1. LIEC, UNESP-Univ Estadual Paulista, P.O. Box 355, 14801-907 Araraquara, SP, Brazil
2. Department of Dental Materials and Prosthodontics, Araraquara Dental School, UNESP-Univ Estadual Paulista, 14801-903 Araraquara, SP, Brazil
3. LIEC, CMDMC, Department of Chemistry, Universidade Federal de São Carlos (UFSCar), 13565-905, São Carlos, SP, Brazil