1. Department of Preventive and Restorative Dental Science UCSF School of Dentistry San Francisco California USA
2. PG Endodontic Resident UCSF School of Dentistry San Francisco California USA
3. Faculty of Dentistry University of Toronto Toronto Ontario Canada
4. Clinical Epidemiology & Health Care Research, Institute of Health Policy, Management and Evaluation University of Toronto Toronto Ontario Canada
5. UCSF School of Dentistry San Francisco California USA
6. Head Division of Endodontics and Research, Director, Department of Dentistry, Faculty of Advanced Training Program in Orofacial, Faculty of Dentistry University of Toronto, Mount Sinai Hospital Toronto Ontario Canada