Role of arginine and fluoride in the prevention of eroded enamel: an in vitro model.

BACKGROUND: The aim of this study was to investigate the effect of arginine and fluoride on the reduction of erosive wear. METHODS: Bovine enamel blocks were randomly allocated into four groups (n = 20) and exposed to: ESPR group (8% arginine, 1450 ppm sodium monofluorophosphate, calcium carbonate and titanium dioxide); ESen group (1450 ppm sodium monofluorophosphate, 5% potassium citrate); positive control PC group (1500 ppm sodium monofluorophosphate) and negative control NC group (water). The samples were submitted to six alternating cycles of demineralization-remineralization (cola, 10 minutes; artificial saliva, 1 hour, respectively). Before and between cyclic demineralization and remineralization, blocks were treated with slurries of the respective toothpastes or water (1 minute). Erosive tissue loss was analysed by microhardness and profilometry. Data were analysed by ANOVA and Tukey tests for individual comparisons among the groups (p < 0.05). RESULTS: In microhardness, the ESPR (217.46 ± 55.45) group was significantly better than the other treatment groups (PC = 302.76 ± 96.10; ESen = 315.56 ± 74.56; p < 0.001). The ESPR group showed a similar loss to NC group (NC = 210.8 ± 49.98; p = 0.991). The mean erosion depth (+/- SE, µm) was detected between NC (14.37 ± 1.72) and dentifrices tested (ESPR (4.11 ± 1.34), ESen group (7.64 ± 1.61) and PC (8.20 ± 2.19) (p = 0.000). CONCLUSIONS: From the results of the present study, the effectiveness of Sensitive Pro Relief in the prevention of erosive surface loss seems to be attributed to the possible effect of the arginine associated with fluoride.

The relationship between tooth wear in the primary and permanent dentitions.

OBJECTIVE: To evaluate the relationship between tooth wear in primary and permanent dentition in 7 to 10-year-old school children, in 2007. METHODS: An epidemiological cross-sectional survey was conducted by trained, calibrated examiners, using the dental wear index (DWI). The cluster sample consisted of 764 children (382 boys, 382 girls) attending 4 public schools selected in different regions of the city. The DWI was proposed to evaluate primary and permanent teeth, coded as letters and numbers, respectively. Data were collected via clinical examinations performed outdoors under natural light, following the WHO recommendations and using a dental mirror and probe. Proportions and confidence intervals were used to describe the prevalence of dental wear. The Mann-Whitney and the Odds Ratio (OR) tests were used to compare the tooth wear prevalence between primary and permanent teeth according to surface (p < 0.05). RESULTS: The 7 to 10-year-old school children presented 16% tooth wear. The tooth wear was mostly seen on the occlusal/incisal surfaces (47%), involving enamel or enamel-dentine. Tooth wear in primary teeth was found in canines and molars (93%) and in permanent teeth in molars (34%). There was significant difference between primary and permanent teeth (p < 0.001) and dental wear in primary teeth was greater in boys than in girls (p = 0.02) but not in permanent teeth. CONCLUSION: The results suggest that 7 to 10-year-old children with tooth wear in primary teeth had more chances of developing tooth wear in permanent dentition. However, the findings of this study are not conclusive as the associations described are not causal.

Preventive effect of iron gel with or without fluoride on bovine enamel erosion in vitro.

BACKGROUND: The aim of this study was to evaluate the preventive effect in vitro of experimental gel containing iron and/or fluoride on the erosion of bovine enamel. METHODS: To standardize the blocks (n = 80), specimens (4 x 4 mm) were previously selected to measure the initial microhardness. The blocks were randomly allocated into four groups of 20 samples each: C (control, placebo gel); F (fluoride gel, 1.23% NaF); Fe (iron gel, 10 mmol/L FeSO(4)) and F + Fe (fluoride + iron gel). The gels were applied and removed after 1 minute. The blocks were then submitted to six alternating remineralization and demineralization cycles. The beverage Coca-Cola (10 minutes, 30 mL) was used for demineralization, and artificial saliva (1 hour) for remineralization. The effect of erosion was measured by wear analysis (profilometry). Data were analysed by ANOVA and the Tukey test for individual comparisons (p <0.05). RESULTS: The mean wear (+/- SD, microm) was C: 0.94 +/- 0.22; F: 0.55 +/- 0.12; Fe: 0.49 +/- 0.11 and F + Fe: 0.55 +/- 0.13. When the experimental gels were used, there was statistically significant reduction in enamel wear in comparison with the control (p <0.001). However, the experimental gels did not differ significantly among them. CONCLUSIONS: The gels containing iron with or without fluoride are capable of interfering with the dissolution dental enamel in the presence of erosive challenge.

Preventive effect of commercial desensitizing toothpastes on bovine enamel erosion in vitro.

