Universidade Estadual de Campinas

Faculdade de Odontologia de Piracicaba

RODRIGO BARROS ESTEVES LINS

Influência da técnica e material restaurador no comportamento

biomecânico em Restaurações Classe II

Influence of the restorative technique and material on the biomechanical

behavior of Class II restorations

Piracicaba

2017

RODRIGO BARROS ESTEVES LINS

Influência da técnica e material restaurador no comportamento

biomecânico em Restaurações Classe II

Influence of the restorative technique and material on the biomechanical

behavior of Class II restorations

Dissertação apresentada à Faculdade de

Odontologia de Piracicaba da Universidade

Estadual de Campinas como parte dos requisitos

exigidos para a obtenção do título de Mestre em

Clínica Odontológica, Área de Dentística.

Dissertation presented to the Piracicaba Dental

School of the University of Campinas in partial

fulfillment of the requirements for the degree of

Master in Odontological Clinic, in Restorative

Dentistry area.

Orientador: Professor Doutor Luis Roberto Marcondes Martins

ESTE EXEMPLAR CORRESPONDE À VERSÃO FINAL

DA DISSERTAÇÃO DEFENDIDA PELO ALUNO

RODRIGO BARROS ESTEVES LINS E ORIENTADA

PELO PROF. DR. LUIS ROBERTO MARCONDES

MARTINS.

Piracicaba

2017

Dedicatória

À Deus e à Nossa Senhora,

Além de dedicar a minha dissertação à Deus e à Nossa Senhora, dedico todo o meu

mestrado, meus estudos, minha vida profissional e pessoal.

Aos meus pais,

Dedico este trabalho de obtenção do título de Mestre aos meus maiores Mestres: ao

meu pai (José Lins) e à minha mãe (Mariângela Lins).

Por terem me apoiado em todas as minhas decisões, incluindo sair de casa para

correr atrás de um futuro profissional que ainda almejo em conquistar. Vocês são meus maiores

exemplos para seguir em busca dos meus ideais, segundo à vontade de Deus.

Muito obrigado por todo apoio e carinho. Amo vocês!

Agradecimentos

Aos meus familiares,

Agradeço a todos os meus familiares pelo apoio e incentivo dados a mim nesta nova

fase de estudos e aprendizados, principalmente às minhas avós.

Em especial aos meus irmãos José Renato Lins e Rafael Lins. A saudade é imensa,

mas sei que vocês estão e estarão sempre torcendo por mim.

A minha querida sobrinha Isabelle Lins, que sinto tanta falta. Estar longe e não

poder acompanhar pessoalmente seu crescimento é extremamente penoso, mas ter o seu carinho

em todas as viagens de retorno à João Pessoa é mais do que reconfortante.

Aos meus amigos Pessoenses,

Aos tantos amigos que fiz durante a vida, incluindo amigos da época de escola

(Augusto Ygor, Paulo Victor e Suzane Souza) e universidade (Alana Dantas, Amanda Solano,

Evllon Sá, Larissa Fernandes, Maíra Ramalho, Mariana Figueiredo, Raissa Marçal, Priscilla

Leite e tantos outros) os quais mantemos contato por redes sociais, agradeço por fazerem parte

da minha vida.

Ao meu orientador Prof. Dr. Luís Roberto Marcondes Martins,

Obrigado por ter me escolhido na seleção de mestrado e por ter acreditado no meu

potencial para desenvolver trabalhos científicos juntos. Nestes dois anos foram tempos de

muitos aprendizados que servirão para a minha vida. Tê-lo como orientador é mais do que um

exemplo.

Aos Professores da Dentística,

A todos os professores da Dentística-FOP, por todos os ensinamentos e atenção

prestados nestes dois anos de convivência diária. Grandes mestres que nos dão muito orgulho

de suas competências profissionais.

Aos funcionários da FOP-UNICAMP

Não poderia deixar de agradecer aos funcionários da FOP-UNICAMP que nos

prestam tantos auxílios nas mais diversas funções, desde aos funcionários da secretaria às

senhoras da limpeza.

Aos amigos Fopianos/Pessoenses,

Aos amigos Pessoenses que estudam na FOP-UNICAMP (Bruno Mariz, Emerson

Tavares, Jaiza Araújo, Jossaria Sousa, Laíse Lima, Marina Moreno, Mayara Abreu, Renally

Wanderley) que tornam a FOP um pouco nordestina e que fazem os nossos dias de estudo mais

divertidos.

Aos amigos da FOP-UNICAMP

Aos grandes amigos que conquistei nestes dois anos de mestrado (Amanda

Bandeira, Camilla Fraga, Carolina Rangel, Filipe Martins, Heloisa Pantaroto, Jairo Cordeiro,

Manoelito Silva, Mariana Barbosa, Olívia Figueiredo, Rafaela Videira, Rahyza Freire, Renato

Machado, Thiago Bessa). Agradeço por todo o companheirismo e apoio nos momentos de

felicidade e principalmente naqueles momentos de preocupação ou estresse inevitáveis à esta

fase.

Aos amigos da Dentística/FOP-UNICAMP

Aos amigos da Dentística que dividimos diariamente conhecimentos científicos

(Renata Pereira, Bruna Guerra, Caroline Mathias, Mayara Zaghi e Marina Faria) e em especial

a Josué Pierote, Mariana Flor e Maicon Sebold pela grande amizade.

À Cristiane Yanikian

Um agradecimento especial à Cristiane Yanikian. Ela que me pôs para trabalhar no

laboratório no meu primeiro dia de mestrado, mas que soube como ninguém me ensinar e

orientar por todos os obstáculos enfrentados durante o mestrado. É sem dúvida, um exemplo

que pretendo seguir.

À Elis Lira e Louise Dornelas

À minha família Piracicabana; às minhas colegas de graduação e pós-graduação; às

minhas grandes amigas: Elis Lira e Louise Dornelas. Mais de 7 anos de amizade. Não sei

expressar o quanto vocês foram e são importantes para mim. Ter ingressado na pós-graduação

com vocês foi, certamente, o ‘combustível’ necessário para suprir a saudade de casa. Tenho

muito orgulho pelas profissionais que são e pelas conquistas que não cessam em acontecer.

Ao Professor Doutor João Carlos Ramos e à Professora Doutora Alexandra Vinagre,

Agradeço aos Professores da Faculdade de Medicina Dentária da Universidade de

Coimbra-Portugal, que me acolheram durante o meu intercâmbio na reta final do meu mestrado.

Exemplo de dedicação à odontologia, orientadores e mestres incríveis. Profissionais que

durante 4 meses me deram suporte e me concederam grandes conhecimentos. Obrigado por

todo o tempo e atenção depositados à mim.

À Universidade Estadual de Campinas

À Faculdade de Odontologia de Piracicaba

Ao Programa de Clínica Odontológica

À CAPES

RESUMO

O advento de materiais restauradores de baixa contração vem ganhando espaço no mercado e

despertando interesse de cirurgiões-dentistas devido as suas características técnicas, economia

de tempo clínico e por ser um material mais estável dentro da cavidade oral. O objetivo deste

estudo foi avaliar o comportamento biomecânico de restaurações extensas classe II mésio-

ocluso-distal (MOD) com técnica direta (compósitos convencional e de baixa contração)

avaliando a tensão de contração de polimerização, deflexão de cúspide, resistência à fratura e o

padrão de fratura. Sessenta terceiros molares humanos hígidos foram selecionados e

randomizados em quatro grupos: resina composta Z100 (Z100); Tetric N-Ceram Bulk Fill

(TNC); Filtek Bulk Fill (FBF); Aura Ultra Universal Restorative Material (ABF). Cavidades

Classe II MOD foram confeccionadas com dimensões padronizadas por meio de uma máquina

de preparo cavitário. As resinas compostas bulk fill foram inseridas na cavidade em um único

incremento de 4 mm e a resina composta convencional em três incrementos de forma oblíqua e

fotopolimerizadas por um LED de alta potência. Os sensores FBG foram inseridos na interface

adesiva a fim de avaliar a tensão de contração do material resinoso durante a fotopolimerização

(n=5). Além disso, extensômetros foram fixados nas bases das cúspides para medirem a

deformação em três momentos (n=10): durante o procedimento restaurador, sob carregamento

de compressão axial em máquina de ensaio universal até 100N e até gerar a fratura do conjunto

dente-restauração. O tipo de fratura foi classificado conforme o seu padrão analisado em

