1. Faculty of Science, Applied Physics Department, University of Granada, Av. Fuente Nueva s/n, 18071 Granada, Spain
2. