Fluoride-releasing core build-up materials and artificial caries.

This study examined the effect of fluoride-releasing core build-up materials upon both enamel and root demineralization in an artificial caries system. Thirty extracted human molars were randomly assigned to three treatment groups consisting of (1) conventional composite core build-up paste, (2) fluoridated core build-up paste and (3) glass cermet. Teeth were thermocycled 350 times between 5 degrees C and 55 degrees C using 30-second dwell times. Acid-resistant varnish was placed on the specimens to within 1 mm of the restoration and the teeth were subjected to an artificial-caries challenge at pH 4.2 for 72 hours. Teeth were then sectioned and the thin sections photographed using a polarized light microscope. Areas of the artificial-caries lesions were measured using a sonic digitizing pad. Mean lesion area (in arbitrary units from the digitizing pad) on enamel for Group 1 was 3.76 +/- 0.54; Group 2 was 2.53 +/- 1.17 and Group 3 was 2.32 +/- 0.68. Mean lesion area on root for Group 1 was 3.04 +/- 0.54; Group 2 was 2.34 +/- 0.58 and Group 3 was 2.51 +/- 0.53. ANOVA with Duncan's multiple range test of contrast indicates a significant difference (P less than 0.001) on both enamel (35 +/- 3%) and root (20 +/- 3%) between the non-fluoridated product and the two fluoridated products. There were no significant differences between Group 2 and 3. Clinical significance: This artificial caries study indicates that a fluoride-releasing core material may be of value in preventing demineralization of tooth structure adjacent to the restorative core material.     

Effect of fluoride varnish on demineralization adjacent to brackets bonded with RMGI cement.

Far too often a less-than-optimal esthetic result occurs after orthodontic treatment due to demineralization of enamel adjacent to fixed orthodontic appliances in patients with inadequate oral hygiene. In vitro studies have shown that a resin-modified glass ionomer (RMGI) cement and a fluoride varnish might help clinicians combat this problem. The purpose of this study was to evaluate, in vitro, the effect of a fluoride-releasing cavity varnish on inhibition of enamel demineralization adjacent to orthodontic brackets bonded with RMGI and composite resin cements. Brackets were bonded to 48 extracted human third molars. Half were bonded with a composite resin (Transbond, 3M Unitek, Monrovia, Calif) and half with an RMGI (Fuji Ortho LC, GC America, Alsip, Ill). Each group was further divided into 2, with half receiving an application of fluoride-releasing varnish (Duraflor, Pharmascience, Montreal, Québec, Canada). The samples were cycled in an artificial caries solution for an hour twice daily for 31 days. After each caries challenge, the teeth were brushed with a soft toothbrush to simulate normal mechanical wear of the varnish. The loss of fluoride varnish was timed. Teeth were sectioned longitudinally and photographed under polarized light microscopy. Mean lesion depth was measured, and analysis of variance (ANOVA) (P 相似文献   

In vitro evaluation of toothbrushing abrasion of differently bleached bovine enamel

PURPOSE: To evaluate in vitro, the effect of different external bleaching agents on the susceptibility of enamel against toothbrushing abrasion. METHODS: 96 bovine enamel specimens were embedded in acrylic resin, polished and covered with tape except for a 1.4 x 10 mm window. The samples were divided into eight groups (A-H), 12 specimens each (A-G) were treated with seven different home-bleaching (A: Whitestrips, B: Rapid White, C: Opalescence 10%, D: Opalescence PF 15%) and in-office-bleaching agents (E: Opalescence Extra, F: Opalescence Quick, G: Opalescence Extra Boost) according to manufacturers' instructions. Before and after each individual bleaching treatment the samples were brushed 40 times in an automatic brushing machine using a slurry containing artificial saliva and fluoridated toothpaste. The control group (Group H) was not bleached, but also brushed. After each cycle the specimens were stored in artificial saliva for 24 hours. RESULTS: After 20 cycles loss of enamel was determined by profilometry, resulting in the following values (mean +/- standard deviation) which were statistically analyzed: Group A: (0.169 microm +/- 0.035), Group B (11.108 microm +/- 0.655), Group C (0.207 microm +/- 0.042), Group D (0.154 microm +/- 0.028), Group E (0.081 microm +/- 0.015), Group F (0.084 microm +/- 0.018), Group G (0.087 microm +/- 0.014), Group H (0.076 microm +/- 0.012). Group B differed significantly from the other groups (r = 0.001). Samples of Groups C, D and A showed a significant difference compared to the control H (r = 0.001). Statistical analysis revealed no significant difference between enamel loss of Groups E, F, G and the Control H. It could be proven that toothbrushing abrasion of bleached enamel may be increased depending on the bleaching agent and application form used. Nevertheless, with the exception of bleaching treatment with Rapid White, toothbrushing abrasion of bleached enamel seems to be clinically less relevant.     

