Assessment of Relationship Between Maxillary Sinus Floor and Maxillary Posterior Teeth Root Tips Position

Inclusion Criteria: * CBCT scans for patients aged from 20 to 70 years. * CBCT scans for patients with at least first and second maxillary premolars and first and secon maxillary molars present on one side (fully erupted teeth and fully formed apices). * CBCT scans taken for pre-evaluation of endodontic treatment, implant placement, impacted teeth removal, obstructive sleep apnea treatment, pre-orthodontic or pre-prosthetic evaluation. * Good quality CBCT scans. Exclusion Criteria: * CBCT scans for patients with no maxillary posterior teeth. * CBCT scans for patients with history of maxillary sinus operation (including sinus floor elevation). * CBCT scans for patients with sign or history of non-odontogenic sinusitis, including air-fluid level, thickening of all the sinus walls and maxillary sinus polyps. * CBCT scans for patients with syndromes, congenital or developmental anomalies. * CBCT scans for patients with bone disease. * CBCT scans for patients with traumatic injuries to the maxillofacial region. * Low quality CBCT scans (any artifact).