Er,Cr:YSGG LASER-TREATED ENAMEL DEMINERALIZATION

Objectives: This study evaluated the effect of different parameters of the Er,Cr:YSGG laser irradiation on enamel mineral loss in a simulated caries model. Methods: Forty five enamel samples obtained from third molar teeth (3 x 3 mm) were randomly divided into 5 groups (n=9): G1−Er,Cr:YSGG laser at 0.25 W, 20 Hz, 2.8 J/cm², G2−Er,Cr:YSGG laser at 0.50 W, 20 Hz, 5.7 J/cm², G3−Er,Cr:YSGG laser at 0.75 W, 20 Hz, 8.5 J/cm², G4−NaF dentifrice (positive control), G5−No treatment (negative control). After the irradiation treatment, samples were submitted to two weeks of pH-cycling, consisting of daily immersion in demineralizing (6 h) and remineralizing (17 h) solutions. After the acid challenge, the samples were assessed by cross-sectional microhardness (25 g, 30 sec) at different depths from the enamel surface. ANOVA and Student Newman Keuls tests were performed (α=5%). Results: The percentage of lesion inhibition for each group was: G1−37%, G2−38%, G3−64% and G4−50.5% respectively. Regarding the relative mineral loss values (µm x vol%), Groups G1 (1392 ± 522) and G2 (1292 ± 657) did not differ significantly from each other, but both were higher than group G3 (753 ± 287); the groups irradiated with the Er,Cr:YSGG laser did not differ from group G4. Conclusions: Although the findings of the present study revealed that the Er,Cr:YSGG laser irradiation at 8.5 J/cm² can be an alternative for the enhancement of enamel acid resistance, lower energy densities also produced a cariostatic potential comparable to the use of fluoride dentifrice.