Study of the effective of efflux pump inhibitors in photodynamic therapy inhibition the cariogenic bacteria in dental plaque biofilms / 国际生物医学工程杂志

Objective To Study the effect of efflux pump-inhibitors(EPI)-Verapamil in photodynamic therapy (PDT) using hematoporphyrin monomethylether (HMME) as photosensitizer on the cariogenic bacteria in dental plaque biofilms.Methods According to the administrator order of the verapamil and photosensitizer in PDT,streptococcus mutans,streptococcus sanguis,eosinophilic lactobacillus and actinomyces viscosus were used to establish the dental plaque biofilm model.The experiment was divided into five groups,group A was incubated with the photosensitizer and verapamil group,group B using verapamil before incubated the photosensitize,group C suing photosensitizer before incubated verapamil,group D with PDT only,group E was control group.After laser treatment,the influence of the dental plaque biofilms was observed by confocal laser scanning microscope.Results As saline-treated group is a group of normal the dental plaque biofilms.In PDT only group,compared with the saline group,red fluorescence increased significantly,the bacteria lose accumulation capacity,and were isolated and scattered in dispersed state.In PDT plus verapamil group,compared with only PDT group,green staining increased,bacterial activity increased.In group B,cells were incubated with verapamil before incubated the photosensitizer group,green staining increased significantly,red fluorescence reduced,indicating live bacteria increased,and bacteria activity was significantly increased.Conclusion PDT is an effective method in eliminating cariogenic bacteria of dental plaque biofilms.Bacterial efflux pump inhibitors can lower HMME-PDT inhibition cariogenic bacteria in dental plaque biofilm,and pre-verapamil administration could significantly inhibit the effect of PDT treatment of dental caries.

Antibacterial efficacy of HMME-PDT on Enterococcus faecalis within infected simulated lateral canals in vitro model with different energy / 国际生物医学工程杂志

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.