1. Department of Periodontics and Dental Hygiene University of Texas Health Science Center at Houston School of Dentistry Houston Texas USA
2. Department of Clinical Sciences University of Nevada School of Dental Medicine Las Vegas Nevada USA
3. Biostatistics and Epidemiology Research Design Core, Center for Clinical and Translational Sciences Department of Internal Medicine Medical School The University of Texas Health Science Center at Houston Houston Texas USA
4. University of Iowa College of Dentistry and Dental Clinics Iowa City Iowa USA