1. Department of Prosthodontics and Dows Institute for Dental Research; College of Dentistry and Dental Clinics; University of Iowa; Iowa City IA USA
2. Department of Endodontics; College of Dentistry and Dental Clinics; University of Iowa; Iowa City IA USA
3. Department of Preventive and Community Dentistry; College of Dentistry and Dental Clinics; University of Iowa; Iowa City IA USA