Effect of a fluoride varnish on demineralization adjacent to orthodontic brackets.

Home fluoride regimens have long been used to reduce the amount of demineralization adjacent to orthodontic appliances. In the absence of patient compliance, another method of applying the fluoride must be used. The purpose of this study was to evaluate, in vitro, the ability of a fluoride varnish, Duraflor, to directly inhibit demineralization of enamel surrounding orthodontic brackets. Brackets were bonded to 36 extracted human canines and premolars with a traditional composite resin and randomly assigned to three equal groups of twelve. Group 1 served as the control with no topical application after bonding. Group 2 was treated with a single application of a nonfluoridated placebo varnish. Group 3 was treated with a single application of Duraflor. All groups were cycled in an artificial caries challenge for 1 hour two times daily for 37 days and were brushed with a medium bristled toothbrush to simulate mechanical wear of the varnish. Demineralization of enamel was evaluated in longitudinal buccolingual tooth sections using polarized light microscopy. Both average depth and area of demineralization were measured with a sonic digitizer. ANOVA (P 相似文献   

Potential inhibition of demineralization in vitro by fluoride-releasing sealants

BACKGROUND: The incorporation of fluoride into sealants has been viewed as a viable way to prevent pit-and-fissure caries by potential inhibition of demineralization through the release of fluoride to enamel. The authors conducted a study to examine the effect of a recently introduced fluoride-releasing sealant (ProSeal, Reliance Orthodontic Products, Itasca, Ill.) on enamel demineralization in an in vitro artificial caries system. METHODS: The authors randomly assigned 45 extracted human third molars to three treatment groups receiving either conventional sealant without fluoride (Group 1), fluoride-releasing sealant (Group 2) or glass ionomer sealant with high fluoride release (Group 3). They placed cavity preparations on the buccal surfaces of the molars and filled them with the assigned material. They placed acid-resistant varnish on the specimens' enamel surfaces to within 1 millimeter of the sealant, leaving a 1-mm rim of sound enamel available for in vitro enamel caries formation. They thermocycled the teeth (500 cycles) in artificial saliva. They subjected the teeth to an in vitro artificial caries challenge for six weeks to produce caries-like lesions in enamel adjacent to the sealant materials. The authors took longitudinal sections from each tooth, immersed them in water and examined them via polarized light microscopy to determine wall lesion frequencies. RESULTS: The mean (+/- standard deviation) lesion depths were 232 +/- 17 micrometers for Group 1, 144 +/- 21 mum for Group 2 and 128 +/- 15 mum for Group 3. The wall lesion frequency was 12 percent for Group 1 and 7 percent for both Groups 2 and 3. There was a significant difference (P < .05) among the fluoride-releasing materials versus the nonfluoride-releasing material. This study indicates that the new fluoride-releasing sealant substantially reduces the amount of enamel demineralization adjacent to the material. CONCLUSION: ProSeal provided increased demineralization inhibition compared with a conventional sealant containing no fluoride, but less than that shown by a glass ionomer sealant. CLINICAL IMPLICATIONS: ProSeal's physical properties and cariostatic effects may allow for applications beyond traditional sealant use.     

Prevention of demineralization by CO2 and Er,Cr:YSGG laser irradiation of overdenture abutments

PURPOSE: To assess the effects of Er,Cr:YSGG and CO2 laser irradiation on the prevention of demineralization of overdenture abutments. METHODS: 32 human canines, premolars, and molars were acquired, cleaned, and scaled. They were randomly divided into two groups. Each tooth had two windows on the occlusal cut dentin. One window on each tooth was irradiated by either Er,Cr:YSGG or CO2 laser, while the other window served as a control. After pH cycling at pH 5.5 for 18 days and pH 4.7 for 16 days, the teeth were sectioned and analyzed using polarized light microscopy with water as the imbibing medium. RESULTS: The Er,Cr:YSGG irradiated dentin had a mean lesion depth of 207 +/- 27 microm while its control had a mean lesion depth of 209 +/- 34 microm. The CO2 laser irradiated dentin had a mean lesion depth of 185 +/- 24 microm while its control had a mean lesion depth of 205 +/- 22 microm. Based on paired t-tests Er,Cr:YSGG laser irradiation of dentin did not reduce demineralization when compared to the controls (P= 0.81), while CO2 laser irradiation of dentin showed that it helped reduce demineralization when compared to the controls (P= 0.025).     

