research article evaluation of extraradicular diffusion of...

Research ArticleEvaluation of Extraradicular Diffusion of Hydrogen Peroxideduring Intracoronal Bleaching Using Different Bleaching Agents

Mohammad E Rokaya1 Khaled Beshr2 Abeer Hashem Mahram23

Samah Samir Pedir2 and Kusai Baroudi4

1Department of Endodontics Faculty of Dentistry Al-Azhar University Assiut Egypt2Department of Restorative Dental Sciences Al-Farabi Colleges Riyadh Saudi Arabia3Department of Endodontics Faculty of Dentistry Ain Shams University Cairo Egypt4Department of Preventive Dental Sciences Al-Farabi Colleges Riyadh Saudi Arabia

Correspondence should be addressed to Kusai Baroudi d kusaiyahoocouk

Received 2 May 2015 Accepted 24 June 2015

Academic Editor Patricia Pereira

Copyright copy 2015 Mohammad E Rokaya et al This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited

Objectives Extra radicular diffusion of hydrogen peroxide associated with intracoronal teeth bleaching was evaluatedMethods 108intact single rooted extracted mandibular first premolars teeth were selected The teeth were instrumented with WaveOne systemand obturated with gutta percha and divided into four groups (119899 = 27) according to the bleaching materials used Each main groupwas divided into three subgroups (119899 = 9) according to the time of extra radicular hydrogen peroxide diffusion measurements at1 7 and 14 days group 1 (35 hydrogen peroxide) group 2 (35 carbamide peroxide) group 3 (sodium perborate-30 hydrogenperoxidemixture) and group 4 (sodiumperborate-watermixture) Four cemental dentinal defects were prepared just below theCEJon each root surface The amount of hydrogen peroxide that leached out was evaluated after 1 7 and 14 days by spectrophotometeranalysis The results were analyzed using the ANOVA and Tukeyrsquos test Results Group 1 showed highest extra radicular diffusionfollowed by group 3 and group 2 while group 4 showed the lowest mean extra radicular diffusion Conclusion Carbamide peroxideand sodium perborate-water mixture are the most suitable bleaching materials used for internal bleaching due to their low extraradicular diffusion of hydrogen peroxide

1 Introduction

In modern society greater emphasis is being placed onthe cosmetic appearance of teeth [1] Tooth discoloration isan aesthetic problem that may require treatment based onbleaching [2]The causes of tooth discoloration are varied andcomplex but are usually classified as being either intrinsic orextrinsic in nature [3]

The main intrinsic factors are pulp hemorrhage decom-position of pulp bacteria and their products tetracyclinepulp necrosis intracanal medicaments some endodonticfilling materials and metallic restorations With the dissemi-nation of blood components into the dentinal tubules causedby pulp extirpation or traumatically induced internal pulpbleeding blood vessels are broken promoting blood over-flow into the pulp chamber [4] Bleaching is considered as

a procedure which involves lightening the color of a tooththrough application of a chemical agent to oxidize the organicpigmentation in the tooth [5]

Correct diagnosis of the cause of tooth discolouration isimportant as shade changes as a result of different etiologiesmay require different treatment strategies Thus teeth withhealthy pulps may be bleached by the home techniquetermed night guard vital bleaching or vital tooth bleachingin-office techniques or an association of both Root filledteeth may be treated by the walking bleach techniquethermocatalytic technique or an association of techniques[6]

Inside outside bleaching at home using carbamide perox-ide in bleaching gel is safe but there are chances of collectionof debris and contamination in the open pulp chamber whentray is not in mouth In-office laser bleaching is a dentist

Hindawi Publishing CorporationInternational Journal of DentistryVolume 2015 Article ID 493795 7 pageshttpdxdoiorg1011552015493795

2 International Journal of Dentistry

controlled bleaching and is safe but may cost the patientquite a bit and one needs to buy specific equipment for thesame Walking bleach procedure on the other hand can beundertaken in remotest places also as no special equipmentis required and material cost is also minimal [7]

The walking bleach technique involves the application ofa bleaching agent to the dentine of the pulp chamber betweendental visits A mixture of sodium perborate and distilledwater has been extensively used as an effective agent for intra-coronal bleaching In order to enhance bleaching efficacy30 hydrogen peroxide (HP) was suggested as a substitutefor water A concentrated hydrogen peroxide (25ndash35) isefficient for bleaching teeth with or without vital pulpAnother bleaching agent 35ndash37 carbamide peroxide (CP)has emerged as a popular and effective agent for both in-officeand intracoronal bleaching techniques [8] One of the mostimportant properties of a bleaching agent is its ability to allowpenetration of the bleaching agent through the dentinal per-meability the deeper the penetration is themore the pigmentthat causes chromatic alteration of the dental tissue can bereversed by the oxidation reaction [9]

