Abstract: PURPOSE: This study was aimed to present a functional surgery for the retrieval of displaced root fragment from the maxillary sinus to preserve the alveolar bone, and evaluate its efficiency. METHODS: Patients with foreign bodies displaced into the maxillary sinus referring to our department were collected from 2011.8 to 2014.12. The tooth of each patient, the delay between displacement and retrieval, the oroantral communication (OAC), and previous treatment procedures were recorded. After examination of orthopantomograms and computed tomograms, all patients underwent surgery to create a bone window from anterolateral wall of the maxillary sinus using piezosurgery, and repositioned with micro-plates after removal of foreign body and lesions in the sinus if the lid was large. In case the foreign body was barely detectable, endoscopy was used to help localization. The length of operating time, the duration of pain and swelling, the condition of alveolar ridge, OAC and maxillary sinus, as well as complications were assessed with clinical and imaging examinations. RESULTS: Twelve foreign bodies were extracted successfully, 4 with the help of endoscopy. Nine bone windows were repositioned while 3 others were not, the operations were completed in 20 minutes. Pain disappeared within 5.7 days on average, and swelling lasted for 14.3 days. Nasal bleeding occurred in 3 patients lasting for 0.5 to 5 days. The amount of alveolar bone loss was small and all the OACs were healed well. No patients developed complications such as facial paresthesia, facial asymmetry and infection. CONCLUSIONS: This surgery for the retrieval of displaced root fragment from the maxillary sinus is worthy of wide clinical use due to high successful rate, quick recovery, preservation of alveolar bone and minimal complications.

Key words: Maxillary sinus, Foreign bodies, Bony window reposition, Piezosurgery, Endoscopy