in vivo effect of a fluoride releasing adhesive on ...composite resin and glass ionomer cements...

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Tanta Dental Journal 10 (2013) 86e96www.elsevier.com/locate/tdj

In vivo effect of a fluoride releasing adhesive on inhibition ofenamel demineralization around orthodontic brackets

O.E. Eissaa*, E.M. El-Shourbagy, S.A. Ghobashy

Orthodontic Department, Faculty of Dentistry, Tanta University, Egypt

Abstract

Objective: The purpose of the present study was to evaluate the in vivo effects of the fluoride releasing Transbond� Plus ColorChange Adhesive in reducing enamel demineralization around orthodontic brackets and compare it with non-fluoride releasingTransbond� XT.Materials and methods: 20 patients were divided into 2 groups. Brackets were bonded with Transbon-Plus and Transbond-XT ingroup I & II respectively. After 60 days, teeth were extracted. Buccal surfaces were examined with SEM. Buccolingual cross-sections were examined with SEM and EDX. Comparisons of mineral contents were performed with student t-test.Results: SEM of group I revealed almost normal topographic features of enamel. Globules of calcium fluoride like material weredetected over enamel. Group II revealed roughened enamel surface with areas of enamel erosion. EDX showed higher levels ofcalcium and fluoride in Transbond� Plus group than in Transbond� XT group.Conclusion: SEM observation and EDX examination showed that the fluoride releasing adhesive (Transbond� Plus Color ChangeAdhesive) resulted in reduction of enamel demineralization around the bracket, when compared with conventional adhesive(Transbond� XT).

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Keywords: Demineralization; Fluoride releasing adhesive; Remineralization; Scanning electron microscope; Energy dispersive x-ray microanalysis

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1. Introduction

Despite advances in orthodontic materials andtechniques in recent years, orthodontic patients are atincreased risk of developing clinically detectable areas

* Corresponding author.

E-mail address: [email protected] (O.E. Eissaa).

Peer Review under the responsibility of the Faculty of Dentistry,

Tanta University

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of decalcification as a consequence of plaque accu-mulation around orthodontics attachments. This mayprogress into frank caries.

An increase in white spot lesions has been reportedin 50% of patients after orthodontic treatment [1].They found that decalcification is caused by ineffectiveoral hygiene and retention of bacterial plaque for anextended period of time on the enamel surface.

Fluoride administration has been proposed as amethod of reducing enamel susceptibility to decalcifi-cation [4]. The fact that fluoride can be integrated intothe crystalline lattice of dental enamel resulting in astructure that is more resistant to the onset of

the Faculty of Dentistry, Tanta University.

.007

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1 3M Unitek Orthodontic Products, Monrovia, California, USA.

87O.E. Eissaa et al. / Tanta Dental Journal 10 (2013) 86e96

dissolution provides the scientific basis for its use incaries prevention. When fluoride ions are incorporatedinto the surface of enamel, it forms a fluoroapatitecrystal structure that has lower solubility in the oralenvironment compared with hydroxyapatite. Fluo-roapatite helps in reducing tooth decay by reminerali-zation of small decalcified areas and reduction in theformation of new lesions [5,6].

Decalcification may be reduced in orthodontic pa-tients by employing a meticulous oral hygiene programincluding the use of fluoride [7].

Various methods of administering fluoride duringorthodontic treatment have been used, including tooth-pastes, mouth rinses, gels, and varnishes. In addition,materials have been introduced delivering fluoride dur-ing treatment such as fluoride-releasing compositebonding materials (resin modified), glass ionomer ce-ments (GIC), compomers, slow-release fluoride devices,and fluoride-releasing elastomeric ligatures [8].

Unfortunately, preventive and chemoprophylacticproducts, such as high-fluoride toothpaste or gel,fluoride varnish, and chlorhexidine rinse, gel, or var-nish, are rarely prescribed by orthodontists. It was re-ported that 95% of orthodontists provided oral hygieneinstructions, while only 52% prescribed fluoride mouthrinse [9].

