequencing of almost all human genome (HG) was announced. HG consists of 23 pairs of chromosomes existing in all diploid cells of human beings, where DNA is found and all genetic features of an individual is stored [6].

The information obtained through HGP has been directly related with the routine of health professionals, including those of Dentistry. Some authors [10] have stated that except from trauma, essentially all pathologies and alterations affecting oral health have a great genetic component. Many genes accounting for tooth disorders, oral and craniofacial diseases have been identified along the project, e.g., the genes responsible for congenital hypodontia or even the most severe cases of dentinogenesis imperfecta. Thus, to know and understand the etiological mechanisms of these diseases will provide better diagnosis, prognosis and treatment.

Despite of the extraordinary importance that all new knowledge on human genetics will have in dental clinics, little efforts have been made to prepare undergraduates in relation to this new information and technology.

In 2001, a research was conducted aiming to analyze all 54 Schools of Dentistry of the United States of America to verify the presence or absence of genetic discipline within the curriculum and the need of a previous course on genetics for admission in Dentistry Course. Of the 53 responding schools, only eight included the discipline in the curriculum; of those not offering the discipline, most did not demand a prior course before admission [4]. In 2004, other authors [1] developed a similar research, also in American schools, to know whether the genetics discipline was taught and whether a previous knowledge was necessary before admission. Of the 56 schools included in the research, only six had the discipline in the curriculum and only one demanded a previous course for admitting the student.

In Brazil a similar research was conducted in 2004 aiming to analyze the knowledge among undergraduates of the last year of Medicine, Law, and Biological Sciences Schools of the State University of Maringá (Paraná, Brazil) in relation to HGP. The result showed that generally the undergraduates had little or none knowledge on this issue [9].

To contribute with the patients’ wellness and health, dentists should understand the role of genetics in oral health care. For this purpose, it is mandatory that they are familiar with the technological advancements and information obtained through HGP [5].

In Brazil, the main source of scient i f ic information production and dissemination is the university. Therefore, it is of great importance to identify whether the information on HGP is being taught to undergraduates of health area.

Thus, the aim of this study was to verify the level of knowledge of last year undergraduates of the School of Dentistry of the Federal University of Santa Catarina (UFSC, Florianópolis/SC, Brazil) on HGP, its importance, repercussion and possible application especially in Dentistry.


The Dentistry course was selected as the sampling field because is one of the areas undergoing immediate HGP impacts. The study participants were the undergraduates regularly enrolled in the last year of the Dentistry Course of the University (UFSC). This study was submitted and approved by the Ethical Committee in Research on Human Beings under process no. #094/08.

The interviews were conducted in the University. All undergraduates of the last year of the Dentistry Course were invited to participate in the study, comprising a total of 96 students. Those agreeing in participating in the study, all read and signed a Free and Clarified Consent Form, resulting in 31 participants.

To obtain the information, a questionnaire was formulated, applied as interview, with the following open questions:a) What do you know on Human Genome Project?b) For you, what is genome?c) How did you acquire knowledge on Human Genome Project?d) Which results and consequences can be expected from Human Genome Project?e) Which applicability do you believe that Human Genome Project has on Dentistry?f) If you have been invited to provide a blood sample to contribute with Human Genome Project or other studies, e.g., to discover a gene involved in a disease without cure; evolutionary studies, would you provide it? Why?g) Human Genome Project can anticipate the diagnosis of some diseases. Which advantages and/or disadvantages do you see in this probability?

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Aware of the objective, dynamics and anonymate guaranty, the permission of using a recorder was asked. One single researcher interviewed all undergraduates. Next, all recorded information was typed on a computer. The obtained data were submitted to a quali-quantitative analysis, by initially grouping equal or similar responses and then trying to detect in the response sets categories that enabled the grouping and differentiation of the answers.

Results

Altogether, 31 undergraduates were interviewed through an open-question questionnaire. Of these, only 4.5% reported they did not know what HGP is.

In the question on genome, most (58%) responded it is the genetic code of the organism and only 3% reported not knowing about it.

Among the undergraduates responding having knowledge on HGP, most of them (83%) reported they had acquired this knowledge through the media. Only 21% of the respondents answered that the genetics discipline was the information source about the issue. Some undergraduates (52%) affirmed they obtained that knowledge also through other sources, while 7% answered that the subject had never been taught during graduation. Only 3% confessed not knowing the source of their knowledge. The answers regarding the results and the consequences expected from HGP are seen in figure 1.

figure 1–ResultsandconsequencesexpectedfromHGP

About HGP applicability in Dentistry, 81% of the undergraduates reported at least one possible application. Among them, the identification of diseases as dentinogenesis imperfecta, amelogenesis imperfecta, agenesis, and other were cited. Only 19% of the undergraduates reported having little or none applicability.

Approximately 97% answered they would be willing to provide a blood sample to contribute with HGP and/or other projects. Only 3% of the undergraduates responded they would not provide a blood sample because they fear the possibility of identifying diseases.

Figures 2 and 3 displays the advantages and disadvantages reported by the undergraduates.

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figure 2 –HPGadvantagesreportedbytherespondents

figure 3 –HGPdisadvantagesreportedbytheparticipants

Discussion

Based on this present study results, notably most of the last year Dentistry undergraduates knew on HGP existence, since only 4.5% revealed they did not know what HGP was. Notwithstanding, some

undergraduates provided more insecure responses, almost with doubt overtones: “I don’t know much stuff, I will be sincere. I have already heard about it, but I don’t know much”; “I have heard that it deals with human DNA, right?”; “It can discover many things, but I don’t know what”.

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Although this knowledge is far from ideal, these data allowed the comparison of the study participants with the general average of Brazilian undergraduates. A previous study, in 2000, just after the announcement of DNA sequencing conclusion, demonstrated that only 4% of the respondents knew what genome was [7].

Data similar to those of this present study were found [9]. The authors reported that although none undergraduate had shown total lack of knowledge on this issue, none showed deep knowledge on HGP and its possible applications.

Most of the respondents reported that the main source of information on HGP was the media and that little knowledge was acquired from the university: “Through lectures, television, specialized journals and internet”. Some undergraduates told they had acquired knowledge also from other sources: “At the school itself, at secondary education I think I had some information, also in journals and internet”. Only 21% of the respondents cited the discipline of genetics as source of knowledge: “At the genetics lectures of the third phase of the Dentistry Course”.

This difficulty in transmitting the knowledge on genetics and its implications is not restricted to Brazil. Researchers found that only six American Schools of Dentistry had this discipline within the curriculum [1].

When the respondents were questioned about the consequences coming from HGP, most emphasized the increase in knowledge on diseases, providing their prevention, treatment and cure: “To discover cure for diseases, improve and prevent the diseases before they appear”. Such result is in agreement with those within the literature, in which was reported that the knowledge acquired from HGP in addition to contribute to the comprehension of human genome, has a significant application in relation to the diagnosis of genetic diseases [2]. Other authors reported that understanding the genetic contribution of some diseases would guide towards a better diagnosis and treatment [5].

With regard to HGP applicability in Dentistry, 86% knew to cite at least one possible applicability: “Likely any other disease, in Dentistry we also find oral diseases having genetic factors, such as cancer, some types of periodontitis, autoimmune diseases with oral repercussion, among others. The genome project may help in their prevention and cure”. Some authors already emphasized HGP applicability in Dentistry. Researches described that many genetic mutations resulting in hypodontia have already been identified, causing different

tooth absences. Many hereditary syndromes are also associated with the congenital absence of teeth [11].

In this study undergraduates were also questioned whether they were willing to provide a blood sample or genetic material to contribute with HGP or other projects, and evolutionary studies, to find out, e.g., a gene involved in a given disease. Most of undergraduates answered that they would provide, claiming they would be contributing for the sake of science and the other human being: “Look, I do think so, because it costs nothing. Many people donate blood to save other people and I believe that donating blood for a research that will help more people is the same thing”. Other authors [9] also found a relevant willingness from undergraduates in contributing with HGP and other studies, in which 72.5% of the respondents reported that they were willing in providing genetic material and 12.5% would provide it with some restrictions as confidentiality, ethics, integrity and knowledge of the objectives.

Finally, when questioned on the advantages and/or disadvantages of HGP anticipating the diagnoses of some diseases, many undergraduates reported, among the advantages that the obtainment of an earlier diagnosis provides a better prognosis: “Definitely, we will be able to plan the treatment of these diseases with the early diagnosis, making a better treatment planning, and having a better outcome and prognosis for the patient”. Others emphasized that it would be possible, through early diagnosis, to avoid some risk factors allowing the development of a given disease.

Concerning to the disadvantages, 31% of the respondents did not reported any disadvantage in anticipating the diagnosis of some diseases. On the other hand, 28% of them were concerned about a possible misuse of the obtained information: “Starting from the disadvantages, many have said on prejudice against people with genes predisposing to heart diseases or anomalies, so that they would undergo discrimination if this is reported, in relation to their jobs and the decision of parents whether a child should or should not be born”. The concern on the misuse of the information from the advancement of molecular genetics is not recent. The ethical problems presented by the great development of molecular genetics and genetic therapy are already beginning [3]. The ethically correct study, treatment and solution are demands that challenge the mankind and should be assured since its beginning [3]. The advancement of molecular genetics also creates ethical fields for deciding on the application of the study outcomes, and which practical purposes of the outcomes can be used [8].

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Therefore, corroborating other authors [10], this present study is an alert, because greater concern on reporting this knowledge should exist inside the schools, so that oral health professionals are graduated, especially dentists, able to understand and apply these new knowledge.

Conclusion

In t he present study, underg raduates demonstrated superficial knowledge on Human Genome Project. This issue is not largely discussed on the Dentistry Course, because the media was the main source of information reported.

References

1. Behnke AR, Hassell TM. Need for genetics education in U.S. Dental and Dental Hygiene Programs. J Dent Educ. 2004;68:819-22.

2. Bueno MRP. O Projeto Genoma Humano. Rev Bioét. 1997;5:145-55.

3. Clotet J. Bioética como ética aplicada e genética. Rev Bioét. 1997;5:173-83.

4. Dudlicek LI, Gettig EA, Etzel KR, Hart TC. Status of genetics education in U.S. Dental Schools. J Dent Educ. 2004;68:809-18.

5. Gettig E, Hart TC. Genetics in Dental Practice: social and ethical issues surrounding genetic testing. J Dent Educ. 2003;67:549-62.

6. International Human Genome Sequencing Consortium. International Consortium Completes Human Genome Project [serial online]. 2003 [cited 2010 May 5]. Available from: URL:http://www.genome.wi.mit.edu/media/2003/pr_03_humangenome.html.

7. Leite M. Biotecnologias, clones e quimeras sob controle social: missão urgente para a divulgação científica. São Paulo Perspec. 2000;14(3):40-6.

8. Pessoa OF. Fronteiras do biopoder [serial online]. 1997 [cited 2010 May 5]. Available from: URL:http://www.portalmedico.org.br/revista/bio2v5/fronteirasbiopoder.htm.

9. Sganzerla LCM, Corazza-Nunes MJ, Nunes WMC, Tomanik EA. Preparados ou não para o futuro? Atitudes de alunos de graduação em relação ao Projeto Genoma Humano. Acta Scient Biol Scienc. 2004;26:239-50.

10. Slavkin HC. The human genome, implications for oral health and diseases, and dental education. J Dent Educ. 2001;65:463-79.

11. Wright JT, Hart TC. The Genome Projects: implications for dental practice and education. J Dent Educ. 2002;66:659-71.


Comparative analysis of four cleaning methods of endodontic files

Bárbara Guandalini¹Ivana Vendramini¹Denise Piotto Leonardi1

Flávia Sens Fagundes Tomazinho1

Paulo Henrique Tomazinho1

Corresponding author:Paulo Henrique TomazinhoDepartamento de Odontologia, Universidade PositivoRua Professor Pedro Viriato Parigot de Souza, n. 5.300 – Campo CompridoCEP 81280-330 – Curitiba – PR – BrasilE-mail: [email protected]

1 Department of Dentistry, Positivo University – Curitiba – PR – Brazil.


Keywords: biosafety; Endodontics; cleaning method.


Abstract

Introduction: Due to the size and design of endodontic files, these instruments have been considered one of the most difficult to clean among all dental instruments. The debris maintenance within the sulcus prevents the effective sterilization and may compromise the disinfection of root canal systems in endodontic therapy. However, there is neither a method nor technique that standardized the cleaning of these instruments. Objective: To evaluate the cleaning ability of four techniques used in dentistry. Material and methods: For this purpose, 30 new size #40 Flexofile were used for the preparation of the canals of mandibular molars of pigs. After instrumentation, the contamination and the presence of debris in the sulcus was confirmed and the files were randomly divided into four groups: control group (without cleaning), group 1 (enzymatic detergent + manual brushing with nylon bristle brush), group 2 (ultrasound + enzymatic detergent), group 3 (ultrasound + water) and group 4 (gauze embedded in 70% alcohol). Next, all files were photographed and photographs were printed at high quality. The spirals containing debris were counted. Results: Manual cleaning with enzymatic detergent and nylon bristle brush, ultrasound with either water or detergent showed

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Guandaliniet al.–Comparative analysis of four cleaning methods of endodontic filesComparativeanalysisoffourcleaningmethodsofendodonticfiles

Introduction

The endodontic files are composed with stainless steel or nickel-titanium and display their active point with different cross-sectional designs, forming their spirals [6]. They have been considered as critical instruments because they penetrate within subepithelial tissues, reaching the vascular system [7]. The action of the file is to scratch the root canal walls to detach dentin portions and remove it towards outside the canals. Accordingly, debris are left along their spirals. Because of the design, presenting angles between the spirals and the long axis of the files, the authors report great difficulty in the cleaning of these instruments [13, 21].

The lack of standardization of the cleaning methods of the endodont ic f i les results in many controversies related to the most effective decontamination protocol, thus raising great interest in this subject [13]. Queiroz [15] emphasized that cleaning techniques aiming at eliminating the debris within the file spirals must be used to prevent the disinfection and sterilization process. On the other hand, Sousa [19] conducted a comparative study on four cleaning methods. The author evaluated the cleaning through dry gauze, flask with sponge, and flask with gauze. The most effective method was the sponge. Figueiredo and Sydney [4] evaluated five techniques: tap water, brush and soap; ultrasound and brushing; brushing and ultrasound; and only ultrasound. They found that although all methods presented debris, the most satisfactory results were found in the group in which ultrasound was used followed by brushing. Manual washing was the least effective technique. Reiss-Araújo et al. [16] evaluated the cleaning technique of endodontic files applied by undergraduates. The students were divided into three groups: 1) cleaning by the method adopted by the dental school (non standardized), 2) cleaning with ultrasound, brushing, and soap and 3) none cleaning technique of endodontic files. After the photomicrographic analysis with stereomicroscopy, the authors concluded that ultrasound was the

most effective technique and the cleaning protocol adopted by the dental school was ineffective for a correct sterilization of the instruments

The maintenance of the aseptic chain is essential for a favorable prognosis in endodontic treatment. To reach endodontic success, one ought to clearly comprehend not only the root canal morphology, but also its variations [18]. If an endodontic file exhibits debris within its spirals, even after sterilization, it may carry the remnants towards inside root canal. This debris may create a protection barrier for microorganisms. Endodontic files autoclaved with organic matter within the spirals may jeopardize the sterilization process because the organic matter protect the microorganism against unsaturated steam and prevent thermocoagulation of the microbial structures accounting for cellular death and the instrument sterilization. The presence of organic matter and residues in endodontic instruments may lead to cross-contamination and, consequently, treatment failure [11].

Because most of endodontists reuse the endodontic files, their cleaning and sterilization is mandatory for treatment success.

The aim of this study was to evaluate different cleaning methods of endodontic files through the analysis of debris by visual method of enlarged photographs.


The sample was composed by 30 new size #40 endodontic files (Maillefer, Ballaigues, Switzerland). Root canal instrumentation was performed in porcine molars in dissected fresh pig. The apparent tooth length was determined with the aid of radiographs. Each file was used to prepare only one canal by using ten repetitive ¼ turn clockwise movements against the root canal walls.

After the instrumentation of each root canal, the files were randomly divided into four groups (n = 6): control (no treatment), group 1 (enzymatic

the best cleaning capacity in which respectively 100%, 98.9% and 96.2%, of the spirals were free of debris. Cleaning with alcohol and gauze proved to be ineffective, showing debris in more than 40% of the spirals by visual analysis. In control group, 91% of the spirals presented debris. It can be concluded that the association between manual and ultrasound cleaning may be promising in ensuring a cleaning protocol for endodontic files cleaning.

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detergent + manual brushing), group 2 (ultrasound + enzymatic detergent), group 3 (ultrasound + water) and group 4 (gauze with alcohol).

Following the use of control group files, they were not submitted to any cleaning process. Then, they were individually stored in test tubes with screw cap, properly identified.

Group 1 files (enzymatic detergent + manual brushing), after their use, were immersed in a flask containing enzymatic detergent (Riozyme, Rioquimica, São José do Rio Preto, Brazil), diluted in water for 5 minutes, according to the manufacturer’s recommendations. Twenty instruments (tweezers, explores, mirrors, curettes, glass plates etc.), all purposefully contaminated with debris from the porcine mandibles, were put together with the endodontic files so that the brushing and cleaning of the files were not evidenced. All instruments were washed by soft nylon bristle brushes under continue flow and dried with air jet. The files were stored in test tubes with screw cap, properly identified. The washing of both the files and instruments were executed by a volunteer who did not know the aims of the research.

After the use, the group 2 files (ultrasound + enzymatic detergent) were placed in ultrasound device (Cristófoli, Campo Mourão, Brazil) with water and enzymatic detergent, for five minutes according to the manufacturer’s recommendations. Elapsed this period, the files were washed under continuous water flow, dried with air jet and stored in a test tube with screw cap, properly identified.

Group 3 files (ultrasound + water) after use were put in the ultrasound device with water for five minutes according the manufacturer’s recommendations. Elapsed this period, they were washed in continuous water flow dried with air jet and stored in a test tube with screw cap, properly identified.

After the use, group 4 files (gauze with alcohol) were cleaned with gauze embedded with 70% alcohol by three repetitions of the cleaning movement (apprehend the active part of the file with the gauze and pull it), followed by air jet and stored in test tube with screw cap, properly identified.

All stored files were taken to the Microbiology Laboratory of the Positive University, where photographs were taken by digital camera (Nikon D90, Nikon, Tokyo, Japan) with 100 mm macro lens (Sigma, Rödermark, Germany) and round flash (Nikon, Tokyo, Japan). The photographs were printed at color high definition (HP LaserJet 1020, Hewlett Packard, Palo Alto, USA), on size A4 photographic paper. The results were evaluated through visual analysis of the amplified photographs of the endodontic files by counting the spiral presenting either debris or organic matter.

Results

The results of the count of either the inorganic debris or organic matter are displayed in table I.

Table I–Cleaningtype,numberofdirtyspirals(DS)andtotalnumber(TN)ofspiralsanalyzedpergroup,percentageofdirtyspirals(%DS)andpercentageofcleanspirals(%CS),pergroups

DS / DT %DS %CL

Control 164/180 91.1% 8.9%

Group 1 0/180 0 100%

Group 2 7/180 3.8% 96.2%

Group 3 2/180 1.1% 98.9%

Group 4 76/180 42.2% 57.8%

Discussion

Many studies reported on the important role of the cleaning of endodontic files before, during and after their use [2, 4, 8, 9, 12, 14, 17]. All these stages assure the proper sterilization, so that endodontic files can be safely reused, contributing for endodontic success. Some authors defend the

exclusively manual cleaning [2, 14]; others claimed that the debris within the files are cleaned by ultrasound [3, 9, 12] while other emphasized the use of both techniques, that is, the use of ultrasound associated with manual cleaning [4, 8, 17].

Evidences have supported that endodontic files are difficult to clean and can carry significant remnants after their washing [5]. The sterilization

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process comprises the destruction or removal of all life forms within a material and it is the most important step of infection control. A partial sterilized instrument does not exist; the instrument is or is not sterilized. However, it should be emphasized that the sterilization effectiveness depends on the previous preparation of the instrument. These preparations have been divided into pre-washing, washing, drying, storage and sterilization [7].

The aim of this present study was to conduct a comparative study on four cleaning methods of endodontic files, to evaluate the cleaning effectiveness of these methods regarding to the presence or absence of visible debris in the file spirals. For this purpose, porcine teeth were used to mimic the instrumentation of root canals, aiming to the debris retention (organic matter or inorganic debris) on the file spirals. This experimental model was very effective in retaining debris on the file spirals and should be considered as an option for further studies with similar aims.

Linsuwanont et al. [10] proposed a methodology for the cleaning of rotary nickel-titanium instruments by associating moist storage, brushing followed by immersion in 1% sodium hypochlorite. The authors affirmed that by using this technique, 100% of the file spirals were cleaned and free of debris. On the other hand, Reiss-Araújo et al. [16] alert that the manual cleaning itself is subject to human error, such as omission or failure in cleaning itself. The authors still emphasized that nylon bristles did not penetrate in the angle formed by the spirals and body of most of the endodontic files. Aasim et al. [1] defended the use of automatized cleaning such as the ultrasound device especially for instruments difficult to clean, as endodontic files. The results of this present study showed that manual cleaning was capable of removing 100% of the debris within the file spirals through visual analysis. Ultrasound associated with either enzymatic detergent or water alone cleaned 96.2% and 98.9% of the spirals, respectively. These results evidenced the excellent cleaning capacity of the ultrasonic mechanical action promotion on these instruments, corroborating previous studies [1, 3, 9, 12].