Microscopia Eletrônica de Varredura (MEV): I-fratura em resina composta; II-fratura em resina

composta e estrutura dental coronal; III-fratura em resina composta e estrutura dental cervical

com possibilidade de reparo periodontal; IV-fratura radicular sem reparo. Foi realizado teste de

homogeneidade dos dados (Shapiro-Wilk, p>0.05) para todos os grupos, seguido do teste

ANOVA um fator com teste post-hoc de Tukey para a avaliação dos sensores FBG, deformação

de cúspide e resistência à fratura. O padrão de fratura foi analisado pelo teste qui-quadrado. A

avaliação da tensão de contração pelos sensores de Bragg mostrou maiores médias para o grupo

Z100 diferindo estatisticamente de todos os outros grupos (p

fratura do TNC foi maior que os demais, porém, estatisticamente significante apenas com o

grupo Z100 (p

ABSTRACT

The appearance of low contraction restorative materials has been introduced and increasing

attention from dental surgeons due to technical features, such as chair time economy and stable

within the oral cavity. The purpose of this study was to evaluate the biomechanical behavior of

extensive Class II mesial-occlusal-distal (MOD) restorations with direct technique

(conventional and low-shrinkage resin composites) by using fiber Bragg grating sensors (FBG)

and extensometry assessing the polymerization contraction stress, cuspal deformation, fracture

resistance and fracture pattern. Sixty human caries-free third molars were selected and

distributed randomly into six groups: Z100 restorative material (Z100); Tetric N-Ceram Bulk

Fill composite (TNC); Filtek Bulk Fill composite (FBF); Aura Ultra Universal Restorative

Material (ABF). Class II cavities MOD was standardized in an abrasion standardizing

equipment. The bulk fill materials were inserted in bulk increment of 4 mm and the

conventional resin composite in three oblique ones by poly-wave LED light-curing unit. The

optical FBG sensors were fixed at adhesive interface due to evaluated the shrinkage stress of

resinous material during the fotopolymerization (n=5). Moreover, strain gauges were fixed on

cuspal base to measure the deformation at three times (n=10): during restorative procedure,

subjected to axial compressive in universal testing machine up to 100N and to occur the sample

fracture. The failure mode was rated according to their standard analyzed in Scanning Electron

Microscopy (SEM): I-fracture at resin composite; II-fracture at resin composite and coronal

tooth structure; III-fracture at resin composite and cervical tooth structure with possible

periodontal repair; IV-root fracture beyond repair. The statistical analysis was performed for

homogeneity distribution (Shapiro-Wilk, p>0.05), followed by parametric statistical tests and

one-way ANOVA with post-hoc Tukey’s test. Data on fracture mode were submitted to Chi-

square test. The optical FBG sensors evaluation showed that Z100 presented the highest means

of stress shrinkage (p

Keywords: Composite Resins. Fiber Optical Technology. Polymerization.

SUMÁRIO

1 INTRODUÇÃO 14

2 ARTIGO: Biomechanical Behavior of Class II Restoration Using Fiber

Bragg Grating Sensors and Extensometry

17

3 CONCLUSÃO 36

REFERÊNCIAS 37

APÊNDICE 1: Metodologia Ilustrada 42

ANEXO 1: Certificado - Comitê de Ética em Pesquisa 46

ANEXO 2: Comprovante de submissão do artigo 47

14

1 INTRODUÇÃO

A exigência por parte da população em adquirir estética do sorriso e saúde bucal

satisfatória tem influenciado no advento de materiais cada vez mais estéticos na clínica

odontológica. Somado a isso, o desenvolvimento tecnológico impulsiona a geração de novos

materiais restauradores e técnicas adesivas mais eficazes e duradoras (Pashley et al., 2011) com

propriedades físicas e ópticas semelhantes aos dos dentes naturais (Nahsan et al., 2012). A partir

desta constante inovação, podemos caracterizar o estado da arte dos materiais odontológicos

(Ferracane, 2011).

A tendência atual de realizar cada vez mais procedimentos preventivos na saúde

pública para impulsionar a diminuição na prevalência da doença cárie não garante ou não

impede a necessidade de substituição de restaurações insatisfatórias, que a partir deste ciclo

restaurador acarreta em perda da estrutura dental. Com isso, na clínica odontológica são

frequentemente realizadas restaurações em cavidades classe II MOD amplas (Deliperi e

Bardwell, 2002; Bonecker et al., 2013).

A resina composta, ao longo dos anos, ganhou grande destaque e aplicabilidade na

clínica odontológica para diversos procedimentos (Ferracane, 2011). Esta é comumente

utilizada em restaurações para dentes anteriores e posteriores, com excelente desempenho

clínico, comprovado em estudos longitudinais (Demarco et al., 2012; Cetin et al., 2013; Ozakar-

Ilday et al., 2013; Demarco et al., 2015; Van Dijken e Pallesen, 2016). Este sucesso clínico,

principalmente em restaurações diretas com compósitos microhíbridos (Da Rosa Rodolpho et

al., 2011; Demarco et al., 2015) estão relacionados às propriedades mecânicas favoráveis, como

adequada resistência à fratura (Ferracane, 2011). Entretanto, algumas desvantagens também são

observadas, como: a necessidade de inserção do material de forma incremental, a qual demanda

maior tempo clínico e incorporação de bolhas no corpo da restauração; alta contração de

polimerização e, consequente, geração de tensão, provocando deslocamento do compósito

resinoso a partir da interface adesiva, criando um ‘gap’ marginal, e portanto, sensibilidade pós-

operatória, microinfiltração, cárie secundária, pigmentação marginal e falha na restauração

(Casselli et al., 2013; Campos et al. 2014; Dominguez et al., 2014; Benetti et al., 2015; Fronza

et al., 2015).

A contração de polimerização ocorre ao longo do processo de conversão dos

monômeros em polímeros, através de forças covalentes fortes, promovendo diminuição da

distância molecular. Além disso, a tensão ocorre na transição da fase gel para um estado amorfo

15

isotrópico quando fotoativado (Lee et al., 2013), contribuindo para a formação de tensões ao

longo da interface adesiva das restaurações (Loguercio et al., 2004).

Algumas alterações nas resinas compostas têm sido propostas com o objetivo de

diminuir os efeitos indesejados da forte tensão gerada na interface dente/restauração, como a

composição química ou estrutural do monômero da matriz resinosa; a quantidade, forma e/ou

tratamento superficial da partícula de carga, além de modificação no sistema iniciador (El-

Damanhoury e Platt, 2014; Kwon et al., 2015; Orlowski et al., 2015; Atalay et al., 2016).

Recentemente, um grupo de resinas compostas de baixa contração foram

desenvolvidas e denominadas “bulk-fill”. Estas permitem a inserção de único incremento de até

4-5 mm de material (Czasch e Ilie, 2013); possuem a capacidade de gerar menor tensão de

contração de polimerização; reduzem a deflexão de cúspide (Moorthy et al., 2012); apresentam

menor tempo e alta reatividade à fotopolimerização, devido ao aumento da translucidez e,

portanto, permitem uma maior penetração de luz e profundidade de polimerização (Roggendorf

et al, 2011; Leprince et al, 2014; Orlowski et al., 2015); além disso, apresentam a vantagem em

diminuir o tempo de execução clínico (Campos et al, 2014).

Na literatura científica encontram-se diversos testes científicos destinados a

avaliarem o comportamento de materiais resinosos, como por exemplo: análise por elementos

finitos (Anatavara; Sitthiseripratip; Senawongse, 2016), tensômetro conectado a um sistema de

cantilever com sensores (Kalliecharan et al., 2016), máquinas de ensaio universal (Witzel et al.,

2005), sistema ‘ring slitting’ (Park e Ferracane, 2005; Park e Ferracane, 2006), sensores de rede

de Bragg em fibra óptica (Rajan et al., 2016; Vinagre et al., 2016; Umesh et al., 2016),

extensometria (Bicalho et al., 2014; Pereira et al., 2015), dentre outros.

O sensor de rede de Bragg em fibra óptica possui a característica de ser

fotossensível e a capacidade de verificar variações, como: temperatura, contração, expansão e

pressão a partir da alteração do comprimento de onda (Yeh et al., 2011; Umesh et al., 2016).

