Abstract:

Objective To study the difference in the flora structure and gene function of dental plaque in caries-free and caries-active preschool children by 16S rRNA sequencing. Methods After oral examination of 96 preschool children aged 3-6 years, they were divided into 3 groups according to their decayed, missing and filled surface (dmfs) index: group CF with no caries (n=31), group ECC with moderate early childhood caries (n=29) and group SECC with severe early childhood caries (n=36). Dental plaques were collected, and DNA was extracted and then underwent metagenomic sequencing by Illumina HiSeq 2 500. The bacterial community structure was analyzed by Qiime. Results A total of 12 phyla, 31 classes, 31 orders, 50 families, 92 genera and 1 104 species were found in the dental plaque samples of the three groups, most of which belonged to 9 dominant genera, including Streptococcus, Veillonella, etc. The microbial diversity of the dental plaques in the three groups was similar (P > 0.05). Veillonella, Lactobacillus, Megasphaera, and Scardovia in the SECC group were significantly higher than those in the other two groups. There was a significant correlation between the decayed, missing and filled surface (dmfs) index and the genus. Bifidobacterium, Veillonella, Lactobacillus had a positive correlation with the dmfs index, while Eikenella had a negative correlation with the dmfs index. Indicator species analysis showed that Atopobium, Veillonella, Megasphaera, Scardovia, Lactobacillus and Bifidobacterium had high indicative values in the SECC group. Conclusion There are significant differences in plaque microbiota among preschool children with different caries sensitivities. Veillonella, Megasphaera, Scardovia, Lactobacillus, Bifidobacterium and Atopobium may be the indicator genera of severe early children caries.

Key words: preschool children, caries, caries sensitivity, early childhood caries, severe early childhood caries, dental plaque, microbiota, high-throughput sequencing, Streptococcus, Veillonella

摘要：

目的 通过高通量测序技术研究不同龋敏感程度学龄前儿童牙菌斑的菌群结构。方法 对96名3~6岁儿童进行口腔检查,根据乳牙龋失补牙面指数分为无龋组(31名)、低龄儿童龋组（29名）和重度低龄儿童龋组(36名),采集牙菌斑样本,提取DNA,使用Illumina HiSeq 2 500测序平台进行高通量测序,Qiime分析细菌群落结构差异。结果 3组牙菌斑标本共发现12门31纲31目50科92属1 104种细菌,绝大多数属于链球菌属（Streptococcus）、韦荣菌属（Veillonella）等9个优势菌属,3组微生物多样性相似（P > 0.05）。重度低龄儿童龋组中韦荣菌属、乳杆菌属（Lactobacillus）、巨球形菌属（Megasphaera）、斯卡多维亚菌属（Scardovia）等菌属丰度高于其余两组。双歧杆菌属（Bifidobacterium）、韦荣菌属、乳杆菌属等与dmfs呈正相关,艾肯菌属（Eikenella）与dmfs呈负相关。Indicator Species分析显示奇异菌属（Atopobium）、韦荣菌属、巨球形菌属、斯卡多维亚菌属、乳杆菌属、双歧杆菌属在重度低龄儿童龋组指示值较高。结论 不同龋敏感程度儿童牙菌斑菌群结构存在差异。韦荣菌属、巨球形菌属、斯卡多维亚菌属、乳杆菌属、双歧杆菌属、奇异菌属可能是重度低龄儿童龋发生的指示菌属。

关键词: 学龄前儿童, 龋病, 龋敏感程度, 低龄儿童龋, 重度低龄儿童龋, 牙菌斑, 微生物菌群, 高通量测序, 链球菌属, 韦荣菌属