1. Department of Periodontics and Oral Medicine (A.D.P., M.T., E.L.E., W.V.G., L.K.M.), University of Michigan School of Dentistry, Ann Arbor, Michigan 48109
2. Department of Periodontology (T.F.T.), Faculty of Dentistry, Hacettepe University, 06100 Ankara, Turkey
3. Center for Statistical Consultation and Research (B.T.W.), University of Michigan, Ann Arbor, Michigan 48109
4. Departments of Surgery (R.E.B., P.G.G.), Michigan 48109
5. Biomedical Engineering (W.V.G.), Ann Arbor, Michigan 48109
6. Pathology (L.K.M.), University of Michigan Medical School, Ann Arbor, Michigan 48109