Method: Planktonic suspensions were analyzed in four different groups: C-L- (no die, no light; control group), C+L- (three concentrations of curcumin:0.75, 1.5 and 3.0 mg /mL), C-L+ ( three light dosimetries:15, 30, and 45J/cm2) and the PDT group (C+L+). Aliquots of each group were transferred to Petri dishes for counting of colony forming units (CFU/mL). The data were analyzed by Kruskal-Wallis and Student Newman Keels test (p<0.05).
Result: In comparison to control group, the isolated effect of the light (30J/cm2, p = 0.01 and 45J /cm2, p = 0.01) showed a reduction of 5% to those wavelengths. The effect of the dye showed no influence on the bacterial reduction. In relation to PDT group the associations of (C)1.5 mg/mL and (L) 30J/cm2 (p = 0, 04), (C)1.5mg / mL and (L) 45J/cm2 (p = 0.03) and (C)3mg/mL and (L) 45J/cm2 (p = 0.03) showed a bacterial reduction of 39.9%, 29% and 38.1%, respectively.
Conclusion: The results demonstrated that, in the parameters studied, PDT has demonstrated effectiveness in the inactivation of S. mutans.