However laboratory studies have demonstrated thatintracoronal hydrogen peroxide can diffuse through the rootand this diffusion is greater in the presence of cemental rootdefects Animal studies have confirmed the association ofintracoronal bleaching with cervical root resorptionThere isspeculation that diffusion of hydrogen ions from intracoronalbleaching agents may provide an acidic environment thatis optimal for osteoclastic activity and bone resorptionresulting in external cervical root resorption over time [10]

Since dentinal tubules are oriented incisally placing aprotective base material at the lower level of the CEJ couldreduce the leakage of hydrogen peroxide to the periodontaltissues Deferent protective base materials have been com-pared No significant differences were found between them[11]

This study aimed to compare by spectrophotometeranalysis using potassium permanganate the extraradiculardiffusion of hydrogen peroxide associated with intracoronalteeth bleaching by Opalescence Endo 35 Opalescence PF35 sodiumperborate with 30hydrogen peroxidemixtureand sodium perborate with water mixture

2 Materials and Methods

108 freshly extracted human single root canals (mandibularfirst premolars) for orthodontic reasons from patient lessthan 21 years old were collected with no sign of cracks orstructural anomalies A prior patientrsquos consent was given touse their extracted teeth to conduct the study Approval of Al-Azhar University Faculty of Oral and Dental Medicine Egypt(under number 2822009) was also obtained The selectedteeth were then immersed in 525 sodium hypochlorite forone hour to dissolve organic debris that was present on theexternal surface of the roots Subsequently they were cleanedwith an ultrasonic scaler (satelec Acteon France) to removecalculus discarding teeth with previous root canal treatmentinternal resorption and external resorption localized or

diffuse calcificationsThe selected teethwere stored in normalsaline at room temperature until the time of use

A standardized access cavity was made using a carbidebur loaded in a high speed handpiece Each root canal orificewas enlarged using Gates-Glidden bur numbers 3 and 4 toenlarge root canals of the same size using 525 NaOClsolution for irrigation The pulp tissues were removed with abarbed broach (Dentsply Maillefer Ballaigues Switzerland)Working length (WL) was determined by inserting a size10 K-file (Dentsply Maillefer Ballaigues Switzerland) whichwas passively introduced into the canal until the tip was seento exit at the major foramen The real length of the canal wasrecorded and the working length calculated by subtracting1mm from this measurement

The preparation was performed with a single rotary filethe WaveOne (Dentsply Maillefer Ballaigues Switzerland)and the preprogrammed motor (X-Smart Plus DentsplyMaillefer Ballaigues Switzerland) using a specificmovementof reciprocation 170∘CCW and 50∘CW at a speed equivalentto 350 rpm

Root canals were initially shaped with WaveOne primaryreciprocating file (2508) in the presence of 525 NaOClas irrigant The primary WaveOne file was used gently in areciprocating slow in- and out-pecking motion with short 2-3mmamplitude strokes to passively advance until it does noteasily progress anymore The shaping step was repeated untilthe coronal two-thirds of the canal has been prepared Theworking length and canal patency were confirmed and thenthe primary file is carried to the full working length in one ormore passes

A larger WaveOne file 4008 was carried to workinglength to fully shape and finish the preparation The finishedshape is confirmed in which the apical flutes of the file areloaded with dentin and a gauging 4002 hand file is snuggedat lengthThe apical foramen of each root was sealedwithwaxduring instrumentation to prevent irrigating solutions frompassing through the apical foramen During instrumentationthe canals were irrigated with 2mL of 525 NaOCl solutionusing a plastic syringe with 30-gauge closed-end needle(Hawe Max-I-probe Hawe Neos Bioggio Switzerland) Theneedle was inserted within 1 to 2mm of the working lengthThen the root canals were dried by size 4008WaveOne paperpoint Root canals are obturated with size 4008 WaveOnegutta-percha using ProRoot Endo Sealer (Dentsply MailleferBallaigues Switzerland)

To simulate standardized breaks in the cemental cov-ering four cemental dentinal defects were prepared justbelow the CEJ on each root surface mesial distal buccaland lingual aspects [10]The hemispherical defects (diameter10mm depth 05mm) were created using a round diamondbur (diameter 10mm) in a high speed handpiece The smearlayer created in the defects was removed with 15 EDTA andthen thoroughly washed with distilled water The apical two-thirds of the root surface was coated with a double layer of anail varnish to seal potential superficial defects as in Figure 1

21 Specimenrsquos Grouping The prepared specimens were thendivided randomly into four groups (119899 = 27) according to thebeaching materials used Each main group was subdivided

