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S C I E N T I F I C A R T I C L E

Impact of different 1047298uoride concentrations and pHof dentifrices on tooth erosionabrasion in vitro

BM Moron SSH Miyazaki N Ito A Wieganddagger F Vilhena MAR Buzalaf AC Magalha ˜ es

Department of Biological Sciences Bauru School of Dentistry University of Sa o Paulo BrazildaggerDepartment of Preventive Dentistry Periodontology and Cariology University of Zurich Switzerland

ABSTRACT

Background This in vitro study analysed the effect of different fluoride concentrations in acidic or neutral liquid denti-frices in protecting enamel and dentine from erosive and abrasive wear Methods Bovine enamel and dentine specimens (n = 132) were randomly allocated to 11 groups (each n = 12) experi-mental liquid dentifrices with 550 ppm F 1100 ppm F 5000 ppm F or 0 ppm Fplacebo (each at pH 45 and pH 70)and commercial dentifrices with 550 ppm F (Colgate Baby pH 70) 1100 ppm F (Crest pH 70) and 5000 ppm F(Duraphat pH 70) The specimens were subjected to erosion for 90 seconds 4 timesday over 7 days Immediatelyafter the first and last erosion the specimens were brushed for 15 seconds using one of the dentifrices Tooth wear wasmeasured profilometrically (lm) and analysed by ANOVA (p lt 005) Results All fluoridated liquid dentifrices significantly reduced enamel wear compared to the placebo and commercialdentifrices Only liquid dentifrices with 1100 and 5000 ppm F significantly reduced dentine wear compared to placebodentifrice The pH had no effect but the consistency had a significant impact on the effect of dentifricesConclusions Liquid dentifrices with high F concentration appear to be a good option to prevent tooth wear

Keywords Abrasion dentine enamel erosion fluoride dentifrice

Abbreviations and acronyms AmF = amine fluoride NaF = sodium fluoride SnF2 = stannous fluoride TiF4 = titanium tetrafluoride

(Accepted for publication 6 May 2012)

INTRODUCTION

Although the role of topical fluoride application onthe prevention of tooth erosion is still controversial1

the most recent research has focused on the effect of different fluoride compounds (NaF ndash sodium fluorideAmF ndash amine fluoride TiF4 ndash titanium tetrafluorideSnF2 ndash stannous fluoride) and vehicles (varnish gelsolution dentifrice) to prevent tooth wear from ero-sion and abrasion2

Fluoridated dentifrices have been tested in severaltooth wear studies as dentifrice is already a wide-spread vehicle used for prevention of dental caries3

Although fluoridated dentifrices have the potential todecrease the development of tooth wear4 recentstudies have shown a limited beneficial effect of con-ventional 1100 ppm F dentifrices compared tonon-fluoridated dentifrices on abrasion of eroded den-tine and enamel respectively56

Based on these findings highly concentrated fluoridedentifrices (5000 ppm F) have been tested but showedinconclusive results In a recent in situ study a com-mercial dentifrice with 5000 ppm F had the same

positive effect as another commercial 1100 ppm F den-tifrice on eroded and eroded-abraded dentine7 Inrespect to enamel no significant differences were foundbetween 0 1100 and 5000 ppm F dentifrices on ero-sion and erosion-abrasion in situ8 Moretto et al9 pro-duced contrasting data showing that an experimental5000 ppm F dentifrice was able to significantly reduceenamel erosion and erosion-abrasion compared to con-ventional 1100 ppm F dentifrice in vitro Thereforethe effect of highly concentrated fluoride dentifrices on

dental erosion and abrasion is still under debateOn the other hand the reduction of the pH and

change of consistency (from paste to liquid or gel) hasbeen shown to be effective in increasing plaquefluoride uptake in vivo10 Acidic dentifrices with550 ppm F have the same effectiveness as neutral1100 ppm F dentifrices in reducing enamel demineral-ization in vitro and caries progression in vivo11 ndash 13

Although dentifrices with lower pH and higher fluidconsistency than commercial dentifrices have beensuccessfully employed in protocols involving cariouslesions they have never been tested in erosive-abrasiveprotocols Their fluidity could increase reactivity with

