The Effect of Different Window-preparation Approaches on the Clinical Outcomes of Lateral Sinus Floor Elevation

Inclusion Criteria: * age ≥18 years; * one or more maxillary posterior teeth were missing, and the healing time was more than 3 months; * complete basic information and detailed operation records; * available CBCT images before surgery, immediately after surgery, and 6 months after surgery; * RBH ≤6 mm shown by CBCT at T0 at the site of the missing tooth； * no systematic diseases and no untreated periapical disease or periodontal disease before surgery. Exclusion Criteria: * (1) maxillary lesions have not been properly treated； * present or past medication of bisphosphonates; * pregnancy or lactation; * present or past radiotherapy of head and neck cancer within 5 years; * acute and chronic inflammation in the maxillary sinus; * in need of additional vertical or horizontal bone augmentation besides LSFE with endo-sinus graft materials; * heavy smoker (\>20 cigarettes/day at the time of surgery).