1. Department of Oral Radiology, Department of Oral Radiology, Faculty of Dentistry, Minia University, El Menia, Egypt.
2. Department of Oral and Maxillofacial Radiology and Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Korea.
3. Division of Oral and Maxillofacial Radiology, Department of Periodontics and Oral Medicine, School of Dentistry, University of Michigan, Ann Arbor, USA.