106 copy 2013 Australian Dental Association

Australian Dental Journal 2013 58 106ndash111

doi 101111adj12016

Australian Dental JournalThe official journal of the Australian Dental Association

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the dental substrate while the low pH could enhancethe tendency for calcium fluoride formation on apatitesubstrates14 Thus the present in vitro study analysedthe effect of different fluoride concentrations in acidicor neutral liquid dentifrices to prevent enamel anddentine erosive and abrasive wear

The null hypotheses tested were as follows (1)there is no significant difference in tooth wearbetween the liquid dentifrices with different F concen-trations regardless of the pH (2) there is no signifi-cant difference in tooth wear between liquiddentifrices with different pH values regardless of theF concentration and (3) there is no significant differ-ence in tooth wear between dentifrices with differentconsistencies (liquid versus paste or experimental ver-sus commercial) that present the same F concentrationand pH (neutral)

MATERIALS AND METHODS

Preparation of the specimens

Enamel and dentine specimens (4 mm x 4 mm x 3 mm)were prepared from the labial surfaces of bovine incisorcrowns and roots respectively The teeth were stored at4 degC in 01 buffered thymol solution (pH 70) duringthis phase The specimens were cut using an ISOMETlow-speed saw (Buehler Ltd Lake Bluff IL USA) with2 diamond discs (Extec Corp Enfield CT USA) sepa-rated by a 4-mm spacer The specimens were groundflat with water-cooled silicon carbide discs (320- 600-

and 1200-grade papers Buehler Lake Bluff IL USA)and polished with felt paper wet with diamond solution(1 lm Buehler)

After polishing the specimens were cleaned in anultrasonic device with deionized water for 2 minutesPrior to the experiment two layers of nail varnishwere applied to two-thirds of the surface of eachspecimen leaving a central test area and protectingreference surfaces for the profilometric measurementThe application of two layers of nail varnish assuredthat it was not rubbed off during the erosive andabrasive procedures The specimens were maintained

in 100 humidity until the beginning of the experi-ment

Twelve enamel and 12 dentine specimens were ran-domly allocated to each group experimental liquiddentifrices with 550 ppm F 1100 ppm F 5000 ppmF and 0 ppm Fplacebo (each at pH 45 and pH 70)and commercial dentifrices with 550 ppm F (ColgateBaby Barney pH 70 Colgate-Palmolive Brazil)1100 ppm F (Crest pH 70 Procter amp Gamble USA)and 5000 ppm F (Prevident pH 70 Colgate USA)A sample size of 12 specimens was calculated consid-ering a-error level of 5 and b-error level of 20based on previous data7 ndash 9

All dentifrices presented NaF as F compound withsilica as abrasive The composition of the liquid denti-frices is in accordance with a previous study10 Theliquid dentifrices have the consistency of a gel butwith more fluidity The RDA values of the experimen-tal liquid dentifrices are displayed in Table 1

Erosive and abrasive challenges

All specimens were submitted to 7-day erosionabra-sion cycles Erosion was performed with freshlyopened bottles of Sprite Zero (Coca-Cola CompanySpal Porto Real RJ Brazil pH 26 30 mlspecimenunstirred 25 degC) 4 times daily for 90 seconds eachAfter demineralization the specimens were rinsedwith tap water (5 seconds) and transferred into artifi-cial saliva (pH 68 30 mlspecimen unstirred 25 degC)for 2 hours After the last daily erosive treatment the

specimens were stored in artificial saliva overnightThe artificial saliva was renewed daily and consistedof 02 mM glucose 99 mM NaCl 15 mMCaCl22H2O 3 mM NH4Cl 17 mM KCl 2 mMNaSCN 24 mM K2HPO4 33 mM urea 24 mMNaH2PO4 and ascorbic acid (pH 68)15