By empirically observation, we noted that the undergraduates of Positivo University cleaned the endodontic files with gauze and 70% alcohol. This observation justified the inclusion of this method in this present study (group 4). In group 4, after the analysis of the enlarged photographs, it was observed that 40% of the spirals remained dirty with debris or organic matter from the pulp tissues of porcine teeth. Although some authors [9, 19, 20]

affirmed that regardless of the cleaning technique the sterilization process is effective, this assumption is denied by other studies [13] discussing the necessity of the cleaning and reduction of the debris and microorganism amount on the instrument surface to improve the effectiveness of the sterilization process.

Aasim et al. [1] showed that the ultrasound is able to remove all debris of the instruments during an interval from 5 to 10 minutes and did not observed changes in the action time longer than 10 minutes to a maximum of one hour. On the other hand, according to the result of this present study, spirals with debris were seen even in the groups submitted to ultrasonic cleaning. Accordingly, it seems licit to propose the following protocol: initial manual cleaning followed by ultrasound with or without enzymatic detergent. Thus, we associated the advantage of the debris removal by manual cleaning with the cleaning capacity of ultrasound, which can reach sites where manual cleaning did not act, such as the angles formed between the spiral and the body of the instrument.

This study drew attention for a process many times neglected during clinical endodontic practice – the cleaning steps previous to sterilization.

Despite of the limitations of this study, such as the microscopic analysis through either optical or electronic microscope; and the absence of microbiological test which could have evidenced a grater or smaller microbiological contamination previous and/or after the sterilization process, it was observed the viability of the use of porcine teeth in this study type because a condition similar to that of human teeth was found, that is, the presence of pulp tissue and dentine debris within the spirals of the endodontic files.

Conclusion

The manual cleaning of endodontic files with enzymatic detergents and nylon bristle brush was effective in cleaning the debris within file spirals through visual analysis. It is suggested a protocol comprising the manual cleaning followed by ultrasound for these instruments.

References

1. Aasim SA, Mellor AC, Qualtrough AJE. The effectThe effect of pre-soaking and time in the ultrasonic cleaner on the cleanliness of sterilized endodontic files. IntInt Endod J. 2006;39:143-9.

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2. Alvarez S. Endodontia clínica. 2. ed. São Paulo: Santos; 1991.

3. Deus QD. Endodontia. 5. ed. Rio de Janeiro: Medsi; 1992.

4. Figueiredo JAP, Sydney GB. Eficácia das técnicas de limpeza de instrumentais endodônticos retentivos. Rev Paranaense Odontol. 1997;2(2):Rev Paranaense Odontol. 1997;2(2): 1-12.

5. Gill DS, Tredwin CJ, Gill SK, Ironside JW. The transmissible spongiform encephalopathies (prion diseases): a review for dental surgeons. Int DentInt Dent J. 2001;51:439-46.

6. Goldberg F, Soares J. Endodontia – técnicas e fundamentos. 2. ed. Porto Alegre: Artmed; 2011.

7. Guandalini SL, Melo NSF, Santos ECP. Biossegurança em Odontologia. 2. ed. Curitiba; 1999.

8. Haïkel Y, Serfaty R, Bleicher P, Lwin TT, Allemann C. Effects of cleaning, disinfection, and sterilization procedures on the cutting efficiency of endodontic files. J Endod. 1996;22(12):657-61.J Endod. 1996;22(12):657-61.

9. Ingle JI, Taintor JF. Endodontia. Rio de Janeiro: Guanabara Koogan; 1989. 730 p.730 p.

10. Linsuwanont P, Parashos P, Messer HH. Cleaning of rotary nickel-titanium endodontic instruments. Int Endod J. 2004;37:19-28.

11. Miller CH. Sterilization: disciplined microbial control. Dent Clin Noorth Am. 1991;35(2):339-55.

12. Murgel CAF, Walton RE, Rittman B, Johnson AA. A comparison techniques for cleaning endodontic files after usage: a quantitative scanning electron microscope study. J Endod. 1990;16(5):214-7.J Endod. 1990;16(5):214-7.

13. Oliveira EPM, Filippini HF, Troian HC, Melo TAF. Análise das condições de esterilidade das limas endodônticas utilizadas pelos alunos de graduação nos três cursos de Odontologia da ULBRA/RS. Stomatos. 2006;12(23):35-40.

14. Paiva JG, Antoniazzi JH. Endodontia: bases para prática clínica. São Paulo: Artes Médicas; 1988. p. 463-80.

15. Queiroz MLP. Avaliação comparativa de eficiência de diferentes técnicas empregadas na limpeza de limas endodônticas. Canoas. Mestrado [Dissertação] – Universidade Luterana do Brasil; 2001.

16. Reiss-Araújo CJ, Araújo SS, Albuquerque DS, Rios MA, Portella ML. Limpeza em limas endodônticas pós-uso e pré-esterilização. RGO. 2008;56(1):17-20.

17. Rossetini SMO. Contágio no consultório odontológico: como entender e prevenir. São Paulo: Santos; 1985. p. 72-89.

18. Simşek N, Keleş A, Bulut ET. ��u�u�l ��tUnusual root canal morphology of the maxillary second molar: a case report. Case Rep Dent. 2013;2013.Case Rep Dent. 2013;2013.

19. Sousa SMG. Análise comparativa de quatro métodos de limpeza de limas endodônticas durante o transoperatório: estudo pela microscopia eletrônica de varredura. Bauru. Dissertação [Mestrado] – Universidade de São Paulo; 1994.

20. Viegas APK. A importância da limpeza de limas endodônticas contaminadas no processo de esterilização. Canoas. Dissertação [Mestrado] – Universidade Luterana do Brasil; 2005.

21. Weine FS. Tratamento endodôntico. 5. ed. São Paulo: Santos; 1998.


Evaluation of oral hygiene index, monitoring and oral hygiene instruction in visually impaired people

Jackyeli Windmuller¹Rafaela Araujo Mendes1

Sheila de Carvalho Stroppa1

Juliana Yassue Barbosa da Silva1

Corresponding author: Juliana Yassue Barbosa da Silva Universidade PositivoRua Professor Pedro Viriato Parigot de Souza, n. 5.300 – Campo CompridoCEP 81280-330 – Curitiba – PR – BrasilE-mail: [email protected]

¹ School of Dentistry, Positivo University – Curitiba – PR – Brazil.


Keywords: oraloral hygiene index; visually impaired people; Dentistry.


Abstract

Introduction: Eyesight can be considered a major human interaction promoter in motor, perceptual and mental activities and its loss can cause social environment changes. Objective: To evaluate and determine Simplified Oral Hygiene Index (OHI-S) in visually impaired individuals, as well as to provide information to promote oral health, to verify the effectiveness of educational activities for index change and to promote the social inclusion of visually impaired people. Material and methods: Study population was constituted by 28 visually impaired people of both genders, aged from 14 to 75 years old, residents and students at the Parana Institute for the Blind (IPC), Curitiba (PR, Brazil). The study was conducted in three stages. At first, the participants individually answered a questionnaire, performed tooth brushing and then the disclosure of oral biofilm was made, as well as the evaluation of Simplified Oral Hygiene Index, oral hygiene instruction and supervised toothbrushing. The second step was performed after seven days and the third after thirty days to reassess the Simplified Oral Hygiene Index to check whether there would a change in their values. Participants were divided into two groups according to Simplified Oral Hygiene Index: those who had only bacterial plaque and those who had

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Windmulleret al.–Evaluation of oral hygiene index, monitoring and oral hygiene instruction in visually impaired peopleEvaluationoforalhygieneindex,monitoringandoralhygieneinstructioninvisuallyimpairedpeople

plaque and calculus. Results: At the first day, patients with plaque and calculus had initial OHI-S mean of 2.3 (regular), 2.1 (regular) after seven days, and 2.4 (regular) after one month. Patients with only plaque at the first day had an average OHI-S of 0.71 (regular), 0.74 (regular) after seven days, and 0.78 (regular) after one month. Conclusion: Within this context, it is possible to understand that it is necessary to implement frequent supervised toothbrushing, oral instruction and motivation activities to promote wellness and health for these patients.

Introduction

According the last research conducted by the Brazilian Institute of Geography and Statistics (IBGE), proved by the Brazilian Census of 2010, visual impairment is the most frequent impairment among all types reaching the Brazilian population. Currently, in Brazil, 18.8% of population had visual impairment [5].

Although the number of visual impaired people is representative of Brazilian population few studies in literature have evaluated the oral health quality in this individual group. Gradually, this situation has been changing through professionals aiming to include these individuals within the society, inserting them in programs of health attention and creating a differentiated service according to the difficulties of each person [6].

A visually impaired person needs a health professional licensed to stimulate the other sensory senses, such as touch, taste and hearing, so that the communication between the professional and patient is positive and the patient does not exhibit social relationship difficulties [3, 11].

Dental care oriented to individuals with special needs, particularly those with visual impairments, is still precarious in Brazil. Visually impaired people have shown oral health problems foreshadowed by factors as lack of motivation, difficult of proper toothbrushing for plaque control and scarce professional guidance turned to this population type [9].

To achieve treatment success and routinely proper oral hygiene, precaution in the instruction, perseverance in teaching the techniques, and the project of health promotion directed to the blind patient, should be accomplished in a controlled manner by the caregivers and/or relatives in addition to the patient’s compliance [1, 3, 6, 14].

Both the compliance and motivation of the patients are indispensable to achieve significant improvement in oral health. Moreover, the dental professional is essential in oral health promotion, providing oral health improvement and quality

of life. Therefore, currently, the Dentistry leaves curative profile and comes towards preventive profile [7, 9].

The Brazilian federal laws no. 10.048, from November 8 of 2000, and no. 10.098, from December 19 of 2000, which establish general guidelines and basic criteria for accessibility promotion for people with disabilities or reduced mobility, claims that visual impairment is considered blindness when visual accuracy is equal or smaller than 0.05º (degrees) at the best eye, with the best optical correction. On the other hand, is considered as poor eyesight when the visual accuracy is between 0.3º and 0.05º at the best eye with the best optical correction [4].

According to the study of Cericato and Fernandes [7], people with poor neuropsychomotor capacity difficultly accept that other people help them in performing oral hygiene, and many times, they are not capable of performing all by themselves. It was also verified that the visual impaired person presents oral hygiene impairment causing some problems in tooth dentition and tooth loss. By starting the treatment at childhood, with proper and specialized treatment, the visual impaired person can perform her/himself hygiene and take care of her/himself oral health. Notwithstanding, it is known that prevention of both caries and periodontal disorders are toothbrushing and oral hygiene performed by the visual impaired individual. Thus, it can be concluded that the most effective technique for removing plaque and preventing oral diseases is proper toothbrushing and flossing [9].

In this context, the aim of this pilot study was to assess the Simplified Oral Hygiene Index (OHI-S) and promote oral health educative activities as oral hygiene instruction and individually supervised toothbrushing in a group of visual impaired people for further verifying the effectiveness of these educative activities to change OHI-S. Moreover, the study also aimed to promote the social inclusion of the visual impaired individual not only by reeducation but also providing wellness and health.

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Twenty-eight individuals of both genders, with visually impairment or poor eyesight, residents and/or enrolled at the Parana Institute for the Blind (IPC) participated in this pilot research. This institute is civil society organization located at Curitiba, Paraná, Brazil, created in 1939, which elaborated and develops its actions aiming at contributing with the social formation of blind and poor sight people.

The individuals received instruction about the research by reading aloud the Free and Clarified Consent Form. This term was signed by either the signature or fingerprint of each person who voluntarily accepted to participate in the study. Additionally, a person without visual impairment witnessed the reading of the term to assure that the read content matched that written within the document.

This study was conducted at three stages. At the first stage, the participants were invited to answer a questionnaire comprising questions on general and oral health and on habits such as smoking, oral health routine, previous dental treatments, among others. Because of the special characteristics of this study population, the questionnaire was individually applied by the responsible researchers integrally reading the questions and options and after recording the response reported by the subject. Next, the person performed toothbrushing with 1.500 ppm (parts per million) fluoride toothpaste and toothbrush with small head and soft bristles provided by the researches. Posteriorly, the disclosure of the biofilm was accomplished with the aid of disclosing solution and cotton swabs. Then, OHI-S was assessed [10]. This index was measured through numbers from degree 0 to degree 3, as follows: degree 0 – absence of plaque or calculus; degree 1 – presence of plaque or calculus on up to 1/3 of tooth surface, degree 2 – presence of plaque or calculus on up to 2/3 of tooth surface; and degree 3 – presence of plaque or calculus on more than 2/3 of tooth surface. The qualitative criteria of this index range from 0 to 6 when debris and calculus sum can be classified as: excellent (0.0), good (0.1-1.2), regular (1.3-3.0) and weak (3.1-6.0). When only the bacterial plaque sum is counted, the classification is as follows: good (0.0 to 0.6), regular (0.7 to 1.8) and poor (1.9 to 3.0). Then, each patient was instructed to perform oral hygiene and supervised toothbrushing was carried out.

According to Rovida et al. [12], plaque indexes are useful and important for clinical evaluation of biofilm, both in researches for evaluation of products and in dental clinics, for monitoring

patients, and for activities of hygiene instruction and toothbrushing techniques.

The second stage of the study was performed seven days after the first, after the oral hygiene instruction and OHI-S was again evaluated and analyzed whether there is or there is not an improvement in the index value.

The third stage was executed 30 days after the first one, and OHI-S was again evaluated to verify whether it changed. Bass modified toothbrushing technique was used for instructing the patients and further modifications could be executed because of the motor impairments of each patient.

Data regarding to gender, age, OHI-S values were recorded and tabulated in Microsoft Office Excel 2007 software, for posterior descriptive analysis.

This present study was submitted and approved by the Ethical Committee in Research of Positivo University under protocol number 269.928/2013.

Results

Table I displays the distribution of demographic data related to oral hygiene and care habits of the participants in absolute (N) and percentage (%) numbers.

Of the 28 individuals, 57% (16) were female and 43% (12) male. The age ranged from 14 to 75 years-old, with mean of 36.5 years. Twelve (43%) patients attended the institute at afternoon, nine (32.1%) lived at IPC, three stayed all day (10.7%), two attended at morning (7.1%), while the attendance frequency of two patients (7.1%) varied according to the week day.

Twenty-one patients were white (75%), six were brown (21.5%) and one was black (3.5%1).

Concerning to education level, 60.7% (17) had incomplete primary school, 14.3% (4) complete secondary school, 14.3% (4) incomplete secondary school, 7.1% (2) incomplete higher education and 3.6% (1) complete primary school. With regard to the family income, the values ranged from R$ 678.00 to R$ 3,000.00, with mean income of R$ 1,115.85.

Of all participants, 96.5% (27) reported to be submitted to dental treatment and only 3.5% (1) did not undergo any treatment. Concerning to the last dental treatment, 59.5% (16) reported it was within the past last year, 18.5% (5) from 1 to 2 years, 18.5% (5) from 2 to 5 years and 3.7% (1) from 5 to 10 years.

By asking about oral hygiene instruction, 96.5% (27) of the patients answered that they had already received some type of instruction, while

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3.5% (1) never had been instructed. Of these, 96.5% affirmed that they had received instruction, 44.5% (12) claimed the instruction was given by a dentist, 33.3% (9) by a relative, 7.4% (2) by an employee of the institute, 3.7% (1) by other oral health professional, 7.4% (2) by other people and 3.7% (1) ignored the question.

Toothbrushing frequency was also questioned and the following results were observed: 46.4% (13) reported to brush three times per day, 21.4% (6) twice per day, 17.9% (5) four times or more per day and 14.3% (4) brushed only once per day.

With regard to flossing habits, 71.4% (20) of the patients reported that they did not floss, 14.3% (4) reported flossing once a day, 10.8% (3) three times per day and 3.5% (1) reported flossing twice per day.

Concerning to mouthrinses, 92.8% (26) did not use, 3.6% (1) had used fluoride mouthrinses once per day and 3.6% (1) did not know which solution, although they used it four times per day.

Twenty patients (75%) reported they did not present any gingival bleeding, six (21.4%) reported gingival bleeding occur during sometimes they performed toothbrushing and one (3.6%) did not know to answer.

Of all the participants, 78.6% (22) did not smoke and 21.4% (6) smoked. Of these latter, 33.3% (2) smoked from 1 to 5 cigarettes per day, 33.3% (2) from 11 to 20 cigarettes per day, 16.7% (1) smoked from 6 to 10 per day and 16.7% (1) answered to smoke only one cigarette per day.

Table I – Demographic data and data related to oralhygieneandcareoftheparticipantsstudied(N=28)

Variables n* %*Gender

MaleFemale

1216

4357

RaceWhiteBrownBlack

2161

7521.53.5

EducationIncomplete primary education Complete primary educationComplete secondary educationIncomplete secondary educationIncomplete higher education

171442

60.73.614.314.37.1

IncomeUp to 1 minimum wageFrom 2 to 3 minimum wagesMore than 3 minimum wages

13132

46.446.47.2

Attendance frequency at IPCMorningAfternoonAll dayLiveDepending on week day

212392

7.143

10.732.17.1

Time attending at IPCUp to 2 yearsFrom 2 to 5 yearsFrom 5 to 10 yearsMore than 10 years

67510

21.525

17.835.7

Dental treatmentUnderwentDid not undergo

271

96.53.5

Last dental treatmentLess than 1 yearFrom 1 to 2 yearsFrom 2 to 5 yearsFrom 5 to 10 years

165 51

59.318.518.53.7

Oral hygiene instructionHave already received Never received

271

96.53.5

Who instructed on oral hygiene DentistRelativeEmployee of IPCOther oral health professional OthersIgnored the question

1292121

44.533.37.43.77.43.7

Toothbrushing habits4 times or more3 times per daytwice per dayonce per day

51364

17.946.421.414.3

Flossing habitsDid not use Did use

208

71.428.6

Gingival bleedingWithout bleedingOnly during toothbrushingDid not know to answer

2161

7521.43.6

SmokerYesNo

622

21.478.6

How many cigarettes smoked per day

Only 1From 1 to 5From 6 to 10From 11 to 20

1212

16.733.316.733.3

* Absolute and relative frequencies based on valid observations

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With regard to OHI-S, the mean values found at the first day before the educative activities was of 2.3, classified as regular, for the five participants evaluated with plaque and calculus index. For the 23 individuals presenting only plaque, the mean index value was of 0.71, classified as regular. Of the five participants classified with plaque and calculus index, 20% (1) showed good OHI-S, 60% (3) regular and 20% (1) weak. Of the 23 patients classified with only plaque index, 60.9% (14) exhibited good OHI-S, while 34.8% (8) showed regular OHI-S, and 4.3% (1) poor OHI-S. After the oral hygiene instruction and supervised toothbrushing, seven days after initial index evaluation, the mean was of 2.1 for plaque and calculus, classified as regular, and of 0.74 for only plaque, classified as regular. Of the five participants classified with plaque and calculus index at that period, 20% (1) showed good OHI-S, 60% (3) regular and 20% (1) weak. Of the 23 patients classified with only plaque index, 52.2% (12) exhibited good OHI-S and 47.8% (11) regular. And 30 days after the initial appointment and oral hygiene instruction, the mean of plaque and calculus index was of 2.4, classified as regular, and 0.78 for only plaque, classified as regular. Of the five participants classified with plaque and calculus index, 60% (3) showed regular OHI-S and 40% (2) weak. Of the 23 patients classified with only plaque index, 43.5% (10) exhibited good OHI-S, 52.2% (12) regular and 4.3% (1) poor.

In table II, individual OHI-S at the first, seventh and thirtieth days can be verified for the group presenting calculus and plaque. Table III displays the same index values for the group exhibiting only plaque.

Table II–OHI-Sforeachparticipantpresentingplaqueandcalculusat thefirst,seventh,andthirtiethdays(N=5)

Participant OHI-S 1 OHI-S 2 OHI-S 3

1 4 4 4

8 3 2.3 3.3

14 2.3 2.1 2.1

17 1.1 0.8 1.6

18 1.3 1.5 1.3

Table III–foreachparticipantpresentingonlyplaqueatthefirst,seventh,andthirtieth(N=23)

Participant OHI -S 1 -S 1 OHI -S 2 -S 2 OHI -S 3 -S 3

2 1.1 1.3 1

3 0.3 0.8 0.8

4 0.8 0.6 1

5 1.5 1.6 0.6

6 0.3 0.6 1.6

7 2.6 1.8 2.1

9 1.5 1.2 1.2

10 0.7 1.6 1.4

11 0 0 1

12 0.4 0.4 0.2

13 1 0.8 0.5

15 0.6 1.3 1

16 0.6 0.8 1.1

19 0.5 1.1 0.6

20 0 0 0.1

21 0 0 0

22 1.2 1 1.2

23 0.6 0.5 0.3

24 0.3 0 0

25 0.5 0.1 0.8

26 0.5 0.3 0.1

27 0 0.3 0.1

28 1 0.6 1.1

Graph 1 demonstrated the mean OHI-S at the first, seventh and thirtieth days, both for the participants exhibiting only plaque and those presenting plaque and calculus.

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Graph 1–OHI-Smeanforparticipantspresentingplaqueandcalculusandthoseexhibitingonlyplaqueatthefirst,seventh,andthirtiethdays(N=28)

Discussion

This study showed that 96.5% (27) of the participants had been submitted to some type of dental treatment. This result was similar to that of the study of Souza Filho et al. [13]. In the study of[13]. In the study ofIn the study of these authors, of 42 visual impaired participants, 95.2% (40) had already searched the dentist.

