Actinomyces radicidentis is a species in the genus of Actinomyces, first isolated from infected root canals of teeth. ITs type strain is CCUG 36733. Once characterised, it has since been found to be present in failed root canal treatments. Its pathogenicity has been suggested to be due to an ability to form cell aggregates, held together by embedding in an extracellular matrix in host tissues. Like other pathogenic Actinomyces, by collectively finding itself in a protected biofilm environment can evade elimination by host defenses, including phagocytosis.