Esta tecnologia tem-se tornado uma das técnicas mais usadas em sistemas de avaliação

biomecânica e reabilitação em diversas áreas científicas, como: automotiva, aeronáutica,

medicina, odontologia e especificamente a biomecânica dental, incluindo estudos in vitro e in

vivo (Al-Fakih; Abu Osman; Mahamd Adikan, 2012; Umesh et al., 2016).

Um método adicional para compreender o comportamento biomecânico de um

material resinoso a partir da alteração da deflexão de cúspides é por meio da extensometria, a

qual é um teste mecânico não destrutivo que avalia diretamente as características do processo

16

restaurador, ou seja, detecta alterações do comportamento da estrutura dental resultantes das

forças atuantes na camada adesiva, que podem ser influenciadas pelo material restaurador,

sistema adesivo, técnica restauradora a ser adotada e o tamanho da cavidade (Bicalho et al.,

2014; Pereira et al., 2016).

Encontram-se na literatura científica estudos sobre resinas compostas ‘bulk fill’,

contudo, o conhecimento sobre o comportamento biomecânico na interface adesiva das mesmas

ainda se apresenta escarça. Pensando nisso, o objetivo do presente estudo foi avaliar o

comportamento biomecânico de restaurações extensas classe II mésio-ocluso-distal (MOD)

com técnica direta (compósitos convencional e de baixa contração) avaliando a tensão de

contração de polimerização, deflexão de cúspide, resistência à fratura e o padrão de fratura.

17

2 ARTIGO:

Biomechanical Behavior of Class II Restoration Using Fiber Bragg Grating Sensors and

Extensometry

Rodrigo Barros Esteves Linsa,*, Cristiane Rumi Fujiwara Yanikiana, Thiago Henrique

Scarabello Stapea, Aline Arêdes Bicalhob, Carlos José Soaresb, Luís Roberto Marcondes

Martinsa

a Department of Restorative Dentistry, Piracicaba Dental School, State University of Campinas,

Av. Limeira, 901, Piracicaba 13414-903, SP, Brazil

b Department of Operative Dentistry and Dental Materials, Dental School, UFU – Federal

University of Uberlândia, Av. Pará, 1720, Campus Umuarama, Uberlândia 38400-902, MG,

Brazil

*Corresponding author. Tel.: +55 83 988527948

E-mail addresses: rodrigowlins@hotmail.com (R.B.E.Lins), cristiane@fyodontologia.com.br

(R.R.F.Yanikian), thiagohs@hotmail.com (T.H.S.Stape), alinearedesbicalho@gmail.com

(A.A.Bicalho), carlosjsoares@ufu.br (C.J.Soares), martins@unicamp.br (L.R.M.Martins)

Funding sources

The CAPES Foundation of Department of Education, Brazil, supported this work.

ABSTRACT

Objective. The purpose of this study was to assess the biomechanical behavior of extensive

Class II mesial-occlusal-distal (MOD) restorations performed direct technique (conventional

and low-shrinkage resin composites) by using fiber Bragg grating sensors (FBG) and research

the polymerization contraction stress as well as evaluate the low-shrinkage resin composite

regarding cuspal deformation and fracture resistance and pattern.

Methods. Sixty human caries-free third molars were selected and distributed randomly into four

groups: Z100 restorative material (Z100); Tetric N-Ceram Bulk Fill composite (TNC); Filtek

Bulk Fill composite (FBF) and Aura Ultra Universal restorative material (ABF). In all samples

were standardized class II MOD cavities. The bulk fill materials were inserted in bulk increment

18

and the conventional resin composite in three ones. Shrinkage stress was evaluated with optical

FBG sensors (n=5). The cuspal deformation with extensometer was measured during

restoration, compressive axial force and until the fracture on universal machine (n=10). The

fracture pattern was analyzed with Scanning Electron Microscopy (SEM). The statistical

analysis was performed for homogeneity distribution (Shapiro-Wilk, p>0.05), followed by

parametric statistical tests and one-way ANOVA with post-hoc Tukey’s test. Data on fracture

mode were submitted to Chi-square test.

Results. The optical FBG sensors evaluation showed that Z100 presented the highest means of

stress shrinkage (p

19

structure. This results in extensive Class II MOD cavity restorations, which are regularly

performed in clinical odontology [7,8].

The clinical success and longevity of direct restorations in posterior teeth by using

micro-hybrid composite resins are related to favorable mechanical properties [2,9], such as

adequate fracture resistance [10]. However, some drawbacks are found: incremental insertion

technique, which demands longer clinic procedures; contraction due to polymerization and

subsequent stress, with risk of dislodging of the resinous composite from the adhesive interface,

causing marginal gap and post-procedure sensitivity; micro-infiltration; secondary caries;

marginal pigmentation; and restoration failure [11-13]. This contraction might occur throughout

the process of polymerization as a result of strong covalent forces, causing abridgement of

molecular distances and tension in the passage from gel to isotropic amorphous state [14], thus

contributing to the formation of stress at the adhesive interface of the restorations [15].

In order to diminish the undesired effects of the composites, such as the tension

created on the tooth/restoration interface, some chemical and structural changes in the

composite resin composition have been proposed. This include changes in the resinous matrix,

quantity, and shape and/or surface treatment of the inorganic particle [1]. Another group of low-

shrinkage composite resins have been recently developed, the bulk-fill resins. They allow the

insertion of a single increment with 4-5-mm [16] due to their capacity of generating less

contraction stress and high reactivity to photopolymerization as result of increased

translucency, improving light penetration and depth of polymerization [17-19]. The incremental

restoration technique, which uses micro-hybrid conventional composite resin inserted into the

cavity in small increments [20], is still the most adequate photopolymerization to modify the

contraction pattern in direct restorations [21]. However, this technique has disadvantages such

as lodging of air bubbles during incremental insertion and longer chair time [22], whereas bulk-

fill composite resins have the advantages of controlling polymerization shrinkage stress [23],

shortening chair time [22] and reducing cuspal deflection [24].

The scientific literature is comprehensive about the study of bulk fill resin

composite, however the biomechanical behavior knowledge in adhesive interface is scarce,

wherefore, the purpose of this study was to evaluate the biomechanical behavior of extensive

Class II mesial-occlusal-distal (MOD) restorations with direct technique (conventional and

low-shrinkage resin composites) by using fiber Bragg grating sensors (FBG) and extensometry

forma the polymerization contraction stress, cuspal deformation, fracture resistance and

fracture pattern. The hypothesis tested here was: bulk-fill composite resins generate less

20

polymerization contraction stress and reduce cuspal deformation compared to conventional

composite resins.

2 MATERIALS & METHODS

Four commercial resin-based composites were investigated: one conventional

incrementally layered composite (Z100 restorative material) (positive control); three bulk-fill

composites (Tetric N-Ceram Bulk Fill, Filtek Bulk Fill and Aura Ultra Universal restorative

materials). Product specifications are listed in Table 1.

All the restorative materials were light-cured by using a poly-wave LED light-

curing unit (VALO, Ultradent Products Inc., South Jordan, UT, USA) operating with

wavelength of 350 and 550 nm and irradiance at 995 ± 2mW/cm2 according to the

manufacturer’s recommendations as follows: 40 seconds for each layer of conventional

composite (three oblique increments), 20 seconds for one bulk layer of bulk-fill composites (10

seconds for mesio-occlusal and 10 for distal-occlusal).

2.1 Specimen Preparation

Sixty human caries-free third molars were extracted and stored in buffered aqueous

solution of 0.2% sodium azide at 4 ⁰C for up to 6 months. The research project was previously

approved by the Research Ethical Committee of Piracicaba Dental School, State University of

Campinas, Piracicaba, Brazil (protocol 127/2014).

The teeth were cleaned by using periodontal curettes to remove organic and

inorganic remnants, including pumice paste, water and Robson brush at low rotation before

storage in distilled water at 4°C. The dimensions of the teeth were determined by using a digital

calliper (Mitutoyo, Tokyo, Japan) to measure the mesio-distal (MD) and lingual-buccal (LB)

dimensions of the occlusal surface. The occlusal surface area was determined by considering

the molar as a rectangle with the sides determined by the MD and LB dimensions. Teeth

selected presented occlusal surface area varying no more than 10% of the sample average.

2.1.1 Inclusion and Simulation of Periodontal Ligament

21

The teeth were inserted into polystyrene resin to simulate the periodontal ligament.