The toothbrushing of the individuals were evaluated through OHI-S from Green and Vermillion [10]. At the first day, previously to oral hygiene instruction, the mean OHI-S for the five individuals showing plaque and calculus was of 2.3, classified as regular. After the instructions regarding to oral hygiene and supervised toothbrushing, they exhibited a discreet improvement in OHI-S mean, which decreased for 2.1, but still classified as regular. However, after a period of 30 days, mean OHI-S increased for 2.4, yet still classified as regular.

For the 23 participants showing only plaque, mean OHI-S at the first appointment was of 0.71, classified as regular. An increase of this mean OHI-S value was observed after seven days, with value of 0.74, still classified as regular. Notwithstanding, after 30 days, OHI -S was maintained as regular, because it exhibited a mean value of 0.78.

In this present study, of the 23 individuals showing plaque, 60.9% (14) had a good OHI-S, 34.8% (8) regular and 4.3% (1) poor. After seven days, 52.2% (12) exhibited good OHI-S and 47.8% (11) regular. And after 30 days, 43.5% (10) presented good OHI-S, 52.2% (12) regular and 4.3% (1) poor, demonstrating a decreasing of the number of participants having

good OHI-S and increasing of those having regular OHI-S. Different values were found in the study of Cericato and Fernandes [7], in which 64.58% of the participants exhibited an inadequate toothbrushing and 35.42% showed adequate toothbrushing according to plaque control index.

In the study of Cericato and Lamha [8], 20.83% of the individuals performed toothbrushing twice a day and 70.83% more than twice a day, in agreement with this present research, which verified that 21.4% of the participants brushed their teeth twice a day and 64.3% three times or more per day.

Concerning the use of mouthrinses, 3.6% of these study participants reported they used fluoride mouthrinses, a value lower than that found by Cericato and Lamha (16.67%) [8].

According the results of the study of Cericato and Fernandes [7], it was verified that 33.33% had never received adequate oral hygiene instruction, 39.59% were instructed by a dentist, 16.67% by relatives and only 10.42% by the professor of the institution. These data disagrees from those of this present study: 44.5% were instructed by the dentist, 33.3% by a relative, 7.4% by an employee of the institution, 7.4% by others, 3.7% by other oral health professionals and 3,7% ignored the question.

Because patients with special needs have some limitations, they sometimes would be not capable of performing their own hygiene or they execute it inadequately, and the parents/guardians not only are concerned about oral health [2].

Although this present study did not evaluate oral health self-perception, it was noted that

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the participants living at the institution had a neglected oral hygiene self-perception. Unlikely, the participants studying at the same institution showed a more accurate self-perception, probably because the closest monitoring by the family, professor, and health professionals.

Considering the lack of scientific studies on this population of the Parana state, especially in the city of Curitiba, it is possible to use the results obtained in this present study to support further studies and stimulate the formulation of new public policies aiming to improve the instruction, stimulus, and consciousness of these patients regarding to oral health care, enabling the dentist to understand the universe of visually impaired people.

Conclusion

Based on the results obtained, it was possible to conclude that although OHI-S had shown a small reduction in the group presenting calculus and bacterial plaque seven days after oral hygiene instruction, the index value worsened after 30 days. In the group displaying only plaque, mean OHI-S value increased after seven and 30 days. It is worth emphasizing the necessity of promoting frequent activities of supervised toothbrushing, oral health instruction and motivation, providing wellness and health for visual impaired population.

Moreover, it is necessary to reconsider the State model that is capable of giving responses for the society. At a time when globalization is intense, barriers comprising prejudice and exclusion should be broken.

References

1. Abreu KCS, Perin PCP, Nunes NA, Prado VR, Constanzi S. Motivação de higiene bucal em deficientes visuais institucionalizados. Revista da Faculdade de Odontologia de Lins. 2005;17(1): 7-14.

2. Aguiar SMHCA, Barbieri CM, Louzada LPA, Saito TE. Eficiência de um programa para a educação e a motivação da higiene buco-dental direcionado a pacientes excepcionais com deficiência mental e disfunções motoras. Revista Faculdade de Odontologia de Lins. 2000;12(1-2):16-23.

3. Braga EC, Sinatra LS, Carvalho DR, Cruvinel VR, Miranda AF, Montenegro FLB. Intervenção odontológica domiciliar em paciente idoso cego institucionalizado: relato de caso. Revista Paulista de Odontologia. 2011;33(2):17-22.

4. Brasil. Decreto n. 5.296. Regulamenta as leis n. 10.048, de 8 de novembro de 2000, e n. 10.098, de 19 de dezembro de 2000, e dá outras providências. Diário Oficial da União; 2004.

5. Brasil. Ministério do Planejamento, Orçamento e Gestão. Instituto Brasileiro de Geografia e Esta t í s t i ca . Censo Demográ f i co 2010. Características gerais da população, religião, e pessoas com deficiências. Available from: URL:ftp://ftp.ibge.gov.br/Censos/Censo_Demografico_2010/Caracteristicas_Gerais_Religiao_Deficiencia/caracteristicas_religiao_deficiencia.pdf.

6. Carvalho ML, Silva FML, Barbosa FQ, Duarte FB, Barbosa KB, Figueiredo V et al. Deficiente? Quem? Cirurgiões dentistas ou pacientes com necessidades especiais? Revista em Extensão. 2004;4(1):65-71.

7. Cericato GO, Fernandes APS. Implicações da deficiência visual na capacidade de controle de placa bacteriana e na perda dental. Revista da Faculdade de Odontologia. 2008;13(2):17-21.

8. Cericato GO, Lamha APSF. Hábitos de saúde bucal de portadores de deficiência visual no contexto da saúde coletiva. Revista da Faculdade de Odontologia. 2012;17(2):137-44.

9. Costa FS, Neves LB, Bonow MLM, Azevedo MS, Schardosim LR. Efetividade de uma estratégia educacional em saúde bucal aplicada a crianças deficientes visuais. Revista da Faculdade de Odontologia. 2012;17(1):12-7.

10. Green JC, Vermillion JR. The simplified oral hygiene index. J Am Dent Assoc. 1964;68:7-13.

11. Povoa CA, Nicolela MT, Valle ALSL, Gomes LES, Neustein I. Prevalência de glaucoma identificada em campanha de detecção em São Paulo. Arq Bras Oftalmol. 2001;64(4):303-7.

12. Rovida TAS, Moimaz SAS, Arcieri RM, Garbin CAS, Lima DP. Controle da placa bacteriana dentária e suas formas de registro. Revista Odontológica de Araçatuba. 2010;31(2):57-62.

13. Souza Filho MD, Nogueira SDM, Martins MCC. Avaliação da saúde bucal de deficientes visuais em Teresina – PI. Arquivos de Odontologia. 2010;46(2):66-74.

14. Souza IR, Caldas CP. Atendimento domiciliário gerontológico: contribuições para o cuidado do idoso na comunidade. Revista Brasileira de Pesquisa em Saúde. 2008;21(1):61-8.


Bacterial infiltration comparison of two root canal filling techniques

Gislaine Pontarollo1

Raphael Hamerschmitt1

Beatriz Coelho1

Denise Piotto Leonardi1

Flávia Sens Fagundes Tomazinho1

Corresponding author:Flávia Sens Fagundes TomazinhoRua Curupaitis, n. 474 – SeminárioCEP 80310-180 – Curitiba – PR – Brasilemail: [email protected]

¹ School of Dentistry, Positivo University – Curitiba – PR – Brazil.


Abstract

Introduction: Root canal system filling aims to the hermetic sealing of the space formerly occupied by the dental pulp. Objective: The aim of this study was to analyze the bacterial infiltration of Enterococcus faecalis in root canals filled through two techniques: single cone technique (group A) and thermoplasticized gutta-percha technique (group B). Material and methods: A total of 40 single-rooted human premolars were divided into two experimental groups (n = 15) and two control groups: positive (n = 5) and negative (n = 5). The root canals were prepared with ProTaper Universal system up to size F3 file and filled with the corresponding gutta-percha point. Teeth were mounted on a dual-chamber model, where the infiltration of E. faecalis was evaluated for a 30-day period by BHI turbidity indicating bacterial growth. Results: After the trial period all specimens in experimental and positive control groups showed turbidity of the culture medium. The average number of days until culture medium turbidity was 11.42 days for group A, 16.69 days for group B, and 5.5 days for positive control. By applying Anova test, there was no statistically significant difference between groups (p > 0.05). This allowed the observation that no difference between the obturation techniques in the infiltration of E. faecalis could be observed by the methodology used. Conclusion: It can be concluded that regardless of the obturation techniques, bacterial infiltration occurred.

Keywords: Endodontics; root canal obturation; dental leakage.


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Pontarolloet al.–Bacterial infiltration comparison of two root canal filling techniquesBacterialinfiltrationcomparisonoftworootcanalfillingtechniques

Introduction

Endodontic treatment success is linked to the maintenance of the sanitation obtained after root preparation. Root canal obturation must eliminate the empty spaces hindering recontamination [10].

The exposure of the filling material to oral cavity may be one of the causes of endodontic treatment failure. This can occur in different clinical situations, such as the loss of the temporary restoration, fracture of tooth crown, marginal leakage of the definitive restoration and secondary caries, enabling bacterial infiltration throughout the filling material [3].

Although gutta-percha has been not considered as the ideal material, it is the main solid material to fill the root canal system and displays its best performance when associated with the endodontic cement. Root canal filling must comprise a greater gutta-percha amount and the cement should fill root canal irregularities and be the linking between the solid material and the dentinal walls. However, the areas filled by cement are more vulnerable because of the cement solubility [7, 18].

The filling technique may influence on bacterial leakage of root canals. Although most of the researches have accepted gutta-percha, the main discussion is about its utilization way. Techniques have been proposed aiming to decrease the operative time and the material consumption and, of course, improve the characteristics of root canal sealing. Thus, many different filling techniques using gutta-percha have appeared [22, 25].

With the advancement of automatized preparation techniques of root canals, the gutta-percha points taper have matched that of nickel-titanium rotary systems used for root canal preparation, so that, at the moment of the canal filling, only one main gutta-percha point is used per canal, which makes unnecessary the use of accessory points and decrease the filling time [10].

In these cases, according to the manufacturers’ instructions, after the use of shaping instruments, one should employ only the point matching the size of the last instrument used for the apical preparation of root canal, surrounded by cement, because this point have the standardized size exactly matching that of the shaping achieved by instrumentation [5, 21].

Oval-shaped canals or canals presenting morphologies different from those of the current systems tend not to be totally filled by a single gutta-percha point. In these canals, the instruments are not capable of cleaning all root canal areas,

resulting in a round-shaped preparation. Single-cone obturation will allow many spaces filled by cement, compromising the obturation sealing and enabling bacterial infiltration [6, 24].

The sealing by resin cements directly influences on the obturation quality. These cements have exhibited good quality, optimum capacity of bonding to dentin and gutta-percha, low solubility, dimensional stability, radiopacity, low contraction, and good leakage resistance [12, 17].

Considering that the ideal obturation would be the filling of root canal system with the greatest volume of solid material as possible [18], techniques of thermoplasticized gutta-percha have been advocated for root canal obturation because they can provide a more homogenous obturation with better adaptation to root canal walls, resulting in a smaller root leakage infiltration in comparison with lateral condensation technique [2, 13].

The aim of this study was to determine which obturation technique is the most effective in preventing bacterial infiltration by E. faecalis: single-cone or thermoplasticized gutta-percha technique.


This study was approved by the Ethical Committee in Research of Positivo University under protocol no. 028/12.

Forty single-rooted human premolars with straight roots were obtained in the tooth bank of Positivo University and used in this study (Curitiba, Paraná, Brazil).

The 40 teeth were divided into four groups: two experimental groups, each one with 15 teeth; two control groups, positive and control group with five teeth each. The teeth of the experimental and positive control groups were prepared and filled, while those from negative control group remained sound.

The coronal portion of the teeth was cut with the aid of a diamond disc and the length of the roots was standardized at 13 mm.

The roots were instrumented by nickel-titanium rotary instruments (Protaper Universal, Dentsply Maillefer, Ballaigues, Switzerland), following the manufacturer’s recommendations, with working length (WL) set at 12 mm. Prior to the use of the rotary system, root canal negotiation and instrumentation was accomplished with hand stainless steel size #10 and #15 K files at WL. Rotary instrumentation was performed with the aid of electrical motor (X-Smart, Dentsply Maillefer, Ballaigues, Switzerland) at speed of 300 RPM and torque of 1.6N, with the following

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file sequence: sizes S1 and S2 at WL; size SX up to the medium third; final preparation by sizes F1, F2 and F3 at WL. At every instrument change, root canal was irrigated with 2 ml of 2.5% sodium hypochlorite (DanaFarma Farmácia de Manipulação, Curitiba, Brazil).

After the complete preparation, root canal was filled with 17% EDTA (DanaFarma, Paraná, Brazil), for five minutes, aiming to remove the smear layer formed during root canal instrumentation. 17% EDTA was removed by 2.5% sodium hypochlorite. Next, root canals were dried with the aid of size F3 absorbent paper points (Dentsply Maillefer, Rio de Janeiro, Brazil) at working length.

The ex terna l port ion of a l l roots were waterproofed with two layers of nail polishing at 3 mm shorter of the apex, except for the teeth of negative control groups that had all roots waterproofed.

Eighty 1.5 ml Eppendorf tubes were used to achieve a system composed of three parts; an upper chamber, a lower chamber, and the tooth between them (figure 1). This set was sterilized in autoclave at temperature of 121ºC for 20 min.

figure 1 – Double-chamber system used to evaluatebacterialinfiltration.Chamber1containingthebacterialagent,chamber2containingthesterilesubstrateandthetoothinterposedbetweenthem

The teeth of the experimental groups were randomly divided into two groups (n = 15) and then filled by two different techniques. Endodontic

cement was AH Plus (Dentsply, Rio de Janeiro, Brazil). Group A (n = 15) – Protaper system single cone; group B (n = 15) –thermoplasticized Protaper system single cone. Positive control group (n = 5) was filled with size F3 single cone without cement and negative control group (n = 5) used sound teeth.

After root canal obturation, the samples were kept in incubator for 24 hours, at 100% humidity at 37°C, to allow the proper cement setting.

To evaluate the bacterial infiltration, E. faecalis (ATCC 19433) from the American Type Culture Collection was used. The microorganisms were cultivated in 5 ml of BHI broth. Test tubes containing BHI broth with the microorganisms already grown were adjusted with the aid of the same broth to the tube number 2 of McFarland Standards, at concentration of about 6x108 cells/ml. The upper chamber was filled with the bacterial solution and the lower chamber with sterilized BHI broth.

The specimens were incubated at 37°C, at proper respiratory conditions for 30 days. The culture medium was renewed at every 72 hours by removing all content of the upper chamber and replacing it by sterilized culture medium. Daily, for 30 days, all specimens were carefully agitated to verify the presence or absence of turbidity of the lower chamber, which would be and indicative of bacterial infiltration through the filling material. When the samples displayed turbidity, indicating bacterial infiltration, they were separated from the others.

Anova test was applied to verify whether there would be statistical differences between groups (p < 0.05).

Results

All specimens of positive control group showed culture medium turbidity at the first ten days. Conversely, negative control group did not show turbidity evidences at all experimental period.

Four of 40 samples were excluded during all study, comprising three of group A and one of negative control group because of the failure of the device during the renewing of the culture medium.

The viability of the inoculum was proved after the experimental period (30 days). At the 30th experimental day, 12 upper chamber samples (four for each group) was randomly seeded on BHI plates, to prove the inoculum viability during the study. In all specimens showing turbidity, the microorganism found was identical to that initially inoculated. In all specimens displaying E. faecalis

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infiltration, the observation of the laminas revealed morphotinctorial features similar to those observed at the beginning of the study.

After the experimental period, all specimens of groups A, B and positive control group showed culture medium turbidity. The mean of days for culture medium turbidity was 11.42 days for group A, 16.69 days for group B and 5.5 days for positive control group.

Data of each group was compared through Anova test using SPSS software.

Anova test did not show statistically significant differences (p > 0.05) between groups, so that it can be affirmed that there were no differences between the filling techniques employed in relation to E. faecalis infiltration.

Graph I demonstrated the specimens infiltrated and the days elapsed.

Graph I–Culturemediumturbidityofthespecimensfromeachexperimentalgroup

Discussion

The endodontic treatment aims at the cleaning and shaping of root canal. After these steps, it is necessary to seal the root canal to keep the sanitation obtained during preparation. The sealing maintain the condition achieve by root canal preparation and is of great importance for endodontic treatment success.

Many in vitro methods have been used to evaluate the sealing capacity of root canal obturation by employing dyes, scanning electronic microscopy, techniques of infiltration of f luids, electrochemical methods, radioisotopes and bacterial infiltration [4, 8, 14, 23].

Among these techniques, the model of bacterial infiltration is one of the most used due to the clinical relevance. This present employed E. faecalis because this microorganism has been associated with many dental infections and identified as the bacterial species more commonly found in root canals showing failures after endodontic treatment.

It is a species very used in many studies on bacterial infiltration [3, 8, 9, 16, 24].

This present study was designed to evaluate in vitro the bacterial infiltration in root canals prepared with Protaper Universal system and filled by two different techniques (single cone and thermoplasticized single cone techniques). The teeth were carefully selected, standardizing the tooth group, number and curvature of canals, root and working lengths, aiming to decrease the number of variables.

The teeth used were the mandibular premolars because they have shown a varied morphology displaying either round- or oval-shaped canals. Because of these anatomical variations the proper cleaning, shaping and filling of root canals can be compromised and result in unsatisfactory long-term outcomes [6]. Oval-shaped canals would have a greater amount of cement between gutta-percha point and root canal wall, making bacterial infiltration easier [6, 24].

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The double-chamber system (upper chamber + tooth + lower chamber) used in this present study was based on the model of the studies of De-Deus et al. [6], Brosco et al. [3], Ito et al. [10], Kangarlou et al. [11], Şimşek et al. [19], Alkahtani et al. [1] and Navarro-Escobar et al. [15], in which all had a chamber containing the bacterial agent and a chamber containing the sterile substrate with a tooth between them to simulate an environment contaminated in the upper chamber, the root with the root exposed to this environment, and the root apex exposed to a sterile culture medium in the lower chamber, and the only access was through the filled root canal.

The results of four studies confirmed the validity of the double-chamber system because both the experimental and positive control groups exhibited culture medium turbidity at different time periods, while the negative control group did not show turbidity during all experimental period.

This study employed ProTaper Universal nickel-titanium rotary system to prepare the root canal. In these cases, root canal filling according to the manufacturers’ recommendations can be accomplished by using only the gutta-percha point matching the size of the last instrument used for the apical preparation because the size of the point is standardized in relation to the shaping left by the instrumentation [5, 21].

The aforementioned description is which has been so-called single-cone technique which has allowed a faster and easier obturation because it used only one gutta-percha point. On the other hand, this technique cannot fill the morphological variations of oval-shaped root canals, which would not be completely filled by gutta-percha, requiring a greater cement amount, leading to root canal sealing failure [5].

To overcome the filling deficiency of single-cone technique, the thermoplasticization of the gutta-percha point can be obtained. This technique aims to improve gutta-percha adaptation to the morphological variations of root canal, thus achieving a sealing with greater gutta-percha and smaller cement amounts [20].

The results of this present study evaluating the root canal sealing capacity through two techniques demonstrated no statistical differences between them in relation to bacterial infiltration. This result corroborates that obtained by Damasceno et al. [5], Tasdemir et al. [21] and Ito et al. [10], which observed no statistically significant differences between different techniques of root canal filling regarding to bacterial infiltration.

In the study of Yücel et al. [24] and Monticelli et al. [13], a better sealing capacity was observed with thermoplasticized gutta-percha technique compared with single-cone technique. These outcome differences could have occurred because of the aforementioned authors employed System B and Thermafill in gutta-percha thermoplasticization, which may increase the adaptation to root canal walls.

Conclusion

Based on the methodology employed and on the results obtained, it can be concluded that both obturation techniques did not show significant differences between them in relation to the method of bacterial infiltration by E. faecalis.

References

1. Alkahtani A, Al-Subait A, Anil S. An in vitro comparative study of the adaptation and sealingability of two carrier-based root canal obturators. The Scientific World Journal. 2013;1-7.

2. Brosco VH, BernardinelIi N, Moraes IG. “In“In vitro” evaluation of the apical sealing of root canals obturated with different techniques. Journal Applied Oral Science. 2003;3(11):181-5.

3. Brosco VH, Bernardineli N, Torres SA, Consolaro A, Bramante CM, Moraes IG et al. Bacterial leakageBacterial leakage in root canals obturated by different techniques. Part 1: microbiologic evaluation. Oral Surgery Oral Medicine Oral Pathology Oral Radiology and Endodontic. 2008;1(105):48-53.

4. Cobankara FK, Asanir N, Belli S, Pashley DHA. Quantitative evaluation of apical leakage of four root-canal sealers. International EndodonticInternational Endodontic Journal. 2002;9(35):79-84.

5. Damasceno JHN, Silva PG, Queiroz ACFS, Vardasca de Oliveira PT, Pereira KFS. Estudo comparativo do selamento apical em canais radiculares obturados pelas técnicas cone único Protaper e termoplástica sistema TC. RevistaRevista Gaúcha de Odontologia. 2008;4(56):417-22.

6. De-Deus G, Murad C, Paciornik S, Reis CM, Coutinho-Filho T. The effect of the canal-filled area on the bacterial leakage of oval-shaped canals. International Endodontic Journal.International Endodontic Journal. 2008(41):183-90.

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7. Dultra F, Barosso JM, Carrasco LD, Capelli A, Guerisoli DMZ, Pécora JD. Evaluation of apicalEvaluation of apical microleakage of teeth sealed with four different root canals sealers. Journal Applied Oral Science. 2006;5(14):341-5.

