Parvimonas micra(P.micra) is a gram-positive anaerobic coccus that is often found in infected root canals of periapical periodontitis. Based on 16S rRNA PCR, correlations exist between P.micra and Fusobacterium nucleatum(F. nucleatum) and Prevotella intermedia and Peptostreptcoccus anaerobius. The detection rate of P.micra after F.nucleatum indicates that the former has obvious proteolytic activity. It can initiate or participate in inflammation by stimulating the release of some inflammatory mediators in macrophages, especially the formation of persistent inflammation. P.micra can use glutathione to produce volatile sulfur compounds, which may be related to root canal stench. This article summarizes research on the distribution of P.micra in the infected root canal, correlation between P.micra, and other dominant bacteria, and pathogenicity of P.micra.
