Effect of different materials on rehardening of initial enamel lesions

The aim of this in vitro study is to evaluate the rehardening of the incipient enamel lesions by the application of the different materials, after the demineralization and remineralization cycle.In this study, 56 samples from 28 caries-free bovine teeth were obtained and teeth were allocated into 7 groups containing 8 samples for each. After the analysis of the initial microhardness values of all samples, citric acid was applied on the enamel surfaces forming active enamel erosion lesions to exhibit the clinical conditions. After the etching, no material was applied on the samples in the control group. Clearfil SE Bond as a resin bonding material was applied to the group 2 whereas Fissurit FX and Helioseal F as fissur sealants to the groups,of 3 and 4, Icon® as a resin infiltrant with different eching times of 60, 90 and 120 seconds with Icon-etch to the groups of 5, 6 and 7 respectively. All the samples were cycled for 1 week through a daily procedure of the demineralization for 5*5 minutes in 15 hours and the continous remineralization for the remaining 9 hours. After this cycle, the teeth were sectioned and evaluated quantitatively by cross-sectional microhardness testing. Each sample was assessed by a microhardness tester with a Vickers diamond. Indentations were made on 5 depths of 20, 30, 50, 70 and 90 ? m on each sample. 3 different indentations were made for each depth and the microhardness values of the samples were indicated as the mean of these values.The statistical analysis of the results were calculated by ?one way ANOVA? and post hoc ?Tukey? tests.In conclusion, significant changes between initial microhardness values and the values of all samples at 20 ? m , 30 ? m, 50 ? m, 70 ? m and 90 ? m were observed. The microhardness values of group 2 (Clearfil SE Bond) did not show significant differences with values of the control group at the depth of 20 ? m, 30 ? m and 50 ? m. Clearfil SE Bond was found to be unsuccessful for the rehardening of the incipient enamel lesions. There was no statistical meaning for the difference between the initial microhardness values and the mean microhardness values of samples at 90 ? m indicating that Icon was insufficient for the rehardening at this depth. There was also no statistical meaning for the change between the groups of the different appIication times of Icon-etch at any depth.