Intraoral Approach for Dental Implant Placement in Pneumatized Maxillary Sinuses With Postoperative Maxillary Cysts: A Report of Two Cases

A postoperative maxillary cyst (POMC) is a delayed complication of the original Caldwell-Luc operation, which was once widely performed to treat chronic rhinosinusitis. Two patients who had previously undergone Caldwell-Luc operations desired dental implant treatment. In both cases, preoperative cone-beam computerized tomography (CBCT) revealed a POMC occupying the entire maxillary sinus on the side where the implants were to be placed. The residual bone height was 3–4 mm. Furthermore, the sinuses were divided into compartments by septum-like structures. An intraoral approach was applied for POMC enucleation and implant placement. The implants were placed with sinus floor penetration due to the small residual bone height. No bone substitute material was grafted in the sinus. Postoperative healing was uneventful. All implants were successfully osseointegrated and performed well (4 and 5 years for each patient). No sinonasal complications were reported. Follow-up CBCTs showed that the exposed implant parts were covered by newly formed bone. The intraoral approach is a feasible option for implant placement in a pneumatized maxillary sinus with POMC.