1. Department of Dental Materials, School of Dentistry, University of São Paulo, São Paulo, SP, Brazil;
2. Dental Materials Section, Department of Oral Rehabilitation, School of Dentistry, Medical College of Georgia, Augusta, GA 30912-1260, USA; and
3. Department of Restorative Dentistry, Dental School of Piracicaba at UNICAMP, Piracicaba, SP, Brazil;