Background <p>The maxillary sinus shows considerable anatomical variation influenced by dentition status and craniofacial factors. Understanding these variations is essential for surgical planning and implant dentistry. This study aimed to evaluate maxillary sinus volume and septa morphology in relation to dentition status, age, and sex using cone-beam computed tomography (CBCT) and semi-automated segmentation.</p> Methods <p>CBCT scans of 84 patients (168 maxillary sinuses) were retrospectively analyzed. Sinus volumes were measured using ITK-SNAP, while septa presence, location, orientation, and height were assessed on multiplanar reformatted images. Patients were categorized as dentate, partially dentate, or edentulous. Statistical analyses were performed using appropriate parametric and non-parametric tests, with significance set at <i>p</i> &lt; 0.05.</p> Results <p>Total maxillary sinus volume differed significantly according to dentition status, with the smallest volumes observed in edentulous individuals (<i>p</i> &lt; 0.001). Male patients exhibited significantly larger sinus volumes than females bilaterally (<i>p</i> &lt; 0.05). Septa were most frequently located in the middle region and predominantly exhibited a coronal orientation. Septa presence showed a significant association with dentition status on the left side (<i>p</i> &lt; 0.05), whereas septa height did not differ significantly among dentition groups. No significant correlations were found between septa characteristics and age or sex.</p> Conclusion <p>Maxillary sinus volume is strongly influenced by dentition status and sex, while septa prevalence shows a partial association with dental status. Semi-automated CBCT-based volumetric analysis provides a reliable method for assessing sinus anatomy and may support safer and more predictable outcomes in sinus augmentation and implant-related procedures.</p>