Prevalence and location of maxillary sinus septa in the Taiwanese population and relationship to the absence of molars.

OBJECTIVES: Understanding the septum structure of the sinus is necessary for correct implant placement in the maxilla if sinus encroachment is required. The exact mechanism that controls septum development is unclear, although a role for the irregular pneumatization of the sinus floor following tooth loss has been suggested. The aims of this study were to examine the prevalence and location of sinus septa in the Taiwanese population and to determine whether there is a relationship between the presence of septa and the absence of molars. MATERIALS AND METHODS: Using computed tomography (CT) scans of sinuses obtained from 423 subjects (216 women and 207 men, mean age 53.65 years), septum morphology and its correlation with the presence of molars was examined. RESULTS: About 30% of subjects (124/423) had sinus septa, corresponding to 20.45% of all sinus segments detected (173/846). Fifty-nine patients had multiple septa, giving a prevalence of septa of 22.93%. Septa were located most frequently in the regions of the first and second molars. The prevalence was not related to tooth loss (edentulous, partially edentulous, or dentate maxillary segments). Logistic regression analysis showed that men were significantly more likely to have septa than were women (OR=1.67; P=0.019). CONCLUSIONS: In the 423 Taiwanese subjects tested, the prevalence of septum was 29.31% according to the subjects and 22.93% according to the sinus segments. The most frequent location of septa was in the region of the first and secondary molars. No correlation was observed between the presence of septa and the absence of molars.