Reduce Enamel Demineralization Research Articles

Effect of tricalcium silicate (Ca3SiO5) bioactive material on reducing enamel demineralization: An in vitro pH-cycling study

ObjectivesThe aim of this study was to investigate the effect of Ca3SiO5 on reducing enamel demineralization under pH-cycling conditions. MethodsForty bovine enamel samples were treated under four conditions: group 1, double distilled water (negative control); group 2, 1000ppm F (as NaF, positive control); group 3, Ca3SiO5 slurry; and group 4, Ca3SiO5–F slurry (Ca3SiO5 with 1000ppm F aq.). All the specimens were treated with treatment materials 4 times each day. Samples in groups 1 and 2 were soaked in test solutions for 2min and samples in groups 3 and 4 were painted in treatment slurry for 2min. At times between treatments, they were immersed in citric acid solution 3 times a day and 15s each time. All the procedures were repeated for 7 days. Knoop microhardness, scanning electron microscopy (SEM), X-ray diffraction (XRD) and atom force microscopy (AFM) were used to examine samples. ResultsAfter treatment for 7 days, enamels in all the groups were significantly softened. The extents of microhardness reduction were 52.3%, 28.5%, 28.5% and 20.2% for groups 1, 2, 3 and 4, respectively. Samples in the negative control group showed a typical acid etched pattern while enamels in other groups were relatively compact. There was no significant difference between samples treated with Ca3SiO5 and F. The combination of Ca3SiO5 with F showed the best effect on reducing enamel demineralization. ConclusionsCa3SiO5 is an effective material against enamel demineralization alone but in combination with F a better anti-demineralization effect may be obtained.

To Evaluate the Clinical Efficiency of Resin Modified Glass Ionomer Varnish in Preventing Enamel Demineralisation During Orthodontie Treatment

Background and objectives: Fixed orthodontic treatment makes oral Hygiene procedures difficult and may resuit in enamel demineralization. Resin Modified Glass Ionomer Varnish (Clinpro XT Varnish) reduces the incidence of enamel demineralization. The objective of this study has been clinically evaluate the effects of RMGIV (Clinpro XT Varnish) application, incidence and progress of enamel demineralization in patients undergoing orthodontic treatment. 30 subjects seeking orthodontic treatment were selected from patients visiting Department of Orthodontics and Dentofacial Orthopedics A. B. Shetty Memorial Institute of Dental Sciences, Mangalore. The subjects were divided into Test and Control group. The study was divided into two parts: ♦ Visual evaluation – incidence of white spot lesion and their progress for six months. ♦ SEM (Scanning Electron Microscopic) evaluation to compare level of surface roughness on samples of both the groups. No White Spot Lesions was clinically appreciable in either Group A or Group B. Oral Hygiene Index of all patients was scored and compared between Group A and Group B. The scores were statistically evaluated which proved to be statistically significant with ‘p’ value below 0.001 with better oral hygiene in Group A. After extracting the teeth, SEM images of surface of the teeth was graded and statistically evaluated with Pearson's Chi square test.The results were significant with ‘p’ value below 0.001 which indicated increased surface roughness in Group B compared to the Group A patients. Use of Resin Modified Glass Ionomer Varnish (Clinpro XT Varnish) as an adjunctive to thorough oral hygiene measures and has proven to be effective in reducing enamel demineralization significantly although not completely. The oral hygiene also improves but, is it the effect of active ingredient of the varnish is not confirmable under this study design.

The effect of iron on Streptococcus mutans biofilm and on enamel demineralization

Iron (Fe) may have an anticaries effect by specific inhibition of glycosyltransferase (GTF) enzymes of Streptococcus mutans, but this hypothesis has not yet been clarified. In this study, S. mutans biofilms were formed on blocks of bovine dental enamel of a predetermined surface hardness (SH). These biofilms were exposed eight times/day to 10% sucrose, and two times/day they were subjected to one of the following treatments: G1, 0.9% NaCl as a negative control; G2, 0.12% chlorhexidine digluconate (CHX) as a positive antibacterial control; G3, 0.05% NaF (225 ppm F) as a positive anticaries control; G4, G5, and G6, ferrous sulfate (Fe2+) at concentrations of 1.0, 10.0, and 100.0 µg Fe/mL, respectively. The experiment was performed in triplicate and was repeated three times (n = 9). The pH of the culture medium was determined every 24 h as an indicator of the biofilm's acidogenicity. The biofilm formed on each block was collected for determination of the viable bacteria and concentration of extracellular polysaccharides (EPS). Enamel SH was again determined and the percentage of SH loss (%SHL) was calculated as an indicator of demineralization. Iron treatment reduced the number of viable bacteria formed in the S. mutans biofilm (p = 0.04), in a dose-dependent manner, and also reduced the enamel's %SHL (p = 0.005). At 100 µg/mL, Fe reduced enamel demineralization as effectively as CHX and NaF (p < 0.05), but it did not inhibit EPS production. In conclusion, the data suggest that the anticaries mechanism of action of Fe may not involve the oxidative inhibition of GTFs.

