Frequency of the Maxillary Sinus Mucous Retention Cyst in Digital Panoramic Radiographs of the Patients attending to the Dental Faculty of Rasht during 2012-2013

Panoramic radiographs taken for dental purposes provide an opportunity for dentists to identify non-symptomatic maxillary sinus abnormalities. The aim of this study was to evaluate the frequency of mucous retention cysts (MRCs) of maxillary sinus and some associated risk factors in the patients attending to the dental faculty of Guilan. In this cross-sectional study, digital panoramic radiographs of patients referred to the department of radiology, dental school of Guilan, from October 2012 to October 2013 were evaluated. A total of 800 digital panoramic radiographs (200 for each season) were evaluated by one oral and maxillofacial radiologist to detect MRC in maxillary sinus. Frequency of MRC and some associated risk factors were assessed. Statistical analysis of the data was performed by Chi-square test. Among the 800 evaluated digital panoramic radiographs, 444 subjects were females (55.5%) and 356 were males (44.5%) aged 8 to 81 (36.02±14.71) years. The frequency of the MRC was 4% (32 radiograghs). Of 32 maxillary sinus MRCs, 13 (40.625%) were right-sided, 13 (40.625%) were left-sided and 6 (18.750%) were bilateral. Although, MRC presented no statistically significant correlation to age (P=0.444), the highest frequency was seen in fifth (6.1%) and third (4.7%) decades. Frequency in males (6.2%) was significantly higher than in females (2.3%); (P=0.005). The highest frequency of MRC was detected in spring (7.5%) and autumn (5%). In this study the frequency of MRC in males was higher than in females and was seen mostly single and unilateral. Also the highest frequency of MRC in spring might emphasize the effect of allergic factors on MRC prevalence, mentioned in some previous studies.