1. Department of Restoration and
2. Department of Stomatology, Faculty of Dentistry, Université de Montréal, Montreal, Canada;
3. Department of Prosthodontics, Peking University, School and Hospital of Stomatology, Beijing, China;
4. Faculty of Dentistry, McGill University, Montreal, Canada; and
5. Department of Epidemiology and Biostatistics and Occupational Health and Department of Oncology, Faculty of Medicine, McGill University, 3550 University St., Montreal, Quebec H3A2A7, Canada