Dental plaque microbiota profiles of children with caries-free and caries-active dentition

Microbiota comparisons between healthy and diseased dental tissues have accentuated the importance of cultivating and identifying bacterial species that play a role in the initiation and progression of dental caries. The objective of this study was to evaluate the bacterial community composition in caries-active and caries-free children.

Supragingival plaque samples were collected from 64 caries-active and 64 caries-free Middle Eastern children. The hypervariable V3-V4 of the bacterial 16S rRNA gene was sequenced with Human Oral Microbe Identification using Next Generation Sequencing. Microbial community structure and composition analyses were performed by processing operational taxonomic units. Bioinformatic analyses, including analysis of similarity, alpha and beta diversities, and principal coordinate analysis, were carried out.

Diversity indices did not find differences between the caries-active and caries-free groups (p > 0.05). Similarity analysis demonstrated that the microbiota composition did not differ between the two groups. Comparative analysis at the species level revealed a significantly higher relative abundance of Leptotrichia shahii, Prevotella melaninogenica, Veillonella dispar, Leptotrichia HOT 498, and Streptococcus mutans in caries-active children (p < 0.05). Corynebacterium matruchotii, Lautropia mirabilis, Neisseria elongata, and Corynebacterium durum were relatively more abundant in the caries-free group (p < 0.05). Species belonging to the Leptotrichia, Prevotella, and Veillonella genera were significantly predominant in the caries-active subjects.

In view of the lack of a clear association between Corynebacterium spp. and dental caries status in the literature, the predominance of these species in caries-free children warrants further research to understand their possible role in a health-associated microbial community.

Understanding the relationship between specific bacteria present in dental biofilms and health and disease is essential for preventing and combating dental caries. Using advanced next generation sequencing techniques, the present study demonstrated the complexity of the caries microbiome and identified species/genera whose virulence or protective properties should be further explored.