Classification and management of antral septa for maxillary sinus augmentation.

The antral septum, a commonly found anatomical variation, has been related to the occurrence of membrane perforation during sinus augmentation. The aims of this study were to review features of antral septa and to propose a classification system and options for managing antral septa during sinus augmentation. A literature search of the PubMed database was performed to identify articles investigating antral septa. Manuscripts using three-dimensional computed tomography, providing direct measurements of human subjects or cadavers, and reporting features of antral septa besides the prevalence were included. Antral septa presented in approximately 20% to 35% of maxillary sinuses. Single septum was much more common than multiple septa. Mediolaterally (transversely) oriented septa were more frequently found than anteroposteriorly (sagittally) oriented septa. Their size varies and commonly increases from the lateral to medial segment within one septum. The proposed classification consists of three categories--easy (E), moderate (M), and difficult (D)--based on the location, number, orientation, and size of antral septa. Corresponding treatment approaches were suggested for each category. Sinus augmentation is complicated by the presence of antral septa, the features of which determine the degree of surgical difficulty. Based on the results of the included studies and clinical experiences, a classification system and treatment strategies of antral septa were proposed and may assist surgeons in managing antral septa during sinus augmentation.