Effect of Er,Cr:YSGG Laser and Professional Fluoride Application on Enamel Demineralization and on Fluoride Retention

This study evaluated the effect of Er,Cr:YSGG laser irradiation and professional fluoride application on enamel demineralization and on fluoride formation and retention. In a blind in vitro study, 264 human enamel slabs were distributed into 8 groups: G1 – untreated; G2 – treated with acidulated phosphate fluoride gel (APF gel, 1.23% F) for 4 min; G3, G4 and G5 – irradiated with Er,Cr:YSGG at 2.8, 5.6 and 8.5 J/cm², respectively; G6, G7 and G8 – preirradiated with Er,Cr:YSGG at 2.8, 5.6 and 8.5 J/cm², respectively, and subjected to APF gel application. Twenty slabs of each group were submitted to a pH-cycling regimen, and enamel demineralization was evaluated in 10 slabs of each group. In the other 10 slabs, CaF₂-like material was determined. To evaluate F formed, 10 additional slabs of each group, not subjected to the pH cycling, were submitted to analysis of CaF₂-like material and fluorapatite, while the other 3 slabs of each group were evaluated by scanning electron microscopy. The F content was also measured in all pH-cycling solutions. Laser at 8.5 J/cm² and APF treatment reduced enamel demineralization compared to the control (p < 0.05), but the combination of these treatments was not more efficient than their isolated effect. A higher concentration of retained CaF₂-like material was found in laser groups followed by APF in comparison with the APF gel treatment group. The findings suggest that laser treatment at 8.5 J/cm² was able to decrease hardness loss, even though no additive effect with APF was observed. In addition, laser treatment increased the formation and retention of CaF₂ on dental enamel.

Carbon dioxide laser and bonding materials reduce enamel demineralization around orthodontic brackets

Altering the structure of the enamel surface around the orthodontic bracket by reducing its content of carbonate and phosphate resulting from application of CO(2) laser may represent a more effective strategy in preventing caries in this region. This study aimed at determining whether irradiation with a CO(2) laser combined with fluoride-releasing bonding material could reduce enamel demineralization around orthodontic brackets subjected to cariogenic challenge. Ninety bovine enamel slabs were divided into five groups (n = 18): non-inoculated brain-heart infusion broth group, non-fluoride-releasing composite resin (NFRCR--control group), resin-modified glass ionomer cement (RMGIC), CO(2) laser + Transbond (L+NFRCR) and CO(2) laser + Fuji (L+RMGIC). Slabs were submitted to a 5-day microbiological caries model. The Streptococcus mutans biofilm formed on the slabs was biochemically and microbiologically analysed, and the enamel Knoop hardness number (KHN) around the brackets was determined. The data were analysed by ANOVA and Tukey tests (α = 0.05). Biochemical and microbiological analyses of the biofilm revealed no statistically significant differences among the groups. Lased groups presented the highest KHN means, which statistically differed from NFRCR; however, no difference was found between these lased groups. RMGIC did not differ from NFRCR which presented the lowest KHN mean. The CO(2) laser (λ = 10.6 μm; 10.0 J/cm(2) per pulse) use with or without F-bonding materials was effective in inhibiting demineralization around orthodontic brackets. However, no additional effect was found when the enamel was treated with the combination of CO(2) laser and an F-releasing material.