In vitro dentin demineralization inhibition effects of an experimental fluoridated HEMA and water wetting agent

The ability of fluoride-releasing resins to inhibit dentin demineralization remains controversial. The purpose of this study was to evaluate the caries inhibition of resin composite restorations with an experimental fluoridated hydroxyethyl methyl methacrylate (HEMA) and water wetting agent. Standardized Class V preparations were placed in 40 molars, the gingival margin placed below the cementoenamel junction. Two dentin primers (sodium fluoride, HEMA and water; HEMA and water) were placed in equal numbers of 20 preparations, then One-Step Dental Adhesive (Bisco) was applied as recommended by the manufacturer, followed by the placement of a resin composite restoration. Amalgam restorations with no primer/adhesive were placed in 10 preparations and 10 preparations were restored by placing One-Step Dental Adhesive, then resin composite. All teeth were subjected to an artificial caries challenge (pH 4.4) for 5 days. Results demonstrated the mean areas (microm2 +/- s.d.) of demineralization 100 microm from the restoration/dentin margin to be: amalgam 5,570 +/- 873; One-Step 7,038 +/- 2,099; HEMA and water 6,126 +/- 634; fluoridated HEMA and water 3,411 +/-593. ANOVA and Duncan's test (P < 0.05) demonstrated the fluoridated HEMA and water wetting agent to have significantly less adjacent dentin demineralization than the other three groups. Eighty percent of HEMA and water wetting agent, 80% of One-Step Dental Adhesive and 100% of amalgam restorations demonstrated wall lesions. One hundred percent of restorations with fluoridated HEMA and water wetting agent demonstrated inhibition zones in adjacent dentin.     

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

INTRODUCTION: 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. METHODS: 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. RESULTS: 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). CONCLUSIONS: 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.     

Demineralization effects of 2 bleaching procedures on enamel surfaces with and without post-treatment fluoride application

In this in vitro study, the demineralization effect of 2 different bleaching procedures on enamel surfaces with and without the post-treatment application of fluoride was determined. Bovine enamel specimens (n= 180) were ground flat, polished and divided into 6 groups. Group A (n=30) specimens were bleached with Opalescence, 10% carbamide peroxide (Ultradent Products, Inc) for 8 hours daily for 2 weeks; Group B (n=30) specimens were treated with Whitestrips, 5.3% hydrogen peroxide (Procter & Gamble) for 1 hour daily for 2 weeks; Group C (n=30): the same as Group A, but after bleaching, a fluoride varnish was applied on the specimens and left for 1 hour (Duraphat, 2.26% F-); Group D (n=30): the same as Group B, followed by the same fluoride application as Group C; Group E (n=30): the specimens were covered with a glycerin gel as a control group; Group F (n=30): specimens were kept in Coca Cola 1 hour daily for 2 weeks. The mineral loss (vol% microm) and lesion depth (microm) were measured by microradiography. Data analysis was accomplished using the Kolmogorov-Smirnov, Kruskal-Wallis and Mann-Whitney U tests (p<0.05) (SPSS 11.0). The median mineral loss was statistically significantly higher in the non-fluoride groups (A: 271.20 vs C: 128.00 and B: 364.90 vs D: 151.10). The highest mineral loss was found in Group F (581.85 vol% microm) and was lowest in Group E (32.80 vol% microm). No statistically significant difference between groups was found for lesion depth.     

The longevity of casein phosphopeptide–amorphous calcium phosphate fluoride varnish's preventative effects: Assessment of white spot lesion formation

Objectives:To test how long casein phosphopeptide–amorphous calcium phosphate (CPP-ACP) fluoride varnish prevents enamel demineralization in vitro.Materials and Methods:Human molars and premolars were sectioned buccolingually and randomly assigned to two groups. Standardized pretreatment images of enamel surfaces were obtained using FluoreCam. The control group received no treatment, and the experimental group received an application of CPP-ACP fluoride varnish. Over simulated periods of 2, 4, 8, and 12 weeks, specimens were placed in a toothbrushing simulator, thermocycled, subjected to 9 days of pH cycling, and imaged with FluoreCam. Samples were sectioned and polished for polarized light microscope (PLM) evaluation.Results:There were statistically significant time (P < .001) and varnish (P < .001) effects on area, intensity, and impact of enamel demineralization. The control group showed significant and progressive demineralization over the 12 weeks (P < .001). The experimental group revealed no significant demineralization during the first 4 weeks (P > .05) and significant (P < .001) increases thereafter. Experimental demineralization after 12 weeks was comparable to 2-week demineralization in the controls, with significant between-group differences (P < .001) in enamel demineralization at all time points. PLM of the control and experimental groups revealed lesion depths of 90 ± 34 μm and 37 ± 9 μm, respectively.Conclusions:Within the limitations of this in vitro study, CPP-ACP fluoride varnish prevents enamel demineralization for at least 4 weeks and limits demineralization up to 12 weeks.     

