Abstract: Objective: To investigate the anatomical variation of maxillary sinus septa by cone-beam CT and provide guidance to sinus floor elevation. Methods: Cone-beam CT scans of 300 adult subjects were evaluated to assess the prevalence, location, height, orientation, and morphology of the maxillary sinus septa. The data were analyzed with SPSS17.0. Results: Sinus septa were present in 80 out of 300 subjects (26.7%). The prevalence of septa was not significantly correlated with gender, age, and presence of tooth loss. 41.4% of the septa were located in the middle of maxillary sinus. The mean height of sinus septa was (6.60±4.08)mm and (6.81±4.24)mm in the right and left maxillary sinus, respectively. The mean length of sinus septa was (9.28±2.99)mm and (9.00±3.00)mm in the right and left maxillary sinus, respectively. 85.2% of the septa orientated buccopalatally. 80.5% of the septa were complete. Conclusion: 26.7% of population in Qinghai have maxillary sinus septa. Much more attention should be paid in maxillary sinus floor elevation to avoid complications.

Key words: Maxillary sinus septa, Cone-beam , CT, Maxillary sinus elevation , High altitude