Purpose: The purpose of this study was to compare the microbial colony composition in the saliva of children with and without caries in a regional ethnic group (Baoan) in China.
Materials and methods: The recruited participants were aged 5-9 years old and from Bonan district, China. Eighteen samples (10 from subjects with caries and 8 from subjects without caries) were taken and divided into two groups respectively (BC and BH). These samples characterized by 16S ribosomal RNA (16S rRNA) were studied using cloning technology. A total of 900 clones were sequenced and 860 qualified reads were obtained for evaluating bacterial diversity.
Results: The overall operational taxonomic units (OTUs) distribution of 16S rRNA gene clones indicated the difference between dental caries and caries-associated salivary microorganisms. The phyla of the samples with caries were the same as caries-free samples, namely: Firmicutes, Proteobacteria, Actinobacteria, Fusobacteria and Bacteroidetes. The family Micrococcaceae and the genus Rothia showed significant difference (p<0.05) between BC and BH groups, the amount of which were higher in BC group.
Conclusion: Our data demonstrated that, at the phyla level, the predominant phyla in saliva of Baoan Children are relatively constant. However, at the genus level, the composition of microbial colony in dental caries and healthy teeth were of significant difference.
Clinical relevance: The attention on the prevention of caries in children should not be only paid to the traditional cariogenic bacteria, but also to the microbial colony composition of saliva.