8. Er K, Tasdemir T, Bayramoglu G, Herguner-Siso S. Comparison of the sealing of different dentin bonding adhesives in root-end cavities: a bacterial leakage study. Oral Surgery Oral Medicine Oral Pathology Oral Radiology and Endodontic. 2008;9(106):76-82.

9. Fransen JN, He J, Glickman GN, Rios A, Shulman JD, Honeyman A. Comparative assessment of ActiV GP/glass ionomer sealer, Resilon/Epiphany, and gutta-percha/AH plus obturation: a bacterial leakage study. Journal of Endodontic. 2008;72(34):5-7.

10. Ito DL, Shimabuko DM, Aun CA, Brum TB. Avaliação da infiltração bacteriana em técnicas de obturação do canal radicular. Revista de Odontologia da Universidade Cidade São Paulo. 2010;3(22):198-215.

11. Kangarlou A, Dianat O, Esfahrood ZR, Asharaf H, Zandi B, Eslami G. Bacterial leakage of GuttaFlow-filled root canals compared with Resilon/Epiphany and Gutta-percha/AH26-filled root canals. Australian Endodontic Journal. 2012;1(38):10-3.

12. Martins AS, Ostroski MM, Silva Neto UX, Westphalen VPD, Frainiuk LF, Moraes IG. Avaliação in vitro da infiltração via coronária em função de diferentes cimentos endodônticos resinosos. Revista Odonto Ciência. 2006;52(21):179-84.

13. Monticelli F, Sadek FT, Schuster GS, Volkmann KR, Looney SW, Ferrari M et al. Efficacy of two contemporary single-cone filling techniques in preventing bacterial leakage. Journal of Endodontic. 2007;3(33):310-3.

14. Nagas E, Altundasar E, Serper A. The effect of master point taper on bond strength and apical sealing ability of different root canal sealers. Oral Surgery Oral Medicine Oral Pathology Oral Radiology and Endodontic. 2009;1(107):e61-4.

15. Navarro-Escobar E, Baca P, González-Rodríguez MP, Arias-Moltz MT, Ruiz M, Ferrer-Luque M. Ex vivo microbial leakage after using different final irrigation regimens with chlorhexidine. Journal Applied Oral Science. 2013;1(21):74-9.

16. Paradella TC, Koga-Ito CY, Jorge AOC. Enterococcus faecalis: considerações clínicas e microbiológicas. Revista de Odontologia daRevista de Odontologia da UNESP. 2007;2(36):163-8.NESP. 2007;2(36):163-8.

17. Pinheiro CR, Guinesi AS, Camargo EJ, Pizzolitto AC, Bonetti-Filho I. Bacterial leakage evaluation of root canals filled with different endodontic sealers. Oral Surgery Oral Medicine Oral Pathology Oral Radiology and Endodontic. 2009;6(108):56-60.

18. Shilder H. Filling root canals in three dimensions. Journal of Endodontic. 2006;4(32):281-90.

19. Şimşek N, Akpi�� KE, Süme� Z. Ev�lu�ti�� of bacterial microleakage of root canals irrigated with different irrigation solutions and KTP laser system. Photomedicine and Laser Surgery. 2006;1(31):3-9.

20. Tanomaru-Filho M, Bosso R, Sant’anna-Júnior A, Berbert FLCV, Guerreiro-Tanomaru JM. Effectiveness of gutta-percha and Resilon in filling lateral root canals using thermomechanical technique. Revista de Odontologia da UNESP. 2013;1(42):37-41.

21. Tasdemir T, Er K, Yildri T, Buruk K, Çelik D, Cora S et al. Comparison of the sealing ability of three filling techniques in canals shaped with two different rotary systems: a bacterial leakage study. Oral Surgery Oral Medicine Oral Pathology Oral Radiology and Endodontic. 2009;3(108):129-34.

22. Yilmaz Z, Deniz D, Ozcelik B, Sahnin C, Cimilli H, Cehreli ZC et al. Sealing efficiency of BeeFill 2 in 1 and System B/Obtura II versus single-cone and cold lateral compaction techniques. Oral Surgery Oral Medicine Oral Pathology Oral Radiology and Endodontic. 2009;6(108):51-9.

23. Yilmaz Z, Tuncel B, Ozdemir HO, Serper A. Microleakage evaluation of roots filled with different obturation techniques and sealers. Oral Surgery Oral Medicine Oral Pathology Oral Radiology and Endodontic. 2009;12(108):4-8.

24. Yücel AÇ, Çiftçi A. Effects of different root canal obturation techniques on bacterial penetration. Oral Surgery Oral Medicine Oral Pathology Oral Radiology and Endodontic. 2006;4(102):88-92.

25. Williamson AE, Marker KL, Drake DR, Dawson DV, Walton RE. Resin-based versus gutta-percha-based root canal obturation: influence on bacterial leakage in an in vitro model system. Oral Surgery Oral Medicine Oral Pathology Oral Radiology and Endodontic. 2009;2(108):292-6.


In vitro study of the morphology of internal lower second molars

Humberto Ramah Menezes de Matos¹Luanni Belmino Mastroianni¹Aldo Angelim Dias2

Corresponding author:Humberto Ramah Menezes de MatosRua Bill Cartaxo, n. 885 – casa 16 – Água FriaCEP 60833-185 – Fortaleza – CE – BrasilE-mail: [email protected]

1 Discipline of Endodontics, School of Dentistry, University of Fortaleza – Fortaleza – CE – Brazil.2 School of Dentistry, University of Fortaleza – Fortaleza – CE – Brazil.

Received for publication: July 22, 2013. Accepted for publication: December 16, 2013.

Keywords: molar; Endodontics; pulp cavity.


Abstract

Introduction: The mandibular molars are a group of teeth that have a complex internal morphology, and its fundamental knowledge is necessary. The second molar has two roots, one mesial and distal, but three canals are more commonly find: two in the mesial root and one in the distal root. Objective: To study through four criteria: radiographic, clinical, microscopic, and anatomy, the internal morphology of the mandibular second molars. Material and methods: This was a cross-sectional, in vitro, descriptive, observational study, in which 50 second molars were selected, having as exclusion criteria teeth destroyed by caries. Inclusion criteria comprised teeth with higid and semi-higid crowns Results: 29% of mandibular29% of mandibular second molars had three canals. The round-shaped cross section was the most common throughout the cervical-apical extension of both mesial (59%) and distal (47%) canals. However, other possible configurations and number of canals can be found in second molars, as the presence of four (12%) or five canals (3%). 36.7% of the mesial canals and 29.4% of distal canals were flattened in the mesial-distal direction and elongated in buccolingual direction; the variation of the "C-shaped" canal was found in 4% of cases. Conclusion: TheThe most frequent configuration and number of canals of mandibular

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Matoset al.–In vitro study of the morphology of internal lower second molarsInvitrostudyofthemorphologyofinternallowersecondmolars

second molars were, respectively, the round-shaped cross section configuration in the entire length of the canal, and three canals. However the professional should be aware that this morphology may vary as shown in each research phase. Therefore, to achieve clinical success, the professional should have the knowledge of the internal morphology of these teeth and their possible variations.

Introduction

Endodontics has been through marked changes of concepts, such as the use of a single instrument for biomechanical preparation and innovative filling techniques. However, established aspects should not be left behind, such as the knowledge on the internal morphology of all teeth and possible variation that may be found; the negotiation of the root canal system with the adequate instruments; the biomechanical preparation that provides the maximum of canal disinfection; maintenance of apical foramen patency and its original position; a filling providing an adequate sealing of root canal systems.

The complexity in root canals, mainly in molars, is directly linked to recurrent infections. If the morphology of root canals is not known by the dentist and endodontist, treatment failure will be eminent, even using latest technology instruments, because root canals not properly negotiated and prepared may shelter infectious foci. Thus, the knowledge of internal morphology and its possible variation should be ample both for the dentists and the endodontists, during the execution of the endodontic intervention.

The mandibular second molar has two roots: a mesial and a distal one; but, it is more common to find three root canals: two in mesial root and one in distal root [15, 18]. A common variation in these teeth is “C shape” canal that is so named because of the root and canal cross section [5, 7]. Instead of exhibiting the entrances of different root canals, the pulp chamber floor presents a ribbon-shaped canal, with 180 degree arch, starting from the mesial-lingual line extending around of the buccal surface to the distal portion of the pulp chamber [10]. Almeida-Gomes et al. [2] affirmed that the previous diagnosis and knowledge of “C-shape” canals are much valuable for the clinical success of the case. Jafarzadeh and Wu [10] affirmed that the diagnosis of this morphological variation can be of difficult conclusion through radiographic examination; however, clinical examination is more accurate in its diagnosis.

Malvar and Corbacho [14] studied the internal morphology of 81 second molars by diaphanization. The authors observed the number of roots, main canals, lateral canals, inter-canals and apical. The mesial root exhibited a prevalence of two different canals and the distal root the greater frequency of only one canal.

The interna l morpholog y doma in is a fundamental step during endodontic therapy, because the adequate preparation of the canal system would avoid the increasing of failure rates. Thus, the aim of this in vitro study was to assess the amount and possible configurations of the canals within mandibular second molars through radiographic, clinical, microscopic and morphological methods.


This present research is an in vitro, descriptive, observational study. All phases were carried out in laboratory with the use of freshly extracted teeth, that is, in vitro. Fifty mandibular second molars were selected after their removal due to therapeutic indication because of either aggressive periodontal disease with great loss of clinical insertion or orthodontic/prosthodontic reasons, whose detailed history is part of the patients’ files. Inclusion criteria were teeth either sound or with carious lesion. Teeth were excluded because of lack of anatomical crown due to severe destruction, regardless of the reason causing such loss; and previous endodontic treatment. This study was submitted and approved by the Ethical Committee in Research of the University of Fortaleza (Coética/UNIFOR) under protocol no. #181.388/12.

After selection, all teeth were submitted to the methods of this present study (radiographic, clinical, microscopic and morphological).

Radiographicassessment

The teeth were fixed with wax to the periapical intraoral film (Kodak Insight, USA). Next, a radiographic shot was executed for 0.22 second.

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To enable the observation of all root canals, an angle of 20 degrees at horizontal plane towards mesial surface of the teeth was employed to mimic Clark’s positioning technique, which corresponds a distortion at the horizontal angle of the x-ray beam incidence to prevent image superposition of root canals, improving their observation [8]. This technique reproduces which would be possible to execute during the clinical treatment, thus enabling a better observation of the root canals.

The film development was carried out in dark chamber for two minutes within developing solution. Following, they were removed and immersed in water for 20 seconds; then the films were fixed for five minutes. The radiographs were immersed in running water for five minutes and left to dry. Only after this sequence, they were evaluated on negatoscope to evaluate the amount of canals of each tooth. The teeth in which the film was not properly exposed or in which the radiographic image not allowed a correct distortion were again exposed to correct the error and make possible an adequate assessment.

Clinicalassessment

All procedures of access and exploration of the pulp chamber were executed by the same operator, previously trained during a pilot study with the same methodology employed in the study.

Firstly, pulp chamber access of the sound teeth was executed with the aid of n. 1013 diamond bur (KG Sorensen, Barueri, Brazil), coupled to high-speed handpiece (Kavo model 605c, Joinville, Brazil). The diamond point was changed at every 30 teeth, to assure its correct use. The initial penetration was performed on the center of the central sulcus of the occlusal surface with the drill parallel to the tooth long axis, obtaining a contour shape according to the tooth morphology [12]. For the teeth presenting carious lesion contour shape was defined according to the extension of the carious tissue, which was removed with the aid of a round carbide drill (KG Sorensen, Barueri, Brazil) with size compatible with that of the cavity, changed at every 30 teeth, coupled to a micro motor and contra-angle at low speed (Kavo model 161 and model 2068, respectively).

After this procedure, the roof of the pulp chamber was removed and the surrounding walls became more divergent towards occlusal, with the

aid of Endo Z drill at high speed (Dentsply Maillefer, Ballaigues, Switzerland), aiming at making easy the direct view, illumination and access of the pulp chamber.

After the conclusion of the access, a straight explorer was used to examine the pulp chamber floor to find all the entrances of the present root canals. Aiming at improving the observation of the found root canals, a file sequence was employed to enlarge the entrances of the canals, starting from sizes #8 and #10 (Dentsply-Maillefer, Ballaigues, Switzerland), followed by size #15 Kerr file (Dentsply-Maillefer, Ballaigues, Switzerland), #20 and #25 Flexofile files (Dentsply-Maillefer, Ballaigues, Switzerland), changed at every tooth groups. Sodium hypochlorite solution at 2.5% concentration (Biodinâmica, Ibiporã, Brazil) was employed during all negotiation phase of root canals.

Microscopicassessment

The visual magnification was executed through an optical microscope (DF Vasconcellos M900, Rio de Janeiro, RJ, Brazil), which improves the floor observation. All teeth were visualized with the aid of the microscope at x16 visual magnification so that the canals not identified could have been visualized and also to confirm more precisely the number of canals.

Microscopicassessmentwithoutanatomicalcrown

Aiming at a better identification of the canals, since atresic canals are difficult to be observed, in this study an anatomical cut of the crown was executed by the same operator.

The anatomical cuts of the crowns were executed at the anatomical neck with the aid of no. 2200 diamond point (KG, Sorensen Barueri, Brazil); this was changed at every tooth groups and coupled to high-speed handpiece (Kavo model 605c). After the cutting of all teeth, each tooth was stored into colorless plastic bags correctly numbered according to the tooth number. The observation and exploration with straight explorer was carried out under visual magnification (optical microscopy at x16 magnification), enabling the identification of root canals that possibly were not identified during clinical access. Root canals found during this step were negotiated by the aforementioned file sequence.

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Results

Through the methodology employed, it was possible to observe regarding to the amount of root canals, a difference according to the assessment type executed, with variations in the number of canals found at each step (graph 1).

Graph 11–Numberofrootcanalsinmandibularsecondmolars

The prevalence of teeth with three canals was noted. Notwithstanding, through the microscopic and anatomical assessments, the amount of four canals increased, making possible to find cases with five canals.

With regard to the configurations of root canals, the radiographic examination (step 1) did not allow to analyze the shape of canals, so that their morphology was established at the subsequent steps. The configuration with the greatest percentage was round-shape canals in both roots, defined during the clinical assessment step (table I).

Table I – Configuration of root canals in mandibularsecond molars, at clinical access step (absolute andrelativefrequencies,at%)

Mesial Distal

Round 56 (60.8%) 29 (49.1%)

Elliptical 0 (0%) 8 (13.5%)

Flattened 32 (34.7%) 20 (33.8%)

C 2 (4%)

Total 92 59

Only two cases of mandibular second were found with “C-shaped” configuration. At the third step of the study, in which visual magnification was used after pulp chamber access, it could be observe an increase in the relative frequencies due to the increase of the number of root canals found (table II).

Table II–Configurationoftherootcanalsinmandibularsecondmolars,atmicroscopicassessmentstep

Mesial Distal

Round 58 (59.1%) 32 (47%)

Elliptical 0 (0%) 14 (20%)

Flattened 36 (36.7%) 20 (29.4%)

C 2 (4%)

Total 98 68

At the step of anatomical observation, some percentages were maintained, while others changed because of the possibility that not previously seen root canals were found after the removal of the anatomical crowns, which allowed a better illumination quality of the pulp chamber floor (table III).

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Table III–Percentageofconfigurationofcanalsatthestep of anatomical observation of mandibular secondmolars

Mesial Distal

Round 58 (59.1%) 32 (47%)

Elliptical 0 (0%) 14 (20%)

Flattened 36 (36.7%) 20 (29.4%)

C 2 (4%)

Total 96 68

Discussion

In this present study, most frequently, the mandibular second molars exhibited round-shaped canals and three canals, respectively regarding to the configuration and number. The relevance of such configuration for endodontic practice is advantageous in relation to the shaping achieved by the instruments after biomechanical preparation, minimizing the percentage of instrument fracture due to torsion, because round-shaped configuration would avoid that the instrument’s t ip were apprehended in the walls due to the shape similar to that of the file [13].

It was demonstrated that the conventional radiographic method limits the identification of canals even without image superposition and with angle standardization for all studied teeth. Current studies have affirmed that only the two-dimensional analysis of radiographs did not provide an accurate diagnosis of the internal morphology of the canals because of image superimposition, contrast and angulation limitations. Other factor limiting the identification of canals is the professional’s expertise. Notwithstanding, even the most experienced professional could not identify changes in root canal system. Thus, the current researches have proposed a new auxiliary method to help in identifying atresic and calcified canals, and isthmus areas, which is computed tomography [4, 11, 17, 19].

Carvalho and Zuolo [3] conducted an in vivo study to evaluate 93 mandibular first and 111 second molars regarding to the number of root canals. At the first appointment, pulp chamber exploration was performed with naked eye, finding 641 canals. At the second appointment, visual magnification through optical microscopy was used, and more 50 canals were found – accounting for an increase of 7.8%. The authors concluded that the use of the optical microscope help in identifying the canals not observed by conventional clinical examination.

Through the aid of visual magnification (optical microscope) after the clinical access and cut of the anatomical crown, it was observed an increasing of the number of canals identified, which is in agreement with previous authors. This demonstrates that the optical microscope help in the identification the canals not observed by conventional clinical examination

Malvar and Corbacho [14] studied the internal morphology of 81 mandibular second molars through diaphanization. The authors observed the number of roots; main and recurrent canals, inter-canals, and apical deltas. They noted that in the mesial roots, there was a greater prevalence of two different canals extending from pulp chamber to the apex. For the distal root, one canal extending from pulp chamber to the apex was more frequently found. In this present study, most of the teeth showed three canals, two mesial and one distal. The presence of teeth with four and five canals after the last step of the study increased; however, it was lower than the amount of teeth with three canals.

Cooke and Cox [6] were the first authors to report a case of “C-shaped” mandibular second molar and affirmed that such variation occur in 8% of the cases. Studies on mandibular second molars have shown that the occurrence of “C-shaped” canals may range among populations: between 2.7% and 7.6% in Caucasians, 6% among Arabs, 14% among Lebanese and 31.5% among Chinese [1, 9, 16, 20, 21]. The percentage of “C-shaped” canals in this present study was of 4%, which is lower than the percentage reported by Cooke and Cox.

The radiographic examinations, even with their limitations, should be used to aid in identifying morphological variations and in choosing resources and materials to be used during endodontic therapy. The access to pulp chamber should be performed allowing an adequate observation of the chamber floor aiming to identify the canals and their configurations. The negotiation of root canal systems should be executed through proper instruments, since it is one of the most important treatment stages and the morphology domain would make ease the subsequent operative steps.

Visual magnification provided by optical microscopy helps to identify atresic and calcified root canals and it can be an auxiliary tool of endodontic armamentarium. The result of the knowledge and domain of the internal morphology will be the increasing of endodontic treatment success rates.

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Conclusion

It was possible to verify that, regarding to configuration, round-shaped cross section prevailed in mandibular second molars, probably because of the conical shape of the roots. The three-canal specimens were the most found; however, with the aid of visual magnification through optical microscope, the identification of teeth with both four and five canals increased during the observation of atresic root canal entrances. A prevalence of “C-shaped” canals was similar to that reported in literature, of approximately 4%.

References

1. Al Fouzan KS. C-shaped root canals in mandibular second molars in a Saudi Arabian population. J Endod. 2002;35(6):499-504.J Endod. 2002;35(6):499-504.

2. Almeida-Gomes F, Maniglia-Ferreira C, Lima Guimarães NLS, Alves dos Santos R, Vitoriano MM. “C shape canal”: uma variação anatômica de interesse clínico. Rev Bras Pesq Saúde. 2010;12(2):57-60.

3. Carvalho MCC, Zuolo ML. Orifice locating withOrifice locating with a microscope. J Endod. 2000;26(9):523-4.J Endod. 2000;26(9):523-4.2000;26(9):523-4.

4. Chandra SS, Rajasekaran M, Shankar P, Indira R. Endodontic management of a mandibular first molar with three distal canals confirmed with the aid of spiral computerized tomography: a case report. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2009;108(4):77-81.

5. Cleghom BM, Cristie WH, Don CC. Root and root canal morphology of the human permanent maxillary first molar: a literature review. J Endod. 2006;32(9):813-21.

6. Cooke HG, Cox FL. C-shaped canal configurations in mandibular molars. J Am Dent Assoc. 1979;99(5):836-9.

7. Fan B, Cheung GS, Fan M, Gutmann JL, Fan W. C-shape canal system in mandibular second molars: part II – radiographic features. J Endod. 2004;30(12):904-8.

8. Freitas A, Rosa JE, Faria e Souza I. Radiologia odontológica. 6. ed. São Paulo: Artes Médicas; 2004.

9. Haddad GY, Nehme WB, Ounsi HF. Diagnosis, classification, and frequency of C-shaped canals in mandibular second molars in the Lebanese population. J Endod. 1999;25(4):268-71.

10. Jafarzadeh H, Wu Y. The c-shaped root canal configuration. J Endod. 2007;33(5):517-23.

11. Lee S, Jang KH, Spangberg LS, Kim E, Jung IY, Lee CY et al. Three-dimensional visualization of a mandibular first molar with three distal roots using computer-aided rapid prototyping. OralOral Surg Oral Med Oral Pathol Oral Radiol Endod. 2006;11(5):383-8.

12. Lopes HP, Siqueira Jr JF. Endodontia: biologia e técnica. 3. ed. Rio de Janeiro: Guanabara-Koogan; 2010.

13. Maia Filho EM, Souza EM, Meneses EO, Rizzi CC. Effect of Gates Glidden, La Axxess,Effect of Gates Glidden, La Axxess, SX and ultrasound on the circularity and area of mesial canals of mandibular molars. RSBO. 2013;10(3):234-9.