International Journal of Dentistry 3

Figure 1 A photograph showing simulated defects below CEJ

into three subgroups (119899 = 9) according to the time ofextraradicular hydrogen peroxide diffusion measurements at1 7 and 14 days

211 Group 1 (Opalescence Endo 35) Opalescence Endo(Ultradent Products South Jordan UT USA) is a 35hydrogen peroxide specially formulated gel for the ldquowalkingrdquobleach technique (pH 5)

212 Group 2 (Opalescence PF 35) Opalescence PF 35(Ultradent Products South Jordan UT USA) is 35 car-bamide peroxide 05 potassium nitrate and 011 weightto weight (1100 ppm) fluoride ion It is clear high-viscosityand sticky (pH 65)

213 Group 3 (Sodium Perborate-30 Hydrogen PeroxideMixture) There is a mixture of sodium perborate (DegussaHanau Germany) and 30 hydrogen peroxide (in the ratio1 g of powder 05mL of liquid) (pH 71)

214 Group 4 (Sodium Perborate-Water Mixture) There isa mixture of sodium perborate (Degussa Hanau Germany)and distilled water (in the ratio 1 g of powder 05mL ofdistilled water) (pH 97)

22 Bleaching Procedure The root filling in the coronal pulpchamber was removed to 2mm below the facial cementoe-namel junction A barrier placement of 2mm layer of glass-ionomer cement (Ketac-Molar 3MESPE St PaulMNUSA)was placed over the gutta-percha [12] A pellet of cotton wasplaced in the chamber it was sealed temporarily with Cavit

0871

1

09

08

07

06

05

04

03

02

01

0

350 400 450 500 525 550 600 650 700

Wavelength

Spec

trum

A

Figure 2 A schematic diagram showing KMnO4

having a standardspectrum (absorbance 0871 A) at wavelength 525 nm

(3MESPE St PaulMNUSA)After 24 hours the temporaryfilling and the cotton pellet were removed completely

The walls of the access cavity were cleaned of any residueusing a small carbide bur followed by thorough rinsing with2mL of 525 NaOCl The bleaching material of each groupwas placed in the pulp chamber and the access cavity of eachspecimen sealed temporarily with Cavit

Each tooth was suspended in a plastic vial of 3mL dis-tilled water using laboratory sealing film Parafilm (ParafilmM Neenah WI USA) The sealing film was cut to fit eachtooth at the level of the CEJ and stabilized with sticky waxto achieve a tight seal and stored in an incubator at 37∘Cand 100 relative humidity during 14 days of bleaching thebleaching materials were changed at 7 days and the amountof hydrogen peroxide that leached out into the distilled waterwas evaluated after 1 7 and 14 days

3 Extraradicular Hydrogen PeroxideDiffusion Measurement

In this study we used titration method of permanganate andhydrogen peroxide according to the following equation [13]

2MnO4minus

+ 5H2O2+

+ 6H+ 997888rarr 2Mn2+

+ 5O2 + 8H2O (1)

The pink color of permanganate would be changed whenreacted with peroxides the color disappears according tothe concentration of peroxide The reaction is fast and doesnot need time or temperature for progression The amountof radicular peroxide was measured using the UV-visiblespectrophotometer (SpectraMax 1601 Molecular DevicesCorp Sunnyvale CA USA) at a wavelength of 480 nm(at room temperature) utilizing the potassium perman-ganate (KMnO

4) as peroxide indicator (redox reaction) and

(KMnO4) having a standard spectrum (absorbance 0871 A)

at wavelength 525 nm (Figure 2)


4 Results

41 After 1 Day Group 1 (Opalescence Endo 35) showedthe statistically significantly highest extraradicular diffusion(0168 plusmn 0049)119875 lt 005There was no statistically significantdifference between Group 2 (Opalescence PF 35) Group3 (sodium perborate-30 hydrogen peroxide mixture) andGroup 4 (sodium perborate-water mixture) which showedthe statistically significantly lowest mean extraradicular dif-fusion (Groups 2 and 4 showed no extraradicular diffusion)

42 After 7 Days Group 1 (Opalescence Endo 35) showedhighest extraradicular diffusion (0482 plusmn 0051) This wasfollowed by Group 3 (sodium perborate-30 hydrogen per-oxide mixture (0375 plusmn 0049)) and Group 2 (OpalescencePF 35 (0210 plusmn 0125)) while Group 4 (sodium perborate-water mixture) showed the lowest mean extraradicular dif-fusion (0141 plusmn 0040) Statistically there was no statisticallysignificant difference between Group 1 and Group 3 whilethere was statistically significant difference between the othertested groupsMeanwhile there was no statistically significantdifference between Groups 2 and 4


