Affiliation: | 1. Department of Dentomaxillofacial Radiology, School of Dentistry, Hamadan University of Medical Sciences, , Hamadan, Iran;2. Department of Epidemiology & Biostatistics, Research Center for Health Sciences, School of Public Health, Hamadan University of Medical Sciences, , Hamadan, Iran;3. Department of Dentomaxillofacial Radiology, Dental Branch, Islamic Azad University, , Tehran, Iran;4. Department of periodontology, Dental Branch, Islamic Azad University, , Tehran, Iran |