Background. Dental caries is considered one of the most common oral health diseases. Objectives. The aim of the study was to evaluate the effects of an experimental chitosan/casein gel on enamel demineralization/remineralization in an environment with a high cariogenic challenge. Material and methods.Thirty-six specimens of bovine enamel (4 mm x 3 mm x 2 mm) were ground flat and polished. Then, the specimens were immersed in acetate buffer for 43 h with half of the surface protected (serving as control) and the other half exposed. All demineralized surfaces were randomly assigned into 3 groups (n = 12 per group) according to the type of treatment (G1 - control, G2 - 1.5% chitosan gel with 1.5% casein, and G3 - 1.5% chitosan gel without casein), and the corresponding treatment was applied once a week for 3 weeks. The specimens were also subjected to pH cycles of demineralization/ remineralization and the treatments were performed 3 times at 7-day intervals for a total of 21 days. Surface images were obtained for the analysis of initial roughness and, after the cariogenic challenge, new images were obtained to evaluate the final roughness, volume loss and wear profile using laser confocal microscopy. After the analyses, the specimens were cut and the depth of demineralization was measured. The data were analyzed using the Kruskal-Wallis analysis of variance (ANOVA) and the Tukey's test. Results. While the chitosan gel with casein showed a similar loss to the control group (p > 0.05), both gels resulted in similar volume loss (p > 0.05). There were no statistical differences regarding the wear profile, surface roughness and depth of demineralization between the groups (p > 0.05). Conclusions. The chitosan gel reduced volume loss of the demineralized enamel without significantly impacting the surface smoothness.