44 On the Other Hand All bleaching material used in thisstudy recorded statistically significant increase inmean extra-radicular diffusion after 7 and 14 days (Table 1)

5 Discussion

The current study employed the use of four different bleach-ing agents with intracoronal teeth bleaching and they are35 hydrogen peroxide (Opalescence Endo) 35 carbamideperoxide (Opalescence PF 35) sodium perborate with 30hydrogen peroxide mixture and sodium perborate withwater mixture

This study has been done to investigate the effect of thesefour bleaching agents on extraradicular hydrogen peroxidediffusion after one and seven days and fourteen days bypotassium permanganate (KMnO

4) as peroxide indicator

Understanding the chemistry of the active ingredient of thebleaching agent would be useful

Hydrogen peroxide (H2O2) is the main whitening agent

employed It is a thermally unstable free radical with a lowmolecular weight which penetrates the enamel and dentinthrough diffusion Complex molecules of organic pigmentsin the tissues are broken down into simpler hydrophilicmolecules through an oxidation reduction reaction by

the action of perhydroxyl ions originating from the degra-dation of H

2O2 These simpler molecules are easily removed

from the dental tissue when being in contact with waterthereby providing the desired whitening effect [14 15]

Carbamide peroxide (CH4N2OsdotH2O2) decomposes to 13

hydrogen peroxide and 23 urea [16] The urea can theoreti-cally be further decomposed to carbon dioxide and ammoniawhich elevates the pH to facilitate the bleaching procedurefurther This can be explained by the fact that in a basicsolution lower activation energy is required for the formationof free radicals from hydrogen peroxide and the reaction rateis higher [17]

Sodium perborate is an oxidizing agent available as apowder It is stable when being dry however in the presenceof acid warm air or water it breaks down to form sodiummetaborate hydrogen peroxide and nascent oxygen Sodiumperborate is easier to control and safer than concentratedhydrogen peroxide solutions [18]

This study compared extraradicular hydrogen peroxidediffusion of various bleaching agents after one and seven daysand fourteen days Previous studies of peroxide penetrationhave utilized different time periods [11 19]

In the present study single rooted mandibular premolarsextracted for orthodontic reasons from patients below 21years were usedTheywere selected because of the availabilityof such teeth andmost reported cases of cervical root resorp-tion associated with intracoronal bleaching were in youngpatients It is probable that the wide and patent dentinaltubules in young teeth would favor ionic diffusion of thebleaching agent through dentine [10]

The walking bleach technique requires a sound coronalseal around the access cavity after application of bleachingpaste in the chamber It can be achieved with GIC resincomposite or compomer to ensure its effectiveness and toavoid leakage of bleaching agent into the oral cavity In addi-tion a good seal also prevents recontamination of the dentinwith microorganisms and reduces the risk of renewed stain-ing [18]

In the present study although the teeth were not totallyimmersed in the distilled water the access openings wereprotected in order to prevent the leakage of bleaching agentsthrough this area Thus the diffusion of the bleachingmaterial occurred only through the cervical dentin tubulesexposed by CJE defects It is important to emphasize the dif-ficulty to obtain teeth with similar CJE characteristics whichlead some researchers to create artificial defects along theexternal cervical area to standardize the diffusion of bleach-ing agents [20]

In this study a 2mm layer of glass-ionomer cementwas applied over the canal filling due to its effectiveness inpreventing penetration of 30 hydrogen peroxide solutioninto the root canal Thus the use of this material as a baseduring bleaching presents the additional advantage that it canbe left in place after bleaching and can serve as a base for thefinal restoration [12]

The result of this study showed that after 1 day Group 1(Opalescence Endo 35) showed the statistically significantlyhighest extraradicular diffusion 119875 lt 005 There was no sta-tistically significant difference between group 2 (Opalescence


Table1Th

emeansstand

arddeviation(SD)v

aluesandresults

ofANOVA

andTu

keyrsquos

testforc

omparis

onof

extraradicular

diffu

sionbetweenfour

grou

ps

Time

Group

1Group

2Group

3Group

4119875value

(Opalescence

Endo

35)

(Opalescence

PF35)

(sod

ium

perborate-30hydrogen

peroxide

mixture)

(sod

ium

perborate-water

mixture)

Mean

SD

Mean

SD

Mean

SD

Mean

SD

1day

0168c

0049

0d0

006

8d0021

0d0

lowast

lt0001

7days

0482b

0051

0210c

0125

0375b

0049

0141c

004

014

days

0865a

0061

0430b

0030

0743a

006

00315b

004

6lowast

Sign

ificant

at119875le005m

eans

with

different

lette

rsares

tatisticallysig

nificantly

different

accordingto

Tukeyrsquos

test


PF 35) group 3 (sodium perborate-30 hydrogen peroxidemixture) and group 4 (sodium perborate-water mixture)after 7 and 14 days Group 1 showed highest extraradiculardiffusion followed by group 3 and group 2 while group 4showed the lowest mean extraradicular diffusion

