en Infectious Diseases Infectious Diseases Original Article Original Article Abstract Background: Diabetic patients are more prone to oral infections and periradicular lesions due to changes in their immune system and qualitative and quantitative changes in normal flora of their mouth. The aim of this study was to evaluate the frequency of periradicular lesions in diabetic patients in Babol, North of Iran. Methods: From October 2011 to March 2012, 135 diabetic patients who referred to the Iranian Diabetes Society - Babol Branch and Endocrinology Clinic of Babol University of Medical Sciences were studied. The demographic features as well as the duration of the diagnosis of diabetes (> 48 months was called long term and < 48 months short term) is the quality of control of their diabetes. For all the patients, panoramic and periapical radiography were performed for the presence of any radicular radiolucent lesions. Vitality test has been done for the recorded teeth except for the root treated ones and periodontal involvement necrotic teeth. The data were collected and analyzed. Results: Periradicular lesions were seen on 90.37% of the patients. The frequency of periradicular lesions in long term patients was 85 (94.4%) and in short term was 37 (82.2%) (p=0.023). The mean of teeth with periradicular lesions in long and short term diabetic patients was 2.63±2.23 and 2.11±1.79, respectively (p=0.174). Conclusion: The results show that the frequency of periradicular lesions in diabetic patients is higher in long-term diabetic patients than the short-term diabetic patients. Diabetes Mellitus, Periradicular lesions, Tooth pulp 22 25 http://caspjim.com/browse.php?a_code=A-10-1-5&slc_lang=en&sid=1 Abbas Mesgarani 1003194753284600206 1003194753284600206 No Department of Endodontic, faculty of Dentistry, Babol University of medical Sciences, Babol, Iran. Sina Haghanifar 1003194753284600207 1003194753284600207 No - Department of Oral & Maxillofacial Radiology, Faculty of Dentistry, Babol University of Medical Sciences, Babol, Iran Narges Eshkevari ehsanimaryam@yahoo.com 1003194753284600208 1003194753284600208 Yes Department of Internal Medicine, Babol University of Medical Sciences, Babol, Iran. Maryam Ehsani 1003194753284600209 1003194753284600209 No Dental Material Research Cneter, Faculty of Dentistry, Babol University of Medical Sciences, Babol, Iran Soraya Khafri 1003194753284600210 1003194753284600210 No Department of Social Medicine and health, Babol University of Medical Sciences, Babol, Iran. Shima Nafarzade 1003194753284600211 1003194753284600211 No Department of Oral Pathology, Faculaty of Dentistry, Babol University of Medical Sciences, Babol, Iran Zahra Damankesh 1003194753284600212 1003194753284600212 No Faculty of Dentistry, Babol University of Medical Sciences, Babol, Iran