All specimens were brushed twice daily with thedentifrices immediately after the first (9 hours) andthe last (19 hours) erosive challenges The dentifriceswere placed on the toothbrushesrsquo heads (liquiddentifrices ~ 015 gcommercial dentifrices ~ 04 g)according to the study by Vilhena et al16 wherethe dentifrice weight applied on toothbrushes by chil-

dren was measured The specimens were then brushedusing an electrical toothbrush (Colgate Motions Multi-action Brazil) for 15 seconds (166 oscillationss25 degC)78 The toothbrushes were fixed in a con-structed device that allowed the heads to be alignedparallel to the specimensrsquo surfaces The toothbrushesrsquoheads were weighed by using a precision scale (PesolaSwitzerland) and the weight was converted to force(1 Kg~ 980665 N F = 15 N)17 The toothbrush

Table 1 Mean and SD of the RDA values of thedentifrices

Dentifrices RDA

550 ppm F pH 45 56 plusmn 7ab

550 ppm F pH 70 62 plusmn 6bc

1100 ppm F pH 45 70 plusmn 5c

1100 ppm F pH 70 52 plusmn 7a


5000 ppm pH 70 69 plusmn 10c

Placebo pH 71 47 plusmn 4a

Placebo pH 45 72 plusmn 5c

Commercial 550 ppm F unknownCommercial 1100 ppm F 100Commercial 5000 ppm F 77

Different letters show significant differences among the experimen-tal dentifrices (one-way ANOVA and Tukeyrsquos test p lt 001)The data were obtained from the literature7

copy 2013 Australian Dental Association 107

Fluoridated dentifrices on tooth wear

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heads were replaced daily Thereafter the specimenswere rinsed in water for 5 seconds before beingimmersed in artificial saliva

Pro1047297lometric measurement

Enamel and dentine wear (lm) was quantitativelydetermined by a contact profilometry (Mahr Pertho-meter Go uml ttingen Germany) after the experiment Thespecimens were maintained wet (100 humidity) toavoid shrinkage of the dentine For profilometric mea-surement the nail varnish was carefully removedusing a scalpel and acetone solution (11 water)78

The diamond stylus moved from the first reference tothe exposed area and then over to the other referencearea (2 mm long and 15 mm wide) Four profile mea-surements were performed for each specimen at inter-vals of 05 mm The vertical distance between the

horizontal line drawn on the reference areas and thehorizontal line drawn on the experimental area wasdefined as tooth wear using the software (SoftwareMahr Surf XT20 2009) The values were averaged(lm) and submitted to statistical analysis The stan-dard deviation of repeated analysis of a given samplewas 08 lm (mean wear of 10 lm)

Statistical analysis

Statistical analysis was performed with GraphPadInStat version 20 and GraphPad Prism software ver-sion 40 for Windows (Graph Pad Software San

Diego CA USA) The assumptions of equality of variances and normal distribution of errors werechecked for all variables tested using Bartlett andKolmogorovndashSmirnov tests respectively Because theassumptions were satisfied one-way ANOVA andTukeyrsquos post hoc test (for comparison among allgroups separately for enamel and dentine GraphPadInStat) and two-way ANOVA and Bonferroni post hoc test (for comparisons among the F concen-trations pH and consistency separately for enameland dentine GraphPad Prism) were applied Thesignificance level was set at 5 (n = 12)

RESULTS

One-way ANOVA followed by Tukeyrsquos test revealedsignificant differences among the dentifrices for enameland dentine respectively (p lt 001 Tables 2 and 3)

Enamel

Two-way ANOVA (only for liquid dentifrices)revealed significant differences among the fluorideconcentrations (p lt 001 F = 1179) but not betweenthe pH values (p gt 005 F = 277) There was no

significant interaction between the factors Bonferroni post hoc test showed that all fluoridated liquid denti-frices were able to similarly reduce enamel wear andwere better than the placebo dentifrices

These results were confirmed by the one-wayANOVA which also showed no differences between

the placebo dentifrices and commercial dentifrices(Table 2)

Regarding consistency two-way ANOVA (liquidversus commercial dentifrices including only denti-frices with the same F concentration and pH) revealedsignificant differences between the fluoride concentra-tions (p lt 005 F = 490) as well as between theconsistencies (p lt 001 F = 1866) There was no sig-nificant interaction between the factors For all fluori-dated dentifrices consistency had a significant impacton their effect ie the liquid dentifrice was moreeffective in reducing enamel wear than the commercialdentifrice