The probable reasons for the results obtained in the presentstudy could be [21] as follows (a) As 35 carbamide peroxidedecomposes on contact with moisture to yield approximatelyonly 12 hydrogen peroxide (b) It could be because ofthe fact that carbamide peroxide does not diffuse throughdentine as fast as hydrogen peroxide (c) With the rise in pHaided by the resultant ammonia from the carbamide perox-ide the deionization of the hydrogen peroxide is facilitatedTherefore little unreacted hydrogen peroxide is left to diffusethrough the root dentin into the extraradicular environmentThese results were in agreement with that of Gokay et al[22] who stated that higher peroxide penetration occurredwith the 30 HP-SP mixture than with the CP bleachinggels and the 37 CP group also promoted greater peroxidepenetration than the other CP groups (119875 lt 005) There wasno statistically significant difference between 10 and 17CP groups (119875 gt 005) Lee et al [10] stated that carbamideperoxide had very low levels of extraradicular diffusion ofHPShivanna and Gupta [21] concluded that radicular peroxidepenetration from carbamide peroxide gels is less than sodiumperborate-hydrogen peroxidemixture therefore carrying lessrisk of postbleaching external root resorption

Heithersay analyzed cervical resorption cases andreported that 241 were caused by orthodontic treatment151 by dental trauma 51 by surgery (eg transplantationor periodontal surgery) and 39 by intracoronal bleachingA combination of internal bleaching with one of the othercauses is responsible for 136 of cervical resorption casesThe combination of bleaching and history of trauma is themost important predisposing factor for cervical resorption[23]

6 Conclusion

Carbamide peroxide and sodium perborate-water mixtureare the most suitable bleaching materials used for internalbleaching due to its low extraradicular diffusion of hydrogenperoxide

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

References

[1] W C de Souza-Zaroni E B Lopes J C Ciccone-Nogueira andR C S P Silva ldquoClinical comparison between the bleachingefficacy of 37 peroxide carbamide gel mixed with sodiumperborate with established intracoronal bleaching agentrdquo OralSurgery Oral Medicine Oral Pathology Oral Radiology andEndodontology vol 107 no 2 pp e43ndashe47 2009

[2] J Kaneko S Inoue S Kawakami andH Sano ldquoBleaching effectof sodium percarbonate on discolored pulpless teeth in vitrordquoJournal of Endodontics vol 26 no 1 pp 25ndash28 2000

[3] M Addy J Moran R Newcombe and P Warren ldquoThe com-parative tea staining potential of phenolic chlorhexidine andanti-adhesive mouthrinsesrdquo Journal of Clinical Periodontologyvol 22 no 12 pp 923ndash928 1995

[4] M C Valera C H R Camargo C A T Carvalho L D deOliveira S E A Camargo and C M Rodrigues ldquoEffectivenessof carbamide peroxide and sodium perborate in non-vitaldiscolored teethrdquo Journal of Applied Oral Science vol 17 no 3pp 254ndash261 2009

[5] A Feiz B Barekatain S Khalesi N Khalighinejad H Badrianand E J Swift ldquoEffect of several bleaching agents on teethstained with a resin-based sealerrdquo International EndodonticJournal vol 47 no 1 pp 3ndash9 2014

[6] K C K Yui J R Rodrigues M N G Mancini I Balducci andS E P Goncalves ldquoEx vivo evaluation of the effectiveness ofbleaching agents on the shade alteration of blood-stained teethrdquoInternational Endodontic Journal vol 41 no 6 pp 485ndash4922008

[7] R Anuradha and G Manisha ldquoWalking bleach-still relevant areview withmdasha case reportrdquo Indian Journal of Dental Sciencesvol 1 pp 32ndash37 2009

[8] V Cavalli M S ShinoharaW Ambrose F MMalafaia P N RPereira and M Giannini ldquoInfluence of intracoronal bleachingagents on the ultimate strength and ultrastructure morphologyof dentinerdquo International Endodontic Journal vol 42 no 7 pp568ndash575 2009

[9] L D Carrasco I C Froner S A M Corona and J D PecoraldquoEffect of internal bleaching agents on dentinal permeability ofnon-vital teeth quantitative assessmentrdquo Dental Traumatologyvol 19 no 2 pp 85ndash89 2003