14. Malvar MFG, Corbacho MM. Estudo da anatomia interna de segundos molares inferiores pela técnica da diafanização. J Bras Endo. 2002;3(11):337-41.

15. Navarro LF, Luzi A, Garcia AA, García AH. Third canal in the mesial root of permanent mandibular first molars: Review of literature and presentation of 3 clinical reports and 2 in vitro studies. Oral Surg Oral Med Oral Pathol OralOral Surg Oral Med Oral Pathol Oral Radiol Endod. 2007;12(8):605-9.

16. Sabala CL, Benenati FW, Neas BR. BilateralBilateral root or root canal aberrations in a dental school patient population. J Endod. 1994;20(1):38-42.J Endod. 1994;20(1):38-42.

17. Toubes KM, Côrtes MI, Valadares MA, Fonseca LC, Nunes E, Silveira FF. Comparative analysis ofComparative analysis of accessory mesial canal identification in mandibular first molars by using four different diagnostic methods. J Endod. 2012;38(4):436-41.J Endod. 2012;38(4):436-41.

18. Vertucci FJ. Root canal morphology and its relationship to endodontic procedures. Endod Topics. 2005;10(1):3-29.

19. Villas-Bôas MH, Bernardineli N, Cavenago BC, Marciano M, Del Carpio-Perochena A, de Moraes IG et al. Micro-computed tomography study ofMicro-computed tomography study of the internal anatomy of mesial root canals of mandibular molars. J Endod. 2011;37(5):1682-6.

20. Weine FS. The C-shaped mandibular second molar: incidence and other considerations. J Endod. 1998;24(5):372-5.

21. Weine FS, Pasiewicz RA, Rice RT. Canal configuration of the mandibular second molar using a clinically oriented in vitro method. J Endod. 1988;14(5):207-13.

Literature Review Article

Photoelasticity in Dentistry: a literature review

Cássia Bellotto Corrêa1

Ana Lúcia Roselino Ribeiro1, 2

José Maurício dos Santos Nunes Reis3

Luís Geraldo Vaz3

Corresponding author:Cássia Bellotto CorrêaRua 3, n. 2.965 – Vila OperáriaCEP 13504-091 – Rio Claro – SP – BrasilE-mail: [email protected]

1 Department of Diagnosis and Surgery, School of Dentistry of Araraquara, São Paulo State University – Araraquara – SP – Brazil.2 School of Science of Tocantins – Araguaína – TO – Brazil.3 Department of Dental Materials and Prosthesis, School of Dentistry of Araraquara, São Paulo State University – Araraquara – SP – Brazil.

Received for publication: March 14, 2013. Accepted for publication: November 26, 2013.

Keywords: biomechanics; dental stress analysis; Dentistry.


Abstract

Introduction and Objective: Photoelasticity consists of an experimental technique of stress analysis. This technique is very used in most different areas including Dentistry. This literature review presents the several applications of photoelastic technique in Dentistrythe several applications of photoelastic technique in Dentistry as well as its advantages and disadvantages. its advantages and disadvantages. Literature review: Based on this method of analysis, it is possible the verification of the stress distribution and deformation in structures with complex geometry as maxilla and mandible. It can be used to evaluate the distribution of stress on several types of prosthesis as removable partial denture systems with different retention systems, conventional implant prosthesis, overdentures and Brånemark protocols. Moreover, photoelasticity can be used to assess the stress generated by variousby various orthodontic movements, different orthodontic systems and different materials (orthodontic wires). In addition, it is used to analyze different defects of maxillectomy, splint types on traumatized tooth and post-core restoration methods. This technique can also be used to assess dental instruments such as evaluation of different designs of periodontal probe. Conclusion: The photoelastic analysis has been a technique of great importance in health area studies, more specifically in Dentistry. Based on this method of analysis, it is possible to measure the stress distribution and deformation in structures with complex geometry as maxilla and mandible.

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Corrêaet al.–Photoelasticity in Dentistry: a literature reviewPhotoelasticityinDentistry:aliteraturereview

Introduction

Photoelasticity consists of an experimental technique of stress analysis. It is based on the property that certain transparent materials have that is to exhibit fringes (optic parameters), when observed through polarized light. This effect is the result of the alteration (refraction) of the polarized light by internal deformations resulted of the stress condition present in the model. The interpretation of these fringes shows all stress distribution and allows the measurement of their direction and magnitude in any model points. In materials with photoelastic properties, the changes in the refraction index happen according to the stress application [6].

In the photoelastic method, a model similar to the studied structure is made in transparent material that has photoelastic properties. This model is submitted to a representative loading of the work conditions, which take to a deformation [13].

An appliance denominated polariscope is used for this method, which allows the establishment of the light propagation plan and, therefore, the main stress directions, as well as the difference between the two components of main stress. This appliance is composed by an association of filters disposed among the observer, the luminous source and the model. The polarized light crosses the filters and the model arrives at the observer as an image of the optic parameters [5].

When the white light is used, the optic effects come out as colored fringes, which have an order number, depending on the load intensity. The fringe order in a determinate point is related with the state of stresses in the model. The fringes exhibited in the photoelastic model appear as successive and continuous series of different colored bands. The whole fringes are located between the red and blue fringes and, the second and consecutives whole fringes are located between the red and green fringes [5].

According to this concept, the aim of this study was to report the different applications ofdifferent applications of photoelasticity in Dentistry.

Literature review

The photoelastic technique has been very used in the Dentistry. Some of its several applications will be described in each specific Dentistry area.

Implantology

The study of photoelasticity in the specific area of Implantology is of great interest since it can be useful to assess the distribution of stress in both abutments (different designs and types) and implants screws (different types and angulations).

Cehreli et al. [6] analyzed the force distribution and magnitude around implants with different designs and abutments types. The authors tested conical and cylindrical Branemark® and Astra Tech® implants and ITI® solid screw implant. The abutments were submitted to vertical and 20° oblique forces of 100 N and 150 N, and then they were analyzed through the photoelastic and strain-gauged techniques. The obtained results showed that the forces distribution was similar in both loading conditions. The strains around the Branemark® implants were smaller than around the other implants, particularly under vertical loads. The study conclusion is that the different types of implant/abutment set used have similar distribution of forces and the implant-abutment mating design is not a decisive factor in the distribution and magnitude of the forces in a simulated bone.

Akça et al. [1] investigated by photoelastic analysis the difference in load distribution of dental implants with different implant neck designs. For this, the models were tested in situations of intact and compromised cortical bone. The Astra Tech®, 3i® and Straumann® abutments were submitted to vertical and 20° oblique loads of 10, 20 and 30 lb and analyzed in a polariscope. The authors observed that the highest stress values, in the condition of intact bone, were localized around the crest and apical region. For the compromised cortical bone group, regarding all designs and load directions, it was observed that the higher stresses occurred in the supporting structures. The study conclusion was that the condition of the cortical bone considerably influenced on stress distribution. Thus, a compromised condition of the cortical bone caused higher stress levels for all implants tested.

Markarian et al. [21] evaluated the stress distribution in 30° angled and parallel implants with and without gap among the implant/abutment junction. Four different models were created to simulate the studied conditions. The models were loaded with 100 N and analyzed by photoelastic analysis. The results showed that for the parallel implants the stress distribution followed the implant axis and, in the model with angled implant, the

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stress magnitude was higher and non-homogeneous around the apical region of the lateral implants. It was concluded that the stress is generated after screws tightening of the abutments and it is increased after mechanical loading. Gaps among implant/abutment junction can generate increase in the stress distribution on parallel implant. The angled implants resulted in patterns of oblique and non-homogeneous stress.

Ochiai et al. [24] studied implant-tooth connected prosthesis with segmented (conical abutment attached to implant by abutment screw) and non-segmented abutments (restoration fabricated directly to machined abutment). In this study, a photoelastic model of a posterior region of a mandible was used with one or two implants. The implants were placed at the first and second molar positions. The restorative technique included the implants and the anterior adjacent tooth. The model was analyzed after the load application in 5 different points on the restoration occlusal surface. The results showed that the stress distribution on the model with two posterior implants was similar compared to the segmented and non-segmented abutments. The stress magnitude observed for both abutments types was also similar on the model with single posterior implant. Vertical loading produced more non-axial stress in the condition of one implant with nonsegmented abutment.

Prosthodontics

In Prosthodontics, the photoelastic technique can be utilized to compare different systems of overdenture retention and to verify the biomechanical behavior of implant-tooth-supported fixed prosthesis as well as removable prosthesis.

Fanuscu and Caputo [14] compared the characteristic of stress distribution of two systems of overdenture retention supported by 4 implants, after protrusive and laterotrusive movements. The first system consisted of splinted-bar ERA (harder bar splinting 4 implants and anterior clip with 2 distal resilient cap attachment) and the other system was composed of four O-ring isolated (4 individual ball/O-ring attachment). The four implants were inserted in a maxillary photoelastic model. Prosthesis in acrylic resin was made for both systems. Protrusive and laterotrusive loads from 1.4 to 14.4 kg were applied. Instability in the overdenture happened in both retention systems when protrusive and laterotrusive loads lower than 4.6 kg were applied. The protrusive loads

were better distributed than the laterotrusive loads in both retention mechanisms. The O-ring system transferred bending load to implants in the laterotrusive loading, mainly for posterior implants. The splinted-bar ERA system transferred higher intensity of stresses to posterior implants during the laterotrusive loads. Higher stresses were observed in the O-ring system in the laterotrusive loads in the distal side. It was concluded that both retention systems demanded an occlusion balanced for the overdenture stability under the application loads that varied from 1.4 to 14 kg. The protrusive and laterotrusive loads were not distributed equally in both mechanisms, and the highest stress happened in the posterior implants.

Another study that used implant-tooth-supported fixed prosthesis was accomplished by Srinivasan and Padmanabhan [28]. In that study one implant and a tooth served as support for a fixed prosthesis of 3 elements. The prosthesis was loaded on 3 different points not simultaneously. The periodontal ligament was simulated in the photoelastic model to evaluate the intrusion of the tooth and the implant that supported the prosthesis. The results indicated that the force cannot be light and continuous and it may not cause dental intrusion. However, intrusion of natural tooth may be not just related to excessive forces as shown in this study and it needs more investigation.

Ochiai et al. [23] used the photoelastic technique to evaluate the effect of palatal support on three different designs of maxillary implant-supported overdentures. The fitting systems tested were: a splinted Harder bar incorporating 2 distal ERA with anterior clips, non-splinted Zaag 4 mm direct abutments and attachments, and non-splinted Locator 2 mm direct abutments and attachments. The three prosthesis types were installed with complete palatal coverage in the maxilla model, made by photoelastic material, containing the 4 implants. The overdentures received 111 N of loading in the first right and left molars and in the incisive papilla area for the stress distribution verification. The same procedure was accomplished in the overdentures after removal of the palatal coverage. The authors concluded that the palatal coverage removal from the maxillary overdentures produced a greater effect of the loading transfer and more difference on the concentrated stress around the implants than the attachment designs used.

Celik and Uludag [7] assessed the stress distribution in different retention mechanisms (ball attachment, direct abutments with attachments, bar framework, bar with distally placed ball

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attachments) for mandibular overdenture retained by 3 implants with parallel or inclined positions, by photoelastic technique. A force of 135 N was applied unilaterally in the right first molar. The study showed that the lowest stress values were observed in the bar-ball attachment system for both parallel and inclined implants.

Jiao et al. [16] accomplished studies using the photoelastic method to analyze the stress distribution in different designs of removable partial denture (RPD). Lyons et al. [20] used the same method to analyze the stress distribution of different sized surgical resection with RPD designed to restore this maxillectomy defects. Jiao et al. [16] compared the stress distribution of three different RPD designs (RPD made by polyacetal, traditional metal framework and hybrid) and concluded that the structure that had the best stress distribution is the traditional metal framework I-bar RPD, which has the most equitable stress distribution. The hybrid structure has an intermediate behavior. Despite these observations, the hybrid structure can be considered a viable alternative when the primary concern is the esthetic.

Lyons et al. [20] compared the photoelastic maxillas models with different sizes of defects (partial maxillectomy, total maxillectomy, and total maxillectomy involving the contralateral premaxilla), rehabilitated with RPD using splinted and non-splinted teeth as abutments. The study results suggest that the splinting of the 2 teeth adjacent to the resection defect can reduce the tension in the teeth pillars and improves stress distribution around the roots during loading.

Costa et al. [12] analyzed by photoelastic technique the stress distribution in the distal-extension of the RPD in three different retainers: T bar, rest proximal plate I bar (RPI), and circumferential with mesialized rest. The photoelastic models represent a Kennedy Class II inferior arch. A force of 20 N was applied in all models with the frameworks with the different retainers. The stress distribution was observed in 8 different points. The best results of stress distribution between teeth and residual ridge were the RPI retainer, following by T bar.

Furthermore, the photoelastic analysis can be used to verify the applicability of a theoretical method as studied by Kim et al. [18]. In their photoelastic experiment, the O-ring specimen was made of epoxy resin, the applied fractional compression was 20% and the lateral pressure was varied as 1.96, 2.94 and 3.92 MPa. The authors obtained similar results in the verification of the pattern and values of the stress in the photoelastic

technique and theoretical method. It was concluded that the theoretical method is valid for the stress analysis and can predict a failure of an O-ring attachment.

Orthodontics

Another area of the dentistry in that which photoelastic technique has been very used is orthodontics. In that area the photoelastic analysis is used to examine the stress produced during the several orthodontics movements as the canine retraction [3], incisor retraction [9], in masse distalization of mandibular premolar and molar [30], increasing the reverse curves of Spee in the rectangular stainless steel archwire when reducing an increased overbite [11]. Nakamura et al. [22] accomplished a study that simulated distal movement of mandibular molars with skeletal Anchorage system, in which almost 3-dimensional technique was used.

Cengiz et al. [8] evaluated the behavior of different splint types on traumatized tooth using the photoelastic analysis. A model with natural teeth positioned equidistantly received three different splint types (the wire-composite splint, fiberglass splint and titanium trauma splint). That model received a static axial and 20° oblique force of 100 N in a circular polariscope. The generated images were registered in a photographic camera and transferred to a computer for quantification of the fringes. The study concluded that the use of the orthodontic wire resulted in lowest fringe orders around of the traumatized tooth and titanium trauma splint did not have any effect on reduction of stresses.

Yamamoto et al. [31] in a study of stress analysis of different post and core restoration methods (composite resin post and core, composite resin with glass fiber post, and cast metal post and core) also used the photoelastic method and suggested that abutment made by composite resin core in combination with fiber post model produced the lowest stress concentration in endodontically treated teeth.

Surgery

In the specific area of maxillofacial surgery, Sato et al. [26] used the photoelastic method to evaluate different techniques of sagittal split ramus osteotomy in mandibular advancement. The positions of tested splint were: linear arrangement at 60°,

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linear arrangement at 90°, reverse L arrangement and miniplates and screws. The hemi-mandibles models made by photoelastic resin were fixed in agreement with different positions. Under analysis in the polariscope, a photographic was taken after 3.0 mm of displacement was reached. The results show that the linear 90° and reversed L arrangements provided the most favorable behavior.

Sato et al. [27] published a comparative study of hybrid technique for fixation of the sagittal split ramus osteotomy in mandibular advancement using a finite element analysis to validate the photoelastic models. The positions of the tested splint were: fixation using a hybrid technique fixation using bicortical screws and fixation using a 4-hole miniplate with monocortical screws. The results suggested that the hybrid technique is most favorable because it increased the resistance and improved the stress distribution.

Lima et al. [19] used photoelasticity to analyze the mechanical behavior of bone and teeth of rapid maxillary expansion with or without separation of pterigomaxillary suture. In this study, a model of maxilla was done in material with photoelastic properties, the orthodontic appliances were installed and then the expansion was carried out with and without osteotomy of suture. The results showed that the model with osteotomy has less stress in molar area, maxillary tuberosity and pterygoid plates.

Moreover, Christopoulos et al. [10] verified the stress in mandible with condylar fracture by means of photoelasticity through three fixation systems. The first system used a miniplate at the posterior border under load, the second system used a miniplate parallel to the sigmoid notch under load and the third system used two miniplates at the position of the first and second system. It was concluded that the use of two miniplates offers better stabilization in all loading conditions studied.

Dental instruments

The photoelastic analysis can also be utilized for investigation of the applicability of new dental instruments. For instance, Vartoukian et al. [29] investigated the physical-mechanical behavior of a new periodontal probe tip design. The control and test probe were embedded axially up to the 5.0 mm mark in photoelastic resin. The blocks were analyzed under white light in a transmission polariscope under loading of 3.15 or 5.0 N. The images were photographed and analyzed. The results

of this study showed that the test probe obtained lower stresses and less local stress concentration than the control (conventional probe).

Discussion

Nowadays, there is a tendency towards replacing experimental analyses by computer-aided techniques (numerical methods). Notwithstanding, with the increasing of the complexity of the structures studied and the development of new advanced materials, the use of experimental techniques still exists and, frequently, it is the only one that can provide reliable results. The techniques of stress analysis most used currently are: strain-gauged (extensometry), finite elements method, photoelasticity and speckle interferometry (ESPI). These technique associations have been very used for numerical methods validation.

The photoelastic method is an experimental technique of stress/deformation analysis that is used to solve complex engineering problems, when the numerical solution is of difficult application. Moreover, the photoelastic method is used in the validation and experimental verification of numerical solutions, in the study of the stress distribution in geometry problems and complex loadings, as well as in the shape optimization. This methodology allows fast qualitative analyses of the stress state through the observation of the optical effects and models. In addition, the association between the photoelastic method and computer software allows a quantitative analysis of the stress in the models.

Despite the information described above, the photoelastic technique presents some limitations when stress quantification is requested. Among them is the requirement of models with faithful reproduction to the original especially. Another important factor that must be observed is that the applied force should not cross the limit of the material resistance. When the value of the applied force reaches the resistance limit of the materials, the results can be modified. Moreover, the material can fail when the applied force exceeds its maximum resistance limit. For the accurate results interpretation, when observed by polariscope, the model should not present tensions prior to the force application [4].

The great advantage of photoelasticity is that it is an experimental method that allows the visualization of the set of internal stresses in the

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models [4, 15]. The method such as strain gauge just can measure the surface stresses in the model. And the finite element method is a computational method highly manipulable.

As limitations of the technique, it is its difficult in faithful reproduction of the original model and that these should be free of stresses before the analysis [4] and, according to Sadowsky and Caputo [25], it is impossible to differentiate cortical and medullar bones.

As the photoelastic technique, the others methods of stress analysis have advantages and disadvantages in its application. The strain gauge is a device used to measure the deformation of an object under load [2]. A great advantage of this method is the possibility to use in studies in vivo, but has disadvantages such as the superficial measuring and the active area of the strain gauge being about 2 to 10 mm.

The finite elements method is a numerical analysis of stress that divides a known geometric problem into much smaller domains with simplified geometry, in which the variables can be interpolated to obtain the solution of the problem. The main advantage of this method is its versatility since every shape or structure can be analyzed and the load applied can have any intensity and direction. However, in some studies the properties of the models do not accurately represent the actual in vivo model conditions and the results can not be extrapolated to the real situation [2].

The ESPI is a technique that uses laser radiation and a video recorder of interferometric patterns for high resolution in the assessment of the displacements on the surface of objects. The fringe The fringe patterns obtained with this non-contact technique show equal displacement regions in the direction of the sensitivity vector [17]. The advantages of ESPI are: non invasive technique and detection of stress values higher than 100 nm. Some disadvantages are: complex procedure and not applicable in models in vivo.

Conclusion

The photoelastic analysis has been a technique of great importance in health area studies, more specifically in Dentistry. Based on this method of analysis, it is possible to measure the stress distribution and deformation in structures with complex geometry as maxilla and mandible. Furthermore, the photoelastic analysis can improve the resolution of problems and can be helpful

to answer questions not solved by conventional methods of analyses used in Dentistry studies.

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Conservative esthetic solution with ceramic laminates: literature review

Gisely Naura Venâncio1 Rosceline Rodrigues Guimarães Júnior2 Sybilla Torres Dias3

Corresponding author:Gisely Naura VenâncioAvenida José Romão, s/n.º – Colina do Aleixo – São JoséCEP 69086-636 – Manaus – AM – BrasilE-mail: [email protected]

1 Department of Dentistry, Federal University of Amazonas – Manaus – AM – Brazil.2 Department of Dentistry, University Nilton Lins – Manaus – AM – Brazil.3 Department of Dentistry, State University of Amazonas – Manaus – AM – Brazil.

Received for publication: June 5, 2013. Accepted for publication: November 26, 2013.

Abstract

Introduction and Objective: Modern dentistry seeks to offer increasingly esthetic treatments, aimed at patient’s well-being and satisfaction. In this perspective, this study aimed to conduct a literature review on the use of ceramic laminates as conservative and esthetic solution, addressing their indications, contraindications, limitations and its importance in dentistry. Literature review: The evidence in the literature show that the ceramic laminates are used for restoring anterior teeth, reestablishing dental function and esthetic mainly due to its excellent optical property, and preserving tooth structure, as it is necessary less tooth wear to return shape, texture, color and harmony to the teeth involved. Conclusion: It was conclude that this is a treatment option with high success rate when properly indicated, planned and executed according to each case.

Introduction

Esthetic Dentistry is increasingly gaining attention because of the great appealing of the media and beauty

pattern imposed by the society itself. Consequently, the patients’ demands are also increasing in relation to the quality of restorations, mainly those involving the anterior restorations [19].