This study evaluated in vitro commercial desensitizing toothpastes with respect to the prevention of erosion and explored the effect of their agents alone or in combination with fluoride. Bovine enamel blocks were randomly allocated to five groups of 20 and exposed to: Sensodyne ProNamel (1,425 ppm F as NaF, 5% KNO(3)), Sensodyne Original (no fluoride, 10% SrCl(2)), Colgate Sensitive (1,450 ppm F as sodium monofluorophosphate, 5% K citrate), Crest (fluoride-only toothpaste, 1,100 ppm F as NaF) and water (negative control). A second experiment was conducted with experimental dentifrices containing fluoride (NaF, 1,100 ppm F), 10% SrCl(2), 5% KNO(3 )or 5% K citrate alone or the latter three combined with F. The samples were submitted to four cycles, alternating demineralization (cola, 10 min) and remineralization (artificial saliva, 1 h). Before and between cyclic de- and remineralization, blocks were treated with slurries of the respective toothpastes or water (1 min). Erosive tissue loss was analyzed by profilometry. Data were analyzed by Kruskal-Wallis and Dunn's tests (p < 0.05). The mean erosion depth (+/- SE, mum) was significantly less for Colgate Sensitive (0.04 +/- 0.00), Sensodyne Original (0.06 +/- 0.01) and Crest (0.07 +/- 0.01) than for Sensodyne ProNamel (2.36 +/- 0.25) or water (2.92 +/- 0.24), which did not significantly differ from each other. Both F and the desensitizing agents alone reduced erosion, but no additive effect was found. In addition, the combination of F and KNO(3) did not reduce erosion. These in vitro results suggest that the presence of fluoride or desensitizing substances in toothpastes, alone or in combination, can reduce erosion of enamel, but this is not valid for all the formulations.

Distribution and prevalence of dental caries in Bauru, Brazil, 1976-2006.

AIMS: To compare caries prevalence and severity, as well as the disease distribution in the permanent dentition of 12-year-old schoolchildren in Bauru, Brazil, from 1976 to 2006. METHODS: Probabilistic samples were obtained in six surveys, from 1976 to 2006, which were conducted by calibrated examiners, following the same protocol. For data analysis, the DMFT (decayed, missing and filled teeth), Significant Caries Index (SiC Index), percentage of caries-free children, Gini Coefficient and Care Index were determined. RESULTS: The means (SD) for DMFT were 9.89 (3.96), 6.98 (3.80), 4.30 (3.11), 4.29(3.44), 1.53(2.07), and 0.90(1.53) in 1976, 1984, 1990, 1995, 2001 and 2006, respectively. Except for years 1990 and 1995 and also for 2001 and 2006, there were statistically significant differences in mean DMFT among the surveys (p < 0.05). The number of caries-free children (DMFT=0), which has significantly increased over the years (p < 0.001), ranged from 0.4% in 1976 to 63.8% in 2006. The SiC Indexes were 14.34, 11.42, 7.74, 8.06, 3.89, and 2.63; the Care Index were 31.9%, 57.4%, 68.7%, 50.5%, 66.4%, and 56.3%; and the Gini Coefficients were 0.23, 0.30, 0.39, 0.43, 0.66, and 0.76 in the surveys. CONCLUSION: Dental caries experience and prevalence in 12-year-old schoolchildren have declined significantly during the last 30 years in Bauru.

Effect of an iron mouthrinse on enamel and dentine erosion subjected or not to abrasion: an in situ/ex vivo study.

OBJECTIVES: This in situ/ex vivo study evaluated whether a rinse with an iron solution could reduce wear and the percentage of microhardness change of human enamel and dentine submitted to erosion followed by brushing after 1 or 30min. DESIGN: During 2 experimental 5-day crossover phases (wash-out period of 10 days), 10 volunteers wore intraoral palatal devices, with 12 specimens (6 of enamel and 6 of dentine) arranged in 3 horizontal rows (4 specimens each). In one phase, the volunteers immersed the device for 5min in 150mL of cola drink, 4 times a day. Immediately after immersion, no treatment was performed in one row. The other row was brushed after 1min using a fluoride dentifrice and the device was replaced into mouth. After 30min, the remaining row was brushed. In the other phase, the procedures were repeated, but after immersion the volunteers rinsed for 1min with 10mL of a 10mM ferrous sulphate solution. Changes in surface microhardness (%SMH) and wear (profilometry) of enamel and dentine were measured. Data were tested using ANOVA and Tukey's tests (p<0.05). RESULTS: The enamel presented more wear than dentine, under all experimental conditions. The iron solution caused a significant reduction on the %SMH in enamel, and a significant reduction on the wear in dentine, regardless the other conditions. CONCLUSIONS: Rinsing with an iron solution after an erosive attack, followed or not by an abrasive episode, may be a viable alternative to reduce the loss of dental structure.