Carbon dioxide laser and bonding materials reduce enamel demineralization around orthodontic brackets

Carbon dioxide laser and bonding materials reduce enamel demineralization around orthodontic brackets

Combination effect of fluoride dentifrices and varnish on deciduous enamel demineralization

The aim of this study was to evaluate the anticaries potential of 500 or 1100 ppm F dentifrices combined with fluoride varnish using a pH-cycling regimen. Seventy primary canines were covered with nail polish, leaving a 4×4 mm window on their buccal surface, and randomly assigned into 7 groups (n = 10): S: sound enamel not submitted to the pH-cycling regimen or treatment; N: negative control, submitted to the pH-cycling regimen without any treatment; D1 and D2: subjected to the pH-cycling regimen and treated twice daily with 1100 or 500 ppm F dentifrice, respectively; VF: fluoride varnish (subjected to F-varnish before and in the middle of the pH-cycling regimen); and VF+D1 and VF+D2. After 10 days, the teeth were sectioned, and enamel demineralization was assessed by cross-sectional hardness at different distances from the dental surface. Data were analyzed using a two-way ANOVA followed by Tukey's test. Dentifrice with 1100 ppm F and the combination of F-varnish with the dentifrices significantly reduced enamel demineralization compared with the negative control (p < 0.05), but the isolated effects of F-varnish and dentifrice with low concentration were not significant (p > 0.05). The effect of combining F-varnish with the dentifrices was not greater than the effect of the dentifrices alone (p < 0.05). The data suggest that the combination of F-varnish with dentifrices containing 500 and 1100 ppm F is not more effective in reducing demineralization in primary teeth than the isolated effect of dentifrice containing 1100 ppm F.

Effect of antibacterial monomer-containing adhesive on enamel demineralization around orthodontic brackets: An in-vivo study

The aims of this study were to evaluate the effect of an antibacterial monomer-containing self-etching adhesive in reducing enamel demineralization around orthodontic brackets in vivo and to compare it with the conventional adhesive system quantitatively. Fourteen orthodontic patients were randomly divided into 2 equal groups; they received brackets fitted to all their teeth, bonded with either Clearfil Protect Bond (Kuraray Medical, Okayama, Japan) (experimental group) or Transbond XT (3M Unitek, Monrovia, Calif) (control group). Block randomization to obtain equal numbers in each group was used. After 30 days, all first premolars were extracted with orthodontic indications and longitudinally sectioned. Demineralization was assessed by cross-sectional microhardness. Determinations were made at the bracket edge cementing limits and at occlusal and cervical points 100 and 200 μm away from the edge. In all of these positions, 6 indentations were made at depths of 10 to 90 μm from the enamel surface. Analysis of variance (ANOVA) and the Tukey post-hoc test were used. The statistical significance level was set at P <0.05. ANOVA showed statistically significant differences for adhesive type, position, depth, and their interactions (P <0.05). The multiple comparison test showed that the antibacterial monomer-containing adhesive was significantly more efficient than the conventional adhesive system, reducing enamel demineralization in almost all evaluations (P <0.05). The results indicated that using antibacterial monomer-containing adhesive for bonding orthodontic brackets successfully inhibited caries in vivo. This cariostatic effect was localized at the area around the brackets and was significant after 30 days.

In vivo effects of amorphous calcium phosphate‐containing orthodontic composite on enamel demineralization around orthodontic brackets

The aim of this study was to evaluate the in vivo effects of an amorphous calcium phosphate-containing orthodontic composite in reducing enamel demineralization around orthodontic brackets, and to compare it with the control. Fourteen orthodontic patients were divided into two equal groups. They received brackets fitted to all first premolars, bonded with either Aegis Ortho® (The Bosworth Co.), an ACP-containing orthodontic composite (experimental group), or Concise® (3M Dental Products), a resin-based orthodontic composite (control group). After 30 days, the teeth were extracted and longitudinally sectioned, and evaluated by superficial-microhardness analysis. The determinations were made at the bracket edge cementing limits and at occlusal and cervical points 100 and 200 μm away from the edge. In all of these positions, indentations were made at depths of 10, 20, 30, 50, 70, and 90 μm from the enamel surface. Analysis of variance (ANOVA) and Tukey post hoc test was used. The statistical significance level was set at p<0.05. The ANOVA showed statistically significant differences for position, material, depth, and their interactions (p<0.001). The multiple comparison test showed that the ACP-containing orthodontic composite was significantly more efficient than the control composite, reducing enamel demineralization in almost all evaluations (p<0.001). Present results indicated that ACP-containing orthodontic composite for bonding orthodontic brackets successfully inhibited demineralization in vivo. This effect was localized to the area around the brackets and was statistically significant after 30 days.

