Apical actinomycosis as a continuum of intraradicular and extraradicular infection: case report and critical review on its involvement with treatment failure.

This article reports a case of extraradicular actinomycosis that clearly formed a continuum with the intraradicular infection. Histobacteriologic and histopathologic analyses of the root tip and attached apical periodontitis lesion obtained by surgery from a tooth with persistent disease were performed to look for the possible reasons for persistent disease. Although no stainable bacteria were observed in the apparently well-treated main canal, apical ramifications were clogged with dense bacterial biofilms that were contiguous to extraradicular actinomycotic aggregates. A critical review of the literature revealed that there is no clear evidence that apical actinomycosis is indeed an independent entity leading to persistent apical periodontitis lesions.