A 0.5 mm graphite pencil was used to mark the insertion site at 2-mm below the amelocemental

junction, thus delineating a radicular portion to be coated with #7 molten paraffin wax. The

teeth were fixed with sticky wax from the crown to the stem of a prosthetic liner. A radiographic

film with central perforation compatible with the dimension of each tooth was positioned at the

same level of the sticky wax. The mobile table of the prosthetic liner was adjusted

perpendicularly to the long axis and on the top of the teeth. Next, a PVC cylinder with a 10-

mm wide central perforation was attached to the radiographic film with sticky wax. The set was

taken to a wooden plate with individual perforations for each tooth. The self-curing polystyrene

resin was prepared and poured into the interior of the PVC cylinder. After polymerization, the

set was removed from the rack.

The teeth were removed from the artificial alveoli and cleaned with jets of baking

soda and water, and the resin cylinders were polished by using a universal sanding machine

(AROPOL-E Arotec, Cotia/São Paulo, Brazil) to eliminate the excesses. The polyether-based

casting material (Polyether Impregum Soft 3M ESPE, St. Paul, USA) was prepared and inserted

into the spaces corresponding to the periodontal ligament [25]. The teeth were inserted by finger

pressure until the 2-mm mark of the amelocemental limit was aligned to the surface of the

cylinder. After polymerization, the excesses were removed by using a scalpel blade and the

specimens were stored in distilled water at 4°C.

The teeth, with their respective artificial alveoli, were randomly divided into four

groups (n = 5 to FBG sensors and n = 10 to cuspal deformation) according to material used for

restoration.

2.1.2 Cavity Preparation

Cavity preparation was performed by using abrasion equipment with three

coordinate axes millimetrically controlled (Mitutoyo Am. Corp., Ontario, Canada). Diamond

drills 2131 and 3131 (KD Sorensen, São Paulo, Brazil) were used to prepare the cavities by

positioning them perpendicularly to the long axis of the tooth, determining 6 degrees of

expulsion in the surrounding and axial walls and inner round angles.

Class II MOD cavities were standardized as follows: lingual-buccal isthmus width

of 4 mm and occlusal depth of 3 mm, occlusal depth of 4 mm in the proximal box and 1-2 mm

above the cemento-enamel junction of the proximal box, ending mesially and distally [26].

22

2.1.3 Insertion of Resin Composite

The resin composite insertion of Z100 group was incremental way from oblique

technique and thickness up until 2 mm. Three incremental were inserted, the first one was to

buccal wall, the second to opposite wall and the last one was to reproduce the teeth occlusal

anatomic.

Already for TNC, FBF and ABF groups were restored with one single increment of

4 mm thickness to fill all bulk MOD cavity.

2.2 Fiber Bragg Grating Sensors (FBG)

Optical FBG sensors were used to assess the shrinkage stress of resinous material

during the photopolymerization with values expressed in micro-strain (µɛ) (n = 5). Fiber Bragg

gratings consist of longitudinal modulations in the refractive index of optical fiber’s core region

with a periodicity in the order of hundreds of nanometers (Smart Fibers Ltd. UK). The refractive

index modulation allows the fundamental core mode to be coupled to a counter propagating

core mode. Coupling occurs at a specific wavelength, λB, given by Eq. (1) – where neff is the

effective refractive index of the fundamental core mode and Λ is the grating pitch.

𝜆𝐵 = 2 𝑛𝑒𝑓𝑓 Λ (1)

As the core mode is coupled to a counter propagating one by the Bragg grating, the

optical response of a FBG can be measured in reflection. Thus, if light from a broadband light

source is launched in a fiber in which a FBG was inscribed, a peak at λB (Bragg peak) can be

measured in the reflection spectrum. Figure 1a shows a typical spectrum from a Bragg grating

used in the experiments reported herein (Λ = 535.6 nm). The sensors were monitored with an

optical spectrum interrogation analyzer (W3-2050 FBG, Smart Fibers Ltd., UK), which can

measure tension up to 42,000 µɛ at maximum measurement frequency of 50Hz [27].

The application of strain to a FBG causes its spectral peak to shift. This shifting is

due to the fact that strain induces changes in the effective refractive index of the fundamental

core mode (via strain-optic effect), neff, and variations in the grating period, Λ. By observing

Eq. (1), it is possible to conclude that variations in neff and Λ imply in a different value for λB.

In order to characterize the Bragg wavelength shift as a function of the applied

strain, one have fixed the optical fiber on motorized translation stages and applied strain

23

increments to the same. Figure 1b shows the evolution of a FBG spectrum as strain increments

are applied to the fiber. Figure 1c presents the wavelength shift as a function of the strain level.

Measured data allowed calculating a strain sensitivity of (1.124 ± 0.005) pm/µε.

The evaluation of resin shrinking by the employment of fiber Bragg gratings was

carried out as follows: initially, the fiber was glued on supports and, in sequence, it was

tensioned. As a second step, the tooth under test was elevated up to fiber level. At this point,

the fiber could be attached on the side buccal wall of the MOD cavity at the level of the dentine

enamel junction (Adper Single Bond 2 adhesive was employed for fixation) [28]. The

restorative technique to be probed was then performed inside the cavity and the Bragg peak was

followed during the curing procedure. Temperatures effects of the light and curing exotherm

were not eliminated.

2.3 Cuspal Deformation

Strain gauges (PA-06-060CC-350-LEN, Excel Sensores, SP, Brazil) were used to

measure cuspal deformation (µɛ) and they were attached parallel to the long axis of the teeth at

the gingival wall level of the proximal box and placed on the external surface of the buccal and

lingual cusps (n = 10). The strain gauges had an internal electrical resistance of 350Ω and gauge

factor of 2.17. Moreover, two strain gauges were positioned to another unimpaired tooth to

compensate for dimensional alteration due to temperature effects on half bridge scheme. The

fixation of strain gauges were performed with 37% acid etching for 30 seconds, cyanoacrylate-

based adhesive (Super Bonder, Loctite, Itapeví, Brazil) and digital pressure for 60 seconds and

the wires were connected to a data acquisition device (ADS0500IP, Lynx, SP, Brazil). The

cuspal deformation values were recorded at 4 Hz during the restorative technique and continued

for 10 minutes after curing the last increment until stabilization [29].

2.4 Fracture Resistance Test

After measurement of cuspal deformation during restoration, the teeth were placed

on universal testing machine (EMIC, 500DL, São José dos Pinhais, Brazil) and submitted to

axial compressive loading with a metal sphere of 8 mm in diameter at speed of 0.5 mm/min up

to 100N in order to cause fracture and assess the cuspal deformation in these moments. The

load required (N) to cause catastrophic fracture of the specimens was recorded by a 500-N load

24

cell hardwired to a computer with control and data acquisition software (TESC 3.04, EMIC)

[30].

2.5 Scanning Electron Microscopy (SEM)

The failure mode of each specimen was analyzed under the SEM (JEOL-JSM

5600LV, Tokyo, Japan). Each sample was gold-sputter coated, submitted to analysis at 15kV

to observe surface characteristics and classified into one of the four categories as follows: (I)

fracture at resin composite; (II) fracture at resin composite and coronal tooth structure; (III)

fracture at resin composite and cervical tooth structure with possible periodontal repair; and

(IV) root fracture beyond repair.

2.6 Statistical Analysis

Statistical analysis was performed by using SPSS 21.0 (SPSS Inc., Chicago, IL,

USA). The evaluation of optical FBG sensors, cuspal deformation and fracture resistance were

tested for normal distribution (Shapiro-Wilk, p > 0.05), followed by parametric statistical tests

and one-way ANOVA with post-hoc Tukey’s test. Data on fracture mode were submitted to

Chi-square test.

3 RESULTS

3.1 Optical FBG Sensors

Average and standard deviation values of FBG evaluation are presented in Table 2

and Figure 1. One-way ANOVA revealed statistically significant differences among the

restorative materials (p < 0.0001). The statistics indicate that the Z100 group presented the

highest values of stress shrinkage as measured by the optical FBG sensors (p < 0.05). The bulk-

fill resin groups presented low polymerization stress values, especially the TNC group which

presented statistically significant difference than FBF group (p < 0.05).

