Introduction:
Chronic sinusitis can be caused by both laryngological and dental factors. The frequency of odontogenic sinusitis (OS) in the last decades has been increasing and seems to be underrated. The unique developmental and microbiological factors causing OS require a different therapeutic approach.

Material and methods:
This study evaluated tomography examinations of 500 patients with a clinical diagnosis of chronic sinusitis. The patients were referred by larygologists, neurologists, and maxillofacial surgeons. The scans were reanalyzed in view of the presence of odontogenic and laryngological pathologies.

Results:
Among the 500 patients, 19.6% showed no inflammatory changes in the mucosa of the paranasal sinuses. All patient groups had numerous teeth missing, ranging from 27.3% to 33.2%. The most common odontogenic pathologies were periapical changes (28.8%) and the presence of teeth after improper endodontic treatment (24.2%). In the group in question dental implants (0.4%) and maxillary sinus augmentation (2.8%) were marginal etiological factors.

Conclusions:
Computed tomography allows a thorough assessment of odontogenic changes. Obstruction of the ostiomeatal complex does not have direct influence on OS development. 43.2% of patients with chronic sinusitis have OS. It can be diagnosed in 50.8% of isolated right, 39.0% of isolated left and 57.8% of bilateral maxillary sinusitis patients. The results of this study can be used by dentists, maxillofacial surgeons and otolaryngologists to improve the standard of diagnosis and treatment in cases of chronic odontogenic sinusitis.