Unveiling Periapical Actinomycosis: A Rare Extraradicular Infection.

Actinomycosis is an insidious infection caused by the facultative anaerobic Gram-positive bacterium Actinomyces, commonly found in the oral microbiome. Among its manifestations, periapical actinomycosis stands out as a rare subtype within cervicofacial actinomycosis, speculated to play a role in the persistence of periapical radiolucencies following root canal therapy. Instances of this occurrence often arise from disruptions in epithelial continuity, stemming from surgical procedures, trauma, or prior infections, paving the way for deep microbial infiltration. A 35-year-old woman presented with persistent pain and swelling in the premolar region of her mandible. Examination unveiled a radiolucent lesion in an endodontically treated premolar. The tooth remained symptomatic, and the draining sinus tract persisted despite multiple attempts at disinfecting and re-medicating the canal. A subsequent apicoectomy was performed, yielding promising outcomes, with satisfactory periapical healing observed at both the 6- and 12-month follow-up evaluations.