Table 2 Mean enamel wear (lm) plusmn SD of specimenssubjected to erosion and abrasion in the presence of different dentifrices

[F] (ppm) Experimental liquid dentifrices

Acidic Neutral

0 96 plusmn 12a 98 plusmn 10a

550 56 plusmn 08b 64 plusmn 04b



Commercial dentifrices

Acidic Neutral

550 _____ 93 plusmn 10a

1100 _____ 88 plusmn 09a

5000 _____ 98 plusmn 08a

Different letters show significant differences among the dentifrices(one-way ANOVA and Tukeyrsquos test p lt 001)

Table 3 Mean dentine wear (lm) plusmn SD of specimenssubjected to erosion and abrasion in the presence of different dentifrices


Acidic Neutral

0 56 plusmn 07cd 53 plusmn 04abc

550 54 plusmn 05bc 53 plusmn 08abc

1100 48 plusmn 05ab 48 plusmn 06ab

5000 48 plusmn 05ab 46 plusmn 06a


Acidic Neutral

550 _____ 52 plusmn 05abc

1100 _____ 58 plusmn 05cd

5000 _____ 64 plusmn 08d



BM Moron et al

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Dentine

Two-way ANOVA (only for liquid dentifrices) alsorevealed significant differences among the fluorideconcentrations (p lt 001 F = 1042) but not betweenthe pH values (p gt 005 F = 171) There was no sig-

nificant interaction between the factors Bonferroni post hoc test showed that liquid dentifrices with 1100and 5000 ppm F were able to significantly reducedentine wear compared to the placebo dentifrices

Table 3 shows the differences between the denti-frices on dentine wear when ANOVATukeyrsquos testswere applied In this case the commercial dentifricespresented the worst results

Regarding the consistency two-way ANOVA(liquid versus commercial dentifrices including onlydentifrices with the same F concentration and pH)revealed significant differences between the consisten-

cies (p lt

001 F =

3771) In this case the effect of Fconcentration was not significant (p gt 005 F =

068) and the interaction between the factors wassignificant (p lt 001 F = 1463) The consistency hada significant impact on the effect of 1100 and5000 ppm F The liquid dentifrice was more effectivein reducing dentine wear than the commercial denti-frice However consistency was not important in thecase of the 550 ppm F dentifrice

Based on the results the null hypotheses were (1)rejected (2) accepted and (3) rejected

DISCUSSIONThe action of conventional fluorides such as NaFincluded in the experimental dentifrices is mainlyattributed to a precipitation of CaF2-like material ontooth surfaces1819 which is able to partially reducetooth wear by subsequent erosive-abrasive chal-lenges6 ndash 9 This layer should behave as a physical bar-rier hampering the contact of the acid with theunderlying enamel or as a mineral reservoir that isattacked by the erosive challenge thus buffering theacids or promoting remineralization2

Ganss et al19 evaluated the retention of calcium fluo-

ride on human enamel and dentine under neutral anderosive conditions in vitro and in situ It was shownthat more calcium fluoride was lost under erosive com-pared to neutral conditions in vitro Compared to thein vitro study the CaF2 precipitates were retained to ahigher extent on the tooth in situ Salivary proteins playa role in the solubility of CaF2-like layers either bymaintaining the supersaturated stage of saliva withrespect to phosphate and calcium or by adsorption tothe surface In addition the precipitates were less stableon dentine than on enamel under erosive conditions

The formation of the CaF2-like layer and its protec-tive effect on demineralization also depends on the

pH and F concentration of the agent20 Regardingtooth abrasion other important factors that should beconsidered are the type size and quantity of denti-fricesrsquo abrasives which seem to be more importantthan the stiffness of the toothbrush filaments21 ndash 23 Inthe present study all experimental dentifrices pre-

sented silica as abrasive with slight differences in theRDA value Therefore it is important to discuss theinteraction among fluoride concentration consistency(it might be related to the abrasivity) and pH of den-tifrices on tooth wear Accordingly the present studyshowed that the F content and consistency influenceenamel and dentine wear while the pH of the liquiddentifrices had no effect on tooth wear