3.2 Cuspal Deformation

Average and standard deviation values of cuspal deformation and fracture

resistance are listed in Table 3. One-way ANOVA analysis demonstrated statistical differences

25

between the groups (p < 0.03). Z100 group presented higher values of cuspal deformation at

restoration time and axial compressive compared of others groups (p < 0.01). The cuspal

deformation until the fracture presented only difference between TNC and FBF groups (p <

0.05). The fracture resistence of TNC group was higher of all groups, but only statistically

different of Z100 group (p < 0.01).

Failure mode distribution is shown in Figure 2 and 3. The Chi-square test (116.000)

indicates that restorative technique influenced the fracture pattern distribution in the different

groups (p < 0,0001), with Z100 and FBF groups presenting predominance of type-II fracture

and TNC and ABF groups presenting type-IV fracture.

4 DISCUSSION

The hypothesis predicting that the bulk-fill composite resins generate less

polymerization contraction stress and reduce cuspal deformation compared to conventional

composite resins was accepted. The results translate the behavior of the material inside the

cavity during photopolymerization (Table 2 and 3).

In dentistry, studies have been introducing optical FBG sensors for assessment of

dental materials, such as Rajan et al. (2016), who are pioneers in evaluating physical properties

of different composite resins by using optical fibers, thus providing conclusions on the

characteristics of these materials during and after photopolymerization. Also, Vinagre et al.

(2016) evaluated the cuspal deformation by using optical FBG sensors on the tips of cusps

during photopolymerization of bulk-fill composite resins. This has helped to understand the

basic characteristics of restorative materials and the influence of polymerization shrinkage

stress regarding the position of the cusps. However, the present study addressed the

biomechanical behavior of these materials inside a large MOD cavity, allowing the evaluation

of the shrinkage stress on the cavity walls and the influenced of the restoration techniques used

through the optical FBG.

Restorative materials inside the dental cavity shrink in volume when submitted to

polymerization, hence producing a tension by contraction, which interacts with their physical

properties and determine their behavior in the tooth cavity walls [33,34]. The results found

show that Z100 composite resin has a high shrinkage stress, significantly different of the other

groups as was reported by Ilie, Kunzelmann and Hickel (2006). The restoration with Z100 was

performed by using the incremental filling technique in order to minimize the tension created

26

on the cavity walls. However, this tension was significantly high in the first increment and

varied strongly in the subsequent ones depending on the position of the increment, also

demanding a longer chair time for restoration.

The force distribution found between restorative material and cavity walls

influenced heavily the prognosis of the restoration procedure, since poorly adapted restorations

are one of the most frequent causes of failure, thus requiring new restoration. Orlowski,

Tarczydlo and Chalas (2015) evaluated the marginal adaptation of different bulk-fill resins,

especially the Filtek and Tetric EvoCream Bulk Fill, and they conclued that the single increment

technique using this material weakly influence the marginal adjustment and marginal gap.

The evaluation of cuspal deformation using extensometry, which is a kind of non

destructive mechanical test, is directly related to the characteristics of the restoration process,

including restorative and adhesive materials and techniques used, and the size of the cavity

influences the behavior of the dental structure under forces acting on the adhesive layer [30,34].

All the specimens were standardized for evaluation of cuspal deformation by using strain

gauges.

Bulk-fill resins have physical characteristics such as high translucence to allow light

passage, different viscosities facilitating their handling, changes in their structure (e.g. volume

filler) and modifications in the photoinitiator to avoid shrinkage stress [19,23,35]. The resin

composite TNC have an initiator system fusion, like a camphorquinone conventional and an

acyl phosphine oxide with Ivocerim® patented system, which it’s more sensitive from

photopolymerization process requiring lower wavelength comparable of conventional [36]. In

addition, it’s presented high molecular weight monomers with long chains due to compensate

the less distance between the formed polymers and particles with low modulus of elasticity [37-

39].

In the literature, there are conflicting studies on the behavior of bulk-fill resins

[12,19]. Our results allow us to state that bulk-fill resins have less polymerization stress than

the conventional composite ones. The forces generated by cuspal deformation were similar.

Hence, extensometry and optical FBG sensor tests complement each other, helping confirm the

behaviour of different materials used for restoring Class II MOD cavity as was observed in the

study of Lee et al. (2007), which evaluated the cusp deflection of premolars from cavity

proportion and selected restorative method and, from this, testify a correlation between the cusp

deflection and stress shrinkage polymerization tests.

27

In this study was preconized an only kind of adhesive used (Adper Single Bond 2)

due to standard the adhesive technique, making possible a specific evaluation of material and

restorative technique to be used, similar of Kim et al. (2015) study.

The fracture resistance of restorations of Class II MOD cavities was described by

Eakle (1986), and it can be augmented by composite resin restorations. The results on fracture

resistance in the present study corroborate the finding reported by Atalay et al. (2016), who

found similarity between bulk-fill and conventional resins. However, the Z100 resin presented

low fracture resistance, with predominance of type-II fractures, possibly influenced by its

behavior during photopolymerization inducing stress accumulation. The higher and significant

fracture resistance of TNC group is related to its filler content and higher flexural strength

consequently [38,43].

5 CONCLUSIONS

Despite the limitations of this in vitro study, the following conclusions may be

drawn:

The bulk fill resin composites inserted in bulk increment of 4 mm depth at short

photo-activation time generate less shrinkage stress and less cuspal deformation than the

conventional resin composite.

The TNC resin composite present low shrinkage stress, cuspal deformation, more

resistant to fractures however reproduce catastrophic fractures.

Acknowledgements

This study was supported by the Gleb Wataghin Institute of Physics (State

University of Campinas) and Dental Research Center Biomechanics, Biomaterials and Cell

Biology (Dental School of Federal University of Uberlândia).

References

[1] Kwon HJ, Oh YJ, Jang JH, Park JE, Hwang KS, Park YD. The effect of polymerization

conditions on the amounts of unreacted monomer and bisphenol A in dental composite resins.

Dent Mater J. 2015;34(3):327-35. doi: 10.4012/dmj.2014-230.

28

[2] Demarco FF, Collares K, Coelho-de-Souza FH, Correa MB, Cenci MS, Moraes RR,Opdam

NJ. Anterior composite restorations: A systematic review on long-term survival and reasons for

failure. Dent Mater. 2015 Oct;31(10):1214-24. doi: 10.1016/j.dental.2015.07.005.

[3] Demarco FF, Corrêa MB, Cenci MS, Moraes RR, Opdam NJ. Longevity of posterior

composite restorations: not only a matter of materials. Dent Mater. 2012 Jan;28(1):87-101. doi:

10.1016/j.dental.2011.09.003.

[4] Cetin AR, Unlu N, Cobanoglu N. A five-year clinical evaluation of direct nanofilled and

indirect composite resin restorations in posterior teeth. Oper Dent. 2013 Mar-Apr;38(2):E1-11.

doi: 10.2341/12-160-C.

[5] Pashley DH, Tay FR, Breschi L, Tjäderhane L, Carvalho RM, Carrilho M, Tezvergil-

Mutluay A. State of the art etch-and-rinse adhesives. Dent Mater. 2011 Jan;27(1):1-16. doi:

10.1016/j.dental.2010.10.016.

[6] Nahsan FP, Mondelli RF, Franco EB, Naufel FS, Ueda JK, Schmitt VL, Baseggio W.

Clinical strategies for esthetic excellence in anterior tooth restorations: understanding color and

composite resin selection. J Appl Oral Sci. 2012 Mar-Apr;20(2):151-6.

[7] Deliperi S, Bardwell DN. An alternative method to reduce polymerization shrinkage in

direct posterior composite restorations. J Am Dent Assoc. 2002 Oct;133(10):1387-98. Review.

Erratum in: J Am Dent Assoc. 2002 Dec;133(12):1614.

[8] Bönecker M, Tenuta LM, Pucca Junior GA, Costa PB, Pitts N. A social movement to reduce

caries prevalence in the world. Braz Oral Res. 2013 Jan-Feb;27(1):5-6.

[9] Da Rosa Rodolpho PA, Donassollo TA, Cenci MS, Loguércio AD, Moraes RR, Bronkhorst

EM, Opdam NJ, Demarco FF. 22-Year clinical evaluation of the performance of two posterior

composites with different filler characteristics. Dent Mater. 2011 Oct;27(10):955-63. doi:

10.1016/j.dental.2011.06.001.

