Accidental Displacement of Dental Implants into the Maxillary Sinus: A Report of Nine Cases

PURPOSE: To report on the clinical, radiological, and anatomical features of patients suffering accidental displacement of dental implants into the maxillary sinus. MATERIALS AND METHODS: A retrospective observational study of nine cases of dental implant displacement into the maxillary sinus was made. Data concerning patients' features, diagnostic criteria, and treatment performed were collected. RESULTS: Mean patient age was 56.7 years, and men predominated (6 : 3). Implant displacement was diagnosed in all cases by clinical and radiological examination. In seven patients, the implant was surgically removed without complications. Only three patients reported sinus symptoms following displacement. CONCLUSIONS: The displacement of implants into the maxillary sinus is usually related with a poor surgical planning or inadequate surgical technique. Because of the anatomy and physiology of the posterior area of the maxilla, it is essential to ensure good primary stability in order to avoid this complication. If the implant migrates into the maxillary sinus, it should be removed in order to avoid sinus pathology.