Keywords: dental veneers; ceramics; dental esthetics.


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Venâncioet al.–Conservative esthetic solution with ceramic laminates: literature reviewConservativeestheticsolutionwithceramiclaminates:literaturereview

Esthetics is the science of either mimicking or harmonizing a restorative treatment with nature, but it should not be restricted to restore shape and function of the teeth; accordingly, it should act on the capacity of reestablish a new smile adapting to the patient’s life style, job, social position as well as highlighting the esthetical features [6].

The development of restorative materials and techniques has been stimulated because of the higher esthetical demanding and searching for a more natural appearance of restorations at dental offices [5]. Current Dentistry seeks “invisible restorations”, which mimics natural teeth executed with the minimum damage to tooth tissues. This union among the improved restorative techniques, materials with biomimetic properties and the philosophy of preserving the remaining tooth structure favors the obtainment of healthy, functional and esthetical smiles [16].

Dental ceramics are a good restorative option attending precepts of smile’s function and esthetics [18]. Among the existing restorative esthetical materials, ceramics has been detached because is the material most similar to the natural appearance of teeth [2]. Ceramics is the material that best reproduces the optical properties of the enamel and dentine, such as fluorescence, opalescence, and translucency, as well as desirable intrinsic features as biocompatibility, high compressive strength and abrasion resistance, and color stability [10].

Ceramic laminates has gained largely acceptance as the main protocol of restoration in esthetics Dentistry. Because patients’ esthetical demands continuously increase, dental staff has been challenged to identify a systematic approach to reach natural oral and facial esthetics with ceramic laminates. The advances in ceramic materials and coating techniques enable the professionals to restore function and esthetics by using conservative and biologically compatible methods to promote oral health at long term [11].

Smile alterations may be caused by different factors, as caries, tooth darkening, aging, bruxism, chemical erosion, and malocclusion providing an imbalance in dentofacial esthetics. Among the procedures indicated to restore the functional esthetical outcome, ceramic laminates are highlighted [4]. Thus, a proper treatment planning comprising study models mounted in semi-adjustable articulator and a good communication with the dental technician will provide greater treatment predictability [18].

The aim of this study was to review the literature on the use of ceramic laminates as conservative

esthetical solution, reporting its indications, contraindications, advantages, and disadvantages, as well as its role in Dentistry as functional and esthetical material.

Literature Review

Definition

Ceramic laminates are a possible conservative esthetical restoration that maintains the tooth structure (because the minimum wear) during the preparations and enable performing a favorable esthetical change with excellent durability [7].

These are an excellent restorative option when well indicated because they require the minimum wear of tooth structure and restore tooth morphology, shape, texture, color and harmony. When bonded to tooth enamel, they show excellent clinical longevity [16].

This type of restoration comprises the coating of the labial surface of tooth enamel by a restorative material, strongly adhered to tooth thorough the most recent advances of the adhesive systems. The restoration can be executed by either direct technique through using resin composite or indirect technique through ceramics [4].

Indications

Ceramic laminates have been indicated in the following situations: teeth with marked color, amelogenesis imperfecta, which require the changing in the crown shape; teeth with large cervical lesions or caries involving the labial surface damaging esthetical appearance; teeth with alteration in positioning on arch, teeth with minimum giroversion or little lingual/labial inclination can be realigned in only two clinical appointments through ceramic laminates. Moreover, short or worn teeth are also indicated because tooth crown lengthening with ceramic laminate achieves a harmonic esthetical outcome in relation to color, shape, and position, but it is essential that the patient shows adequate posterior support [7].

They can be indicated in cases of fractures in young tooth, teeth exhibiting large erosion on labial surface, anterior teeth with cervical restoration, teeth requiring diastema closure, and individual tooth with marked lingual inclination; also, patients desiring whiter and more esthetical teeth [16]. They have been indicated in the case of alteration and

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correction of occlusal relationships, such as guide change and vertical dimension [9].

Contraindications

Teet h w it h reduced crow n s t r uc t u re contraindicates the use of ceramic laminates because when less than the half of the coronal structure is present because of removing large caries lesion or presence multiple restorations, normally there will be a very large limitation to indicate ceramic laminates. Patients showing parafunctional habits, such as harmful mechanical habits (pencil, nail biting) are not ideal candidate for ceramic laminates [7].

Ceramic laminates have been contraindicated in patients presenting severe bruxism; anterior teeth with large composite restoration or excessive destruction; high carious activity; and poor oral hygiene [25].

Advantages

The main advantage of ceramic laminates is esthetics, in addition to less accumulation of plaque when compared with resin composite and longer clinical longevity. Current longitudinal studies, ceramic laminates had a success rate above 90% after 10 years when ceramic restorations were bonded through adhesive technique. Tooth preparation should preserve the enamel as much as possible, because when ceramic laminate is cemented onto teeth prepared on dentine, the success rates may fall close to 60% [1].

Ceramic laminates show as advantage, the longest clinical longevity in comparison with direct resin composite veneers in addition to provide reinforcement to tooth structure [7].

The preparation of veneers with minimum wear, most times, is limited to the labial surface and incisal edge of clinical crown. Generally, laminates have a supragingival terminus or slightly subgingival, sealed with resin cements, so that the gingival health is little or not compromised [25].

Disadvantages

Ceramic laminates show as disadvantages the possibility of dentinal sensitivity and difficult of repairing if fracture occurs. The construction of ceramic laminates exhibited a complex execution both at the clinical and laboratorial steps [2].

It is always a big challenge to aggregate color, shape, surface texture and individual features within a restrained space, leading to high costs. The irreversibility is also a disadvantage, because once installed, future correction is only very limited. A ceramic laminate can only be removed through wearing and replaced by a crown [25].

Very invasive preparations increase the failure chances because the more invasive the preparation, the greater is the risk of fracture or displacement [4].

Over time, color changes may occur due to either ceramic or cement discoloration which causes a slight darkening of the ceramic laminate, jeopardizing the esthetics which is very unpleasant for the patient [25].

Limitations

Additionally to higher cost when compared with direct composite resin technique, the construction of ceramic laminates demands the expertise, ability and knowledge from the dental technician. It also demands care in their handling during the proof and cementation steps, because they are very fragile before the bonding with resin cement [7].

Teeth exhibiting marked crowding, giroversion or labial inclination are very challenge because they normally require the need of executing a large wear during the preparation, which generally makes difficult or even derails the indication of ceramic laminates [7, 25].

Still, other factors can also limit the use of ceramic laminates, such as periodonta l inflammations, low insertion of the labial frenulum, large restorations and marked diastemas [9].

Importance inDentistry

Currently, because of the improvements of adhesive systems, resin cements, and ceramics, it is possible to execute restorative treatments with high esthetical standards and maximum preservation of tooth structure. Among the minimally invasive options, the construction of ceramic laminates have gained attention due to their satisfactory clinical outcomes and proved longevity [6].

Usually, restorative Dentistry executes tooth preparations based on the necessity of minimum thickness for materials, without taking into consideration that, most of times in esthetics, the shape and final position of the tooth will be changed, which causes considerable discrepancies

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in the wear of tooth structure, and consequently in excessive removal of healthy tooth tissue [12].

Ceramic laminates have proved to be a well successful treatment modality for esthetical rehabilitation in clinical practice and in controlled clinical trials. Longitudinal studies have shown excellent outcomes, including low prevalence of displacement, microleakage, fracture and caries [20].

Preparation typesofceramic laminates

By studying the effect of different preparation designs of alumina-reinforced ceramic laminates on tension distribution, researches have compared preparations on the maxillary central incisor comprising only the labial surface with those involving the incisal edge. The study demonstrated that the involvement of the incisal edge exhibited the best outcomes, but the ceramics concentrates most part of the tensions because of its mechanical properties of high rigidity (modulus of elasticity) and low compressibility rate (Poisson coefficient) [28].

The preparation deepness is determined by the color alteration, extension of old composite restorations and tooth position on the arch. At the ending of the preparation, this should be refined with fine-grit diamond points, aiming to remove irregularities and round the angles, making ease the laminate construction and reducing the tension concentration [7]. The preparation of ceramic laminates should be executed conservatively, preserving the incisal edge of the tooth to obtain a wear thickness of 0.5 mm, with chamfer terminus, either supra- or subgingival [23].

The preparation uniformity can be easily achieved by using round diamond points on the cervical area compatible with the wear thickness to be achieved on the labial surface. Approximal wear should be performed with the aid of metal sandpapers to create spaces between the teeth, making easy the impression and posterior cementation. It is important to use a silicon matrix to guide the amount of tooth reduction. Finally, all angles should be rounded through fine-grit diamond points, silicon rubber points, abrasive discs and flet polishing discs, to achieve a final wear of 0.8 mm at medium third height and 0.4 mm at cervical third [24].

Typesofceramics indicated forconstructinglaminates

To construct laminates, there are two options of available ceramics: feldspathic and lithium disilicate [23]. Feldspathic ceramics of low fusion applied on refractory die are the most used for laminates because they provide better adaptation and safeness and are capable of undergoing acid etching [15].

Highly esthetical dental ceramics have a high content of glass and better mimic the optical properties of the enamel and dentine because of the translucity and opacity degree of these totally ceramic systems. Thus, it is important that the professional has a good knowledge on these systems to maximize the esthetical outcome and select materials properly to assure treatment longevity [13].

With regard to the color alteration of pure ceramic restorations and the challenge of choosing the ideal color in minimum preparations on enamel, researches have analyzed the optical properties of different ceramic systems. They believed that the temperature difference and pressing or milling could interfere on ceramic texture and consequently optical property. Thus, 60 specimens with 10 mm of diameter and 5 mm of thickness were constructed with shade A1 of: IPS e-max Press, IPS e-max CAD, IPS Empress Esthetic, IPS e-max Ceram, IPS Inline and IPS Zir Press. The color was evaluated through visual and electronic color scale three times by three calibrated evaluators. Next, the specimens were submitted to aging machine. None of the ceramic systems was capable of altering the color obtained by the color scale; the chemical structure of the ceramics have more effect on determining the optical effect than the construction technique and aging result in a darker, more opaque and yellowish ceramic [3].

Cementationofceramic laminates

Resin cement is the most indicated for cementing laminates with light and chemically-cured (dual) or only light-cured because of the thickness and transparency of laminates [23].

The la minates shou ld be posit ioned simultaneously on teeth, without the use of matrix, with caution regarding to the cement viscosity so that it does not occur maladaptation of laminates, and light-curing for five seconds to make easy the cleaning of the resin excess around the margins [27].

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A study concluded that the increase of the ceramic coating from 0.5 to 0.7 mm does not significantly affect the final color of ceramic laminates constructed through CAD-CAM system after cementation; however, the final color is significantly affected whether this thickness is reduced to 0.3 mm and the type of resin cement is a factor influencing on the color alteration of laminates in addition to their thickness [22].

The longevity of ceramic laminates is associated with the outcome predictability by planning and execution techniques, favoring the patient/professional relationship and surpassing positively the mutual expectations. Thus, it is important to use the proof paste previously to the cementation of ceramic laminates, an important tool to decrease errors, define esthetical outcome predictability and consequently the patients’ satisfaction, because the use of Try-In paste is an essential step in the rehabilitation process with ceramic laminates [4].

A study conducted aiming to evaluate the color influence of the resin cement on the final shade of minimally invasive ceramic laminates after the artificial accelerated aging (AAA), was performed with 20 bovine teeth. These were collected, prepared, and divided into two groups. For group I (n = 10) the resin cement White-Opaque (WO) base paste was used, and for group II (n = 10) Yellow (Y) base paste. Each specimen was light-cured for 60 seconds. The specimens were then submitted to AAA. Color readings were executed with the aid of a spectrophotometer at three moments: after preparation (only the substrate), after cementation and polymerization and after AAA. Values of L*, a* and b* were obtained and total color change was c�lcul�ted (�E��. T�e �ut�� c��cluded t��t ��t��E��. T�e �ut�� c��cluded t��t ��t�E*). The authors concluded that both cements were capable of masking the substrate color. After AAA, only Y showed a clinically unacceptable �E� v�lue, �ec�mi�� m��e �ell�� (��e�te� �� dE* value, becoming more yellow (greater b*) and loosing luminosity (smaller L*) [17].

The cementation technique itself consists of separately treating the internal surface of the laminate with 10% hydrofluoric acid aiming to create retentions and improve bonding strength between the ceramic and resin cement; following, to wash the laminate for 60 seconds, dry and activate the surface with silane agent for 60 seconds. However, it could be differences in the preparation of the laminate regarding to the exposure time to hydrofluoric acid, which ranges according to the restoration material, from 2 minutes for feldspathic ceramics, 60 seconds for leucite-reinforced ceramics and 20 seconds for lithium disilicate ceramics [8, 14].

Discussion

The esthetics, for the human being, is a highly subjective concept, because it is related to social, cultural and psychological factors that are altered in function of time, life values and individual’s age. Accordingly, the evaluation of the patients’ expectations and the understanding of the therapeutic solutions are essential previous to begin any treatment planning [5, 6, 21].

In this context, an observational cross-sectional study conducted through questionnaire with undergraduates aimed to verify the esthetical self-perception of the smile. The results showed that women were more dissatisfied with their own smile than men and the first semester undergraduates would like to have whiter teeth [21].

The ceramic restorat ive materia ls have demonstrated many advantages, with main advantage a natural esthetics without presenting significant alterations regarding to its color or superficial texture. Undoubtedly, it is material that best mimics natural teeth in color and translucency in addition to show biocompatibility, good compressive strength, color stability, radiopacity, and simulate tooth appearance [10, 18, 19, 21].

Ceramic have also exhibited some disadvantages, such as low mechanical resistance and the presence of microporosities on the surface. These latter may predispose the material to crack propagations that may lead to restoration failure. Moreover, they have presented high costs and difficulty of repair in cases of fractures [2, 25].

Current restorative Dentistry states that, for any procedure type, the dental professional should always opt by the most conservative treatment. Thus, the esthetical rehabilitation through ceramic laminates is the most indicated treatment because its preparation preserves the tooth remnant the most [2, 4, 6, 19].

Ceramic laminates are contraindicated for patients exhibiting parafunctional habits as bruxism and those with poor oral hygiene; however, a strict and multidisciplinary planning enables the adequacy of probable contraindications of ceramic laminates [5, 6, 25].

The preparation for ceramic laminates should preserve the maximum of tooth enamel, because when the preparation is executed on dentine, the success rates may decrease. The preparations on enamel have exhibited greater advantage, because the adhesive systems show smaller degradation and greater bonding strength to tooth enamel. Enamel terminus assures a smaller microleakage rate and greater restoration longevity [1]. On the other hand,

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a dentine terminus demand the dentinal sealing technique immediately after the preparation ending to improve the bonding of the laminates and decrease microleakage that is significant when the cervical margin of the preparation is on dentin [6]. Because of the thin thickness of ceramic laminates, the color of tooth substrate may compromise the final esthetic outcome. Therefore, to neutralize the influence of this substrate, the professional should previously perform tooth bleaching and/or employ a variety of color of resin cements [4].

When the ceramic/resin cement ratio is greater, a larger ceramic area exists to distribution the tensions to the adhesive interface and underlying dentin. However, the desirable action of the adhesive interface in promoting a tension absorber layer is doubtful, because the alumina-reinforced ceramics does not react to acid treatment and adhesive cementation as similar as the feldspathic ceramics and thus, certainly concentrates more tensions [28].

To achieve restorative treatment success, one should have a good treatment planning comprising study models mounted in semi-adjustable articulator and a good communication between the dentist and technician to allow greater treatment predictability through the interaction among the dentist, technician and patient [5, 18].

Conclusion

According to the evidences found in the literature reviewed, it can be concluded that ceramic laminates are an excellent esthetic solution for anterior teeth, because of the good optical properties of dental ceramics in addition to the very conservative treatment that returns the patient’s health, wellness and harmonic smile.

References

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2. Aquino APT, Cardoso PC, Rodrigues MB, Takano AE, Porfírio V. Facetas de porcelana: solução estética e funcional. Clín Int J Braz Dent. 2009Clín Int J Braz Dent. 2009 Apr-Jun;5(2):142-52.

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5. Carvalheira TB, Goyatá FR, Rodrigues CRT, Souza MCA. Resolução estética em dentes anteriores com coroas totais livres de metal – relato de caso clínico. IJD. 2010 Apr-Jun;9(2):102-6.

6. Clavijo VGR, Monsano R, Oliveira-Júnior OB, Andrade MF. Laminados cerâmicos. Clín Int J Braz Dent. 2008 Apr-Jun;4(2):164-73.

7. Conceição EM. Dentística: saúde e estética. 2. ed. Porto Alegre: Artmed; 2007. p. 480-6.

8. Della Bona A, Donassollo TA, Demarco FF, Barrett AA, Mecholsky Jr JJ. Characterization andCharacterization and surface treatment effects on topography of a glass-infiltrated alumina/zirconia-reinforced ceramic. Dent Mat. 2007 Jun;23(6):769-75.

9. Gonzalez RM, Rit to FP, Lacerda RAS, Sampaio HR, Monnerat AF, Pinto BD. Falhas em restaurações com facetas laminadas: uma revisão de literatura de 20 anos. Rev Bras Odontol. 2011 Jul-Dec;68(2):238-43.

10. Guerra CMF, Neves CAF, Almeida ECB, Valones MAA, Guimarães RP. Estágio atual das cerâmicas odontológicas. IJD. 2007 Jul-Sep;6(3):90-5.

11. Gupta S, Raisingani D, Misra P. Esthetic rehabilitation with ceramic veneers: a case report. IJCD. 2011 Jan;2(1):13-7.

12. Hirata R, Andrade OS, Kina S, Fukugawa AF. Laminados cerâmicos: visão clínica. Jornal do ILAPEO. 2009 Jan-Mar;3(1):16-20.2009 Jan-Mar;3(1):16-20.

13. Kelly JR. Dental ceramics: what is this stuff anyway? J Am Dent Assoc. 2008;138:4S-7S.

14. Kim BK, Bae HE, Shim JS, Lee KW. The influence of ceramic surface treatments on the tensile bond strength of composite resin to all-ceramic coping materials. J Prosthet Dent. 2005J Prosthet Dent. 2005 Oct;94(4):357-62.

15. Kina S. Cerâmicas dentárias. R Dental Press Estét. 2005;2(2):112-28.

16. Lobo M, Stefani A, Siqueira-Júnior S, Pena CE, Andrade OS. Caso clínico selecionado: laminados cerâmicos minimamente invasivos. Dent Bras. 2011 Mar;31:1-38.

17. Magalhães APR, Siqueira PC, Cardoso PC, Souza JB, Fonseca RB, Souza FCPP et al. InfluenceInfluence of the resin cement color on the shade of porcelain veneers after accelerated artificial aging. ROBRAC.ROBRAC. 2013;21(60):11-5.

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18. Marques JLS, Fernandes CMO, Cardoso PC, Torres EM, Rocha SS. Reabilitação estética-funcional com ajuste prévio da oclusão em relação cêntrica. ROBRAC. 2010;19(51):356-61.

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Relining of removable dentures: a literature review

Cinthia Sawamura Kubo¹Fabrício Reskalla Amaral¹Edson Alves de Campos¹

Corresponding author:Cinthia Sawamura KuboDepartamento de Odontologia Restauradora Faculdade de Odontologia de Araraquara – Universidade Estadual Paulista Júlio de Mesquita FilhoRua Humaitá, n. 1.680CEP 14801-903 – Araraquara – SP – BrasilE-mail: [email protected]

¹ Department of Restorative Dentistry, School of Dentistry of Araraquara, Sao Paulo State University – Araraquara – SP – Brazil.

Received for publication: June 26, 2013. Accepted for publication: November 12, 2013.

Keywords: denture; partial denture; reline materials; literature review.


Abstract

Introduction: The alveolar bone resorption that occurs after tooth loss leads to maladaptation of prostheses over the mucosa, causing discomfort to the patient. However, these maladaptations can be solved by prosthesis relining. Objective: The aim of this study was to discuss based on the literature, the relining of complete and partial removable dentures. Literature review: Dentistry makes use of relining materials that can be either rigid or resilient, having a temporary or permanent characteristic. However, to obtain a satisfactory result, the knowledge of their indications, contraindications, advantages, disadvantages is required, in addition to the characteristics and types of materials. Patients should be aware of the importance of constant monitoring, or even the need to reline their dentures, as it is not possible to determine the biological tolerance of each individual. Conclusion: The installation and proservation phases become essential to minimize bone resorption, and also to achieve rehabilitative treatment success.

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Kuboet al.–Relining of removable dentures: a literature reviewReliningofremovabledentures:aliteraturereview

Introduction

The alveolar bone resorption occurring after tooth loss has been classified as a chronic, progressive, and cumulative disease of bone repairing that can lead to maladaptations of the prostheses. It appears to be continuous over the life of totally-edentulous or partially-edentulous patients [30]. In rehabilitative cases with complete and partial removable dentures, this resorption compromises the adaptation of the prostheses, many times also damaging the speech and mastication. Therefore, prosthesis relining is indispensable to recover the biomechanical properties and occlusion and to provide comfort to patient [19].

According to Silva et al. [29], when properly indicated and used, relining materials promote interesting final outcomes in relation to patient’s comfort. Notwithstanding, the clinical effectiveness depends on the knowledge of its features, indications and properties, having a definitive or temporary characteristic [5]. Prosthesis relining can be achieved through direct or indirect techniques; rigid or resilient materials especially made for this purpose [30, 33, 34].

