Impact of the in situ formed salivary pellicle on enamel and dentine erosion induced by different acids

Objective. To investigate and compare the protective impact of the in situ formed salivary pellicle on enamel and dentine erosion caused by different acids at pH 2.6. Methods. Bovine enamel and dentine samples were exposed for 120 min in the oral cavity of 10 healthy volunteers. Subsequently, enamel and dentine pellicle-covered specimens were extraorally immersed in 1 ml hydrochloric, citric or phosphoric acid (pH 2.6, 60 s, each acid n=30 samples). Pellicle-free samples (each acid n=10) served as controls. Calcium release into the acid was determined by atomic absorption spectroscopy. The data were analysed by two-way ANOVA and Tukey's test (alpha=0.05). Results. Pellicle-covered samples showed significantly less calcium loss compared to pellicle-free samples in all acid groups. The mean (SD) pellicle protection (% reduction of calcium loss) was significantly better for enamel samples [60.9 (5.3)] than for dentine samples [30.5 (5.0)], but revealed no differences among the acids. Conclusion. The efficacy of the in situ pellicle in reducing erosion was 2-fold better for enamel than for dentine. Protection of the pellicle was not influenced by the kind of acid when enamel and dentine erosion was performed at pH 2.6.

Surface dental enamel lead levels and antisocial behavior in Brazilian adolescents

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of Different Fluoride Concentrations of Experimental Dentifrices on Enamel Erosion and Abrasion

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Effect of iron on enamel demineralization and remineralization in vitro

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Evaluation of fermented milk containing probiotic on dental enamel and biofilm: In situ study

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Influence of enamel matrix derivative (Emdogain((R))) and sodium fluoride on the healing process in delayed tooth replantation: histologic and histometric analysis in rats

Although it has already been shown that enamel matrix derivative (Emdogain((R))) promotes periodontal regeneration in the treatment of intrabony periodontal defects, there is little information concerning its regenerative capacity in cases of delayed tooth replantation. To evaluate the alterations in the periodontal healing of replanted teeth after use of Emdogain((R)), the central incisors of 24 Wistar rats (Rattus norvegicus albinus) were extracted and left on the bench for 6 h. Thereafter, the dental papilla and the enamel organ of each tooth were sectioned for pulp removal by a retrograde way and the canal was irrigated with 1% sodium hypochlorite. The teeth were assigned to two groups:in group I, root surface was treated with 1% sodium hypochlorite for 10 min (changing the solution every 5 min), rinsed with saline for 10 min and immersed in 2% acidulated-phosphate sodium fluoride for 10 min; in group II, root surfaces were treated in the same way as described above, except for the application of Emdogain((R)) instead of sodium fluoride. The teeth were filled with calcium hydroxide (in group II right before Emdogain((R)) was applied) and replanted. All animals received antibiotic therapy. The rats were killed by anesthetic overdose 10 and 60 days after replantation. The pieces containing the replanted teeth were removed, fixated, decalcified and paraffin-embedded. Semi-serial 6-mu m-thick sections were obtained and stained with hematoxylin and eosin for histologic and histometric analyses. The use of 2% acidulated-phosphate sodium fluoride provided more areas of replacement resorption. The use of Emdogain((R)) resulted in more areas of ankylosis and was therefore not able to avoid dentoalveolar ankylosis. It may be concluded that neither 2% acidulated-phosphate sodium fluoride nor Emdogain((R)) were able to prevent root resorption in delayed tooth replantation in rats.

pH-cycling Model to Verify the Efficacy of Fluoride-releasing Materials in Enamel Demineralization

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Effect of Sodium Ascorbate on Tag Formation in Bleached Enamel

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of application time of APF and NaF gels on microhardness and fluoride uptake of in vitro enamel caries

Purpose : To evaluate the effect of time of fluoride application gel, acidulated or neutral, on in vitro enamel resistance to demineralization and fluoride uptake. Materials and Methods: One hundred and ninety-two human enamel blocks were used in this study and 144 were treated with fluoride gel, acidulated or neutral, for I or 4 minutes. Ninety-six blocks treated with fluoride and 24 control blocks were submitted to a high cariogenic challenge. After the pH-cycling, enamel demineralization was assessed by surface and cross-sectional microhardness. Fluoride in the enamel blocks was also determined after removing an enamel layer by etching acid. Results: Acidulated fluoride gel formed more fluoride in enamel than neutral gel (P < 0.05), and it was also more efficient in reducing the demineralization of the enamel blocks submitted to a cariogenic challenge than the neutral one (P < 0.05). It was found that the time of application was significant in terms of fluoride uptake, but it did not render the enamel more resistant to dernineralization.

