1. Department of Endodontics, School of Dentistry, Ardabil University of Medical Science, Ardabil, Iran
2. Department of Endodontics, School of Dentistry, Tabriz University of Medical Science, Tabriz, Iran
3. Department of Pediatric Dentistry, Ardabil University of Medical Science, Ardabil, Iran
4. Department of Radiology, University of Southern California, Los Angeles, USA