成膜基质对氟化物涂膜抑制釉质早期龋的效果

目的:比较含不同成膜基质的氟化物涂膜抑制釉质早期龋的效果。方法:将制备的90个釉质试样块随机分成6组,分别应用以5种成膜基质(珂巴树脂、渗透型丙烯酸树脂、甲基丙烯酸乙酯共聚树脂、聚合松香、聚乙烯醇缩丁醛)配制的氟涂膜材料和Duraphat氟涂膜进行处理。采用荧光显微镜和显微硬度计测定各组釉质试样块在pH循环前后的荧光值和硬度值的变化;并通过偏光显微镜观察其脱矿深度。结果:pH循环后各组釉质试样块的荧光值和硬度值均较pH循环前明显降低,其中渗透型丙烯酸组与其他组相比,荧光损失率和硬度值变化率最小,与其他各组相比差异均有统计学意义(P<0.05);偏光显微镜观察显示:各组釉质表面均无实质性缺损,渗透型丙烯酸组釉质脱矿深度最浅。结论:氟化物涂膜具有明显的抑制釉质脱矿的作用,含渗透型丙烯酸树脂的氟涂膜效果最好。     

In vitro evaluation of fluoride varnish on overdenture abutments

STATEMENT OF PROBLEM: No clinical study has evaluated the efficacy of fluoride varnish as a topical fluoride agent for the protection of overdenture abutments from dental caries. PURPOSE: This study assessed the efficacy of a fluoride varnish in protecting overdenture abutments from demineralization in an in vitro environment. MATERIAL AND METHODS: Eighty caries-free, extracted teeth were sectioned and domed immediately below the cementoenamel junction, simulating overdenture abutment preparations. Acid resistant nail varnish was painted on all surfaces except for a window (1 x 4 mm) on the prepared occlusal dentin surfaces. Teeth were randomly divided into 4 groups of 20 specimens: control, washed with deionized/distilled water; Daily Gel, treated with Karigel-N (5,000 ppm) for 4 minutes daily; Weekly Gel, treated with Karigel-N for 4 minutes weekly; and Weekly Varnish, treated with Duraflor (22,600 ppm) weekly. The varnish was removed using a blade 24 hours after each application to simulate the clinical loss of the varnish. Teeth were then placed in a cycle of demineralization (2.2 mMol/L CaCl(2)2H(2)O, 2.2 mMol/L KH(2)PO(4), and 50 mMol/L acetic acid at pH 4.3) for 6 hours and remineralization (1.5 mMol/L CaCl(2)2H(2)O, 0.9 mMol/L KH(2)PO(4), and 150 mMol/L KCl at pH 7.0 for 17 hours) for 21 days. Half the teeth in each group were brushed with no dentifrice for 10 seconds, twice daily. Teeth were sectioned at 100 +/- 10 microm buccolingually and evaluated under polarized light microscopy and contact microradiography. The depth of each lesion and the width of the remineralization bands were measured (mm). Analysis of variance models and T-tests were used to assess the effects of different treatments (alpha=.05). Duncan multiple range tests were then chosen as post hoc tests to evaluate the statistical significance of all pairwise comparisons. RESULTS: The control group had the deepest lesions (mean depth 400 +/- 39 microm). The lesions from the varnish and daily gel groups were significantly shallower than the lesions in both the control group and the weekly gel group. The remineralization bands in the varnish group were 52% wider than the control group bands. However, the daily gel group had the largest increase in band width (117% increase) compared with the control group. There were significant differences between all groups for net depth (lesion depth minus the remineralization band) (P<.0001). Daily application of fluoride gel was significantly more effective than the other treatments tested. Brushing was not a significant factor. CONCLUSION: Within the limitations of this in vitro study, treatment of overdenture abutment with various topical fluorides significantly inhibited demineralization and enhanced remineralization of cut occlusal dentin surfaces. Daily use of Karigel-N was the most effective treatment, followed by the weekly application of Duraflor varnish.     