[10] Ferracane JL. Resin composite--state of the art. Dent Mater. 2011 Jan;27(1):29-38. doi:

10.1016/j.dental.2010.10.020.

[11] Casselli DS, Faria-e-Silva AL, Casselli H, Martins LR. Marginal adaptation of class V

composite restorations submitted to thermal and mechanical cycling. J Appl Oral Sci. 2013 Jan-

Feb;21(1):68-73.

29

[12] Benetti AR, Havndrup-Pedersen C, Honoré D, Pedersen MK, Pallesen U. Bulk-fill resin

composites: polymerization contraction, depth of cure, and gap formation. Oper Dent. 2015

Mar-Apr;40(2):190-200. doi: 10.2341/13-324-L.

[13] Fronza BM, Rueggeberg FA, Braga RR, Mogilevych B, Soares LE, Martin AA,

Ambrosano G, Giannini M. Monomer conversion, microhardness, internal marginal adaptation,

and shrinkage stress of bulk-fill resin composites. Dent Mater. 2015 Dec;31(12):1542-51. doi:

10.1016/j.dental.2015.10.001.

[14] Lee SK, Kim TW, Son SA, Park JK, Kim JH, Kim HI, Kwon YH. Influence of light-curing

units on the polymerization of low-shrinkage composite resins. Dent Mater J. 2013;32(5):688-

94.

[15] Loguercio AD, Reis A, Schroeder M, Balducci I, Versluis A, Ballester RY. Polymerization

shrinkage: effects of boundary conditions and filling technique of resin composite restorations.

J Dent. 2004 Aug;32(6):459-70.

[16] Czasch P, Ilie N. In vitro comparison of mechanical properties and degree of cure of bulk

fill composites. Clin Oral Investig. 2013 Jan;17(1):227-35. doi: 10.1007/s00784-012-0702-8.

[17] Roggendorf MJ, Krämer N, Appelt A, Naumann M, Frankenberger R. Marginal quality of

flowable 4-mm base vs. conventionally layered resin composite. J Dent. 2011 Oct;39(10):643-

7. doi: 10.1016/j.jdent.2011.07.004.

[18] Leprince JG, Palin WM, Vanacker J, Sabbagh J, Devaux J, Leloup G. Physico-mechanical

characteristics of commercially available bulk-fill composites. J Dent. 2014 Aug;42(8):993-

1000. doi: 10.1016/j.jdent.2014.05.009.

[19] Orłowski M, Tarczydło B, Chałas R. Evaluation of marginal integrity of four bulk-fill

dental composite materials: in vitro study. Scientific World Journal. 2015; 2015:701262. doi:

10.1155/2015/701262.

[20] Kwon Y, Ferracane J, Lee IB. Effect of layering methods, composite type, and flowable

liner on the polymerization shrinkage stress of light cured composites. Dent Mater. 2012

Jul;28(7):801-9. doi: 10.1016/j.dental.2012.04.028.

[21] Khosravi K, Mousavinasab SM, Samani MS. Comparison of microleakage in Class II

cavities restored with silorane-based and methacrylate-based composite resins using different

restorative techniques over time. Dent Res J (Isfahan). 2015 Mar-Apr;12(2):150-6.

[22] Campos EA, Ardu S, Lefever D, Jassé FF, Bortolotto T, Krejci I. Marginal adaptation of

class II cavities restored with bulk-fill composites. J Dent. 2014 May;42(5):575-81. doi:

10.1016/j.jdent.2014.02.007.

30

[23] El-Damanhoury H, Platt J. Polymerization shrinkage stress kinetics and related properties

of bulk-fill resin composites. Oper Dent. 2014 Jul-Aug;39(4):374-82. doi: 10.2341/13-017-L.

[24] Moorthy A, Hogg CH, Dowling AH, Grufferty BF, Benetti AR, Fleming GJ. Cuspal

deflection and microleakage in premolar teeth restored with bulk-fill flowable resin-based

composite base materials. J Dent. 2012 Jun;40(6):500-5. doi: 10.1016/j.jdent.2012.02.015.

[25] Soares CJ, Pizi EC, Fonseca RB, Martins LR. Influence of root embedment material and

periodontal ligament simulation on fracture resistance tests. Braz Oral Res. 2005 Jan-

Mar;19(1):11-6.

[26] Frankenberger R, Krämer N, Appelt A, Lohbauer U, Naumann M, Roggendorf MJ.

Chairside vs. labside ceramic inlays: effect of temporary restoration and adhesive luting on

enamel cracks and marginal integrity. Dent Mater. 2011 Sep;27(9):892-8. doi:

10.1016/j.dental.2011.05.007.

[27] Anttila EJ, Krintilä OH, Laurila TK, Lassila LV, Vallittu PK, Hernberg RG. Evaluation of

polymerization shrinkage and hydroscopic expansion of fiber-reinforced biocomposites using

optical fiber Bragg grating sensors. Dent Mater. 2008 Dec;24(12):1720-7. doi:

10.1016/j.dental.2008.07.006.

[28] Urabe I, Nakajima S, Sano H, Tagami J. Physical properties of the dentin-enamel junction

region. Am J Dent. 2000 Jun;13(3):129-35.

[29] Bicalho AA, Pereira RD, Zanatta RF, Franco SD, Tantbirojn D, Versluis A, Soares CJ.

Incremental filling technique and composite material--part I: cuspal deformation, bond

strength, and physical properties. Oper Dent. 2014 Mar-Apr;39(2):E71-82. doi: 10.2341/12-

441-L.

[30] Pereira R, Bicalho AA, Franco SD, Tantbirojn D, Versluis A, Soares CJ. Effect of

Restorative Protocol on Cuspal Strain and Residual Stress in Endodontically Treated Molars.

Oper Dent. 2016 Jan-Feb;41(1):23-33. doi: 10.2341/14-178-L.

[31] Rajan G, Shouha P, Ellakwa A, Bhowmik K, Xi J, Prusty G. Evaluation of the physical

properties of dental resin composites using optical fiber sensing technology. Dent Mater. 2016

Sep;32(9):1113-23. doi: 10.1016/j.dental.2016.06.015.

[32] Vinagre A, Ramos J, Alves S, Messias A, Alberto N, Nogueira R. Cuspal Displacement

Induced by Bulk Fill Resin Composite Polymerization: Biomechanical Evaluation Using Fiber

Bragg Grating Sensors. Int J Biomater. 2016;2016:7134283. doi: 10.1155/2016/7134283.

[33] Ilie N, Kunzelmann KH, Hickel R. Evaluation of micro-tensile bond strengths of composite

materials in comparison to their polymerization shrinkage. Dent Mater. 2006 Nov;22(7):593-

601.

31

[34] Bicalho AA, Valdívia AD, Barreto BC, Tantbirojn D, Versluis A, Soares CJ. Incremental

filling technique and composite material--part II: shrinkage and shrinkage stresses. Oper Dent.

2014 Mar-Apr;39(2):E83-92. doi: 10.2341/12-442-L.

[35] Atalay C, Yazici AR, Horuztepe A, Nagas E, Ertan A, Ozgunaltay G. Fracture Resistance

of Endodontically Treated Teeth Restored With Bulk Fill, Bulk Fill Flowable, Fiber-reinforced,

and Conventional Resin Composite. Oper Dent. 2016 Jun 28.

[36] Zorzin J, Maier E, Harre S, Fey T, Belli R, Lohbauer U, Petschelt A, Taschner M. Bulk-

fill resin composites: polymerization properties and extended light curing. Dent Mater. 2015

Mar;31(3):293-301. doi: 10.1016/j.dental.2014.12.010.

[37] Miletic V, Peric D, Milosevic M, Manojlovic D, Mitrovic N. Local deformation fields and

marginal integrity of sculptable bulk-fill, low-shrinkage and conventional composites. Dent

Mater. 2016 Nov;32(11):1441-1451. doi: 10.1016/j.dental.2016.09.011.

[38] Omran TA, Garoushi S, Abdulmajeed AA, Lassila LV, Vallittu PK. Influence of increment

thickness on dentin bond strength and light transmission of composite base materials. Clin Oral

Investig. 2016 Sep 10.

