In vitro evaluation of erbium, chromium:yttrium–scandium–gallium–garnet laser-treated enamel demineralization

This study evaluated the effect of different parameters of erbium, chromium:yttrium–scandium–gallium–garnet (Er,Cr:YSGG) laser irradiation on enamel mineral loss in a simulated caries model. Forty-five enamel samples obtained from third molar teeth (3 mm× 3 mm) were randomly divided into five 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—sodium fluoride (NaF) dentifrice (positive control); G5—no treatment (negative control). After irradiation, the samples were submitted to 2 weeks of pH cycling. After the acid challenge, the samples were assessed by cross-sectional microhardness at different depths from the enamel surface. Analysis of variance (ANOVA) and Student–Newman–Keuls tests were performed (α = 5%). The percentage of lesion inhibition for each group was: G1 37%; G2 38%; G3 64%, and G4 50.5%. Regarding the relative mineral loss values (micrometers × volume percent), groups G1 (1,392 ± 522) and G2 (1,292 ± 657) did not differ significantly from each other, but both had higher values than group G3 (753 ± 287); the groups irradiated with Er,Cr:YSGG laser did not differ from group G4. Although the findings of the study revealed that Er,Cr:YSGG laser irradiation at 8.5 J/cm² can be an alternative for the enhancement of the enamel’s resistance to acid, lower energy densities also produced a cariostatic potential comparable to the use of fluoride dentifrice.