1. Department of Operative Dentistry, Tokyo Medical and Dental University, Tokyo, Japan
2. Department of Restorative Dentistry and Endodontics, University of Geneva, Switzerland
3. Office of Biostatistics and Department of Oral Diagnosis and Patient Services, Medical College of Georgia, Augusta
4. Department of Oral Biology, School of Dentistry, Medical College of Georgia, Augusta, GA 30912-1129