1. a Professor, Department of Orthodontics, University of Iowa, Iowa City, Iowa
2. b Dental student, College of Dentistry, University of Iowa, Iowa City, Iowa
3. c Associate Professor, General Dentistry, Baylor, College of Dentistry, Texas A&M Health Science System, Dallas, Tex
4. d Research Assistant, DOWS Research Institute, University of Iowa, Iowa City, Iowa
5. e Associate Professor, Department of Preventive and Community Dentistry, College of Dentistry, University of Iowa, Iowa City, Iowa