The caries risk of prolonged duration of orthodontictreatment can be minimized by a continuous fluoriderelease from the bonding system around the bracketbase. The introduction of fluoride-releasing adhesivesystems, sealants, and glass ionomer cements forbracket bonding offered a means of fluoride deliveryadjacent to bracketeenamel interface independent ofpatient cooperation [10]. The critical factors for suc-cess of these materials are adequate bond strength fororthodontic appliances and sustained fluoride release.Fluoride materials that have previously been investi-gated as bonding agents include fluoride-releasingcomposite resin and glass ionomer cements [11].Glass ionomers have been shown in vitro to be effec-tive at protecting the enamel from decalcificationbeneath and also 1 mm around an orthodontic attach-ment [12]. However, highly significant weaker bondstrength of glass ionomer cement was found comparedwith conventional bonding adhesives. Because of thisweaker bond strength, the clinical acceptability ofthese adhesives as orthodontic bonding material hasbeen questioned [13,14]. The potential advantages of aproduct delivering fluoride beneath and closely aroundthe orthodontic bonded attachments, independent ofpatient compliance, has led to the development offluoride releasing adhesives [15].

The new Transbond� Plus Color Change Adhesivecontains a fluoroaluminosilicate glass as the fluoridesource. The hydrophilic nature of the adhesive allowsfluoride diffusion through the cured cross-linked ma-trix in an aqueous medium [16]. Its pink color providesa visual aid for bracket positioning and excess removalof the adhesive. Upon light curing, the color immedi-ately fades.

The purpose of the present study was to evaluate thein vivo effects of the fluoride releasing Transbond� PlusColor Change Adhesive in reducing enamel demineral-ization around orthodontic brackets and compare it withnon-fluoride releasing Transbond� XT. Enamel surfacetopography around orthodontic brackets was assessedusing scanning electron microscope and the mineralcontents of the enamel surface were evaluated usingenergy dispersive x-ray microanalysis.

2. Materials and methods

This study was carried on twenty patients from or-thodontic clinic at Faculty of Dentistry, Tanta Univer-sity, scheduled to have maxillary premolars extractedas a part of orthodontic treatment. The age was 13e16years. The criteria for teeth selection in this studyincluded intact buccal enamel with no caries or hy-poplastic areas, no cracks or gross irregularities, norestorations and not subjected to any chemical agentaffecting the enamel such as alcohol, hydrogenperoxide, formaldehyde and so forth.

All patients and their guardians involved in thisstudy signed a written consent. The patients in thisstudy were randomly divided into 2 groups of 10 eachaccording to the type of adhesive used: Group I;Twenty brackets were bonded with the fluoridereleasing Transbond� Plus Color Change Adhesive*while Group II; Twenty brackets were bonded withthe conventional non-fluoride releasing Transbond�XT1 to upper first premolars.

2.1. Bonding procedures

The enamel surface of each tooth was polished withfluoride-free pumice and rubber cup for 10 s, sprayedwith water and dried with compressed oil-free stream. Apiece of tapewith a cut-out the size of a bracket basewasapplied to each tooth during bonding. This was done torestrict spread of etchant on the adjacent enamel, whichcould prematurely initiate demineralization. Tape was

88 O.E. Eissaa et al. / Tanta Dental Journal 10 (2013) 86e96

used on all experimental teeth to standardize theprotocol.

Enamel surface was treated with 37% phosphoricacid for 30 s then the piece of tape was carefullyremoved. The tooth was rinsed with water for another30 s and dried. A thin uniform coating of sealant resinwas applied on the etched area with a disposable brushand gently air-dried. The paste was gently pressed ontothe bracket base with a spatula. The bracket was thenimmediately placed onto the tooth surface. Premolarbrackets were randomly bonded to the treated enamelsurfaces with either Transbond� Plus Color ChangeAdhesive or Transbond� XT following manufacturer’sinstructions The brackets were positioned on the facialsurface at the height of contour mesiodistally, in themiddle one third occlusogingivally, and parallel to thelong axis of the tooth. The brackets were pressed onthe enamel surface until fully seated. Excess adhesivearound the bracket was carefully removed with aclinical probe before curing. The bonding agent wascured with a Chromalux, visible light curing unit for40 s. T-loops were formed with 0.014 inch stainlesssteel wire and engaged on experimental and controlteeth with elastomeric rings to increase plaque accu-mulation Fig. 1.