Current studies have indicated an alternative method for the polishing of dentures [7], indicators of the measurement of bone resorption [20] and reduction of alveolar bone resorption [11]. Although the prosthesis clinical success over time has been high, the continuous monitoring of the patient should be considered [3, 22, 33]. Thus, the installation and monitoring are indispensable steps for the success of the rehabilitative treatment. Questions of the installation and monitoring of the prostheses have been raised because the latter are important to minimize bone resorption and consequently leading to rehabilitative treatment success. Therefore, it seems appropriate the conduction of a literature review to discuss the guidelines of complete and complete denture relining.

Literature review

Boneresorption

Bone resorption is the main cause of removable prosthesis maladaptations; however this latter may also occur due to failures in impression or acrylization during the prosthesis construction. Many factors may alter the balance between the process of bone formation and resorption. According to Baat et al. [10], the main factors related to the

resorption intensity have been the edentulous period and the mechanical action on the mucosa. Aquino et al. [1] have also cited the time of prosthesis use, age, route of force transmission towards the alveolar bone, site of the edentulous area, antagonist arch, adaptation of the niche support and saddle extension, finding the mean maladaptation of the saddle base of removable partial dentures (RPD) of 0.27 mm at the period from 1 to 5 years of use. Among the systemic factors, the literature has reported the advanced age, low calcium ingestion, diabetes, osteoporosis, corticosteroids use and estrogen deficiency [10, 11, 24].

Alveolar bone resorption (ABR) involves the chronic, progressive, and cumulative bone resorption process, so that the bone tissue undergoes an intermittent metabolic activity over life, resulting in the gain or loss of bone mass [27]. Kliemann and Oliveira [19] emphasized the importance of RPD relining because even if the patient is undergoing resorption stability, due to a systemic disease the physiologic tolerance balance may be altered and functional forces become damaging.

Barbosa et al. [3] studied the cl inica l procedures for the installation of complete dentures, highlighting the evaluation of the prosthesis edges and occlusal adjustment. The authors concluded that the continuous monitoring of the patient by the professional should be considered. The CD installation is an important procedure to aid in rehabilitative treatment predictability because it is not possible to determine the biological tolerance of each individual. The proper installation provides greater comfort and consequently a greater prosthesis acceptance. Some techniques have been employed to improve prosthesis stability. Barbosa et al. [4] considered that one of the limitations occurring due to resorption is the shallow labial vestibule, which may compromise the prosthesis stability at the impression act. Among the techniques of vestibule deepening, vestibuloplasty with secondary epithelialization is the one providing the most adequate outcome in addition to an advantageous procedure.

Oliveira et al. [24], by discussing on the osteoporosis manifestations, emphasized the importance of panoramic radiographs in the evaluation of the alteration rates of oral cavity, making possible to achieve a proper referral of the patients in addition to the access of bone quality. Telles [33] highlighted that patients rehabilitated through mucous-supported dentures should be annually monitored so that the levels of bone resorption and possible maladaptation of the base with the mucosa can be verified.

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By relating bone resorption with the use of de�tu�e�, K��jčić et al. [20] proposed as bone resorption indicators the measurement between the thickness of the RPD base and the space of interocclusal resting, before and after the relining of prostheses. The interocclusal resting space has been defined as the distance (in mm) between the maxillary and mandibular central incisors when the patient’s mandible is at physiologic resting position. The results showed statistically significant differences between the measurements performed in the study.

Relining technique

Tamaki [32] defined the relining as the readjustment of the denture base by the addition of a new material amount, which is indicated: in cases of maladapted CD not responding to retention and stability tests at the delivery moment; or in cases after use they lost these properties. Notwithstanding, during the technique description through employing a surgical guide for alveolotomy, the author affirmed that relining is not necessary. Telles [33] indicated immediate CD relining at 3 to 6 months after its installation; in maladapted prosthesis due to residual edge resorption; for correcting maladaptation problems of new prosthesis base; and in prosthesis that will be used as templates for planning and installation of osseointegrated implants.

By considering removable partial dentures (RPD), Kliemann and Oliveira [19] has classified the relining regarding to procedure type (mediate and immediate); support type (tooth-supported and tooth-mucosa-supported); prosthesis treatment type (relining and rebasing). They considered the mediate better than immediate relining in relation to technique, durability, materials used, greater reproduction of details, adequate flow, and low porosity and it is commonly indicated in cases of free-end PRD.

Reliningmaterials

Rigid materials

Acrylic resins appear in Dentistry at middle 1930s to replace vulcanized rubber that although showing satisfactory physical and mechanical properties did not present good esthetic [26, 28, 29, 33]. Acrylic resins have been indicated for immediate and mediate relining, also for rebasing

of maladapted prostheses not responding to the retention and stability tests at the delivery moment, and in case of property lost after sometime of use [9, 32].

Silva [30] recommended as alternative for CD maladaptation the acrylic resin relining. The author assumption is based in a clinical case in which a considerable improve of patient’s mastication and speech was seen. The author considered this a simple technique, at one stage, with excellent outcomes for the patient, also highlighting that relining would be contraindicated in cases of prostheses with great tooth wear or malpositioned teeth; premature contacts or interferences; patients exhibiting an inflamed or hyperplastic support mucosa; loss of vertical dimension greater than 3 mm or lack of interocclusal space.

The composition of acrylic resins for relining is an important factor to be analyzed. Urban et al. [34] evaluated the percentage of residual monomer within different brands and concluded that some of the most used resins exhibited high percentage of residual monomers that can compromise the mechanical properties and cause allergic reactions. By evaluating the cytotoxicity of three acrylic resins, Ebrahimi et al. [12] found that all tested resins exhibited a certain cytotoxicity degree and indicated to emerge the prostheses in water for 24 hours previous to their delivery.

The materials employed as prosthesis bases should show proper mechanical properties. Azevedo et al. [2] observed the hardness of three acrylic resins. The authors concluded that hardness increased during the dry storage period and after this, water immersion resulted in softening of the specimens generating significant hardness reduction. Acrylic resin hardness may cause discomfort, accordingly Eduardo [13] researched the tension behavior on support structures of CD finding that the specimens constructed in acrylic resin and resilient material (silicon) promoted a more comprehensive tension distribution and they were the base type more recommended for CD.

The shear bond strength of four rigid resins for relining was evaluated by Neppelenbroek et al. [23]. The bond strength values of rigid relining resins were similar. Acrylic resin samples were polished conventionally at the laboratory or polished by using in-office polishing kits. It was found that this latter was an alternative and effective procedure when the laboratorial polishing was not applicable [7].

According to Silva et al. [28], many researches have been developed aiming to improve the acrylic resin characteristics, highlighting microwave

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polymerization. Its use has been described as an excellent method because these resins can be an important alternative for the faster and lower cost production of prostheses. Because of the good properties presented, Costa Junior et al. [8] concluded that microwave polymerization technique provides a decrease of the polymerization time, reducing the laboratorial working time. The pores within thermo-activated resin may hinder the esthetic and lead to fracture possibility and distortion of the prosthesis bases. By analyzing the acrylic resin polymerization with microwave oven on water immersion, Rossato et al. [26] found that there was no alteration on the resin porosity, with or without water immersion.

Currently, the acrylic resin is the most accepted material for relining because it is considered as adequate for readapt ing on ora l cav ity, without damaging the tissues. According to the manufacturers, these resins are definitive immediate reliners and did not require posterior replacement due to material degradation. I can be inferred that their properties are similar to those of the material used in the prosthesis base [9].

Resilient materials

Resilient materials can be used to stabilize the prosthesis and condition the mucosa. In cases of maladapted prostheses, these materials reduce inflammations and lesions and have been indicated for implanted-supported prostheses [13]. According to Carvalho [6], chemically-activated resilient resins can be used as either temporary or permanent material, with advantage of enabling the best adaptation of patients to prostheses. Tissue conditioners are other option of temporary materials used in prosthesis relining after surgeries or to recover an irritated or inflamed tissue.

Many indications for the use of resilient materials have been cited, e.g., retentive areas, resorbed alveolar edges, alveolar crest areas, areas of compression relief, recently operated patients, patients presenting tooth development alterations or xerostomia, as reported by Carvalho [6], Eduardo [13] and Silva et al. [29]. Bulad et al. [5] listed some limitations regarding the use of resilient materials: problems when the rigid base thickness is minimum; instability in water; porosity; discoloration caused by some cleaning methods; failure in the adhesion between the resilient and acrylic base; difficulty in finishing and polishing.

For soft tissue surgeries, Eduardo et al. [14] indicated the immediate relining through tissue

conditioners. The authors affirmed to obtain a provisional prosthesis that was kept stable during all period of tissue recovering with satisfactory post-operative period, excellent clinical appearance and faster and painless recovering period.

By evaluating the inf luence of chemical disinfection and storage, permanent deformation and porosity of three resilient reliners, Goiato et al. [16] found that all resilient reliners underwent deformation, even when submitted to chemical disinfection. By assessing the microorganism presence on soft reliner surface, with or without glaze application, Goyatá et al. [18] concluded that glazed reliners showed smaller microorganism presence. Landa et al. [21] evaluated the influence of glaze application on the superficial roughness of three reliners. The authors observed that Soft Comfort Denso was the resilient reliner that presented the smallest alteration on the superficial roughness with and without glaze application.

The lack of retention and stability and prosthesis fracture has been the major causes of searching for treatment at dental offices [17]. Both the repair and posterior relining promote stability and retention, giving more safeness and comfort, returning the function, speech and esthetics. Eduardo [13] emphasized that resilient materials have limited durability, fact also confirmed by Elsemann et al. [15].

Oliveira et al. [25] verified the effect of sealant application and storage time on the permanent deformation of a tissue conditioner (Coe Comfort-GC). The authors demonstrated that the studied conditioner showed longevity of at maximum one week, and after that it requires replacement, without advantages for sealant application. Silva et al. [29] affirmed that the use of resilient bases promoted interesting final outcomes regarding patient’s comfort, but these materials can deteriorate within a short time period. The authors emphasized that clinical effectiveness depends on the knowledge of this characteristics, indications and properties. Patients submitted to this treatment should be aware of the need of constant monitoring or reliner replacement due to the material limitations.

Discussion

Many authors are unanimous in affirming that because of tooth and periodontal ligament loss, and consequently of the local stimulus acting on alveolar bone, such periodontosis and traumas, bone resorption is initiated [1, 4, 19]. This seems to be

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continuous over edentulous or partially-edentulous patients’ life and may cause the maladaptation of prostheses during speech and mastication [20, 30].

The prosthesis can be relined by laboratorial or in-office procedures. Direct (immediate) relining does not require that the patient stays without the prosthesis. It is a simple technique that extends the usage time [23, 30]. On the other hand, indirect (mediate) relining consists in a laboratorial clinical procedure, generally employing the prosthesis itself as customized tray. Mediate is better than immediate relining due to its technique, durability, material employed, greater detail reproduction, proper flow and low porosity [19, 33]. Notwithstanding, the period that the patient is without the prosthesis and the laboratorial steps that may induce error have been cited as disadvantages [13, 19, 33]. It is commonly indicated for free-end RPD, according to Kliemann and Oliveira [19], and complete dentures according Telles [33].

The relining materials should exhibited adequate properties, such as easy technique, high durability, good dimensional stability and detail reproduction, proper flow, and low porosity [19]. Rigid compared with resilient resins have shown superior qualities, as greater color stability, lower porosities, lower heat releasing, and greater durability [30].

Self-curing acrylic resins have been the most accepted for relining because of the lower polymerization temperature, which is adequate for oral cavity without damaging the tissues [30, 34]. Also they show good resistance and acceptance by patients [13, 25], resistance to abrasion, are impermeable to oral fluids [8] and have certain dimensional stability and esthetic feature [26]. The application of resilient/soft materials for prosthesis relining has been researched aiming at the comfort and masticatory effectiveness. Soft liners, so-called resilient reliners, are a group of elastic materials that can be used either temporary or definitive, decreasing the impact of the masticatory force on the underlying mucosa [13, 15, 29].

Resin liners presenting polymethylmethacrylate causes an important irritation on oral mucosa [34]. Additionally to the replacement of this component, the introduction of other monomers improved these materials, fact proved by Azevedo et al. [2] and Silva [30]. Acrylic resins are commercially available in two flasks containing the polymer and monomer. The polymerization process, in which the monomers are converted into polymer is not complete, always resulting in residual monomer [15, 16]. Ebrahimi et al. [12] evaluated the cytotoxicity of three acrylic

resins and found that all tested resins induced a certain cytotoxicity degree.

Resilient reliners do not exhibit a satisfactory longevity. Its use should be associated with a strict monitoring because of the resilient characteristic of the material may be lost over time [15, 29]. Additionally, frequent displacements between resilient reliners and the prosthesis base also decrease its useful lifetime [15, 29, 30]. In an attempt to extend the softness and resilience and avoid porosity of tissue conditioners, Eduardo [13] and Eduardo et al. [14] indicated the immediate post-surgical relining and affirmed that the reliners can stay for 5 to 6 months, decreasing the costs and avoiding successive material changes.

According to Bulad et al. [5] and Silva et al. [29], resilient materials have some limitations regarding to its use, such as the instability in water, porosity, discoloration and difficulty of polishing. Some authors have recommended using as temporary material [14, 18]. In the study of Landa et al. [21] glaze application influenced on superficial roughness of reliners. Goyatá et al. [18] reported that it also decreased the accumulation of oral microorganisms.

Thus, regardless of the material choice, to perform an adequate relining, it is necessary that both oral cavity and the mucosa are at a good health state. Otherwise, the use of tissue conditioners or temporary materials is the most indicated [19]. Patients should be aware that their prostheses will not last forever. Periodically, the degree of bone resorption, prosthesis adaptation, masticatory efficiency, and hygiene conditions should be assessed.

The literature has established that, except from immediate complete dentures requiring relining at a shorter time period [33], the mean period for periodical relining procedures is six years for a complete denture [22] and three years for removable partial prostheses [19]. Although many prostheses are successfully for years, the continuous monitoring of the patient ought to be considered, because it is not possible to determine the biological tolerance of each individual [3, 9, 33]. Therefore, both the installation and monitoring of removable prostheses are indispensable steps for rehabilitative treatment success.

Conclusion

Based on this literature review, it can be concluded that removable prosthesis relining should

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be performed from 1 to 4 months after tooth extractions, preferably through immediate relining technique and with self-curing acrylic resin. In-use removable prostheses should be relined from 1 to 5 years, preferably through mediate relining technique and with self-curing acrylic resin. It is worth emphasizing that to reach complete and partial prosthesis relining success, it is necessary the knowledge of the indications, contraindications, advantages, disadvantages, characteristics and types of relining materials.

References

1. Aquino AR, Barreto AO, de Aquino LM, Ferreira ÂM, Carreiro Ada F. Longitudinal clinical evaluation of undercut areas and rest seats of abutment teeth in removable partial denture treatment. JJ Prosthodont. 2011 Dec;20(8):639-42.

2. Azevedo A, Machado AL, Vergani CE, Giampaolo ET, Pavarina AC. HardnessHardness of denture base and hard chair-side reline acrylic resins. J Appl OralJ Appl Oral Sci. 2005 Sep;13(3):291-5.

3. Barbosa DB, Barão VAR, Assunção WG, Gennari Filho H, Goiato MC. Instalação de prótese total: uma revisão de literatura. Rev Odontol UNESP. 2006;35(1):53-60.

4. Barbosa FQ, Rocha FS, Batista JD, Magalhães AEO, Zane t t a -Barbosa D , Marquez IM . Aprofundamento de vestíbulo pela técnica de Kazanjian modificada: relato de caso. Rev InpeoRev Inpeo Odontol. 2008 Aug-Dec;2(2):1-56.

5. Bulad K, Taylor RL, Verran J, McCord JF. Colonization and penetration of denture soft lining materials by Candida albicans. Dent Mat. 2004Dent Mat. 2004 Feb;20(2):167-75.

6. Carvalho LPR. Soluções para quem perdeu (todos) os dentes. Rev APCD. 2001 Mar-Apr;55(2):73-81.Rev APCD. 2001 Mar-Apr;55(2):73-81.

7. Chatzivasileiou K, Emmanouil I, Kotsiomiti E, Pissioti A. Polishing of denture base acrylic resin with chairside polishing kits: an SEM and surface soughness study. Int J Prosthodont. 2013 Jan-Feb;26(1):79-81.

8. Costa Junior HC, Zanetti RV, Junqueira JLC, Santos VMA. Análise de resinas acrílicas polimerizadas por energia de microondas em relação ao método convencional. Rev Gaúc Odontol. 2005 Oct-Dec;53(4):307-12.

9. Cucci AL, Vergani CE, Giampaolo ET, Pavarina AC, Bercial ME. Resinas para reembasamento imediato: resistência à tração e alongamento. RevRev Odontol UNESP. 1998;27(1):299-309.

10. De Baat C, Kalk W, Van’t Hof M. Factors connected with alveolar bone resorption among institutionalized elderly people. Community DentCommunity Dent Oral Epidemiol. 1993 Oct;21(5):317-20.

11. Deves C, de Assunção TM, Ducati RG, Campos MM, Basso LA, Santos DS et al. The transition state analog inhibitor of purine nucleoside phosphorylase (PNP) Immucillin-H arrests bone loss in rat periodontal disease models. Bone. 2013 Jan;52(1):167-75.

12. Ebrahimi SM, Vojdani M, Bahrani F. Evaluation of cellular toxicity of three denture base acrylic resins. J Dent. 2012 Dec;9(4):180-8.J Dent. 2012 Dec;9(4):180-8.

13. Eduardo JVP. Materiais macios usados em base de prótese total para reembasamento direto e indireto. Rev APCD. 1997 Nov-Dec;51(6):531-3.

14. Eduardo JVP, Haypek P, Machado MSS. Cirurgia pré-protética utilizando laser de diodo associada a reembasamento com condicionador de tecidos: relato de caso clínico. Rev Bras Prot Clín Lab. 2003;5(27):396-401.

15. Elsemann RB, Santos VMA, Ishikiriama A, Zanetti RV, Zanetti AL. Reembasamento das próteses totais. Rev Gaúc Odontol. 2003 Oct;51(4):371-6.

16. Goiato MC, Guiotti MA, Ribeiro PP, Santos DM, Antenucci RMF. Materiais reembasadores: estudo da deformação inicial, permanente e porosidade. Ciências Odontol Bras. 2007 Jul-Sep;10(3):44-52.

17. Goyatá FR, Gonçalves PAM, Manta GF, Carvalheira TB, Ferreira NG. Reembasamento em prótese total: relato de caso clínico. Dental Scien Clin e Pesq Integ. 2009;393:39-46.

18. Goyatá FR, Gonçalves PAM, Bello RF, Ferreira NG, Ferreira TG, Coelho SM. Avaliação quantitativa de microrganismos orais em materiais reembasadores de prótese total. Int J Dent. 2009 Apr-Jun;8(2):79-81.

19. Kliemann C, Oliveira W. Manual de prótese parcial removível. 1. ed. Santos: Livraria; 2006.

20. K��jčić J, K��telić Stu�ić M, Cele�ić A, K�m�� D, Me�ulić K, V�jv�dić D. Denture relining as an indicator of residual ridge resorption. Med Glas Ljek Komore Zenicko-doboj Kantona. 2013 Feb;10(1):126-32.

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21. Landa FV, Goyatá FR, Hespanhol FL, Dias AL, Cunha LG, Gonçalves PAM et al. Influência da aplicação do glaze na rugosidade superficial de três materiais reembasadores. Int J Dent. 2009 Jul-Sep;8(3):124-7.

22. Nakamae AEM, Cunha EF, Tamaki R, Guarnieri TC. Avaliação da retenção de próteses totais bimaxilares em função das características da área basal. RPG Rev Pós Grad. 2006;13(1):69-76.

23. Neppelenbroek KH, Pavarina AC, Gomes MN, Machado AL, Vergani CE. Bond strength of hard chairside reline resins to a rapid polymerizing denture base resin before and after thermal cycling. J Appl Oral Sci. 2006 Dec;14(6):436-42.

24. Oliveira LSAF, Neves FS, Torres MGG, Crusoé-Rebello IM, Campos PSF. Características radiográficas dos portadores de osteoporose e o papel do cirurgião-dentista no diagnóstico. Rev Ciênc Méd Biol. 2009 Jan-Apr;8(1):85-90.

25. Oliveira LV, Matta RVL, Mesquita MF, Henriques GHP, Consani RLX. Efeito da aplicação de selante e da armazenagem sobre a deformação permanente de um condicionador de tecidos. Rev Saú Com. 2008;4(2):97-104.

26. Rossato MB, Montagner H, Scheid PA, Burmann PA, Braun KO. Influência da imersão em água na porosidade de resina acrílica polimerizada por energia de microondas. Rev Odontol Ciênc. 2008;23(4):342-5.

27. Santiago JL, Marcucci M, Avolio G. Osteoporose e Odontologia. Rev Reg Araçatuba Assoc Paul Cir Dent. 2006;12:4-5.

28. Silva SMLM, Bindo MJF, Leão MP. O uso de energia de microondas para polimerização de resinas acrílicas. Rev Dens. 2006 May-Oct;14(1):12-21.

29. Silva AG, Seraidan PI, Jansen WC. BasesBases resilientes: uma revisão. Rev Odontol de Araçatuba. 2007 Sep-Dec;28(3):56-62.

30. Silva RJ. Reembasamento direto para prótese total: uma alternativa simples e eficiente – relato de caso clínico. Int J Dent. 2008 Jul-Int J Dent. 2008 Jul-Sep;7(3):190-4.

31. Sverzut CE, Gabrielli MFR, Vieira EH, Sverzut AT. Avaliação radiográfica da altura mandibular anterior após vestibuloplastia por inversão de retalhos: estudo em humanos. Pesq Odontol Bras. 2001 Apr-Jun;15(2):133-7.