Effects of different topical agents on enamel demineralization around orthodontic brackets: an in vivo and in vitro study

The aim of this study was to evaluate the in vivo and in vitro effects of a casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) and fluoride containing topical agents in reducing enamel demineralization around orthodontic brackets, and to compare this with a control group. Twenty-one patients and 60 extracted premolars were divided into three groups: two experimental and one control. Tooth Mousse® (CPP-ACP gel; GC-Corp, Tokyo, Japan) and Fluoridin N5® (Fluoride gel; Voco-GmbH, Cuxhaven, Germany) were applied to tooth surfaces around orthodontic brackets in the experimental groups. Teeth were extracted after 60 days to evaluate the in vivo effects of the testing materials. For the in vitro experiment, samples were cycled for 14 days through a daily procedure of demineralization. All teeth were sectioned and evaluated by superficial microhardness analysis. An indentation was made from two positions (occlusal-cervical) and one depth (10 μm). Comparisons of occlusal and cervical microhardness scores for all specimens showed no statistically significant side differences. A multiple comparison test showed that the use of CPP-ACP and fluoride containing topical gels were more significantly efficient than the control group (p<0.001). No significant differences were detected between CPP-ACP and the fluoride groups against demineralization. In vivo and in vitro evaluations indicated that CPP-ACP and fluoride containing agents successfully inhibited caries around orthodontic brackets.

Impact of two toothpastes on repairing enamel erosion produced by a soft drink: An AFM in vitro study

Objectives The aim of the present in vitro study was the evaluation of two toothpastes (Sensodyne Pronamel and Biorepair Plus on repairing enamel erosion produced by a soft drink (Coca Cola), using Atomic Force Microscopy (AFM). Methods Fifty extracted human central incisors free of caries were selected and divided in a treatment and a control half; they were kept in artificial saliva during whole experimentation. The treatment halves were divided into five groups; group 1: demineralization with soft drink; group 2: demineralization with soft drink + Pronamel; group 3: demineralization with soft drink + Biorepair Plus; group 4: intact enamel + Pronamel; group 5: intact enamel + Biorepair Plus. Specimen demineralization was carried on in 4 intervals of 2 min. In groups 2, 3, 4, and 5 the toothpastes were applied for 3 min at 0, 8, 24 and 36 h. The surface of each specimen was imaged by AFM and R rms, root-mean-square roughness, and Maximum Depth of the cavities were registered. Results Amongst treatment specimens of groups 1, 2, and 3 a statistically significant difference ( P < 0.01) in R rms and Maximum Depth values was registered: the toothpastes reduced enamel demineralization. No statistical differences in R rms values were registered between the two toothpastes. Conclusions The toothpastes tested (Pronamel and BioRepair Plus) offer a degree of protection from erosive drinks.

Effect of APF gel application time on enamel demineralization and fluoride uptake in situ

This in situ crossover and blind study was conducted to investigate the effect of professional acidulated phosphate fluoride (APF) gel application time on the subsequent inhibition of enamel demineralization. During 3 phases of 28 days each, 15 volunteers wore palatal appliances containing 4 enamel blocks, which were subjected to 3 treatment groups: not treated (control) and pre-treated with APF gel for 1 or 4 min. Dental plaque was allowed to accumulate on the blocks and the appliances were immersed in 10% sucrose solution 3 times a day simulating a cariogenic challenge. After each phase, the blocks were removed to evaluate enamel demineralization and concentration of fluoride (F) remaining after the cariogenic challenge. F formed on enamel was determined in additional enamel blocks subjected only to APF gel application. APF gel was efficient in reducing enamel demineralization (p<0.05), irrespective of the application time (p>0.05). Also, the concentration of the F formed and retained on enamel was significantly higher after APF gel application (p<0.05), but the effect of time of application was not statistically significant (p>0.05). The results suggest that APF application for either 1 or 4 min is equally efficient to increase F concentration in enamel and reduce enamel demineralization.

Fluoride Release from CaF2 and Enamel Demineralization

The anticaries effect of professional fluoride (F) application has been attributed to calcium-fluoride-like deposits (CaF(2)) formed on enamel, but this has not been clearly demonstrated. We hypothesized that CaF(2) formed on plaque-free enamel by F application would reduce enamel demineralization due to the increase of F availability in fluid of subsequently formed plaque. We created distinct levels of CaF(2) on enamel to evaluate a dose-response effect. Enamel blocks were mounted in contact with a S. mutans test plaque and used in situ by 10 volunteers. F released to the fluid phase of this substrate ("plaque fluid") was measured before a cariogenic challenge. "Plaque fluid" F concentration was highly correlated to the enamel CaF(2) concentration (r = 0.96, p < 0.001) and to consequent enamel demineralization (r = -0.75, p < 0.001). The results suggest that F released to plaque fluid from CaF(2) formed on enamel may play a significant role in the anticaries effect of professionally applied F agents.