[10] G P Lee M Y Lee S O Y Lum R S C Poh and K-C LimldquoExtraradicular diffusion of hydrogen peroxide and pH changesassociated with intracoronal bleaching of discoloured teethusing different bleaching agentsrdquo International Endodontic Jour-nal vol 37 no 7 pp 500ndash506 2004

[11] T Lambrianidis A Kapalas andMMazinis ldquoEffect of calciumhydroxide as a supplementary barrier in the radicular pene-tration of hydrogen peroxide during intracoronal bleaching invitrordquo International Endodontic Journal vol 35 no 12 pp 985ndash990 2002

[12] I Rotstein D Zyskind I Lewinstein andN Bamberger ldquoEffectof different protective base materials on hydrogen peroxideleakage during intracoronal bleaching in vitrordquo Journal ofEndodontics vol 18 no 3 pp 114ndash117 1992

[13] L Campanella R Roversi M P Sammartino and M Tomas-setti ldquoHydrogen peroxide determination in pharmaceuticalformulations and cosmetics using a new catalase biosensorrdquoJournal of Pharmaceutical and Biomedical Analysis vol 18 no1-2 pp 105ndash116 1998

[14] M Pinto C H de Godoy C Bortoletto et al ldquoTooth whiteningwith hydrogen peroxide in adolescents study protocol for arandomized controlled trialrdquo Trials vol 15 article 395 2014

[15] M M Pinto S K Bussadori A C Guedes-Pinto M A Regoand P Eberson ldquoEsthetic alternative for fluorosis blemisheswith the usage of a dual bleaching system based on hydrogenperoxide at 35rdquo Journal of Clinical Pediatric Dentistry vol 28pp 143ndash146 2004

[16] A Baltzer and V Kaufmann-Jinoian ldquoShading of ceramiccrowns using digital tooth shade matching devicesrdquo Interna-tional Journal of Computerized Dentistry vol 8 no 2 pp 129ndash152 2005


[17] G S Heithersay S W Dahlstrom and P D Marin ldquoIncidenceof invasive cervical resorption in bleached root-filled teethrdquoAustralian Dental Journal vol 39 no 2 pp 82ndash87 1994

[18] G Plotino L Buono N M Grande C H Pameijer and FSomma ldquoNonvital tooth bleaching a review of the literatureand clinical proceduresrdquo Journal of Endodontics vol 34 no 4pp 394ndash407 2008

[19] A R Benetti M C Valera M N G Mancini C B Mirandaand I Balducci ldquoIn vitro penetration of bleaching agents intothe pulp chamberrdquo International Endodontic Journal vol 37 no2 pp 120ndash124 2004

[20] I Rotstein Y Torek and RMisgav ldquoEffect of cementumdefectson radicular penetration of 30 H

2

O2

during intracoronalbleachingrdquo Journal of Endodontics vol 17 no 5 pp 230ndash2331991

[21] V Shivanna and K Gupta ldquoA spectrophotometric analysisof radicular peroxide penetration after intracoronal bleachingusing different concentrations of carbamide peroxide gelsrdquoEndodontology vol 24 pp 99ndash103 2012

[22] O Gokay F Ziraman A C Asal and O M Saka ldquoRadicularperoxide penetration from carbamide peroxide gels duringintracoronal bleachingrdquo International Endodontic Journal vol41 no 7 pp 556ndash560 2008

[23] G S Heithersay ldquoInvasive cervical resorption followingtraumardquoAustralian Endodontic Journal vol 25 no 2 pp 79ndash851999

Submit your manuscripts athttpwwwhindawicom

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

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Radiology Research and Practice

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The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014


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Preventive MedicineAdvances in


EndocrinologyInternational Journal of



OrthopedicsAdvances in


controlled bleaching and is safe but may cost the patientquite a bit and one needs to buy specific equipment for thesame Walking bleach procedure on the other hand can beundertaken in remotest places also as no special equipmentis required and material cost is also minimal [7]

The walking bleach technique involves the application ofa bleaching agent to the dentine of the pulp chamber betweendental visits A mixture of sodium perborate and distilledwater has been extensively used as an effective agent for intra-coronal bleaching In order to enhance bleaching efficacy30 hydrogen peroxide (HP) was suggested as a substitutefor water A concentrated hydrogen peroxide (25ndash35) isefficient for bleaching teeth with or without vital pulpAnother bleaching agent 35ndash37 carbamide peroxide (CP)has emerged as a popular and effective agent for both in-officeand intracoronal bleaching techniques [8] One of the mostimportant properties of a bleaching agent is its ability to allowpenetration of the bleaching agent through the dentinal per-meability the deeper the penetration is themore the pigmentthat causes chromatic alteration of the dental tissue can bereversed by the oxidation reaction [9]

