Abstract: Objectives:To analyze the effect of covering oral prosthesis membrane in apical resection of different bone defect areas. Methods: The shadow of digital periapical radiographs of 20 patients with bone defect covered by oral restorative membrane during apicectomy were measured before and 6 months after operation, and the healing of the lesions was analyzed combined with clinical manifestations. According to the diameter range (x) of the apical shadow of the 28 teeth before operation, they are divided into 4 groups: x＜4 mm, 4 mm≤x＜6 mm, 6 mm≤x＜8 mm, x≥8 mm. Results: The disappearance of clinical symptoms or imaging manifestations of reduction or disappearance of the periapical transmission area was regarded as success. 19 patients and 26 teeth were successfully treated. Among them, the failure of 1 case and 2 teeth belonged to the fourth group. The clinical manifestations were as follows: There is still discomfort on percussion, and discomfort on palpation. X-ray film shows that the shadow of the root tip has not been reduced. Conclusion: In the case of apical shadow less than 8 mm, it is better to cover the defect area with prosthodontic membrane.

Key words: apical resection, oral prostheyic membrance, periapical inflammation, bone defect, bone healing