1. Health Policy Research Program, Public Policy Center, Department of Preventive and Community Dentistry, University of Iowa, Iowa City, Iowa.
2. Public Policy Center, University of Iowa, Iowa City, Iowa.
3. Department of Epidemiology, University of Iowa, Iowa City, Iowa.
4. Department of Plastic and Reconstructive Surgery, University of Iowa, Iowa City, Iowa.
5. Departments of Speech Pathology and Audiology and Otolaryngology, University of Iowa, Iowa City, Iowa.
6. Departments of Pediatrics, Pediatric Dentistry, and Biological Sciences, University of Iowa, Iowa City, Iowa