During the experimental period, the patientsreceived detailed verbal and written oral hygiene in-struction and were informed to brush three times dailywith a dentifrice provided to them, containing1450 ppm fluoride. The patients or their parents wereasked to complete a log of their daily tooth-brushingschedules. The patients were instructed not to useany mouth wash. The patients were recalled every 2weeks to reinforce oral hygiene instruction. After 60days, the brackets were debonded and teeth werecarefully extracted. The teeth were scrapped andcleaned of remnants of periodontal ligaments, dis-infected and stored in distilled water before use. The

Fig. 1. T-loop engaged on bracket with elastomeric ring.

extracted teeth of each group were divided into twoequal subgroups of ten each (diagram).

2.1.1. Teeth preparation for scanning electron micro-scope examination

The crowns of each subgroup (A and A*) were firstsectioned from the roots with a low speed double sideddiamond disk and continuous water spray irrigation.Then each crown was cut on a mesiodistal line fromocclusal to cervical and the buccal surfaces were storedin distilled water. All specimens were mounted onstubs and prepared for scanning electron microscopeby sputtering with gold. They were examined inscanning electron microscope (JEOL JSM-5200Japan), operated at 15 KV. The buccal surfaces of theteeth were examined carefully occlusal, proximal andgingival to the orthodontic bonding area to obtain therepresentative photomicrographs.

2.1.2. Teeth preparation for scanning electron micro-scope and energy dispersive X ray microanalysis

The crowns of each subgroup (B and B*)were firstsectioned from the roots with a low speed double sideddiamond disk and continuous water spray irrigation.Then each crown was cut on a buccolingual line fromlingual to half way the buccal surface then the twoparts were separated using osteotome and hammer tohave clean cuts and the cut surfaces were stored indistilled water. All specimens were mounted on stubswithout coating and examined in scanning electronmicroscope (JEOL JSM-6510LA Japan), then theelemental analysis was performed using the energydispersive X ray microanalysis unit attached to thesame scanning electron microscope. The cut surfacesof the teeth were examined carefully occlusal andgingival to the orthodontic bonding area to obtain therepresentative photomicrographs.


2.1.3. Statistical analysisDescriptive statistics including the mean, standard

deviation, and maximum and minimum values werecalculated for each element in both groups. Compari-sons of the mineral contents within the same groupwere performed with Paired t-test whereas compari-sons of the mineral contents between the two groupswere performed with student t-test. Significant differ-ences for all statistical tests were predetermined atP � 0.05. All statistical evaluations were made with asoftware program (SPSS version 15).

3. Results

3.1. SEM examination

3.1.1. Group I (the fluoride releasing Transbond�Plus Color Change Adhesive)

SEM examination of the enamel surface occlusal tothe orthodontic bonding area (OBA) revealed almostnormal topographic features of enamel. In some cases,there were globules of calcium fluoride like materialirregularly distributed over the enamel surface. Thisglobular calcification were arranged around enamel rodperipheries whereas some rods were occluded Fig. 2.The enamel surface proximal to the OBA revealedalmost normal topographic features of enamel. Signsof remineralization of enamel were clearly observed inclose proximity to as well as away from compositeremnants Fig. 3. In other specimens, globules of cal-cium fluoride like material were detected resulting inareas of enamel remineralization with occlusion ofenamel rods and repair of fractured enamel surface.Despite the presence of globules of calcium fluoridelike material over the enamel surface gingival to theOBA, there were some focal holes spread throughoutthe relatively smooth enamel surface Fig. 4 A

Fig. 2. SEM of enamel surface occlusal to OBA of group I showing: (A

appearance similar to normal enamel. (B) Irregularly distributed globules

Localized areas of enamel erosion in the form of accentuated focal holes

(arrows). Some enamel rods are occluded (arrow head).

buccolingual cross section of the buccal surfacerevealed the presence of globular calcification of cal-cium fluoride like particles all the way around the rodperiphery occlusally and gingivally. Fig. 5 resulting incomplete and/or partial remineralization of erodedenamel prisms and fractured enamel.

