粪肠球菌根管感染模型的扫描电镜观察

目的:建立粪肠球菌根管感染模型,观察粪肠球菌感染根管的情况和生存形式。方法:选择因牙周病拔除的上颌中切牙16颗,于釉牙骨质界处截除牙冠,根管预备后高温高压灭菌。接种McFarland为2的粪肠球菌菌液于无菌根管内,37℃恒温水浴培养箱中培养,隔日根管内更换新鲜菌液。在感染后1、3、5d及1、2、3周随机抽取2个标本行扫描电镜检查。结果:粪肠球菌形成生物膜定植于根管牙本质壁上并侵入牙本质小管,随着感染时间的增加,生物膜的形态发生变化,细菌侵入牙本质小管的深度加深。21d后可观察到成熟、稳定的生物膜形成。结论:单一的粪肠球菌菌种在离体牙根管内可形成生物膜,并侵入牙本质小管造成深层的感染。

Scanning electron microscopic study on model of infection of Enterococcus faecalis in root canal

Objective: To establish in vitro root canal model infected by Enterococcus faecalis and to observe the situation of infected root canals and the live pattern of Enterococcus faecalis.Methods:Sixteen maxillary central incisor teeth extracted for periodontal disease were collected,crowns of the teeth were cut at enamelo-cemental junction.After preparation and sterilization,these specimens were inoculated with Enterococcus faecalis suspension with a concentration of McFarland 2 and the suspension was replaced for new every other day.They were cultivated in thermostatic waterbath incubator at 37℃.1 day,3 days,5 days,1 week,2 weeks and 3 weeks after infection,2 samples were randomly selected for scanning electron microscopy.Results:Enterococcus faecalis biofilm got colonization on root canal dentin walls and invaded dentinal tubules.With the time of infection increasing,the form of biofilms was changed,and the depth of bacteria invaded the dentinal tubules was increased.The formation of mature biofilm was observed after 21 days.Conclusion:Single strain of Enterococcus faecalis in vitro root canals can form biofilms,and invade dentinal tubules to cause deep layer infection.