Incidental maxillary sinus findings in orthodontic patients: a radiographic analysis using cone‐beam computed tomography (CBCT)

UNLABELLED: To determine the frequency of incidental maxillary sinus findings using cone-beam computed tomography (CBCT) images made for orthodontic purposes. SETTING AND SAMPLE POPULATION: One hundred thirty-nine consecutive CBCTs from 134 patients treated at the Department of Orthodontics and Dentofacial Orthopedics, University of Bern, Bern, Switzerland. Indications for CBCT imaging included the localization of impacted teeth and root resorption related to impacted teeth. MATERIAL AND METHODS POPULATION: Two experienced observers reviewed the CBCT scans (fields of view: 4 × 4/6 × 6/8 × 8 cm) and recorded all incidental maxillary sinus findings according to standardized categories. The patient's age and gender, the size of the field of view, the season of CBCT image taking, and the thickness of the Schneiderian membrane were evaluated to identify potential influencing factors. RESULTS: In 65 CBCTs (46.8%), incidental maxillary sinus findings were found (interrater classification agreement of 95.7%/95% CI: 90.9-97.9%). Three types of incidental findings were diagnosed: flat mucosal thickening (23.7%), polypoid mucosal thickening (19.4%), and signs of acute sinusitis (3.6%). There was no correlation between the field of view of the CBCT and the number of incidental findings inside the field. There was no correlation between the season during which the CBCT was made and the number of incidental findings. The mean thickness of the mucosal lining in the maxillary sinus was 1.58 mm (95% CI: 1.17-1.98 mm). CONCLUSIONS: A high percentage of the CBCTs made for orthodontic diagnostic purposes exhibit incidental maxillary sinus findings not associated with the primary indication.