Abstract: Objective: To observe the location and diameter of vessel through the lateral wall of maxillary sinus and assess the risk of bleeding during sinus elevation by cone-beam computed tomography. Methods: CBCT images of maxilla in 104 patients(208 maxillary sinus)with maxillary posterior teeth loss from 2016 to 2017 were selected and studied. The distance on lateral wall of maxillary sinus from the lower border of the vessel running through lateral wall to the bottom of the sinus was measured and its relationship to the operating window was estimated the risk of bleeding. Results: The average distance from the blood vessel to the sinus floor was 8.26±3.43mm. 26.4% of blood vessels were located within the area of operating window, posing potential risk of injury, and 2.2% of blood vessels whose diameter were greater than 2mm might cause serious bleeding. Conclusion: The probability of bleeding caused by injury of blood vessel is low in maxillary sinus lateral wall fenestration. The lateral wall distance within 7mm between upper edge of window and the bottom of the maxillary sinus is relatively safe. Preoperative application of CBCT can guide the fenestration and thus reduce the risk of vascular injury.

Key words: Sinus floor elevation, Fenestration, Blood vessels, Cone-beam computed tomography