1. Department of Periodontics, College of Dentistry, University of Iowa, Iowa City, IA, USA
2. Private practice, Saint George, UT, USA
3. Department of Orthodontics, University of Illinois at Chicago, Chicago, IL, USA
4. Biostatistics Consulting Center, College of Public Health, University of Iowa, Iowa City, IA, USA
5. Department of Family Dentistry, College of Dentistry, University of Iowa, Iowa City, IA, USA