Purpose: Dislocation of implants into the maxillary sinus typically occurs during surgery or in the early postoperative period. This case study presents an instance of implant dislocation that occurred after 30 years under functional loading due to peri-implantitis.
Materials and methods: An 87-year-old woman presented with a loosened fixed partial denture, revealing a missing implant in the maxillary left second molar site upon clinical examination. The patient showed no symptoms of sinusitis. Imaging confirmed the dislocation of the implant, along with a pathological radiodensity filling the sinus. Maxillary sinus revision was performed via a bone lid under conscious sedation. The implant was removed along with a polypous mass, and the latter was sent for pathological examination. Following debridement, disinfection (3% hydrogen peroxide, photodynamic decontamination) was performed. The oroantral fistula was closed through double-layer closure with a pedicled connective tissue flap and a mucoperiosteal flap. Two months after surgery, sinus floor elevation using the layering technique and implant placement were performed. After 3 months, the implants were exposed, and the restoration was placed 6 weeks later.
Results: Histopathological examination confirmed chronic sinusitis with the presence of polyps. A 2-month follow-up CBCT scan revealed a healthy sinus with an open ostium. Subsequent procedures went uneventfully.
Conclusions: Progressive peri-implantitis in the posterior maxilla can lead to the dislocation of dental implants into the sinus and subsequent chronic sinusitis. Removing the implant through a bone lid from the lateral sinus wall with simultaneous sinus revision is an effective way to treat this condition and allows for later bone grafting and implant placement.