3.1.2. Group II (The conventional non-fluoridereleasing Transbond� XT)

SEM observation of the enamel surface occlusal tothe OBA revealed roughened enamel surface withmultiple areas of enamel erosion Fig. 6. Various pat-terns of enamel decalcification were observed proximalto the OBA in the form of open focal holes anddemineralization of enamel rod core as well as cracksand accentuated perikymata which resulted in the for-mation of gap in the enamel surface Fig. 7. Thegingival region next to the OBA exhibited highlyroughened enamel surface and erosion of enamel rodcores Fig. 8. A buccolingual cross section of the buccalsurface occlusal to the OBA revealed erosion ofenamel rods in close proximity to enamel surfacewhich resulted in formation of gaps between rods andenamel surface Fig. 9. On other hand, extensive ero-sions of enamel rods were detected gingival to theOBA which resulted in gaps between enamel rods aswell as gap between rods and enamel surface Fig. 10.

3.1.3. EDX evaluationThe descriptive statistics for the percentage of cal-

cium mass for each group are presented in Table 1including the mean, standard deviation, maximumand minimum values.

The mean Calcium mass % occlusal and gingival toOBA for each group is graphically presented inFig. 11. Calcium mass % occlusal to OBA in group Iyielded the highest mean whereas Calcium mass %

) Relatively smooth surface topographic features of enamel with an

of calcium fluoride like material (arrow) over the enamel surface.

(arrow heads). (C) Globular calcification of enamel rod peripheries

Fig. 3. SEM of enamel surface proximal to OBA of group I showing (A) Signs of remineralization of enamel surface in close proximity (arrows)

to composite remnants (C), whereas partial repair is seen away from composite remnant (arrow head). (B) Relatively smooth surface topographic

features of enamel with an appearance almost similar to normal enamel. (C) Enamel remineralization with occluded enamel rods by globules of

calcium fluoride like material (arrows). Repair of fractured enamel surface is also seen (arrow head).


gingival to OBA in group II yielded the lowest mean.Table 1, Fig. 11.

Calcium mass % values occlusal to the OBAyieldedhigh significant increase relative to its gingival coun-terpart in the Transbond Plus group (P ¼ 0.001), Also,it was significantly increased in the Transbond XTgroup (P ¼ 0.027) compared with its gingival coun-terpart. Table 2. The Transbond Plus group yieldedsignificant increase in Calcium mass % values bothocclusal and gingival to the OBA compared with theTransbond XT group (P ¼ 0.019, P ¼ 0.006 respec-tively). Table 2.

The descriptive statistics for the percentage ofFluoride mass for each group are presented in Table 3including the mean, standard deviation, maximum andminimum values.

The mean Fluoride mass % occlusal and gingival tothe OBA for each group is graphically presented inFig. 12. Fluoride mass % occlusal to OBA in group Iproduced the highest mean whereas Fluoride mass %gingival to OBA in group II produced the lowest mean.Table 3, Fig. 12.

Fig. 4. SEM of enamel surface gingival to OBA of group I showing

relatively smooth enamel surface with focal holes spread throughout

the enamel surface (arrows). Globules of calcium fluoride like ma-

terial are seen over the enamel surface (arrow head).

The statistical analysis of Fluoride mass % valuesbetween occlusal and gingival to OBA within group I(The Transbond Plus group) was statistically nonsig-nificant (P ¼ 0.284) whereas in group II (TransbondXT group), it revealed significant difference(P ¼ 0.039). It is clear that the Transbond Plus groupyielded highly significant increase in Fluoride mass %values both occlusal and gingival to the OBA incomparison with the Transbond XT group (P ¼ 0.001,P ¼ 0.000 respectively) Table 4.