[39] Rauber GB, Bernardon JK, Vieira LC, Maia HP, Horn F, Roesler CR. In Vitro Fatigue

Resistance of Teeth Restored With Bulk Fill versus Conventional Composite Resin. Braz Dent

J. 2016 Jul-Aug;27(4):452-7. doi: 10.1590/0103-6440201600836.

[40] Lee MR, Cho BH, Son HH, Um CM, Lee IB. Influence of cavity dimension and restoration

methods on the cusp deflection of premolars in composite restoration. Dent Mater. 2007

Mar;23(3):288-95.

[41] Kim RJ, Kim YJ, Choi NS, Lee IB. Polymerization shrinkage, modulus, and shrinkage

stress related to tooth-restoration interfacial debonding in bulk-fill composites. J Dent. 2015

Apr;43(4):430-9. doi: 10.1016/j.jdent.2015.02.002.

[42] Eakle WS. Fracture resistance of teeth restored with class II bonded composite resin. J

Dent Res. 1986 Feb;65(2):149-53.

[43] Zhang H, Zhang ML, Qiu LH, Yu JT, Zhan FL. [Comparison of wear resistance and

flexural strength of three kinds of bulk-fill composite resins]. Shanghai Kou Qiang Yi Xue.

2016 Jun;25(3):292-5. Chinese.

32

Tables

33

Table 2 – Results of FBG evaluation ( µε)

Z100 TNC FBF ABF

Average (Standard

Deviation) 949.1 ± 236.9 A 105.3 ± 205.3 C 525.8 ± 71.2 B 434.8 ± 306.0 BC

Average followed by the same letter are not statistically different (p > 0.05). n = 5 specimens /

group.

Table 3 – Results of cuspal deformation ( µε) and fracture resistance (N)

Cuspal Deformation

Restoration Axial Compressive (100N) Fracture Fracture Resistence

Z100 136.2 ± 41.4 A 89.8 ± 43.1 A 999.1 ± 228.4 AB 1624.2 ± 561.2 B

TNC 82.6 ± 25.0 B 50.3 ± 31.7 B 1074.5 ± 381.1 A 2925.8 ± 906.6 A

FBF 87.3 ± 25.9 B 34.1 ± 12.8 B 751.6 ± 243.6 B 1989.9 ± 846.1 AB

ABF 70.9 ± 11.8 B 34.9 ± 10.4 B 838.1 ± 119.8 AB 2166.1 ± 867.6 AB

Average followed by the same letter are not statistically different (p > 0.05). n = 10 specimens / group.

34

Figures

Figure 1. (a) Typical FBG reflection spectrum. (b) FBG spectra as a function of the applied

strain. (c) Wavelength shift as a function of the applied strain.

Figure 2. Percentage of specimens (%) according to fracture pattern classification.

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Z100 TNC FBF ABF

Failu

re m

od

e

IV (root fracture beyondrepair)

III (resin composite andcervical tooth structure withpossible periodontal repair)

II (resin composite andcoronal structure)

I (resin composite)

35

Figure 3. SEM representative images of fracture pattern classification. A) Type-1 fracture at

composite resin (RC); B) Type-2 fracture at composite resin and dentin (D); C) Type-3

fracture at composite resin and cervical tooth structure, enamel (E) and dentin (D); D) Type-4

fracture with pulp canal (PC) exposure.

36

3 CONCLUSÃO

De acordo com os resultados obtidos e considerando as limitações das metodologias

utilizadas, pôde-se concluir que:

1. Resinas compostas bulk fill apresentam menor tensão de contração e deformação

de cúspide durante a fotopolimerização de um único incremento com 4 mm de espessura em

relação à resina composta convencional.

2. A resina composta TNC apresenta menor tensão de contração de polimerização,

menor deformação de cúspide, além de ser mais resistente à fraturas, contudo, apresenta maior

frequência de fraturas catastróficas.

3. O padrão de fratura das resinas compostas quando induzidas por forças

compressivas é diretamente dependente do material resinoso utilizado.

37

REFERÊNCIAS

Al-Fakih E, Abu Osman NA, Mahamd Adikan FR. The use of fiber Bragg grating sensors in

biomechanics and rehabilitation applications: the state-of-the-art and ongoing research topics.

Sensors (Basel). 2012 Sep 25;12(10):12890-926. doi: 10.3390/s121012890.

Anatavara S, Sitthiseripratip K, Senawongse P. Stress relieving behaviour of flowable

composite liners: A finite element analysis. Dent Mater J. 2016;35(3):369-78. doi:

10.4012/dmj.2015-204

Atalay C, Yazici AR, Horuztepe A, Nagas E, Ertan A, Ozgunaltay G. Fracture Resistance of

Endodontically Treated Teeth Restored With Bulk Fill, Bulk Fill Flowable, Fiber-reinforced,

and Conventional Resin Composite. Oper Dent. 2016 Jun 28.

Benetti AR, Havndrup-Pedersen C, Honoré D, Pedersen MK, Pallesen U. Bulk-fill resin

composites: polymerization contraction, depth of cure, and gap formation. Oper Dent. 2015

Mar-Apr;40(2):190-200. doi: 10.2341/13-324-L.

Bicalho AA, Pereira RD, Zanatta RF, Franco SD, Tantbirojn D, Versluis A, Soares CJ.

Incremental filling technique and composite material--part I: cuspal deformation, bond

strength, and physical properties. Oper Dent. 2014 Mar-Apr;39(2):E71-82. doi: 10.2341/12-

441-L.

Bönecker M, Tenuta LM, Pucca Junior GA, Costa PB, Pitts N. A social movement to reduce

caries prevalence in the world. Braz Oral Res. 2013 Jan-Feb;27(1):5-6.

Campos EA, Ardu S, Lefever D, Jassé FF, Bortolotto T, Krejci I. Marginal adaptation of class

II cavities restored with bulk-fill composites. J Dent. 2014 May;42(5):575-81. doi:

10.1016/j.jdent.2014.02.007.

De acordo com as normas da UNICAMP/FOP, baseadas na padronização do International Committee of Medical

Journal Editors – Vancouver Group. Abreviatura dos periódicos em conformidade com o PubMed.

38

Casselli DS, Faria-e-Silva AL, Casselli H, Martins LR. Marginal adaptation of class V

composite restorations submitted to thermal and mechanical cycling. J Appl Oral Sci. 2013

Jan-Feb;21(1):68-73.

Cetin AR, Unlu N, Cobanoglu N. A five-year clinical evaluation of direct nanofilled and

indirect composite resin restorations in posterior teeth. Oper Dent. 2013 Mar-Apr;38(2):E1-

11. doi: 10.2341/12-160-C.

Czasch P, Ilie N. In vitro comparison of mechanical properties and degree of cure of bulk fill

composites. Clin Oral Investig. 2013 Jan;17(1):227-35. doi: 10.1007/s00784-012-0702-8.

Da Rosa Rodolpho PA, Donassollo TA, Cenci MS, Loguércio AD, Moraes RR, Bronkhorst

EM, et al. 22-Year clinical evaluation of the performance of two posterior composites with

different filler characteristics. Dent Mater. 2011 Oct;27(10):955-63. doi:

10.1016/j.dental.2011.06.001.

Deliperi S, Bardwell DN. An alternative method to reduce polymerization shrinkage in direct

posterior composite restorations. The Journal of the American Dental Association. 2002;

133(10): 1387-1398.

Demarco FF, Collares K, Coelho-de-Souza FH, Correa MB, Cenci MS, Moraes RR, et al.

Anterior composite restorations: A systematic review on long-term survival and reasons for

failure. Dent Mater. 2015 Oct;31(10):1214-24. doi: 10.1016/j.dental.2015.07.005.

Demarco FF, Corrêa MB, Cenci MS, Moraes RR, Opdam NJ. Longevity of posterior

composite restorations: not only a matter of materials. Dent Mater. 2012 Jan;28(1):87-101.

doi: 10.1016/j.dental.2011.09.003.

Dominguez JA, Bittencourt BF, Farago PV, Pinheiro LA, Gomes OMM. Shrinkage stress of

resin composites: effect of material composition - sistematic review. Braz Dent Sci 2014

Jul/Sep;17(3).

El-Damanhoury H, Platt J. Polymerization shrinkage stress kinetics and related properties of

bulk-fill resin composites. Oper Dent. 2014 Jul-Aug;39(4):374-82. doi: 10.2341/13-017-L.

39

Ferracane JL. Resin composite--state of the art. Dent Mater. 2011 Jan;27(1):29-38. doi:

10.1016/j.dental.2010.10.020.

