Tehran University of Medical Sciences Journal of Craniomaxillofacial Research 2345-5489 9 1 2022 10 01 23 30 Majid Mirmohammadkhani Social Determinants of Health Research Center, Semnan University of Medical Sciences, Semnan, Iran AND Department of Epidemiology and Biostatistics, Semnan University of Medical Sciences, Semnan, Iran. Marjan Tofighian Department of Oral and Maxillofacial Pathology, Dental School, Semnan University of Medical Sciences, Semnan, Iran. Kamyar Mansori Department of Epidemiology and Biostatistics, School of Medicine, Zanjan University of Medical Sciences, Zanjan, Iran. Omid Mirmohammadkhani Department of Oral and Maxillofacial Pathology, School of Dentistry, Semnan University of Medical Sciences, Semnan, Iran. 2022 04 19 2022 09 09 Background: The aim of this study was to evaluate the histopathological findings of oral lesions in patients referred to the pathology department of Kosar Hospital of Semnan city (Iran) in 2012-2018. Materials and Methods: This population-based cross-sectional study was concocted on the histopathological findings of oral lesions 137 patients referred to the pathology department of Kosar Hospital of Semnan city (Iran) in 2012-2018. The sampling method was census. The data collection tool was a check including demographics and dentistry (type of dental lesion, location of the lesion, malignancy of lesions, origin of dental lesions, side of the lesion conflict, jaw involved, anterior-posterior position and type of biopsy). SPSS24 was used for data analysis and a significance level of less than 0.05 was considered. Results: The most common type and the most common location of oral lesions were periapical cyst (16.7%) and periapical (28.3%); respectively. The most common sources of oral lesions were related to inflammation and connective tissue with 27.5 and 26.8%, respectively. Mandible (47.8%) was the most common involved jaw and 5.1% of reported lesions were malignant. In addition, the prevalence of periapical cyst (78.3 vs. 21.7%) and pyogenic granuloma (82.4 vs. 17.6%) were significantly higher in women than men (P-Value=0.035).The highest rates of periapical cyst (43.5%)and pyogenic granuloma (58.5%) were observed in the age group ≤30 and 31-40 years; respectively(P-Value=0.013). Conclusion: This study suggests that the female patients and over 40 years should be more careful to check for periapical cyst. However, more detailed studies with higher sample sizes are recommended. https://jcr.tums.ac.ir/index.php/jcr/article/view/406 https://jcr.tums.ac.ir/index.php/jcr/article/download/406/345