However laboratory studies have demonstrated thatintracoronal hydrogen peroxide can diffuse through the rootand this diffusion is greater in the presence of cemental rootdefects Animal studies have confirmed the association ofintracoronal bleaching with cervical root resorptionThere isspeculation that diffusion of hydrogen ions from intracoronalbleaching agents may provide an acidic environment thatis optimal for osteoclastic activity and bone resorptionresulting in external cervical root resorption over time [10]

Since dentinal tubules are oriented incisally placing aprotective base material at the lower level of the CEJ couldreduce the leakage of hydrogen peroxide to the periodontaltissues Deferent protective base materials have been com-pared No significant differences were found between them[11]

This study aimed to compare by spectrophotometeranalysis using potassium permanganate the extraradiculardiffusion of hydrogen peroxide associated with intracoronalteeth bleaching by Opalescence Endo 35 Opalescence PF35 sodiumperborate with 30hydrogen peroxidemixtureand sodium perborate with water mixture

2 Materials and Methods

108 freshly extracted human single root canals (mandibularfirst premolars) for orthodontic reasons from patient lessthan 21 years old were collected with no sign of cracks orstructural anomalies A prior patientrsquos consent was given touse their extracted teeth to conduct the study Approval of Al-Azhar University Faculty of Oral and Dental Medicine Egypt(under number 2822009) was also obtained The selectedteeth were then immersed in 525 sodium hypochlorite forone hour to dissolve organic debris that was present on theexternal surface of the roots Subsequently they were cleanedwith an ultrasonic scaler (satelec Acteon France) to removecalculus discarding teeth with previous root canal treatmentinternal resorption and external resorption localized or

diffuse calcificationsThe selected teethwere stored in normalsaline at room temperature until the time of use

A standardized access cavity was made using a carbidebur loaded in a high speed handpiece Each root canal orificewas enlarged using Gates-Glidden bur numbers 3 and 4 toenlarge root canals of the same size using 525 NaOClsolution for irrigation The pulp tissues were removed with abarbed broach (Dentsply Maillefer Ballaigues Switzerland)Working length (WL) was determined by inserting a size10 K-file (Dentsply Maillefer Ballaigues Switzerland) whichwas passively introduced into the canal until the tip was seento exit at the major foramen The real length of the canal wasrecorded and the working length calculated by subtracting1mm from this measurement

The preparation was performed with a single rotary filethe WaveOne (Dentsply Maillefer Ballaigues Switzerland)and the preprogrammed motor (X-Smart Plus DentsplyMaillefer Ballaigues Switzerland) using a specificmovementof reciprocation 170∘CCW and 50∘CW at a speed equivalentto 350 rpm

Root canals were initially shaped with WaveOne primaryreciprocating file (2508) in the presence of 525 NaOClas irrigant The primary WaveOne file was used gently in areciprocating slow in- and out-pecking motion with short 2-3mmamplitude strokes to passively advance until it does noteasily progress anymore The shaping step was repeated untilthe coronal two-thirds of the canal has been prepared Theworking length and canal patency were confirmed and thenthe primary file is carried to the full working length in one ormore passes

A larger WaveOne file 4008 was carried to workinglength to fully shape and finish the preparation The finishedshape is confirmed in which the apical flutes of the file areloaded with dentin and a gauging 4002 hand file is snuggedat lengthThe apical foramen of each root was sealedwithwaxduring instrumentation to prevent irrigating solutions frompassing through the apical foramen During instrumentationthe canals were irrigated with 2mL of 525 NaOCl solutionusing a plastic syringe with 30-gauge closed-end needle(Hawe Max-I-probe Hawe Neos Bioggio Switzerland) Theneedle was inserted within 1 to 2mm of the working lengthThen the root canals were dried by size 4008WaveOne paperpoint Root canals are obturated with size 4008 WaveOnegutta-percha using ProRoot Endo Sealer (Dentsply MailleferBallaigues Switzerland)

To simulate standardized breaks in the cemental cov-ering four cemental dentinal defects were prepared justbelow the CEJ on each root surface mesial distal buccaland lingual aspects [10]The hemispherical defects (diameter10mm depth 05mm) were created using a round diamondbur (diameter 10mm) in a high speed handpiece The smearlayer created in the defects was removed with 15 EDTA andthen thoroughly washed with distilled water The apical two-thirds of the root surface was coated with a double layer of anail varnish to seal potential superficial defects as in Figure 1

21 Specimenrsquos Grouping The prepared specimens were thendivided randomly into four groups (119899 = 27) according to thebeaching materials used Each main group was subdivided









