ABSTRACT
Objective The purpose of this study was to assess the antibacterial effects of hematoporphyrin monomethylether-photodynamic therapy (HMME-PDT) on Enterococcus faecalis within infected simulated lateral canals in vitro with different energy.Methods Simulated lateral canals were prepared on extracted teeth.The specimens were infected with Enterococcus faecalis and then were randomly divided into eight groups.Group A was considered as negative control,its specimens were irrigated with physiological saline.Group B was the positive control,they were irrigated with 5.25％ NaClO.Other groups were incubated with HMME at concentration of 40 μg/ml for 5 min,followed by exposure to light at 532 nm for 120 s with different powers in a spiral pattern.Groups were named C-H,in corresponding with the power 50,60,70,80,90,100 mW.Microbial samples (the dentin chips from simulated lateral canals) were taken before and after the treatments.The survival fractions in each simulated lateral canal was calculated by counting colony-forming units(CFUs).Results 1.The HMME-PDT-treated groups resulted in a significant reduction in the number of E.faecalis in simulated lateral canals compared with the negative controls(P＜0.05).2.The antibacterial effects of group D、E、F、G、H were higher than the NaCl0-irrigated group(P＜0.05).3.The difference of antibacterial effects between the F、G、H groups was in significant(P＞0.05).Conclusion HMME-PDT had significant inhibitive efficacy on Enterococcus faecalis within infected simulated lateral canals and the efficacy was power-depended.It can play the best effect with the power of 80 mW.