PH-cycling models to evaluate the effect of low fluoride dentifrice on enamel de- and remineralization

Since the currently available pH-cycling models do not differentiate the anti-caries potential of dentifrices with low fluoride (F) concentration, two models were developed and tested in the present. Bovine enamel blocks were subjected to the models and treated with F solutions containing from 70 to 280 microg F/mL in order to validate them in terms of dose-response effect. The models were also tested by evaluating the dentifrices Colgate Baby (500 microg F/g, as a low fluoride dentifrice), Tandy (1,100 microg F/g, as an active F-dentifrice) and Crest (1,100 microg F/g, as positive control). Enamel mineral loss or gain was assessed by surface and cross-sectional microhardness, and lesion depth was analyzed by polarized light microscopy. The pH-cycling models showed F dose-response effect either reducing enamel demineralization or enhancing remineralization. The low F dentifrice presented anti-caries potential, but it was not equivalent to the dentifrices containing 1,100 microg F/g. These data suggest that the models developed in this study were able to evaluate the anti-caries potential of low F dentifrice either on resistance to demineralization or on enhancement of remineralization.

Effect of Frequency of Sucrose Exposure on Dental Biofilm Composition and Enamel Demineralization in the Presence of Fluoride

It has been suggested that enamel would resist higher frequencies of sucrose exposure if fluoride from water or dentifrice is being used. However, the effect of increasing frequencies of sugar on dental biofilm composition is not well known. Ten volunteers living in a fluoridated area wore palatal appliances bearing human enamel slabs during 14 days. The slabs were exposed to 20% sucrose solution 0 (control), 2, 4, 6, 8 or 10 times/day and the volunteers used fluoride dentifrice 3 times/day. Enamel demineralization was significantly greater than control for sucrose frequencies higher than 6 times/day. However, biofilm mass, total microbiota, total streptococci, lactobacilli counts and insoluble extracellular polysaccharide concentration increased, while Ca, P_i and F concentration in whole biofilm decreased significantly, with frequencies of sucrose exposure lower than 6 times/day. The findings confirm that fluoride can reduce enamel demineralization if sucrose consumption is not higher than 6 times/day, but changes in the biochemical and microbiological composition of the biofilm are observed with lower frequencies of sucrose use.

In-vivo effects of fluoridated antiplaque dentifrice and bonding material on enamel demineralization adjacent to orthodontic appliances

The effect of a fluoridated antiplaque dentifrice on the development of caries lesions adjacent to dental appliances bonded with ionomeric material is unknown. Fourteen orthodontic patients were randomly divided into 2 groups of 7. One group brushed 3 times a day with a fluoridated dentifrice, and the other used an experimental antiplaque fluoridated formulation. Bracket bases were randomly bonded with either resin-modified glass ionomer cement or composite resin to the buccal surfaces of either the maxillary left or right premolars in each subject. The teeth were banded, leaving a space on the buccal surface to allow dental plaque accumulation. After 28 days of dentifrice use, the teeth were extracted, and mineral loss in the enamel adjacent to the bonded material was assessed by cross-sectional microhardness. Mineral loss in the enamel surrounding the bond with the resin-modified glass ionomer cement was lower (P <.05) than around the composite bond. Enamel demineralization was lower (P <.05) in subjects who used the experimental antiplaque fluoridated formulation than in those who used the fluoridated one. The data suggest that an antiplaque fluoridated dentifrice is superior to one that is only fluoridated for reducing enamel demineralization adjacent to dental material bonded with composite, but the effect seems irrelevant when bonding is done with the ionomeric material.

Effect of xylitol:sorbitol on fluoride enamel demineralization reduction in situ

To evaluate if sugar alcohols would reduce enamel demineralization enhancing the fluoride (F) effect. A crossover in situ study was conducted in four phases, during which 10 volunteers were submitted to one of the treatments: (I) Distilled and deionized water, as a negative control; (II) F (226 microg F/ml as NaF; concentration used in commercial mouthrinse); (III) X:S (xylitol:sorbitol 1:3; final concentration 1.6M; 28% of sugar alcohols) and (IV) F+X:S (same final concentration that groups II and III). The volunteers wore palatal appliances containing four bovine enamel blocks of known surface microhardness (SMH), covered with a 'test plaque' of mutans streptococci, which were immersed during 1 min in one of the allocated treatment solutions simultaneously that the volunteers rinsed their mouths with the same solution. After the rinsing the appliances were put in the mouth and after 20 min a cariogenic challenge was made with 20% sucrose solution during 1 min. After further 45 min the 'test plaque' was collected for F analysis, enamel SMH was again determined and the percentage of change in relation to baseline was calculated; F uptake in enamel was also determined. With respect to all the analyses made, the group F+X:S did not differ from the F treatment (p>0.05) and the groups treated with F and F+X:S differed from the negative control (p<0.05). The results suggest that xylitol:sorbitol may not enhance the effect of fluoride present in mouth rinse on the reduction of enamel demineralization.

