OBJECTIVES: This study assessed the efficacy of photodynamic therapy (PDT) with toluidine blue (TB) for decontamination of resorbable membranes inoculated with Streptococcus mutans (S. mutans). MATERIALS AND METHODS: In this in vitro study, Mucoderm and Jason resorbable membranes were cut into 15 pieces each, and were inoculated with S. mutans at 10 RESULTS: In both membrane types, the difference in colony count was significant among the three subgroups (P=0.002). The lowest colony count was noted in the CHX subgroup, and the highest was recorded in the PBS subgroup. PDT caused a significant reduction in colony count compared with the negative control group (P=0.002). Significant differences were found between all three groups in pairwise comparisons (P<
0.05). The efficacy of PDT was not significantly different for decontamination of the two membrane types (P=635). CONCLUSION: PDT with 635 nm diode laser and TB had optimal efficacy (although inferior to CHX) for decontamination of both Jason and Mucoderm resorbable membranes inoculated with S. mutans.