Surgical solution for retrograde peri-implantitis: A case report on managing implant-associated apical infection

Retrograde peri-implantitis (RPI) represents an infrequent yet clinically consequential postoperative complication characterized by apical pathology around an implant exhibiting otherwise intact coronal osseointegration. This case report details the diagnosis and management of active RPI in a 66-year-old female with history of hypertension and diabetes mellitus, presenting with persistent postoperative pain, swelling, and sinus tract formation one month after delayed implant placement in a site previously affected by apical periodontitis. Radiographic and CBCT evaluation revealed a well-defined periapical radiolucency with preservation of marginal bone levels. Initial conservative therapy resulted in transient symptom relief, with recurrence following prosthetic rehabilitation. Definitive management involved surgical access, thorough mechanical debridement, chemical surface detoxification, and guided bone regeneration using combined autogenous and allogeneic grafting beneath a resorbable membrane. The intervention yielded uneventful healing, progressive radiographic bone regeneration, and complete lesion, without compromising implant stability. This case highlights the critical importance of early recognition, comprehensive diagnostic assessment, and timely regenerative surgical intervention for achieving predictable outcomes in RPI, particularly in sites with prior periapical pathology.