Fronza BM, Rueggeberg FA, Braga RR, Mogilevych B, Soares LE, Martin AA, et al.

Monomer conversion, microhardness, internal marginal adaptation, and shrinkage stress of

bulk-fill resin composites. Dent Mater. 2015 Dec;31(12):1542-51. doi:

10.1016/j.dental.2015.10.001.

Kalliecharan D, Germscheid W, Price RB, Stansbury J, Labrie D. Shrinkage stress kinetics of

Bulk Fill resin-based composites at tooth temperature and long time. Dent Mater. 2016

Nov;32(11):1322-1331. doi: 10.1016/j.dental.2016.07.015.

Kwon HJ, Oh YJ, Jang JH, Park JE, Hwang KS, Park YD. The effect of polymerization

conditions on the amounts of unreacted monomer and bisphenol A in dental composite resins.

Dent Mater J. 2015;34(3):327-35. doi: 10.4012/dmj.2014-230.

Lee SK, Kim TW, Son SA, Park JK, Kim JH, Kim HI, et al. Influence of light-curing units on

the polymerization of low-shrinkage composite resins. Dent Mater J. 2013;32(5):688-94.

Leprince JG, Palin WM, Vanacker J, Sabbagh J, Devaux J, Leloup G. Physico-mechanical

characteristics of commercially available bulk-fill composites. J Dent. 2014 Aug;42(8):993-

1000. doi: 10.1016/j.jdent.2014.05.009.

Loguercio AD, Reis A, Schroeder M, Balducci I, Versluis A, Ballester RY. Polymerization

shrinkage: effects of boundary conditions and filling technique of resin composite

restorations. J Dent. 2004 Aug;32(6):459-70.

Moorthy A, Hogg CH, Dowling AH, Grufferty BF, Benetti AR, Fleming GJ. Cuspal

deflection and microleakage in premolar teeth restored with bulk-fill flowable resin-based

composite base materials. J Dent. 2012 Jun;40(6):500-5. doi: 10.1016/j.jdent.2012.02.015.

40

Nahsan FP, Mondelli RF, Franco EB, Naufel FS, Ueda JK, Schmitt VL, et al. Clinical

strategies for esthetic excellence in anterior tooth restorations: understanding color and

composite resin selection. J Appl Oral Sci. 2012 Mar-Apr;20(2):151-6.

Orłowski M, Tarczydło B, Chałas R. Evaluation of marginal integrity of four bulk-fill dental

composite materials: in vitro study. Scientific World Journal. 2015; 2015:701262. doi:

10.1155/2015/701262.

Ozakar-Ilday N, Zorba YO, Yildiz M, Erdem V, Seven N, Demirbuga S. Three-year clinical

performance of two indirect composite inlays compared to direct composite restorations. Med

Oral Patol Oral Cir Bucal. 2013 May 1;18(3):e521-8.

Park JW, Ferracane JL. Measuring the residual stress in dental composites using a ring slitting

method. Dent Mater. 2005 Sep;21(9):882-9.

Park JW, Ferracane JL. Residual stress in composites with the thin-ring-slitting approach. J

Dent Res. 2006 Oct;85(10):945-9.

Pashley DH, Tay FR, Breschi L, Tjäderhane L, Carvalho RM, Carrilho M, et al. State of the

art etch-and-rinse adhesives. Dent Mater. 2011 Jan;27(1):1-16. doi:

10.1016/j.dental.2010.10.016.

Pereira R, Bicalho AA, Franco SD, Tantbirojn D, Versluis A, Soares CJ. Effect of Restorative

Protocol on Cuspal Strain and Residual Stress in Endodontically Treated Molars. Oper Dent.

2016 Jan-Feb;41(1):23-33. doi: 10.2341/14-178-L.

Rajan G, Shouha P, Ellakwa A, Bhowmik K, Xi J, Prusty G. Evaluation of the physical

properties of dental resin composites using optical fiber sensing technology. Dent Mater. 2016

Sep;32(9):1113-23. doi: 10.1016/j.dental.2016.06.015.

Roggendorf MJ, Krämer N, Appelt A, Naumann M, Frankenberger R. Marginal quality of

flowable 4-mm base vs. conventionally layered resin composite. J Dent. 2011

Oct;39(10):643-7. doi: 10.1016/j.jdent.2011.07.004.

41

Umesh S, Padma S, Asokan S, Srinivas T. Fiber Bragg Grating based bite force measurement.

J Biomech. 2016 Jul 1. pii: S0021-9290(16)30732-1. doi:10.1016/j.jbiomech.2016.06.036.

Van Dijken JW, Pallesen U. Posterior bulk-filled resin composite restorations: A 5-year

randomized controlled clinical study. J Dent. 2016 Aug;51:29-35.

doi:10.1016/j.jdent.2016.05.008.

Vinagre A, Ramos J, Alves S, Messias A, Alberto N, Nogueira R. Cuspal Displacement

Induced by Bulk Fill Resin Composite Polymerization: Biomechanical Evaluation Using

Fiber Bragg Grating Sensors. Int J Biomater. 2016;2016:7134283. doi:

10.1155/2016/7134283.

Witzel MF, Braga RR, Ballester RY, Lima RG. Influence of specimen dimensions on nominal

polymerization contraction stress of a dental composite. J. of the Braz. Soc. of Mech. Sci. &

Eng. 2005 Jul-Sept 27(3):283-287.

Yeh CH, Chow CW, Wu PC, Tseng FG. A simple fiber Bragg grating-based sensor network

architecture with self-protecting and monitoring functions. Sensors (Basel). 2011;11(2):1375-

82. doi: 10.3390/s110201375.

42

APÊNDICE 1

Metodologia Ilustrada

Figura 1. Preparo das amostras. A) Seleção de molares hígidos; B) Simulação do

ligamento periodontal 2 mm abaixo da junção amelocementária com cera 7; C) Posicionamento

do dente à haste de um delineador protético; D) Centralização de uma película radiográfica com

perfuração central ao dente; E) Posicionamento de um tubo de PVC para inclusão da porção

radicular em resina de poliestireno; F) Inclusão do dente na resina de poliestireno; G) Remoção

dos dentes nos alvéolos artificiais e eliminação da cera 7 na raiz do dente; H) Realização da

cavidade MOD em máquina de preparo; I) Cavidade MOD confeccionada; J) Inclusão do

poliéter Impregum.

43

Figura 2. Avaliação da tensão de contração de polimerização dos materiais

restauradores pelos sensores de Bragg. A) Condicionamento com ácido fosfórico a 37% no

esmalte por 15 segundos; B) Condicionamento com ácido fosfórico sobre a dentina por 15

segundos e no esmalte por mais 15 segundos; C) Lavagem abundante com água por 30

segundos; D) Controle da umidade mantendo a dentina levemente úmida; E) Fibra óptica

esticada com a presença dos sensores de Bragg na região azul; F) Posicionamento dos sensores

de Bragg na região amelodentinária justaposto à parede vestibular da cavidade MOD; G)

Aplicação do adesivo Adper Single Bond 2 seguido da volatilização do solvente por 5 segundos;

H) Fotopolimerização do adesivo por 40 segundos; I) Fibra óptica posicionada na parede

vestibular da cavidade MOD com o sensor de Bragg aderido à parede com adesivo fotoativado.

44

Figura 3. Teste de extensometria para avaliação da deformação de cúspide. A)

Aplicação de ácido fosfórico por 30 segundos na região determinada para instalação do

extensômetro; B) Posicionamento do extensômetro na base da cúspide vestibular e

lingual/palatina ao nível da parede gengival das caixas proximais da cavidade MOD com cola

a base de cianoacrilato; C) Fotopolimerização das restaurações conforme o protocolo dos

grupos de tratamento e avaliação da deformação de cúspide pelos extensômetros; D) Ligação

dos extensômetros à máquina analisadora por meio de pontos de solda; E) Avaliação da

45

deformação de cúspide durante carregamento de 100N e até a fratura em máquina de ensaio

universal.

Figura 4. Protocolo restaurador dos grupos com resina convencional e resina bulk

fill. A) Inserção de forma incremental do G Z100; B C e D) Inserção de um único incremento

de 4mm dos grupos TNC, FBF e ABF, respectivamente.

46

ANEXO 1

47

ANEXO 2: Dental Materials