The descriptive statistics for the percentage ofphosphorous mass for each group are presented inTable 5 including the mean, standard deviation,maximum and minimum values.

The mean phosphorous mass % occlusal andgingival to the OBA for each group is graphicallypresented in Fig. 13. Phosphorous mass % occlusal toOBA in group I showed the lowest mean whereasphosphorous mass % gingival to OBA in group IIshowed the highest mean. Table 5, Fig. 13.

As illustrated in Table 6 there was variation inPhosphorous mass % values between occlusal andgingival to OBA within the Transbond Plus group, butthis difference didn’t reach the statistical significance(P ¼ 0.283) whereas in Transbond XT group, therewas statistically significant difference (P ¼ 0.021). InTransbond Plus group, highly significant reduction ofPhosphorous mass % occurred whether occlusal orgingival to the OBA relative to its counterpart inTransbond XT group (P ¼ 0.001, P ¼ 0.000respectively).

4. Discussion

There is no doubt that the prevention of deminer-alization is one of the responsibilities of the ortho-dontist who is concerned with high quality treatment.

Fig. 5. SEM of a buccolingual crosses section occlusal to OBA of group I revealing: (A) Multiple globular calcification of calcium fluoride like

particles all the way around the rod periphery (arrows). Areas of enamel rods demineralization are also seen (arrowhead). (B) Remineralization of

eroded enamel prisms (arrow) and fractured enamel. (C) Enamel rods appear with nearly regular orientation (arrows). Deposition of calcified

globules all way of inter-rod region surrounding the enamel rods (arrow heads).


Thus, using fluoride containing sealants and adhesivesto bond brackets has been attempted [10]. The newTransbond� Plus Color Change Adhesive contains afluoroaluminosilicate glass as the fluoride source. Thehydrophilic nature of the adhesive allows fluoridediffusion through the cured cross-linked matrix in anaqueous medium [16].

Although several studies have been conducted onthe cariostatic effect of fluoride-releasing materials byusing a split-mouth design, in the current study thesubjects were randomly divided into 2 groups, andeach received only one tested material, because theprior clinical and radiographic examinations showedthat the patients were equivalent with regard to cariesrisk or activity. This experimental design was chosenrather than the split-mouth technique, to avoid thecarry-across effect due to fluoride release by the fluo-ride releasing adhesive on enamel around the bracketsbonded with non-fluoride releasing adhesive. This mayconfound the results and limit the robustness of anyfindings.

For ethical reasons and because of the long durationof the in-vivo experiment (2 months), it was

Fig. 6. SEM of enamel surface occlusal to OBA of group II showing

roughened enamel surface with multiple areas of enamel erosion

(arrows).

inappropriate to ask the patients not to brush theirteeth. So, they were instructed to brush twice dailywith a fluoride containing toothpaste. Nevertheless, tominimize the bias of additional external fluoride sup-plements, they were strictly asked to refrain from anyfluoride mouth rinses and not to have fluoride treat-ment from their dentists during the 2 months of thestudy.

In the present study, only upper premolars weresubjected to the experiment. This might lessen theremineralizing capacity of saliva. Ogaard et al. (1988)[3] suggested a relationship between resistance towhite spot formation and the rate of salivary flow. Thelower dentition might be more susceptible to influenceof the saliva because of the anatomic situation of thesalivary glands and gravity that may result in a higherdegree of saliva contact in the lower jaw.

Measurable demineralization can be observedaround orthodontic appliances 1 month after bonding[3]. A two months experimental period was used in thepresent study. The ligated T loops were left on anadditional 30 days in an attempt to obtain a longerperiod of caries attack.

