第一恒磨牙窝沟菌群组成

Microflora of dental plaque in pits and fissures of first permanent molars

目的 分析儿童第一恒磨牙窝沟菌群的组成,为进一步分析窝沟致龋细菌与龋的关系打下基础。方法 取健康第一恒磨牙咬合面窝沟处菌斑接种于BHIS、MSA和RogosaSL培养基,分析菌群构成;API 2 0Strep试剂盒鉴定链球菌。结果 窝沟菌斑中以镜检革兰氏染色阳性杆菌居多,占总菌的(6 1 .87±4 .85 ) %,其次是革兰氏染色阳性球菌(37.6 8±5 .6 1 ) %。菌斑中的优势链球菌为变形链球菌(S .mutans) (1 8.2 6±4 .73) %、血链球菌(S .sanguis) (3.32±1 .2 9) %、缓症链球菌Ⅰ型(S .mitisⅠ) (2 .5 5±0 .96 ) %和口腔链球菌(S .oralis) (0 .76±0 .36 ) %。结论 儿童健康恒磨牙窝沟菌群中,杆菌数多于球菌;这些杆菌与疾病特别是龋病的关系有待于进一步的研究。

Objective To investigate composition of microflora in pits and fissures of healthy first permanent molars,and to provide a baseline data for further studies.Methods Twenty school-aged children were enrolled in the study.Plaque samples were taken from 20 sound fissures of first permanent molars.The predominant bacteria were isolated by using conventional plating methods.Supplemented Brain Heart Infusion Agar (BHIS) was used to determine the total bacteria count.Streptococcus spp.were isolated by using the mitis salivarius agar (MSA).Lactobacillus spp.were isolated on Rogosa agar (Rogosa SL).Streptococcus spp.were identified by means of API 20 Strep commercial kit.Results Of the isolates obtained from the sound fissure, 61.87± 4.85% were gram-positive rods and 37.68± 5.61% were gram-positive cocci.The predominant Streptococci in the plaque were S.mutans ( 18.26± 4.73)%,S.sanguis ( 3.32± 1.29)% ,S.mitisⅠ ( 2.55± 0.96)% and S.oralis ( 0.76± 0.36)%.Conclusion Gram-positive rods isolated were much more than the Gram-positive cocci in quantity.Further studies are needed to give a clear idea whether and how the rods may play an important role in the oral disease especially caries.