Quantitative microbiome profiling of root canal samples from apical periodontitis patients

This study investigates the root canal microbiota of apical periodontitis (AP) using spike-in-based absolute quantitative 16S rRNA gene sequencing. We analyzed 53 root canal samples from patients with primary apical periodontitis to simultaneously determine absolute microbial load and relative microbial abundance. The aim was to address the challenge of high inter-individual microbial heterogeneity and its inconsistent associations with clinical features, including percussion tenderness, large periapical lesions, and sinus tract formation.