The displacement of dental implants into the maxillary sinus is a common complication of maxillary implant surgery, and it is therefore important to investigate how such displacements occur and methods for removing the implants. We describe 11 cases in which dental implants were accidentally displaced into the maxillary sinus from 2005 to 2015. All cases were referred to our clinic from private dental clinics. Five males and 6 females, whose ages ranged from 32 to 81 years, participated in the study. The implants were parallel in design in eight cases, and tapered in design in three cases. In seven of the 11 cases, the implant had been placed in combination with a socket lift in the maxilla. Bone height at the displaced implant sites was 3.6±1.7 mm as measured by computed tomography. One dental implant was displaced into the maxillary sinus during implant placement. In three cases, the implants were displaced into the maxillary sinus in the post-first stage surgery period, and in four cases, during the second stage surgery. Two cases were sleeping implants. In one case, displacement occurred while the implant was being extracted because of peri-implantitis.
Removal of implants from the maxillary sinus was achieved using three different approaches: access through the bone crestal defect in two cases, fenestration of the anterior wall of the maxillary sinus in seven cases, and endoscopic sinus surgery in one case. Fenestration of the anterior wall of the maxillary sinus is most commonly used because it is a simple technique that allows good surgical access. Endoscopic sinus surgery is the preferred choice for patients with chronic sinusitis. A crestal approach should only be used when a large defect is present on the alveolar ridge.
Displaced dental implants in the maxillary sinus should be removed as soon as possible to avoid the development of maxillary sinusitis. Careful clinical and radiographic evaluation and appropriate treatment planning should take place before removal is undertaken.