1. Department of Periodontics University of Iowa College of Dentistry Iowa City IA USA
2. Department of Epidemiology University of Iowa College of Public Health Iowa City IA USA
3. Iowa Institute for Oral Health Research University of Iowa College of Dentistry Iowa City IA USA
4. Department of Oral Pathology, Radiology and Medicine University of Iowa College of Dentistry Iowa City IA USA
5. Department of Oral Surgery and Implant Dentistry, School of Dentistry University of Granada Granada Spain