(PR94) Metagenomic study of the microbiomes of root canals of teeth with true-combined endodontic-periodontal lesions associated with clinical features

Few metagenomic studies have associated the microbial communities with the clinical features presented by patients. The aim of this study was to determine the bacterial microbiota present in the root canals (RCs) of teeth with true combined endodontic-periodontal lesions and their relationship with the clinical features using NGS. Bacterial samples were collected from the RCs of 10 patients undergoing endodontic treatment. DNA was extracted from the samples and the microbiome examined using the Illumina MiSeq platform to focus on the V3-V4 hypervariable region of the 16S rRNA gene, . The composition and diversity of microbial communities in the RCs and their relationships with clinical features were analyzed. A total of 300 different operational taxonomic units (OTUs) were identified in the samples and nine phyla and 70 genera were identified. Comparative studies considered gender, age, periapical lesion (PL) size and periodontal pocket (PP) depth. The most abundant genera in women were Parvimonas (40.13%), Enterococcus (13.78%), and Stomatobaculum (6.26%). Males showed a predominance of Enterococcus (45.22%), Parvimonas (11.13%) and Fretibacterium (9.78%). Parvimonas (48.23%) predominated in patients aged 40 years old and up, while Enterococcus predominated in patients below 40 (42.58%). Clinical criteria such as PP <6, and PL <3 revealed a predominance of Parvimonas, Enterococcus and Streptococcus. It was concluded that there is a close relationship between several clinical features and the proportion of specific bacterial genera in teeth with true-combined endodontic-periodontal lesions.