0871

1

09

08

07

06

05

04

03

02

01

0

350 400 450 500 525 550 600 650 700

Wavelength

Spec

trum

A








2MnO4minus

+ 5H2O2+

+ 6H+ 997888rarr 2Mn2+

+ 5O2 + 8H2O (1)






4 Results





5 Discussion




















Table1Th

emeansstand

arddeviation(SD)v

aluesandresults

ofANOVA

andTu

keyrsquos

testforc

omparis

onof

extraradicular

diffu

sionbetweenfour

grou

ps

Time

Group

1Group

2Group

3Group

4119875value

(Opalescence

Endo

35)

(Opalescence

PF35)

(sod

ium


peroxide

mixture)

(sod

ium

perborate-water

mixture)

Mean

SD

Mean

SD

Mean

SD

Mean

SD

1day

0168c

0049

0d0

006

8d0021

0d0

lowast

lt0001

7days

0482b

0051

0210c

0125

0375b

0049

0141c

004

014

days

0865a

0061

0430b

0030

0743a

006

00315b

004

6lowast

Sign

ificant

at119875le005m

eans

with

different

lette

rsares

tatisticallysig

nificantly

different

accordingto

Tukeyrsquos

test





6 Conclusion




References






















2

O2












Biomaterials












Journal of



























0871

1

09

08

07

06

05

04

03

02

01

0

350 400 450 500 525 550 600 650 700

Wavelength

Spec

trum

A








2MnO4minus

+ 5H2O2+

+ 6H+ 997888rarr 2Mn2+

+ 5O2 + 8H2O (1)






4 Results





5 Discussion




















Table1Th

emeansstand

arddeviation(SD)v

aluesandresults

ofANOVA

andTu

keyrsquos

testforc

omparis

onof

extraradicular

diffu

sionbetweenfour

grou

ps

Time

Group

1Group

2Group

3Group

4119875value

(Opalescence

Endo

35)

(Opalescence

PF35)

(sod

ium


peroxide

mixture)

(sod

ium

perborate-water

mixture)

Mean

SD

Mean

SD

Mean

SD

Mean

SD

1day

0168c

0049

0d0

006

8d0021

0d0

lowast

lt0001

7days

0482b

0051

0210c

0125

0375b

0049

0141c

004

014

days

0865a

0061

0430b

0030

0743a

006

00315b

004

6lowast

Sign

ificant

at119875le005m

eans

with

different

lette

rsares

tatisticallysig

nificantly

different

accordingto

Tukeyrsquos

test





6 Conclusion




References






















2

O2












Biomaterials












Journal of




















4 Results





5 Discussion




















Table1Th

emeansstand

arddeviation(SD)v

aluesandresults

ofANOVA

andTu

keyrsquos

testforc

omparis

onof

extraradicular

diffu

sionbetweenfour

grou

ps

Time

Group

1Group

2Group

3Group

4119875value

(Opalescence

Endo

35)

(Opalescence

PF35)

(sod

ium


peroxide

mixture)

(sod

ium

perborate-water

mixture)

Mean

SD

Mean

SD

Mean

SD

Mean

SD

1day

0168c

0049

0d0

006

8d0021

0d0

lowast

lt0001

7days

0482b

0051

0210c

0125

0375b

0049

0141c

004

014

days

0865a

0061

0430b

0030

0743a

006

00315b

004

6lowast

Sign

ificant

at119875le005m

eans

with

different

lette

rsares

tatisticallysig

nificantly

different

accordingto

Tukeyrsquos

test





6 Conclusion




References






















2

O2












Biomaterials












Journal of




















Table1Th

emeansstand

arddeviation(SD)v

aluesandresults

ofANOVA

andTu

keyrsquos

testforc

omparis

onof

extraradicular

diffu

sionbetweenfour

grou

ps

Time

Group

1Group

2Group

3Group

4119875value

(Opalescence

Endo

35)

(Opalescence

PF35)

(sod

ium


peroxide

mixture)

(sod

ium

perborate-water

mixture)

Mean

SD

Mean

SD

Mean

SD

Mean

SD

1day

0168c

0049

0d0

006

8d0021

0d0

lowast

lt0001

7days

0482b

0051

0210c

0125

0375b

0049

0141c

004

014

days

0865a

0061

0430b

0030

0743a

006

00315b

004

6lowast

Sign

ificant

at119875le005m

eans

with

different

lette

rsares

tatisticallysig

nificantly

different

accordingto

Tukeyrsquos

test





6 Conclusion




References






















2

O2












Biomaterials












Journal of























6 Conclusion




References






















2

O2












Biomaterials












Journal of
























2

O2












Biomaterials












Journal of


























Biomaterials












Journal of



















research article evaluation of extraradicular diffusion of...

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