Effect of fluoridated carbamide peroxide gels on enamel microtensile bond strength

The aim of this study was to examine the resin bond strength on enamel treated with different fluoridated bleaching agents. Forty-eight bovine incisors were divided into four groups to receive bleaching treatments, over a 14-d period, as follows: no treatment; 10% carbamide peroxide (CP) bleaching; 10% CP containing 0.11% fluoride; and 10% CP containing 0.37% fluoride. Immediately, and 7 and 14 d after bleaching, the enamel surfaces were respectively bonded with composite and sectioned to create resin–enamel beams. These beams were subjected to the microtensile bond strength (μTBS) test, then assessed for failure mode under scanning electron microscopy. The results showed that the 0.37% fluoridated group demonstrated a μTBS equivalent to that of the unbleached group at all stages. Non-fluoridated and 0.11% fluoridated groups showed a weaker μTBS after bleaching but regained the bond strength after 14 or 7 d of storage, respectively. In the non-fluoridated group, adhesive failure was the predominant fracture pattern that comprised the enamel prism demineralization change and widely dispersed voids on the resin–enamel interfaces. No evident enamel erosion and fewer microporosities were found in the 0.37% fluoridated group. Accordingly, treatment with 0.37% fluoridated CP maintained the μTBS as effectively as the unbleached enamel. Additional fluoride in the bleaching agents may facilitate subsequent restorative treatment by inhibiting enamel demineralization.     

4种防龋方法在固定矫治中预防牙釉质脱矿的研究

目的:比较4种防龋方法在正畸固定矫治中预防牙釉质脱矿的效果.方法:采用固定矫治器矫治的200名患者随机分为4组(n=50),分别用普通牙膏、含氟牙膏、氟保护漆和护牙素对牙釉质进行处理,定期随访,比较矫治完成后4组患者的牙釉质脱矿情况.结果:按牙齿数计算含氟牙膏、普通牙膏、氟保护漆和护牙素4组牙釉质的脱矿率分别为16.3％、21.9％、9.3％和8.5％ (x2=99.7,P=0.000001)氟保护漆和护牙素组脱矿率低于其他2组,该2组脱矿率之间的差异无统计学意义(x2=0.39,P=0.529851).结论:应用含氟制剂可以有效预防固定矫治中牙釉质脱矿的发生,护牙素和氟保护漆的效果更明显.     

Effect of silver and fluoride ions on enamel demineralization: a quantitative study using micro-computed tomography

Background: This study aimed to investigate the effect of silver and fluoride ions on demineralization of enamel. Methods: The coronal parts of 40 extracted sound premolars were prepared into tooth blocks. An unvarnished occlusal surface window (OW) and a flat buccal/lingual surface window (FW) were created for each tooth by covering all other surfaces with an acid‐resistant varnish. These blocks were randomly allocated into four groups of 10 blocks each and immersed in respective solutions for 5 minutes: Group 1 – 2.36 M silver fluoride; Group 2 – 2.36 M potassium fluoride; Group 3 – 2.36 M silver nitrate; and Group 4 – deionized water. After 7‐day immersion in a buffered demineralization solution at pH 4.4, micro‐CT scans were taken. Results: Mean lesion depth in the FW area for tooth blocks in AgF, KF, AgNO₃ and control groups were 0 μm, 3.3 ± 10.3 μm, 156.3 ± 30.8 μm, and 173.6 ± 48.6 μm, respectively (p < 0.001). The difference in mean lesion depth between the AgNO₃ and control groups was not statistically significant (p > 0.05). Similar OW and FW lesions were observed in tooth blocks in the AgNO₃ and control groups. Conclusions: Topical application of a 2.36 M fluoride solution can inhibit demineralization of enamel while topical application of silver ions has little effect.     

Effect of Nd:YAG laser combined with fluoride on the prevention of primary tooth enamel demineralization

