Objective: To analyze the differences between the bacterial diversities in the saliva of caries-free and caries-susceptible adolescents through polymerase chain reaction (PCR)-denaturing gradient gel electrophoresis (DGGE).
Methods: Twenty adolescent subjects aged 12-18 years were recruited and subdivided into two groups: caries-free adolescents (n = 10) and caries-susceptible adolescents (n = 10). Saliva samples were collected. Total DNA was isolated directly from each sample. A portion of the 16S rRNA gene locus was PCR-amplified by using universal primers. Microbial diversity was analyzed through PCR-DGGE.
Results: Analyzing the DGGE profile, we found that the composition of the saliva microbiome exhibited great intra-individual differences; the average band numbers of the caries-free adolescent group and the caries-susceptible adolescent group were 32.5 ± 3.7 and 27.3 ± 3.4, respectively. The differences between the groups were statistically significant (P = 0.008). Shannon-Wiener's indexes of the caries-susceptible adolescent group and the caries-free adolescent group were 2.5 ± 0.2 and 2.6 ± 0.2, respectively, but the differences between the groups were not significant (P = 0.405). Clustering analysis results suggested that most of the samples in the same group clustered together; this observation showed a high community structure similarity.
Conclusion: The microbial diversity and complexity of bacteria in saliva are significantly higher in caries-free adolescents than in caries-susceptible adolescents. During caries development, bacterial diversity in the saliva likely decreases.
目的: 通过聚合酶链反应（PCR）-变性梯度凝胶电泳（DGGE）分析无龋及高龋青少年的唾液细菌多样性的差异。
方法: 随机选择20名12~18岁青少年分为无龋组（n=10）和高龋组（n=10），收集其非刺激性唾液，提取细菌全基因组DNA，采用通用引物进行PCR扩增，采用Quantity One软件对扩增产物DGGE指纹图谱进行分析。
结果: DGGE图谱分析表明：唾液细菌的组成具有个体差异性；唾液样本中检测到的条带数无龋组为32.5±3.7，高龋组为27.3±3.4，差异有统计学意义（P=0.008）。高龋组和无龋组的Shannon-Wiener's指数分别为2.5±0.2和2.6±0.2，二者之间的差异无统计学意义（P=0.405）。聚类分析发现，同组内大部分样本聚类位置相近，群落结构表现出较高的相似性；不同组的大部分样本未聚类在一起，群落结构呈现出一定的差异。
结论: 无龋青少年唾液细菌的多样性显著高于高龋青少年，唾液细菌的多样性在龋病发展过程中有减少的趋势。