In the case of dentine the best treatments to reducewear were the liquid 1100 and 5000 ppm F denti-frices On the other hand Duraphat dentifrice thecommercial dentifrice with the highest F concentra-

tion was least effective in preventing dentine wearThis result might be related to its higher abrasivity(RDA 77) compared to the experimental one(5000 ppm F pH 70 RDA 69) This finding is not inagreement with a previous in situ study in which thesame commercial dentifrice with 5000 ppm F was bet-ter than a placebo (placebo formulation was differentfrom the placebo dentifrice used in the present study)for the prevention of erosion and abrasion7 In thepresent study the commercial dentifrice was appliedundiluted on the dentine surface while in the previousin situ study the dentifrice was diluted using water(slurry 13) The application of the undiluted denti-

frice directly on the surface might allow more fluoridein contact with the tooth but it would also enhancethe impact of the abrasive of the dentifrice comparedto the slurry24 Additionally in the in situ conditionthe abrasive challenges might be modulated by salivaand acquired pellicle

Different from dentine all experimental F denti-frices had some impact on enamel erosion as F precip-itates are more stable on enamel than on dentine19

Regarding the commercial dentifrices Rios et al8

could not demonstrate a preventive effect of 5000 ppm F (Duraphat) and 1100 ppm F (Crest) den-

tifrices on enamel erosion-abrasion in situ in agree-ment with the present results As the remainingsoftened layer of eroded enamel is considerablysmaller compared to the amount of enamel wear itmight be speculated that the fluoride application pre-dominantly prevents further erosive tissue wear byforming a mechanical barrier rather than by reminer-alizing the softened surface Furthermore toothbrush-ing with conventional fluoridated dentifrices whichmight be more abrasive than the experimental onesmight have completely removed this thin softenedlayer rather than allowed the remineralization and theformation of CaF2 precipitates



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On the other hand Moretto et al9 showed a signifi-cantly higher preventive effect of an experimental5000 ppm F compared to 1100 ppm F dentifrice onenamel erosion-abrasion in vitro We could not seesuch a difference between our experimental fluoridateddentifrices (5000 vs 1100 ppm F) This finding might

be related to the liquid consistency of our experimen-tal dentifrices which seems to have a remarkableinfluence on the tooth erosive and abrasive wear

Confirming previous studies fluoride seems to bemore effective on enamel compared to dentine2 Thefact that liquid dentifrices were better than the com-mercial ones confirms the hypothesis that consis-tency might also have an impact on the effect of the fluoridated dentifrice on tooth erosion-abrasionIt can be speculated that liquid dentifrices allowhigher CaF2 formation compared to commercial den-tifrices This speculation is based on a previous clin-

ical study showing that liquid dentifrices enhancedthe incorporation of fluoride on dental plaque com-pared to commercial dentifrices10 Furthermore theRDA values were slightly higher for the commercialdentifrices compared to the experimental liquidones

Regarding the lack of effect of the acidic versusneutral pH of the liquid dentifrices as seen with thepresent protocol our findings do not agree with pre-vious publications that showed a beneficial effect of acidic dentifrices when used in cariogenic chal-lenges1112 On the other hand Lussi et al25 showedno differences among commercial dentifrices with

different pH ranges (pH 40 ndash 70) on the preventionof enamel erosion Because erosive lesions occur in apH range lower than the one associated with theoccurrence of carious lesions the reduction of thedentifrices pH might be unable to enhance the reac-tion between fluoride and eroded tooth surface thusnot improving its preventive effect against toothwear

Based on the results it was concluded that theexperimental liquid dentifrices especially those withhigh fluoride concentrations might be beneficialin reducing tooth wear by mild erosive and abrasive

challenges in vitro Further studies should be con-ducted in vivo to confirm the present findings Suchstudies could also combine high concentrated fluoridedentifrices with other remineralizing products such asCPP-ACP which have shown some effect against ero-sion26

