Supragingival microbial profiles in caries-free and caries-active adolescents treated with fixed orthodontics.

Background: Dental caries occur primarily due to the formation of excessive dental plaque biofilm on teeth surfaces. This study aims to analyze the supragingival microbial profiles of permanent teeth in caries-free and caries-active adolescents with fixed orthodontic appliances and to identify bacterial biomarkers that may be indicative of caries activity in specific population.

Methods: Twelve-year-old adolescents treated with fixed orthodontic appliances were selected as the study population, with 5 caries-free and 5 caries-active subjects. Supragingival plaque samples were collected from the first permanent molars for the 16S rRNA high-throughput sequencing analysis of the V3-V4 region.

Results: There was no significant difference in alpha diversity and beta diversity between the caries-free and caries-active groups. LEfSe analysis showed that differentially abundant genera such as (), and species in the caries-free group, and (), , and species in the caries-active group, could be identified as potential biomarkers ( < 0.05). Co-occurrence network analysis revealed significant synergistic relationships among bacteria, with spp displaying the strongest associations with other genera.

Conclusions: Increases in and bacteria from the genera and were strongly associated with the caries-active status of adolescents undergoing orthodontic treatment with fixed appliances. While increases in and were linked to caries-free status. These findings highlight the importance of managing the oral microbiome in adolescents with fixed orthodontic appliances, as certain bacterial species can serve as indicators of caries risk.