SEM of the enamel surface of the fluoride-releasingmaterial (group I) occlusal and proximal to the OBArevealed almost normal topographic features ofenamel. It also revealed deposition of globules ofcalcium fluoride like material over the enamel surfaceresulting in areas of enamel remineralization with oc-clusion of enamel rods and repair of fractured enamelsurface. These globular calcification were arrangedaround enamel rod peripheries as well as all way ofinter-rod region surrounding the enamel rods. In thecontrol samples, no such globules were observed. Suchobservations are similar to those reported by Nelsonet al., (1983) [17] Ogaard, (1990) [18] and Bykyilmazet al. (1994) [19] after topical fluoride applications.

Fig. 7. SEM of enamel surface proximal to OBA of group II showing: (A) Multiple deep areas of enamel erosion (arrows) and demineralization of

enamel rod core (arrowheads). (B) Accentuated perikymata (arrows) and extensive crack (C) making gap of the enamel surface. (C) Enamel with

surface erosions with focal destruction areas (arrows) spread throughout the enamel surface.


Because of their resemblance in appearance to calciumfluoride (spherical globules), one could speculate thatthese particle depositions most likely represent calciumfluoride, a salt with clearly cariostatic properties [20].Calcium fluoride that has formed on the enamel surfacemay act as a potential reservoir, slowly releasingfluoride ions available for use in remineralization orredeposition into areas of demineralization, or actingas a diffusion barrier during acid attacks [18]. Disso-ciation of fluoride ions from calcium fluoride crystalsand diffusion into the pores in the enamel may haveoccurred, either during the initial intense release orlater during the slow but regular exposure to fluoride,followed by incorporation into the enamel apatitecrystals as fluoroapatite during demineralization andremineralization procedures, finally forming larger,more acid resistant crystals [20].

During remineralization minerals are initiallydeposited in or near the surface layer and then aregradually transferred inward in the deeper part of thelesion body [21]. This corroborates the findings in thepresent study where globules of calcium fluoride likematerial were deposited in the subsurface and deeperpart of the enamel all the way along enamel rod

Fig. 8. SEM of enamel surface gingival to OBA of group II showing

highly roughened enamel surface with deep areas of enamel erosions

(arrows). There are erosions of enamel rod core (arrowheads).

peripheries. It indicates sustained release of low fluo-ride level in Transbond� Plus Color Change Adhesive.This finding confirms investigations which showed thatcontinuous application of a low dose of fluoride had agreater cariostatic effect than did individual applica-tions of high doses [22e24].

However, scanning electron micrograph of enamelsurface gingival to bracket of group I revealed somefocal holes spread throughout the enamel surface. Thiscan be explained by the fact that fluoride cannot pre-vent the formation of such enamel lesions, but it didreduce their progression. This agrees with the findingsof Farhadian et al. (2008) [25] who found somedemineralization in all experimental teeth. However,these findings disagree with a lot of authors [4,26e28]who found that fluoride containing adhesive showed noreduction in decalcification when compared to con-ventional orthodontic bonding resin. The difference indemineralization protection may be attributed to theamount of fluoride released by materials as stated byBasdra et al. (1996) [20]. Chadwick and Gordon,(1995) [29] reported that 70 percent of fluorideis released in the first month. Another possible

Fig. 9. SEM of a buccolingual cross section occlusal to OBA of

group II showing erosions of enamel rods in close proximity to

enamel surface making gap (arrow head) between enamel rods and

enamel surface.

Fig. 10. SEM of a buccolingual cross section gingival to OBA of

group II showing enamel rods appear with severe erosions making

gaps (arrow) between enamel rods as well as gap between rods and

enamel surface (arrow head). Fig. 11. Mean Calcium mass % occlusal and gingival to OBA in the

two studied groups.

Table 2

Comparative statistics of calcium mass % within each group and

between the two studied groups.


explanation for this difference may be the bacterialchallenge which can overcome the protection affordedby fluoride and remineralization [30].

