为探讨光动力疗法(PDT)对人工龋菌斑生物膜的的作用,选用变形链球菌在体外构建符合人体生理环境的人工龋模型,选择血卟啉单甲醚(HMME)为光敏剂,激光照射选用半导体激光器,波长为635 nm,输出功率为10 mW,能量密度为12.47 J/cm2。用50个釉质块形成人工龋模型,随机分成5组,每组10块,分别为:1) HMME组;2) 激光照射组;3) PDT防龋组;4) 0.05%(质量分数)洗必泰处理组为阳性对照;5) 0.9%(质量分数)生理盐水处理组为阴性对照。依照平板细菌计数法观察不同处理方法对人工龋菌斑生物膜变形链球菌活力的影响。结果表明,与阴性对照组相比,HMME组人工龋口腔生物膜中变形链球菌数量(CFU/mL)无显著性差异(P>0.05),杀菌率仅为0.05%;激光照射和0.05%洗必泰均能使人工龋口腔生物膜中变形链球菌数量显著减少(P<0.05),杀菌率分别为59.94%和58.52%;而PDT防龋处理可使人工龋口腔生物膜中变形链球菌数量更为显著减少(P<0.05),杀菌率高达99.36%。HMME-PDT可有效杀灭人工龋口腔生物膜中的变形链球菌,为预防龋病提供了一种有效的新途径。

To discuss the effects of photodynamic therapy (PDT) on the mainly oral cariogenic biofilm bacteria,an artificial caries model was built consistent with the physiological environment with streptococcus mutans. Hematoporyrin monomethyl ether was selected for photosensitizer. 635 nm diode laser was used for irradiation,with delivered power 10 mW and energy density 12.47 J/cm2. Fifty enamel blocks were formed artificial caries models. Separated them into five groups random,ten blocks each group:1) Group of HMME;2) Group of laser;3) Group of PDT;4) Positive control group of 0.05% chlorhexidine;and 5) Negative control group of 0.9% saline. The influence of on dental plaque oral biofilm of artificial dental caries was observed according to plate counting of bacteria method. Compared to negative control group,the number of streptococcus mutans (CFU/mL) of oral biofilm in artificial caries model of HMME group was not significant different (P>0.05),with the bactericidal rate only 0.05%;laser irradiation and 0.05% chlorhexidine made the number of streptococcus mutans of oral biofilm in artificial caries model significantly reduced (P<0.05),with the bactericidal rate 59.94% and 58.52% separately;after PDT treatment against dental caries,the number of streptococcus mutans of oral biofilm in artificial caries model significantly reduced (P<0.05),the bactericidal rate up to 99.36%. HMME-PDT is an effective method in eliminate streptococcus mutans of oral biofilm for artificial caries model. It provides an new effective approach for dental caries prevention.