1. Department of Periodontics, University of Pennsylvania, Philadelphia, PA 19104, USA
2. School of Dentistry, University of Detroit Mercy, Detroit, MI 48221, USA
3. Department of Graduate Periodontics, University of Maryland, Baltimore, MD 20742, USA
4. Department of Graduate Prosthodontics, University of Washington, Seattle, WA 98195, USA
5. Department of Graduate Periodontics, Nova Southeastern University, Fort Lauderdale, FL 33314, USA
6. Department of Microbiology and Immunology (Medicine), Temple University, Philadelphia, PA 19140, USA
7. Department of Periodontology and Oral Implantology (Dentistry), Temple University, Philadelphia, PA 19140, USA