In spite of brushing daily with fluoride containingtoothpaste, SEM observation of group II (TransbondXT group) revealed various patterns of enamel decal-cification in the form of open focal holes and demin-eralization of enamel rod core as well as cracks andaccentuated perikymata which resulted in the forma-tion of gap in the enamel surface. This is parallel to astudy by O’Reilly and Featherstone (1987) [2] showingthat regular use of fluoridated tooth pastes during or-thodontic treatment was not sufficient to inhibit cariesdevelopment.

Also, researchers reported that the numerous focalholes observed are natural defects always present insound enamel [3]. The focal holes are not empty spacesbut most likely are filled with organic material. It hasbeen suggested that these spots appear to be the initialsites of acid penetration during lesion formation asacids diffuse easily into the defects and then into thespaces between the crystallites [31e34]. This supportsthe current findings.

Previous studies have reported that acid etchingprior to enamel bonding is a possible causative factorin the decalcification associated with orthodontictreatment [2]. Etching demineralizes the enamel sur-face at depths ranging from 5 mm to 25 mm [35].Importantly, the acid-etched surface allows the less

Table 1

Descriptive statistics for the percentage of calcium mass.

Calcium Mean S.D. Max. Min.

Group I

(Transbond Plus)

Occlusal 68.4 2.68773 71.63 64.10

Gingival 64.5 2.36110 69.95 61.64

Group II

(Transbond XT)

Occlusal 64.08 4.57067 71.69 55.18

Gingival 58.64 5.40446 66.23 52.01

mineralized underlying enamel to be exposed to apotentially acidic microenvironment [36]. Etchedenamel exposed to cariogenic solutions has beenshown to be more severely affected than is unetchedenamel [37]. Enamel decalcification may also becaused by the adhesive resin used to bond brackets toenamel. The polymeric structure of resins hosts a va-riety of microorganisms. Increases in bacterial accu-mulation have been reported at composite sites [38].Bacteria not only adhere to, but also consume andcolonize within, the composite resin Ref. [39]. An in-crease in bacterial accumulation following orthodonticappliance placement has been observed [40]. Thefirmly ligated T loops were used in the current studyproviding more areas for plaque and bacteria retentionand make plaque removal more difficult.

EDX is defined as a quantitative, semi quantitativeor qualitative method for identification of chemicalelements in a wide variety of samples. The techniquesensitivity of this method depends on the atomicnumber of the element to be identified, the atomicnumber of all elements present in the sample and thetechnique used during sample preparation for

Calcium mass %

Occlusal Gingival Paired t-test

Groups Mean � SD Mean � SD t P-valueGroup I 68.404 � 2.688 64.500 � 2.361 4.542 0.001**Group II 64.086 � 4.571 58.644 � 5.404 2.633 0.027*t-test t 2.575 3.140

P-value 0.019* 0.006*

*P � 0.05 (Significant).**P � 0.001 (Highly significant).

Fig. 12. Mean Fluoride mass % occlusal and gingival to OBA in the

two studied groups.Table 5

Descriptive statistics for the percentage of phosphorous mass.

Phosphorous Mean S.D. Max. Min.

Group I

(Transbond Plus)

Occlusal 23.11 3.3 28.3 19.47

Gingival 24.66 3.6 29.4 19.45

Group II

(Transbond XT)

Occlusal 29.86 4.4 37.69 24.15

Gingival 33.01 3.6 39.2 25.5

Table 4

Comparative statistics of Fluoride mass % within each group and


Fluoride mass %


Groups Mean � SD Mean � SD t P-valueGroup I 9.117 � 4.274 7.369 � 1.869 1.138 0.284Group II 3.813 � 1.027 2.552 � 1.204 2.407 0.039*t-test t 3.816 6.851

P-value 0.001** 0.000**

P > 0.05 (Non significant).



microanalysis [41]. The present study analyzed onlycalcium, phosphorus and fluoride, whose atomicnumbers are 20, 15, and 9, respectively. The calcium,phosphorous and fluoride present show considerableevidence as being caries preventive agents [42]. Ifpresent at the time of acid attack, fluoride in particularwill diffuse with the acid and inhibit enamel dissolu-tion [43]. If present during remineralization, it en-hances crystal growth and encourages mineralprecipitation. It may in fact render the enamel moreresistant to subsequent attacks [44].