ACKNOWLEDGEMENTS

The authors are grateful to Dentalprev Laboratory(Lorena-SP Brazil) for providing the liquid dentifricesand to Ms Beatrice Sener and Professor ThomasImfeld from the University of Zurich Switzerland for

the RDA analysis The authors also thank the Sa ˜ oPaulo State Research Foundation for the concession of scholarship for the second and third authors (FAPESP200907470-7 and 200908400-2)

REFERENCES1 Wiegand A Attin T Influence of fluoride on the prevention of

erosive lesions a review Oral Health Prev Dent 20031245 ndash 253

2 Magalha ˜ es AC Wiegand A Rios D Buzalaf MA Lussi AFluoride in dental erosion Monogr Oral Sci 201122158 ndash 170

3 Walsh T Worthington HV Glenny AM Appelbe P MarinhoVC Shi X Fluoride toothpastes of different concentrations forpreventing dental caries in children and adolescents CochraneDatabase Syst Rev 201020CD007868

4 Bartlett DW Smith BG Wilson RF Comparison of the effectof fluoride and non-fluoride toothpaste on tooth wear in vitroand the influence of enamel fluoride concentration and hardnessof enamel Br Dent J 19946346 ndash 348

5 Ponduri S Macdonald E Addy M A study in vitro of the com-bined effects of soft drinks and tooth brushing with fluoridetoothpaste on the wear of dentine Int J Dent Hyg 200537 ndash 12

6 Magalha ˜ es AC Rios D Delbem ACB Buzalaf MAR MachadoMAAM Influence of fluoride dentifrice on brushing abrasion of eroded human enamel an in situ ex vivo study Caries Res20074177 ndash 79

7 Magalha ˜ es AC Rios D Moino AL Wiegand A Attin T Buza-laf MAR Effect of different concentrations of fluoride in denti-frices on dentin erosion subjected or not to abrasion in situ exvivo Caries Res 200842112 ndash 116

8 Rios D Magalha ˜ es AC Braga RO Wiegand A Attin T Buza-laf MAR The efficacy of a highly concentrated fluoride denti-frice on bovine enamel subjected to erosion and abrasion J AmDent Assoc 20081391652 ndash 1656

9 Moretto MJ Magalha ˜ es AC Sassaki KT Delbem ACB Martin-

hon CCR Effect of different fluoride concentrations of experi-mental dentifrices on enamel erosion and abrasion Caries Res201044135 ndash 140

10 Buzalaf MA Vilhena FV Iano FG et al The effect of differentfluoride concentrations and pH of dentifrices on plaque andnail fluoride levels in young children Caries Res 200943142 ndash 146

11 Brighenti FL Delbem AC Buzalaf MA Oliveira FA RibeiroDB Sassaki KT In vitro evaluation of acidified toothpasteswith low fluoride content Caries Res 200640239 ndash 244

12 Alves KM Pessan JP Brighenti FL et al In vitro evaluation of the effectiveness of acidic fluoride dentifrices Caries Res200741263 ndash 267

13 Vilhena FV Olympio KP Lauris JR Delbem AC Buzalaf MALow-fluoride acidic dentifrice a randomized clinical trial in a

fluoridated area Caries Res 201044478 ndash 484

14 Petersson LG Lodding A Hakeberg M Koch G Fluorine pro-files in human enamel after in vitro treatment with dentifricesof different compositions and acidities Swed Dent J 198913177 ndash 183

15 Klimek J Hellwig E Ahrens G Fluoride taken up by plaqueby the underlying enamel and by clean enamel from three fluo-ride compounds in vitro Caries Res 198216156 ndash 161

16 Vilhena FV Silva HM Peres SH Caldana ML Buzalaf MARThe drop technique a method to control the amount of fluoridedentifrice used by young children Oral Health Prev Dent2008661 ndash 65

17 Voronets J Jaeggi T Buergin W Lussi A Controlled tooth-brush abrasion of softened human enamel Caries Res 200842286 ndash 290