Prevention of enamel demineralization: An in-vitro study using light-cured filled sealant

Enamel demineralization is an undesirable side effect of orthodontic treatment with fixed appliances. The purpose of this in-vitro study was to evaluate the efficacy of applying a light-cured filled sealant onto the buccal tooth surfaces to prevent demineralization. Fifty extracted human third molars were allocated to 1 of 5 groups: (1) enamel surface untreated (control); (2) surface etched; (3) fluoride varnish applied; (4) enamel etched and coated with a light-cured, unfilled sealant (control sealant); and (5) enamel etched and coated with a light-cured, filled sealant (Pro Seal, Reliance Orthodontic Products, Itasca, Ill). The enamel surface of each specimen was brushed for 15,000 strokes with nonfluoride toothpaste slurry with a piston-action brushing machine under a standardized load. All samples were then cycled for 14 days through a daily procedure of demineralization for 6 hours and remineralization for 17 hours. Then the teeth were sectioned and evaluated quantitatively by cross-sectional microhardness testing. Demineralization in the Pro Seal group was significantly less (P < .05) than in the other groups. Teeth treated with fluoride varnish exhibited 30% less demineralization than the control teeth, the enamel-etched teeth, and the teeth treated with a light-cured, unfilled sealant (P < .05). Pro Seal can be considered for use as a preventive method to reduce enamel demineralization adjacent to orthodontic attachments, particularly in patients who exhibit poor compliance with oral hygiene and home fluoride use.

Caries inhibition around composite restorations by pulsed carbon dioxide laser application

This in vitro study aimed to evaluate whether laser irradiation of cavity margins reduces enamel demineralization around composite restoration. Enamel cavities were prepared in 33 human enamel slabs, which were randomly divided into three groups. One group was kept as a control, and the cavosurface margin of the cavities of the other groups were irradiated, using a CO(2) laser (lambda = 10.6 microm), at 8 J.cm(-2) or 16 J.cm(-2). The cavities were restored with a resin-based composite, according to the manufacturer's specifications. Before restoration, scanning electron microscopy was performed on one specimen of each group. The remaining slabs were submitted to thermal and pH-cycling models. Enamel mineral loss, at 50 and 100 microm from the restoration margin, was assessed by cross-sectional microhardness analyses. Fusion and melting were observed in the irradiated groups. Mineral loss at 50 microm from the restoration margin was significantly inhibited in the irradiated groups compared to the control group, but at 100 microm from the restoration margin, mineral loss at only the highest laser energy density differed statistically from the control group. The difference between the irradiated groups was not statistically significant at either 50 or 100 microm from the restoration margin. In conclusion, irradiation of the cavosurface margin of cavities, using a pulsed CO(2) laser, is able to inhibit enamel demineralization around composite restorations, and an energy density of 16 J.cm(-2) is efficient, even at 100 microm from the cavity margin.

The efficacy of a fluoride varnish in reducing enamel demineralization adjacent to orthodontic brackets: an in vitro study

To test the hypothesis that fluoride varnish is effective in reducing demineralization (white spot) lesions adjacent to bonded orthodontic brackets. Two similar samples of extracted bovine incisors, with bonded orthodontic brackets, were separated into an experimental group (fluoride varnish was applied) and control group (no fluoride varnish) to examine the preventive effects of fluoride varnish. The dental clinic of the State University of Maringá--UEM (Maringá, Paraná, Brazil). Thirty-eight extracted bovine incisors with bonded orthodontic brackets. Fluoride varnish was applied topically to half of the sample of extracted bovine teeth. No varnish was applied to the other half. The depths of enamel demineralization (white spot) lesions were measured from polarized light microscopy images using image analysis software. The teeth in both the experimental and control groups had been exposed to a cariogenic environment twice a day for 35 days. Those teeth that had been treated with two applications of fluoride varnish (one at the outset and another 15 days later) demonstrated about 38% less mean lesion depth than teeth where no varnish had been applied. Orthodontists may wish to consider the application of fluoride varnish during fixed orthodontic therapy to help reduce the development of enamel white spot lesions.