Abstract: PURPOSE: To investigate the value of using con-beam computer tomography (CBCT) to evaluate bone volume in the edentulous area of posterior maxilla, and guide sinus floor elevation. METHODS: Twenty eight patients who planed to receive dental implant in the posterior maxilla underwent CBCT scan. After analysis of residual bone height, 19 patients with 5-10 mm bone height below the sinus floor underwent transcrestal sinus floor elevation, while 7 patients with less than 5 mm bone height below the sinus floor underwent lateral window sinus floor elevation. The treatment outcomes were assessed postoperatively. RESULTS: CBCT detected bone deficiency in the posterior maxillary alveolar bone in 26 patients, mucus cyst of maxillary sinus in 1 patient and sinus septa in 2 patients. Nineteen patients underwent transcrestal sinus floor elevation, and 7 patients underwent lateral window sinus floor elevation. All patients completed final dental restorations, and the restorations achieved satisfactory function and esthetic. CONCLUSIONS: CBCT imaging plays an important role in determining bone quality in posterior maxilla and guiding sinus floor elevation.

Key words: CBCT, Maxillary sinus floor elevation, Dental implant