The results of the present study showed a significantdifference in calcium, phosphorus and fluoride con-tents in the Transbond Plus group compared to theTransbond XT group. There were higher levels ofcalcium and fluoride in Transbond Plus group. It isattributed to calcium fluoride deposition on the teethbonded with fluoride releasing composite on enamelsurface adjacent to the OBA.

EDX analysis revealed higher phosphorus contentin the Transbond XT group, which could be explainedby the greater presence of calcium and fluoride in theTransbond Plus group. In other words, an increment incalcium and fluoride content is dependent on adecrease in phosphorus content. These findingscorroborate those of others [45,46].

Table 3

Descriptive statistics for the percentage of fluoride mass.

Fluoride Mean S.D. Max. Min.

Group I

(Transbond Plus)

Occlusal 9.117 4.273 18.34 3.52

Gingival 7.369 1.869 10.57 4.62

Group II

(Transbond XT)

Occlusal 3.813 1.027 4.67 1.37

Gingival 2.552 1.2 3.9 0.59

The results of the present study showed decreasedmineral content (calcium and fluoride) in the cervicalregion than in the occlusal area. This result is matchedwith SEM observation. This might be due to greaterdental plaque accumulation and the patient’s difficultyin cleaning this area [47]. This finding is in accordancewith that of Gorelick et al. (1982) [1] and Øgaard(1989) [48] who found that enamel demineralizationaround the brackets is commonly seen on the buccalsurfaces of teeth, especially in the gingival region.

The results of the present study indicate that one canin fact decrease the formation of very early deminer-alization of enamel surrounding the orthodontic ap-pliances with the use of fluoride releasing adhesive

Fig. 13. Mean Phosphorus mass % occlusal and gingival to OBA in

the two studied groups.

Table 6

Comparative statistics of phosphorous mass % within each group and


Phosphorous mass %


Groups Mean � SD Mean � SD t P-valueGroup I 23.113 � 3.307 24.661 � 3.601 �1.141 0.283Group II 29.866 � 4.416 33.016 � 3.630 �2.801 0.021*t-test t �3.871 �5.168

P-value 0.001** 0.000**

P > 0.05 (Non significant).



independent of patient cooperation. Sustained releaseof a low level of fluoride leads to the formation of acalcium-fluoride coat at the enamel surface. Thisreservoir of fluoride at the enamel surface has a highsubstantivity that can provide fluoride for reminerali-zation and calcium for neutralization of the acid attack.

5. Conclusion

On the basis of the current results, it’s suggested touse the fluoride releasing Transbond� Plus ColorChange Adhesive with orthodontic brackets especiallyin patients exhibiting poor oral hygiene or have dietaryrisks.

Acknowledgment

We do appreciate the work done by Dr. Olfat M.Gaballah Prof. and head of Oral Biology Department,Faculty of Dentistry, Tanta University in the histolog-ical part of the work.

References

[1] Gorelick L, Geiger AM, Gwinnett AJ. Incidence of white spot

formation after bonding and banding. Am J Orthod Dentofacial

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In vivo effect of a fluoride releasing adhesive on inhibition of enamel demineralization around orthodontic brackets1 Introduction2 Materials and methods2.1 Bonding procedures2.1.1 Teeth preparation for scanning electron microscope examination2.1.2 Teeth preparation for scanning electron microscope and energy dispersive X ray microanalysis2.1.3 Statistical analysis

3 Results3.1 SEM examination3.1.1 Group I (the fluoride releasing Transbond™ Plus Color Change Adhesive)3.1.2 Group II (The conventional non-fluoride releasing Transbond™ XT)3.1.3 EDX evaluation

4 Discussion5 ConclusionAcknowledgementsReferences

in vivo effect of a fluoride releasing adhesive on ...composite resin and glass ionomer cements...

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