Materials and Methods: Twenty-five enamel slabs were divided into three treatment groups: light-activated bleaching, laser-activated bleaching, and control. The baseline data were recorded for enamel microhardness (Vickers microhardness [VMH]) and surface roughness (Roughness average, Ra). The specimens were cured for 10 min upon hydrogen peroxide application for the light-activated bleaching group and activated with a laser source, 8 cycles, 10 s per cycle for the laser-activated group. The changes in VMH and Ra at days 1, 7, and 28 were evaluated. Kruskal-Wallis, Friedman, Wilcoxon, and Mann-Whitney tests were used to analyze both VMH and Ra between the treatment groups at different time intervals.

Results: There were a significant reduction in VMH values and significant differences between days 1, 7, and 28 against the baseline in the light-activated bleaching group (P = 0.001). The Ra values revealed significant differences in both light- (P = 0.001) and laser-activated (P = 0.033) groups.

Objective: The objective of this study is to determine the antimicrobial effects of MP, AV, and MP + AV in comparison with Ca(OH)2 against E. faecalis, as an intracanal medicament.

Materials and Methods: Antimicrobial activity of MP, AV, MP + AV, Ca(OH)2, and dimethyl sulfoxide was tested against E. faecalis using antimicrobial sensitivity testing, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC). The results were analyzed by Kruskal-Wallis test with Mann-Whitney post hoc test and repeated measures analysis of variance with Bonferroni post hoc test (P < 0.05).

Results: For agar well-diffusion method, MP + AV gave maximum inhibition zone diameter (mean: 8.11 ± 0.015 mm), MP (mean: 6.21 ± 0.046 mm, Ca(OH)2 (mean: 5.5 ± 0.006), and AV (mean: 5.05 ± 0.012) with P < 0.05. MIC for MP + AV was 2 mg/ml, MP at 8 mg/ml, Ca(OH)2 at 8 mg/ml, and AV at 16 mg/ml. The MBC for MP + AV is at 4 mg/ml, MP at 16 mg/ml, Ca(OH)2 at 16 mg/ml, and AV at 32 mg/ml.