Supragingival Plaque Microbial Signatures Between Radiation Related Caries and Common Caries.

OBJECTIVES

The clinical manifestations of radiation-related caries (RRC) differ considerably from those of common caries. This study aims to investigate potential differences in the microbial compositions of supragingival plaque between RRC and common caries.

METHODS

Supragingival plaque samples from 10 RRC and 10 patients with common caries were analyzed using Type IIB Restriction-site Associated DNA sequencing for Microbiome (2bRAD-M). Analyses of microbial diversity, relative abundance and composition were performed. LEfSe analysis was employed to identify differentially abundant species between the 2 groups. Additionally, 24 RRC and 33 common caries samples were examined using qRT-PCR. Species indicators of RRC were identified through random forest analysis. KEGG and COG functional prediction analyses were conducted to assess microbial functional pathways.

RESULTS

2bRAD-M sequencing revealed a significant enrichment of Prevotella conceptionensis, Treponema vincentii, and 4 Nanoperiomorbus species in the RRC group. These findings were further validated by LEfSe and qRT-PCR analyses, which confirmed the dominance of P. conceptionensis in RRC. Random forest analysis identified P. conceptionensis as a potential biomarker for RRC. The bacterial abundance in RRC samples was higher than in common caries, particularly in pathways related to glucose metabolism, including 6-phosphofructokinase activity and sugar transferases involved in LPS biosynthesis.

CONCLUSIONS

This study uniquely identifies distinct microbial signatures in supragingival plaque associated with RRC compared to common caries. Prevotella conceptionensis was identified as a specific pathogenic bacterium linked to RRC. The underlying mechanisms may involve enhanced microbial glucose metabolism and an inflammatory response mediated by ferroptosis.