Microbial invasion of dentinal tubules: a literature review and a new perspective

Various features of endodontic microbiology have been investigated using various methods. The aim of the present study was to review the existing literature on endodontic microbiology in dentinal tubules, and to present the features of two cases with endodontic pathology. An electronic search was performed with a search string created ad hoc. Ex vivo and in vitro studies were included, recording the method of detection and characteristics of analyzed teeth. Twenty studies fulfilled the inclusion criteria. Seven of them were in vitro laboratory studies on teeth inoculated after extraction, while 13 were ex vivo studies on extracted, infected teeth. Endodontic bacteria were detected in dentinal tubules, both as single units and as biofilm aggregates. Two similar in vitro cases presented here corroborate the latter findings. A number of techniques have been utilized to observe bacteria in the dentinal tubule ecosystem. Dentinal tubules are favorable niches for microbial survival, either in the form of monomicrobial or polymicrobial communities.