Background and purpose: Mucous retention cysts (MRCs) are radiographically visible as dome-shaped soft-tissue opacities attached to the bony walls of the paranasal sinuses. Their presence may complicate sinus-related surgical procedures. Given the clinical relevance of MRCs in the maxillary sinus and the limited available evidence, this study aimed to determine the prevalence and anatomical distribution of maxillary sinus MRCs using cone-beam computed tomography (CBCT) in Sari, Iran, between 2024 and 2025.
Materials and methods: This descriptive study included patient records and CBCT scans obtained from individuals referred to the Department of Radiology at the Faculty of Dentistry, Mazandaran University of Medical Sciences, between 2024 and 2025 who met the inclusion criteria. Demographic data, including age and sex, and the presence and location of MRCs on CBCT images were recorded. Associations between MRC presence and dental status, endodontic pathology, and periodontal pathology were also examined. Data were analysed using SPSS, with statistical significance set at P < 0.05.
Results: The study included 163 women (55.6%) and 130 men (44.4%), with a mean age of 42.23 years. MRCs were identified in 7.8% of participants. The floor was the most common location, accounting for 52.17% of MRCs. No statistically significant associations were found between MRC presence and age, sex, dental status, endodontic pathology, or periodontal pathology (P > 0.05).
Conclusion: The prevalence of maxillary sinus MRCs in this population in northern Iran was 7.8%, with the sinus floor being the most common anatomical location. Further studies are needed to investigate the clinical implications of these cysts for sinus surgery.