Surgical endodontics for management of progressive actinomycosis.

Actinomycosis is caused by gram-positive, branching, filamentous, anaerobic bacteria of the genus Actinomyces. This case report describes treatment of a 35-year-old woman who had a progressive apical lesion after nonsurgical endodontic retreatment of her maxillary left lateral incisor. The area had localized soft tissue swelling, and the tooth was sensitive to percussion. Radiographic evaluation showed a large apical lesion with a clear margin. After treatment options, including extraction, were discussed, the patient chose to preserve the tooth through endodontic surgery. Root-end resection, canal preparation, and filling with calcium-enriched mixture cement were performed. Histopathologic examination of surgical specimens revealed a radicular cyst associated with actinomycosis. At an 18-month follow-up, the patient was symptom free and bone healing was almost completed. Periradicular actinomycosis is one of the most common reasons for the failure of nonsurgical endodontic treatment and retreatment. If a tooth is nonresponsive to nonsurgical endodontic treatments, apical actinomycotic infection should be suspected and a surgical approach should be planned to obtain a successful outcome.