Anti-erosive effect of fluoride solutions associated with Aminomethacrylate copolymer: a randomized crossover in situ study

In order to understand and characterize the preventive mechanism of action. The objective of this work was to measure the effect of the association of solutions in the anti-erosion potential of the acquired pellicle over enamel and dentin, in the face of erosive challenges, using a randomized cross-over in situ study. For this, twelve previously selected volunteers installed an intraoral device containing six specimens of bovine teeth (three in enamel and three in dentin) and waited 5 minutes for the formation of the initial acquired pellicle. Afterwards, they rinsed the mouth with one of the solutions to be tested (1 minute), and remained for 30 minutes without eating using the palatal device, to allow the maturation of the acquired pellicle. Then, the specimens were subjected to the erosive challenge with 0.03% hydrochloric acid, pH 2.3 for 3 minutes extra-orally. These steps were repeated, implementing an erosive cycle, with six applications of the treatment solutions, being: Ultrapure water (negative control); F; S; AMC; FS; AMC associated with F; AMC associated with FS. Each solution was tested in a phase with the same volunteers, with a two-day washout interval. After the end of cycling, the specimens were removed from the device, four (two enamel and two dentin) separated for analysis microbiopsy of enamel and dentin for later reading of the concentration of calcium and phosphorus in the acid collected by method colorimetric in spectrophotometer which were later converted into erosive loss values in micrometer (μm). The enamel specimens were also subjected to analysis of surface microhardness in enamel to calculate the percentage of microhardness reduction (%KHNred). The two remaining specimens (one enamel and one dentin) were stored for further reading of the concentration of KOH-soluble fluoride (µg/cm²). The data obtained were submitted to statistical analysis ANOVA of repeated measures (Rm-ANOVA) and Tukey (5%). The analysis of calculated erosive loss for the enamel substrate was: C (8,46-3 ± 0,7-3 ) A, S (8,61-3 ± 0,1-2 ) A, AMC (7,76-3 ± 0,9-3 ) AB, F (7,15-3 ± 0,7-3 ) B, FS (7,82-3 ± 0,1-2 ) AB, AMC+F (5,98-3 ± 0,1-2 ) C, AMC+FS (6,86-3 ± 0,1-2 ) BC. For the dentin substrate, the calculated erosive loss values were: C (11,2-3 ± 0,7-3 ) A, S (11,2-3 ± 0,1-2 ) A, AMC (9,86-3 ± 0,8-3 ) B, F (9,5 -3 ± 0,5-3 ) B, FS (9,7-3 ± 0,8-3 ) B, AMC+F (7,0 -3 ± 0,1-2 ) C, AMC+FS (8,13-3 ± 0,1-2 ) D. As for the percentage of KHN reduction against enamel erosion measured by microhardness, the groups containing polymer and fluoridated solutions (AMC+F and AMC+FS) performed better. The F, FS, and AMC groups showed intermediate and significantly greater protective potential than the negative control. The KOH-soluble fluoride concentration values for the enamel were: C = S = AMC < F < AMC+F ≤ AMC+FS ≤ FS and in dentin were: C = S = AMC < F = AMC+F = AMC+FS < FS. It is concluded that there was no difference in the concentration of KOH-soluble fluoride in enamel and dentin between the groups that did not contain fluoride and the FS group exhibited a higher concentration of fluoride adsorbed on the surface. The Aminomethacrylate increased the protective effect of fluoride solutions in the presence of acquired pellicle on enamel and dentin, being a promising agent to be incorporated into solutions to control erosive dental wear. (AU)