ABSTRACT Aims To investigate the associations between oral‐rinse microbiota and distinct oral conditions, and further evaluate its potential ability to distinguish periodontitis severity. Methods Oral‐rinse‐sourced microbiota with 16S ribosomal RNA sequencing from 3770 adults in US National Health and Nutrition Examination Survey 2009–2012 were analysed across oral health, caries, periodontitis, co‐existing caries and periodontitis and edentulism. Diagnostic potential of the oral‐rinse microbiota for periodontitis severity was evaluated using multi‐class random forest (RF) model with internal validation and external validation in an independent cohort ( n = 392). Results Oral condition accounted for substantial variance in oral‐rinse microbiota, revealing disease or tooth loss–associated shifts. Increasing acidogenic/aciduric taxa ( Veillonella , Lactobacillus , Atopobium ) or periodontitis‐associated taxa ( Filifactor , Treponema , Tannerella ) were identified in caries‐only or periodontitis‐only groups, respectively, while the co‐existing disease group showed overlapping shifts. Taxa shifted dose‐dependently with increasing periodontitis severity. The RF model achieved moderate performance in identifying severe periodontitis, with the area under the receiver operating characteristic curve (AUROC) of 0.81 (0.75–0.87) internally and 0.83 (0.77–0.88) externally. Key contributing taxa aligned with established periodontitis‐associated genera, supporting model interpretability. Conclusion Based on our results, oral‐rinse microbiota captures disease‐specific signatures across oral conditions, supporting its potential as a non‐invasive tool to monitor oral microbial ecology and assess periodontitis severity at the population level.
Xie et al. (Wed,) studied this question.