1. Graduate Program in Dentistry, School of Dentistry Federal University of Pelotas Pelotas Rio Grande do Sul Brazil
2. Dental Materials Laboratory, Academic Area of Dentistry Autonomous University of Hidalgo Sate Pachuca Hgo Mexico
3. Department of Restorative Dentistry, School of Dentistry University of Detroit Mercy Detroit Michigan USA
4. Graduate Program in Materials Science and Engineering, CDTEc Federal University of Pelotas Pelotas Brazil