Explantation, Guided Bone Regeneration, and Digitally Planned Implant Replacement in Advanced Peri-Implantitis: A Case Report With 12-Month Follow-Up.

Abstract

When advanced peri-implantitis affects several implants, it is necessary to decide which implants to retain and which to remove before planning any reconstruction. This case highlights the indications for explantation in advanced peri-implantitis, the role of guided bone regeneration in reconstructing compromised sites, and the benefits of digitally planned placement of new implants. The 12-month follow-up underscores the clinical relevance of sustained peri-implant health. We present the clinical case of a 65-year-old man with arterial hypertension and type 2 diabetes mellitus under treatment (glycated hemoglobin 6% at baseline, non-smoker) who presented with a fracture of his upper fixed prosthesis and esthetic concerns. Generalized stage IV grade B periodontitis was diagnosed, along with peri-implantitis in the seven existing implants, whose defects were classified on cone beam computed tomography between classes Ib and IIIc. Six implants were assigned a hopeless prognosis, and one was given a guarded prognosis. After initial periodontal and prosthetic therapy, six implants were removed, with forceps in the maxilla and with a trephine followed by forceps in the mandible, and the root remnants were extracted. The retained implant was treated by implantoplasty and surface decontamination. The explantation sites were regenerated with allograft and a resorbable collagen membrane. Four months later, 12 implants were placed with static guided surgery, using a mucosa-supported guide in the maxilla and two bone-supported guides for trimming and placement in the mandible, all achieving an insertion torque above 35 N·cm. At position 44, plasma rich in growth factors mixed with autologous bone was added. Rehabilitation was completed with screw-retained fixed prostheses in both arches. At 12 months after delivery of the definitive prostheses, the probing depth remained between 3 and 4 mm in all the implants, with no bleeding on probing and no evident radiographic progression of marginal bone loss compared to the initial record. This case demonstrates that a stepwise sequence of selective explantation, regeneration, and guided placement of new implants is feasible in advanced peri-implantitis; however, as a single observation in a well-controlled, non-smoking patient, it demonstrates short-term clinical feasibility only and cannot establish effectiveness, predictability, or reproducibility.