BM Moron et al

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18 Ganss C Klimek J Brune V Schumann A Effects of two fluo-ridation measures in erosion progression on enamel and dentinin situ Caries Res 200438561 ndash 566

19 Ganss C Schlueter N Klimek J Retention of KOH-soluble fluo-ride on enamel and dentine under erosive conditions a compari-son of in vitro and in situ results Arch Oral Biol 2007529 ndash 14

20 Saxegaard E Rolla G Fluoride acquisition on and in human

enamel during topical application in vitro Scand J Dent Res198896523 ndash 535

21 Wiegand A Schwerzmann M Sener B et al Impact of tooth-paste slurry abrasivity and toothbrush filament stiffness onabrasion of eroded enamel an in vitro study Acta OdontolScand 200866231 ndash 236

22 Wiegand A Kuhn M Sener B Roos M Attin T Abrasion of eroded dentin caused by toothpaste slurries of different abrasiv-ity and toothbrushes of different filament diameter J Dent200937480 ndash 484

23 Wiegand A Attin T Design of erosionabrasion studies ndash insightsand rational concepts Caries Res 20114553 ndash 59

24 Turssi CP Messias DC Hara A Hughes N Garcia-Godoy FBrushing abrasion of dentin effect of diluent and dilution rateof toothpaste Am J Dent 201023247 ndash 250

25 Lussi A Megert B Eggenberger D Jaeggi T Impact of differenttoothpastes on the prevention of dental erosion Caries Res20084262 ndash 67

26 Piekarz C Ranjitkar S Hunt D McIntyre J An in vitro assess-

ment of the role of tooth mousse in preventing wine erosionAust Dent J 20085322 ndash 25

Address for correspondenceProfessor Ana Carolina Magalha es

Al Dr Octa vio Pinheiro Brisolla 9-75Bauru-SP 17012-190

Brazil Email acmuspbr



7272019 adj12016pdf


the dental substrate while the low pH could enhancethe tendency for calcium fluoride formation on apatitesubstrates14 Thus the present in vitro study analysedthe effect of different fluoride concentrations in acidicor neutral liquid dentifrices to prevent enamel anddentine erosive and abrasive wear

The null hypotheses tested were as follows (1)there is no significant difference in tooth wearbetween the liquid dentifrices with different F concen-trations regardless of the pH (2) there is no signifi-cant difference in tooth wear between liquiddentifrices with different pH values regardless of theF concentration and (3) there is no significant differ-ence in tooth wear between dentifrices with differentconsistencies (liquid versus paste or experimental ver-sus commercial) that present the same F concentrationand pH (neutral)

MATERIALS AND METHODS

Preparation of the specimens

Enamel and dentine specimens (4 mm x 4 mm x 3 mm)were prepared from the labial surfaces of bovine incisorcrowns and roots respectively The teeth were stored at4 degC in 01 buffered thymol solution (pH 70) duringthis phase The specimens were cut using an ISOMETlow-speed saw (Buehler Ltd Lake Bluff IL USA) with2 diamond discs (Extec Corp Enfield CT USA) sepa-rated by a 4-mm spacer The specimens were groundflat with water-cooled silicon carbide discs (320- 600-

and 1200-grade papers Buehler Lake Bluff IL USA)and polished with felt paper wet with diamond solution(1 lm Buehler)

After polishing the specimens were cleaned in anultrasonic device with deionized water for 2 minutesPrior to the experiment two layers of nail varnishwere applied to two-thirds of the surface of eachspecimen leaving a central test area and protectingreference surfaces for the profilometric measurementThe application of two layers of nail varnish assuredthat it was not rubbed off during the erosive andabrasive procedures The specimens were maintained

in 100 humidity until the beginning of the experi-ment

Twelve enamel and 12 dentine specimens were ran-domly allocated to each group experimental liquiddentifrices with 550 ppm F 1100 ppm F 5000 ppmF and 0 ppm Fplacebo (each at pH 45 and pH 70)and commercial dentifrices with 550 ppm F (ColgateBaby Barney pH 70 Colgate-Palmolive Brazil)1100 ppm F (Crest pH 70 Procter amp Gamble USA)and 5000 ppm F (Prevident pH 70 Colgate USA)A sample size of 12 specimens was calculated consid-ering a-error level of 5 and b-error level of 20based on previous data7 ndash 9

