目的:探讨以血卟啉单醚(HMME)为光敏剂的光动力疗法(PDT)在龋病预防中的作用.方法:采用变形链球菌接种Wistar大鼠磨牙,给予致龋饲料,建立龋病模型.将大鼠分为5组,分别用10 ng/L HMME-PDT(A组)、20ng/L HMME-PDT(B组)、40 ng/L HMME-PDT(C组)、0.2 g/L氟化钠水溶液(D组)和生理盐水(E组)处理各组大鼠磨牙,每周1次,连续4周,记录大鼠口腔变形链球菌生长情况.处死大鼠后用扫描电镜观察各组磨牙龋损区的表面形态.结果:第1周和第2周各组菌落数差异均无统计学意义(P>0.05),第3周B组、C组菌落数低于E组,C组低于D组.(P<0.05).第4周A组、B组和C组菌落数均低于E组(P<0.05或P<0.01),C组菌落数低于A组、B组和D组(P<0.05),扫描电镜观察发现C组与D组龋损破坏程度最轻且表面相对平滑.结论:PDT具有抑制龋病的作用,将为龋病的预防提供一种新的有效途径.%Objective: To study the role of photodynamic therapy (PDT) using hematoporphyrin monomethyl ether (HMME) as photosensitizer in the prevention of dental caries by establishing the caries of rat model. Methods: The molars of Wistar rats were inoculated with Streptococcus mutans (S. mutans). Rats were fed with caries - inducing diet to establish the rat model of caries. Rats were divided into five groups. Molars of rats were treated with 10 ng/L HMME-PDT (group A), 20 ng/L HMME-PDT (group B), 40 ng/L HMME-PDT (group C), 0.2 g/L sodium fluoride as positive control (group D) and 0.9％ sterile physiological saline as negative control (group E) once a week for four weeks. The changes of S. mutans were recorded every week. The rats were then killed. The surface morphology of dental caries of rats was observed by scanning electron microscope. Results: The colony count in each group were no significant difference in the first and second weeks (P ＞ 0.05). The colony counts were significantly reduced in group B and C compared with those of group E in the third week (P ＜ 0.05). In the fourth week the colony counts were significantly reduced in group A, B and C compared with those of group E (P ＜ 0.05 or P＜0.01). Meanwhile the colony count of group C was significantly lower than that of group A and B (P ＜ 0.05). The tooth enamel was found to he damaged most slightly in group C and D, and the tooth surfaces of the two groups were relatively smooth. Conclusion : PDT has anticaries effect in vivo, which is thought to be a promising method in the prevention of caries.
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