Most studies dealing with the caries preventive action of Nd:YAG laser have been done in permanent teeth and studies on primary teeth are still lacking. The aim of this study was to evaluate in vitro the effect of Nd:YAG laser combined or not with fluoride sources on the acid resistance of primary tooth enamel after artificial caries induction by assessing longitudinal microhardness and demineralization depth. Sixty enamel blocks obtained from the buccal/lingual surface of exfoliated human primary molars were coated with nail polish/wax, leaving only a 9 mm2 area exposed on the outer enamel surface, and randomly assigned to 6 groups (n=10) according to the type of treatment: C-control (no treatment); APF: 1.23% acidulated phosphate fluoride gel; FV: 5% fluoride varnish; L: Nd:YAG laser 0.5 W/10 Hz in contact mode; APFL: fluoride gel + laser; FVL: fluoride varnish + laser. After treatment, the specimens were subjected to a des-remineralization cycle for induction of artificial caries lesions. Longitudinal microhardness data (%LMC) were analyzed by the Kruskal-Wallis test and demineralization depth data were analyzed by oneway ANOVA and Fisher's LSD test (á=0.05). APFL and APF groups presented the lowest percentage of microhardness change (p<0.05). Demineralization depth was smaller in all treated groups compared with the untreated control. In conclusion, Nd:YAG laser combined or not with fluoride gel/varnish was not more effective than fluoride alone to prevent enamel demineralization within the experimental period.     

In vivo effect of a resin-modified glass ionomer cement on enamel demineralization around orthodontic brackets.

Because the risk of dental caries increases with the use of orthodontic appliances and its control cannot depend only on the patient's self-care, this study evaluated the effect of a glass ionomer cement on reducing enamel demineralization around orthodontic brackets. Fourteen orthodontic patients were randomly divided into 2 groups of 7; they received 23 brackets fitted to their premolars, bonded with either Concise (3M Dental Products, St Paul, Minn), a composite resin (control group), or Fuji Ortho LC (GC America, Chicago, Ill), a resin-modified glass ionomer cement (experimental group). The volunteers lived in a city that has fluoridated water, but they did not use fluoridated dentifrices during the study. After 30 days, the teeth were extracted and longitudinally sectioned; in the enamel around the brackets, demineralization was assessed by cross-sectional microhardness. The determinations were made at the bracket edge cementing limits, and at occlusal and cervical points 100 and 200 microm away from them. In all of these positions, indentations were made at depths from 10 to 90 microm from enamel surface. Analysis of variance showed statistically significant effects for position, material, depth, and their interactions (P<.05). The Tukey test showed that the glass ionomer cement was statistically more efficient than the control, reducing enamel demineralization in all analyses (P<.05). The use of glass ionomer cement for bonding can be encouraged because it decreases the development of caries around orthodontic brackets.     

Fluoride uptake by enamel and dentin from bonding agents and composite resins: a comparative study

The present study was performed to compare the amount of in vitro fluoride uptake by enamel and dentin from fluoridated bonding agent with non-fluoridated composite (Group I), non-fluoridated bonding agent with fluoridated composite (Group II) and fluoridated bonding agent with fluoridated composite resin (Group III). Sixty extracted premolars were selected and divided into three groups of 20 teeth each. Restorative materials were applied according to manufacturer's instructions into standard windows created in the teeth, cured and placed in de-ionised water for three months. The fluoride content of successive acid etch biopsy was determined by specific ion-electrode analysis. Although significant amount of fluoride uptake occurred in all the test groups, fluoride uptake was found to be highly significant in dentin when compared to enamel in Group, I, II and III (P<0.001). The fluoride uptake was greater by both enamel and dentin in Group III ie fluoridated bonding agent with fluoridated composite resin.     

The effect of casein phosphopeptide-amorphous calcium phosphate on remineralization of artificial caries-like lesions: an in vitro study

BACKGROUND: The aims of this study were to investigate the efficacy of CPP-ACP containing Tooth Mousse on the remineralization of enamel lesions and to compare its efficacy to that of a fluoride-containing toothpaste. METHODS: Permanent teeth were placed in demineralizing solution for 96 hours to produce artificial caries-like lesions 120-200 microm in depth. They were sectioned into 100-150 microm thick samples and randomly assigned to five groups: for Group A, a fluoridated toothpaste (1100 ppm) was used as a positive control and in Group B, a non-fluoridated toothpaste was used as a negative control. Tooth Mousse containing CPP-ACP was tested by three different means: as a toothpaste (Group C); as a topical coating (Group D); and (Group E) as a topical coating after treating the sections with the same fluoridated toothpaste as in Group A. RESULTS: The lesion depth decreased significantly by 7 per cent in Group A, 10.1 per cent in Groups C and D, and 13.1 per cent in Group E (Paired t- test, p < 0.05), while in Group B the lesion depth increased significantly by 23 per cent. CONCLUSIONS: Based on the data obtained, CPP-ACP containing Tooth Mousse remineralized initial enamel lesions and it showed a higher remineralizing potential when applied as a topical coating after the use of a fluoridated toothpaste.     

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.