All dentifrices presented NaF as F compound withsilica as abrasive The composition of the liquid denti-frices is in accordance with a previous study10 Theliquid dentifrices have the consistency of a gel butwith more fluidity The RDA values of the experimen-tal liquid dentifrices are displayed in Table 1

Erosive and abrasive challenges

All specimens were submitted to 7-day erosionabra-sion cycles Erosion was performed with freshlyopened bottles of Sprite Zero (Coca-Cola CompanySpal Porto Real RJ Brazil pH 26 30 mlspecimenunstirred 25 degC) 4 times daily for 90 seconds eachAfter demineralization the specimens were rinsedwith tap water (5 seconds) and transferred into artifi-cial saliva (pH 68 30 mlspecimen unstirred 25 degC)for 2 hours After the last daily erosive treatment the

specimens were stored in artificial saliva overnightThe artificial saliva was renewed daily and consistedof 02 mM glucose 99 mM NaCl 15 mMCaCl22H2O 3 mM NH4Cl 17 mM KCl 2 mMNaSCN 24 mM K2HPO4 33 mM urea 24 mMNaH2PO4 and ascorbic acid (pH 68)15

All specimens were brushed twice daily with thedentifrices immediately after the first (9 hours) andthe last (19 hours) erosive challenges The dentifriceswere placed on the toothbrushesrsquo heads (liquiddentifrices ~ 015 gcommercial dentifrices ~ 04 g)according to the study by Vilhena et al16 wherethe dentifrice weight applied on toothbrushes by chil-

dren was measured The specimens were then brushedusing an electrical toothbrush (Colgate Motions Multi-action Brazil) for 15 seconds (166 oscillationss25 degC)78 The toothbrushes were fixed in a con-structed device that allowed the heads to be alignedparallel to the specimensrsquo surfaces The toothbrushesrsquoheads were weighed by using a precision scale (PesolaSwitzerland) and the weight was converted to force(1 Kg~ 980665 N F = 15 N)17 The toothbrush

Table 1 Mean and SD of the RDA values of thedentifrices

Dentifrices RDA

550 ppm F pH 45 56 plusmn 7ab

550 ppm F pH 70 62 plusmn 6bc


1100 ppm F pH 70 52 plusmn 7a


5000 ppm pH 70 69 plusmn 10c

Placebo pH 71 47 plusmn 4a

Placebo pH 45 72 plusmn 5c

Commercial 550 ppm F unknownCommercial 1100 ppm F 100Commercial 5000 ppm F 77

Different letters show significant differences among the experimen-tal dentifrices (one-way ANOVA and Tukeyrsquos test p lt 001)The data were obtained from the literature7



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RESULTS


Enamel








Acidic Neutral






Acidic Neutral

550 _____ 93 plusmn 10a

1100 _____ 88 plusmn 09a

5000 _____ 98 plusmn 08a




Acidic Neutral






Acidic Neutral

550 _____ 52 plusmn 05abc

1100 _____ 58 plusmn 05cd

5000 _____ 64 plusmn 08d



BM Moron et al

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Dentine





cies (p lt

001 F =



















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ACKNOWLEDGEMENTS
























BM Moron et al

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RESULTS


Enamel








Acidic Neutral






Acidic Neutral

550 _____ 93 plusmn 10a

1100 _____ 88 plusmn 09a

5000 _____ 98 plusmn 08a




Acidic Neutral






Acidic Neutral

550 _____ 52 plusmn 05abc

1100 _____ 58 plusmn 05cd

5000 _____ 64 plusmn 08d



BM Moron et al

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Dentine





cies (p lt

001 F =



















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ACKNOWLEDGEMENTS
























BM Moron et al

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Dentine





cies (p lt

001 F =



















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ACKNOWLEDGEMENTS
























BM Moron et al

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ACKNOWLEDGEMENTS
























BM Moron et al

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