1. Department of Restorative Dentistry, School of Dentistry; Oregon Health and Science University; Portland OR
2. Iowa Institute for Oral Health Research, College of Dentistry; The University of Iowa; Iowa City IA
3. Department of Prosthodontics, College of Dentistry; The University of Iowa; Iowa City IA
4. Department of Periodontics, College of Dentistry; The University of Iowa; Iowa City IA
5. College of Dentistry; University of Nebraska Medical Center; Lincoln NE
6. College of Dentistry; University of Illinois at Chicago; IL