1. Department of Periodontics, University of Pennsylvania, Philadelphia, PA 19104, USA
2. General Practice Residency, Albert Einstein Medical Center, Philadelphia, PA 19141, USA
3. Think Dental Learning Institute, Paoli, PA 19301, USA
4. Department of Graduate Periodontics, University of Maryland, Baltimore, MD 21201, USA
5. Department of Graduate Prosthodontics, University of Washington, Seattle, WA 98015, USA
6. Department of Graduate Periodontics, Nova Southeastern University, Ft. Lauderdale, FL 33314, USA