Inclusion Criteria:  CBCT scans of Adult Egyptian population older than 18 years. CBCT scans showing the floor of the maxillary sinus. No artifacts in the maxillary region, which will affect the quality of the image  Exclusion Criteria:  CBCT sans of completely edentulous maxilla. Patients with trauma, craniofacial surgery, orthognathic surgery and malignancies involving the maxillofacial region. Patients with cleft palate and other craniofacial anomalies. Dental implants in the alveolar region of premolars and molars due to artifacts.