1. Department of Dental Public Health Sciences, School of Dentistry, Box 357475, University of Washington, Seattle, Washington 98195, Department of Epidemiology, School of Dentistry, Box 357475, University of Washington, Seattle, Washington 98195
2. Department of Dental Public Health Sciences, School of Dentistry, Box 357475, University of Washington, Seattle, Washington 98195, Department of Biostatistics, School of Dentistry, Box 357475, University of Washington, Seattle, Washington 98195
3. Restorative Dentistry, School of Dentistry, Box 357475, University of Washington, Seattle, Washington 98195
4. Oral and Maxillofacial Surgery, School of Dentistry, Box 357475, University of Washington, Seattle, Washington 98195