32. Tamaki T. Dentaduras completas. 4. ed. São Paulo: Sarvier; 1988.

33. Telles D. Prótese total – convencional e sobre implantes. 1. ed. São Paulo: Santos; 2009.

34. Urban VM, Machado AL, Vergani CE, Giampaolo ET, Pavarina AC, Almeida FG et al. Effect of water-Effect of water-bath post-polymerization on the mechanical properties, degree of conversion, and leaching of residual compounds of hard chairside reline resins. Dent Mat. 2009 May;25(5):662-71.2009 May;25(5):662-71.25(5):662-71.662-71.

Case Report Article

Hypochlorite-induced severe cellulitis during endodontic treatment: case report

Bernardo Almeida Aguiar1

Fábio Almeida Gomes2

Cláudio Maniglia Ferreira2

Bruno Carvalho de Sousa3

Fábio Wildson Gurgel Costa4

Corresponding author:Bruno Carvalho de Sousa Rua Andrade Furtado, n. 1.245 – ap. 602 – CocóCEP 60192-072 – Fortaleza – CE – BrasilE-mail: [email protected]

1 Department of Endodontics, Center of Dental Specialties Odontológicas Ícaro de Souza Moreira – Sobral – CE – Brazil.2 Department of Endodontics, Fortaleza University – Fortaleza – CE – Brazil.3 Department of Endodontics, Federal University of Ceará – Campus Sobral – Sobral – CE – Brazil.4 Department of Oral Radiology and Stomatology, Federal University of Ceará – Campus Sobral – Sobral – Brazil.

Received for publication: March 27, 2013. Accepted for publication: September 10, 2013.

Keywords: sodium hypochlorite; root canal treatment; complications; management.


Abstract

Introduction: Sodium hypochlorite is a solution used in endodontic treatment, and if an accidental apical extrusion occurs, serious complications may affect soft tissue. Objective: The aim of this article is to present a case of apical extrusion of sodium hypochlorite (NaOCl) during root canal system instrumentation. Case report: A 28-year-old woman sought a local dental service for root canal treatment of tooth #24. Conventional endodontic treatment was adopted, which consisted of the use of 2.5% NaOCl solution as irrigation solution applied with a 10-ml syringe and 22G hypodermic needle. At that time, the patient reported extreme pain and a burning sensation in the left maxillary region, followed by the formation of intense edema. A clinical diagnosis of hypochlorite-induced cellulitis was made. The patient was treated immediately with amoxicillin (500 mg, orally) at intervals of 8 h for 7 days and dexamethasone (4 mg, intramuscularly) at intervals of 24 h for 3 days. In the subsequent endodontic treatment, 2% chlorhexidine gel applied with a 5-ml syringe and 24G needle was used as irrigation for a better control of treatment and to prevent new accidents. The root canals were instrumented using adequate crown-down technique, which provides a conical shape, and filled by lateral condensation technique. The patient was symptom free at the 8-month clinical

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Aguiaret al.–Hypochlorite-induced severe cellulitis during endodontic treatment: case reportHypochlorite-inducedseverecellulitisduringendodontictreatment:casereport

follow-up. Conclusion: Dentists should always carefully follow all stages of dental treatment planning without neglecting any of them, paying attention to the solutions used and their storage as well as performing a specific technique with maximum accuracy. If an accident occurs, the appropriate handling of the situation will enable the satisfactory completion of treatment.

Introduction

Sodium hypochlorite (NaOCl) is a commonly used irrigation solution in root instrumentation, showing the property of dissolving organic tissue [7, 8]. Accidental apical extrusion of NaOCl during endodontic canal preparation can cause serious soft tissue complications [2]. These complications are probably a consequence of the alkaline and hypertonic nature of different NaOCl solutions that have cytotoxic effects, causing tissue damage especially at concentrations higher than 0.01% [15].

Several problems have been associated to NaOCl toxicity, including soft tissue and bone necrosis [14] ulceration [7], facial nerve disturbance [16], as well as inhibited neutrophil migration, hemolysis and damage to endothelial and fibroblast cells [2, 4, 9]. Forty nine cases of NaOCl accidents were reviewed from the literature and added a case in which NaOCl was mistaken for anesthetic solution and infiltrated into the buccal mucosa during routine root canal treatment [13]. We recently attended a healthy adult woman who developed important facial cellulitis during a conventional endodontic treatment. The purpose of this case is to present a serious problem that may occur during irrigation of root canal, discuss how to avoid it and present a protocol suitable for solving the problem of effective and safe manner.

Case report

A 28-year-old woman sought a local dental service for root canal treatment of tooth #24. Diagnosis radiograph showed two canals in this tooth, no periapical lesion and clinical diagnosis was irreversible pulpitis. Conventional endodontic treatment was adopted, which consisted of the use of infiltrative anesthesia and endodontic access.infiltrative anesthesia and endodontic access. Radiographic odontometry was performed using technique of changing the horizontal angle of incidence to avoid overlapping of root canals. Instrumentation was performed using step down technique with K-type files and file Gates Glidden drills. Solution of choice for irrigation of the root canal system was 2.5% sodium hypochlorite, with 10ml disposable hypodermic syringe and 22G disposable needle. 17% EDTA was applied for 3 minutes at the end of preparation, and its removal was performed with a solution of 2.5%sodium hypochlorite. Either the Either the crash or obstruction of the needle in irrigation canals was not noticed. At that time, the patient reported extreme pain and a burning sensation in the left maxillary region, followed by the formation of intense edema. Thus, a clinical diagnosis of hypochlorite-induced cellulitis was made (figures 1A and 1B).

figures 1A and 1B–Formationofintenseedema.Clinicaldiagnosisofhypochlorite-inducedcellulitis

1A 1B

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The patient received oral analgesic and was referred to a endodontist at the Acaraú Center for Dental Specialties (Brazil). Examination revealed the presence of extensive facial cellulitis, submandibular and infraorbital ecchymosis, and severe trismus. The patient was treated immediately with amoxicillin (500 mg, orally) at 8 h intervals for 7 days and

dexamethasone (4 mg, intramuscularly) at 24 h intervals for 3 days. After one week, clinical evaluation revealed edema reduction. However, the painful symptoms were still present and restricted mouth opening prevented any treatment of the affected tooth. Finally, complete remission of the symptoms was observed after 21 days (figures 2A and 2B).

figures 2A and 2B–Completeremissionofthesymptomsafter21days

With the remission of signs and symptoms, endodont ic treatment was resumed. It was observed that the instrumentation previously performed promoted excessive expansion of the apical foramen, and conformation and wide cylindrical root canals. This fact favors the flow of solution through the foramen. Chlorhexidine gel was applied with a 5-ml syringe and 24Gpplied with a 5-ml syringe and 24G needle was used as irrigant for a better control of treatment and to prevent new accidents. The root canals were instrumented using the more adequate crown-down technique, which provides a conical shape. Apical preparation was finishedApical preparation was finished with size # 50 K type files, in both canals, 1 mm short of the apical foramen, determined through the use of an electronic apex locator (Root ZX II, J Morita, Japan). Finally, canals were filled Finally, canals were filled by lateral condensation technique (figure 3). The patient was revalued after 8 months and remainedrevalued after 8 months and remained asymptomatic.

figure 3 – Endodontic treatment was resumed usingndodontic treatment was resumed usingchlorhexidine gel as irrigant and lateral condensationtechniquetofillthecanals

2A 2B

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Discussion

Careful mechanical instrumentation of the root canal system associated to a copious irrigation is a fundamental step during endodontic treatment [7]. Effective irrigating solution is important to remove debris formed during instrumentation, to act as a lubricant for instruments, and to remove the smear layer produced after mechanical instrumentation [4, 11, 17].

In this present case, several factors have contributed to the accidental injection of NaOCl through the apical foramen. First, it was not usedFirst, it was not used an electronic apex locator to assist the process of determining the apical limit of instrumentation. When only radiographic technique is used to perform this step, an apical limit can be determined incorrectly, because this technique does not identify the location of the apical foramen, but the position of the radiographic apex.

Second, inspection of the root canals showed excessive enlargement of the apical foramen, in which an endodontic K-file #40 was positioned withoutwas positioned without difficulty. This event favors the extravasation of the extravasation of irrigation solution. In addition, the canals presented a cylindrical instead of a conical shape, a fact favoring snug fit of the irrigation needle that in this present case had a large caliber (22G) that prevented reflux of the irrigation solution. Electronic odontometry showed that both the palatine and buccal canal had a length of 17 mm, a value considered to be short for the upper premolars. The failure to observe this short length also favored the accidental injection of the irrigation solution into the periapical tissues. The in vitro extrusion of 5.25% NaOCl solution through the apical foramina of mesial-buccal root canals of maxillary first molars was analyzed. According to authors, 5.25% NaOCl solution showed a great capacity to extrude beyond intact and small-sized apical foramina of mesial-buccal root canals of upper first molars, as apical extrusion occurred with and without previous use of patency files of different sizes [3]. Other study showed positive correlation between the amount of extrusion into the apical tissues and endodontic technique-related factors (apical preparation size and the method of activation and delivery of NaOCl into the apical one-third [12].

The principal harm is to the cells because they are dependent on the specic uid environment in which they are found; NaOCl changes that environment, causing cellular necrosis and apoptosis. The damaged matrix can then become a nidus for infection. Trabecular bone was damaged by the toxic effects of NaOCl [10].

The antibiotic treatment has been used in this case to prevent an opportunistic infection in the periapical tissue necrosis, and thereby protect the patient from infection that could be installed and aggravate the already complicated case.

Careless use of NaOCl solutions has been associated with different complications during or after endodontic treatment, ranging from accidental injection into periapical tissues and maxillary sinuses, accidental injection instead of an anesthetic solution and seepage through lateral root perforations to allergic reactions [3]. An interesting study among the professionals of the American Board of Endodontics [11] revealed some common findings related to these complications: prevalence of women, maxillary and posterior teeth have been more affected, clinical diagnosis of pulp necrosis with periradicular radiolucency in the associated tooth, complete resolution of patient symptomatology within a month, and no changes in the prognosis of the involved tooth.

The management of complications following NaOCl irrigation to periapical tissues has been well described in the literature [9, 14, 16]. We agree with the next topics: 1) following an accident with NaOCl, the professional must be calm and should explain to the patient about what happened; 2) initially it is recommended the use of cold compresses that should be replaced by warm compresses after a 24 hour period; 3) according to severity of the case, antibiotics may be necessary; 4) the patient should be advised about the range in the healing process; 5) after remission of acute symptoms, endodontic treatment may be continued; 6) NaOCl solution should be replaced by a non-irritant irrigation solution [9].

Different substances have been used as alternative irrigation solutions, such as lower concentrations of NaOCl, chlorhexidine, and electrochemically active water [5]. In this present case, we used chlorhexidine as irrigation solution to prevent new accidents. Knowledge about the length and integrity of the root canal system before irrigating procedure is essential to avoid complications [4].

Although the substance that caused local toxicity in the present case was different from that reported on another study [6] in which facial cellulitis was due to inadvertent injection of formalin instead of the local anesthetic, both cases demonstrate the possibility of dental treatment failures even when apparently conventional techniques are used.

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Conclusion

Dentists should always carefully follow all stages of dental treatment planning without neglecting any of them, paying attention to the solutions used and their storage as well as performing a specific technique with maximum accuracy. And if evenAnd if even with all these precautions an accident happens, a protocol comprising appropriate intervention and patient following-up will allow the reversal of the unfavorable situation and satisfactory completion of therapy.

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5. Gernhardt CR, Eppendorf K, Kozlowski A, Brandt M. Toxicity of concentrated sodium hypochlorite used as an endodontic irrigant. Inter Endod J. 2004;37:272-80.

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Case Report Article

Aesthetic management of molar-incisor hypomineralization

Juliana Feltrin de Souza1

Camila Maria Bullio Fragelli2

Manuel Restrepo2

Amanda Mahammad Mushashe1

Estela Maris Losso1

Leonardo Fernandes da Cunha1

Corresponding author: Juliana Feltrin de SouzaUniversidade PositivoRua Professor Pedro Viriato Parigot de Souza, n. 5.300 – Campo CompridoCEP 81280-330 – Curitiba – PR – BrasilE-mail: [email protected]

1 Master Program in Clinical Dentistry, Positivo University – Curitiba – PR – Brazil.2 São Paulo State University, School of Dentistry of Araraquara, Department of Child Clinics – Araraquara – SP – Brazil.

Received for publication: September 12, 2013. Accepted for publication: November 11, 2013.

Keywords: dental enamel hypoplasia; children; aesthetics; dental aesthetics.


Abstract

Introduction: Molar-incisor hypomineralization (MIH) has been challenging for clinical practice. The term refers to an enamel defect that affects permanent molars and often permanent incisors. This defect may result in high sensibility, coronal destruction of the molars, aesthetic problem when incisors are affected, which can jeopardize the child s̀ emotional and psychological development. Objective: The aim of this paper is to report two cases in which a conservative approach was adopted using new technologies for direct restorative treatment of incisor with MIH opacities. Case report: Patients aged 11 and 12 years-old attended to the clinics of the School of Dentistry (Sao Paulo State University – Unesp) complaining about the appearance of incisors due to the presence of opacities on the labial surface. The cases were diagnosed as MIH, presenting enamel defects on the permanent molars and incisors. Direct restorations were carried out with minimal removal of the opacities using CVD diamond tip (CVDentus, São José dos Campos, São Paulo, Brazil) coupled to an ultrasonic device (CVDentus, São José dos Campos,

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Souzaet al.–Aesthetic management of molar-incisor hypomineralizationAestheticmanagementofmolar-incisorhypomineralization

São Paulo, Brazil) and direct restorations with composite resin. The result of the restorative treatment was satisfactory in both cases, with children showing immediate satisfaction. Conclusion: The incisors affected by MIH should be treated to improve the child s̀ self-esteem and avoid negative effects on their psychology development. The aesthetic treatment of the incisors should be conservative, since the replacements of restorations are needed throughout life.

Introduction

The enamel alteration so-called molar-incisor hypomineralization (MIH) is currently one of the most challenging problem of pediatric dentistry clinics [23]. Studies have reported a considerable prevalence in Brazilian communities ranging from 12% to 40% [6, 15].

This defect affects the permanent first molars and can be associated with permanent incisors [14]. The enamel affect by MIH exhibits opacities varying from white to yellow-brownish with well-defined edges of the normal enamel. Most severe cases show loss of enamel structure, favoring sensitivity and the fast development of caries lesions [11, 15, 18, 21]. The asymmetry of this alteration suggests that the ameloblasts are affected by systemic or environmental factors during amelogenesis [1, 2]. Among the possible causes, respiratory problems, complications at the pre-natal period, low weight at birth, metabolic calcium and phosphate disorder, and childhood diseases associated with high fever have been considered [1, 3, 4, 13, 17, 19, 24].

Microscopically, the affected enamel is porous, with smaller inorganic content and enamel prism disorganization and consequently the mechanical properties are reduced [7, 8]. The most severe cases present enamel structure loss and the masticatory forces expose the dentin favoring sensitivity and the fast development of caries lesions [10, 15, 21, 22], a situation requiring restorative treatment.

Because of the structural alterations, teeth affected by MIH have shown difficulty of bonding of bonding to restorative materials, thus demanding recurrent treatments [12]. Because the treatment of molars12]. Because the treatment of molars]. Because the treatment of molars is challenging, the dentist frequently neglects the management of the incisors, normally affected by opacities. However, the aesthetical appearance may result in negative effects on the psychological and emotional development of the child leading to implications on social interaction [20]. Therefore,20]. Therefore,]. Therefore, the treatment of incisors affected by this hypoplasia is also a challenge for the dentist. The aim of this study was to report two clinical cases of MIH in incisors and discuss the conservative restorative management for this alteration.

Case reports

Case1

Patient N.A.U., female, 12 years-old, has been followed-up since 9 years of age at the Pediatric Dentistry Clinics of the School of Dentistry of – Araraquara (Unesp) because of MIH. At initial evaluation, only the posterior teeth affected by MIH were included in treatment planning. During 3 years, the opacities and atypical restorations of the molars were followed-up aiming to reduce sensitivity and preserve the sound and affected tooth structure. The complaint about the incisor opacities occurred around 11 years of age, when both the child and the parents reported dissatisfaction about the opacities. Clearly, the aesthetical appearance of the anterior teeth was affecting the development of the child who was more shy and introspective at every appointment.

A conservative restorative treatment was chosen to manage the white-yellowish opacities on teeth #21, #12 and #31, after the evaluation of the emotional and psychological impact of the opacities in the child.

Conservative treatment of teeth #21 and #12 comprised a minimally invasive superficial wear on the opacities followed by the restoration with microparticle resin composite (Point 4 – Kerr).

First ly, an interpapi l lary anesthesia in permanent canines with 3% mepivacaine was carried out followed by rubber dam isolation with the aid of clamps. The removal of the superficial portion of the opacity was obtained with the aid of CVD T1 diamond tip (CVDentus, São José dos Campos, São Paulo, Brazil). Next, phosphoric acid etching was executed and adhesive system was applied (Optibond FL, Kerr) according to the manufacturers’ instructions. Shade A2 (enamel) resin composite restoration (Point 4, Kerr) was inserted at increments. Finishing and polishing procedure was accomplished with the aid of discs (Super Tray, Kerr).

The result was satisfactory for both the child and the parents.

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figure 1A–Initialaspectsofteeth#12and#21affectedby MIH. Note the demarcated opacity with white-yellowishcolor

figure 1B–Incisorsaftertheaesthetictreatmentoftheopacities

Case2

Patient C.G.M., male, 11 years-old, sought the Pediatric Dentistry Clinics of the School of Dentistry of Araraquara (Unesp) with his parents complaining about the lack of aesthetic of anterior teeth. At clinical examination, MIH was diagnosed in teeth #16, #26, #36 and #11. Teeth #26 and #16 had yellow-brownish opacities, without structural loss. Tooth #36 had already been restored with an atypical resin composite. It was also observed a white-yellowish opacity on tooth #11, which triggered the aesthetic complaint. According to the parents, the child dissatisfaction started after school bullying during the past 3 months.

Both the child and the parents were instructed in relation to the steps of direct restorative treatment. Although the tooth structure was sound, the child exhibited social life sequelae so that the restorative treatment was chosen. The conservative treatment comprised the superficial removal followed by aesthetic restoration of tooth #11.

Prior to restorative technique, a topical anesthesia was performed with Emla followed by rubber dam isolation with the aid of ligations. Then the superficial portion of the opacity was removed with the aid of CVD T1 diamond tip (CVDentus, São José dos Campos, São Paulo, Brazil) followed by 37% phosphoric acid etching, application of the adhesive system (Optbond S, Kerr), according with the manufacturer’s instructions, and resin composite (Premisa, Kerr A1 dentin and A1 enamel shades) inserted at increments. Finishing and polishing procedures were accomplished with the aid of discs (Super Tray – Kerr).

Restorative treatment outcome was satisfactory demonstrated by the immediate satisfaction of the child.

figure 2A–Initialaspectoftooth#11affectedbyMHI.Notethedemarcatedopacity

figure 2B –Aspectof tooth#11after the restorativetreatment

Discussion

Dentists, especially pediatric ones have faced MIH comprising alterations ranging from demarcated opacities to enamel fracture, resulting in larges coronal destructions [21]. These teeth21]. These teeth]. These teeth have raised special attention because of sensitivity complaints, aesthetical involvement, and repeated treatment demands [12, 16].12, 16].].

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In literature, the treatments proposed for affected molars vary according to the severity observed. Teeth affected by opacities have been treated with the use of either f luoride varnish or sealants, while teeth exhibiting structure loss have been restored with glass ionomer cement or resin composite, crowns, or extractions followed by orthodontic treatment [16]. In the cases reported16]. In the cases reported]. In the cases reported herein, resin composite restoration was chosen. Respectively, microparticle and nano-hybrid composites were applied. Da Costa. Da CostaDa Costa et al. [5] reported5] reported] reported that resins with smaller particles, such the ones employed in the present cases, exhibited less brightness loss and superficial roughness increase. Moreover, Furuse et al. [9] also reporting a clinical9] also reporting a clinical] also reporting a clinical case of enamel hypoplasia, affirmed that whenever possible, a more conservative approach should be opted. Considering the age of the patients and consequently the further need of replacement of these restorations, more conservative preparations were carried out. Thus, the opacity of the alteration was only reduced, but tooth structure was maintained for further replacement of the restorations.

Although the occurrence of defects on incisors is smaller than those on molars [10] and the10] and the] and the incisor enamel rarely undergoes structural loss [21], pediatric dentists should be aware of the21], pediatric dentists should be aware of the], pediatric dentists should be aware of the psychosocial impacts of the disease. The appearance of the anterior teeth may result in an unfavorable self-image for the child and jeopardize the social interaction. Dissatisfaction related to the smile is common, normally followed by school bullying and interaction with other children.

One ought to understand all MIH aspects and comprehensively consider the child to measure the impact of MIH in the child’s life by comparing it to the clinical sequelae of an early restorative treatment.

The conservative management of the treatment is necessary because of the child’s age and opacity extension, which frequently affects all enamel thickness. This is an early treatment, so that one should consider the pulp chamber size and the preparation must be limited to the enamel. Although the amount of wear does not provide an aesthetic restoration covering all opacity, at a conversation distance such alteration cannot be perceived.

Conclusion

In summary, the child affected by MIH should be comprehensively treated so that the emotionally and psychological development are not negatively

affected. The aesthetical aspects of the alterations of incisors should be observed and whenever necessary treated through conservative approaches.

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