1. Department of Restorative Dentistry, Dental Materials, Piracicaba School of Dentistry, University of Campinas, Piracicaba, SP, Brazil;
2. Department of Prosthodontics, Bauru School of Dentistry, University of São Paulo, Bauru, SP, Brazil;
3. Dows Institute for Dental Research and Department of Operative Dentistry, University of Iowa, Iowa City, USA;
4. Department of Oral Biology and Maxillofacial Pathology, School of Dentistry, Medical College of Georgia, Augusta, GA, USA; and
5. Institute of Dentistry, University of Helsinki, PO Box 41, 00014 University of Helsinki, and Department of Oral and Maxillofacial Diseases, Helsinki University Central Hospital, Helsinki, Finland