1. Department of Periodontics and Oral Medicine University of Michigan School of Dentistry Ann Arbor MI
2. Department of Reconstructive Dentistry University Center for Dental Medicine Basel, University of Basel Basel Switzerland
3. Department of Biologic & Materials Sciences Division of Prosthodontics University of Michigan School of Dentistry Ann Arbor MI
4. Department of Clinical and Experimental Medicine University of Foggia School of Dentistry Foggia Italy