Effect of salivary stimulation on erosion of human and bovine enamel subjected or not to subsequent abrasion: An in situ/ex vivo study

This in situ/ex vivo study evaluated whether saliva stimulated by chewing gum could prevent or reduce the wear and the percent change in microhardness (%SMH) of bovine and human enamel submitted to erosion followed by brushing abrasion immediately or after 1 h. During 2 experimental 7-day crossover phases, 9 previously selected volunteers wore intraoral palatal devices, with 12 enamel specimens (6 human and 6 bovine). In the first phase, the volunteers immersed the device for 5 min in 150 ml of cola drink, 4 times per day (at 8, 12, 16 and 20 h). Immediately after the immersions, no treatment was performed in 4 specimens, 4 other specimens were immediately brushed (0 min) using a fluoride dentifrice, and the device was replaced into the mouth. After 60 min, the remaining 4 specimens were brushed. In the second phase, the procedures were repeated, but after the immersions, the volunteers stimulated the salivary flow rate by chewing a sugar-free gum for 30 min. Changes in wear and %SMH were measured. ANOVA and Tukey's test showed statistical differences (p < 0.05) for the following comparisons. The chewing gum promoted less wear and %SMH. A decreasing %SMH and an increasing enamel wear were observed in the following conditions: erosion only, 60 min and 0 min. The human enamel presented greater %SMH and less wear compared to bovine enamel. The data suggest that the salivary stimulation after an erosive or erosive/abrasive attack can reduce the dental wear and the %SMH.

Protection of short-time enamel erosion by different tetrafluoride compounds

objective: This in vitro study aimed to analyse the protective effect of differently concentrated titanium (TiF4), zirconium (ZrF4) and hafnium (HfF4) tetrafluoride on enamel erosion. Methods: Polished enamel surfaces of 36 bovine crowns were covered with tape leaving 4 enamel windows each 3 mm in diameter exposed. The crowns were randomly assigned to six groups (each n = 6) and pretreated with 4% TiF4, 10% TiF4, 4% ZrF4, 10% ZrF4, 4% HfF4 or 10% HfF4 for 4 min (first window), 10 min (second window) or 15 min (third window). The fourth window of each crown was not pretreated and served as control. Erosion was performed stepwise with 1% HCl (pH 2) in five consecutive intervals of each 15 s (total 75 s). Enamel dissolution was quantified by colorimetric determination of phosphate release into the acid. For each tooth, cumulative phosphate loss of enamel pretreated with one of the tetrafluoride compounds was calculated as percentage of the respective control and statistically analysed using two-way ANOVA.Results: Enamel erosion was significantly reduced by TiF4, ZrF4 and HfF4 application. Cumulative phosphate loss (mean % of control, 75 s erosion) after 4-15 min application was significantly lower for 4% ZrF4 (7-11%), 10% ZrF4 (2-6%), 4% HfF4 (11-9%) and 10% HfF4 (12-16%) compared to 4% TiF4 (42-27%) and 10% TiF4 (54-33%). Only for 4% and 10% TiF4, phosphate loss decreased with increasing duration of application, but also increased with increasing acid intervals.Conclusion: TiF4, ZrF4 and HfF4 might protect enamel against short-time erosion, but protection was more enhanced by ZrF4 and HfF4 compared to TiF4 application overtime. (C) 2008 Elsevier Ltd. All rights reserved.

12-Month color stability of enamel, dentine, and enamel-dentine samples after bleaching

The study aimed to quantify the color regression of enamel (E), dentine (D), and combined enamel-dentine (ED) of differently bleached ED specimens over a period of 12 months in vitro. Two ED samples were obtained from the labial surfaces of bovine teeth and prepared to a standardized thickness with the enamel and dentine layer each 1 mm. The ED samples were distributed on four groups (each n=80), in which the different bleaching products were applied on enamel (1, Whitestrips; 2, Illumine 15%; 3, Opalescence Xtra Boost) or dentine surfaces (4, mixture of sodium perborate/distilled water). Eighty ED samples were not bleached (control). Color (L*a*b*) of ED was assessed at baseline, subsequently after bleaching and at 3, 6, and 12 months of storage after bleaching (each 20 samples/group). E and D samples were prepared by removing the dentine or enamel layer of ED samples to allow for separate color analysis. Bleaching resulted in a significant color change (Delta E) of ED specimens. Within the observation period, Delta L but not Delta b declined to baseline. L* values of E and D samples also declined and were not significantly different from control samples after 12 months, while b* values did not decrease to baseline. Generally, no differences between the bleaching agents could be observed. Color change of enamel, dentine, and combined ED of in vitro bleached tooth samples is not stable over time with regard to lightness. However, yellowness did not return to baseline within 1 year.

Infant formula and enamel fluorosis A systematic review

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)