Mandibular Actinomycosis Disguised as a Periapical Lesion.

 is a rare chronic suppurative granulomatous disease caused by commensal bacteria of Actinomyces species. We report an unusual case of a 20-year-old male patient presenting with pain and swelling to the right lower posterior teeth for a few months. Radiographs revealed a well-defined osteolytic lesion extending from the periapical region of the right mandibular first premolar to the right mandibular second molar.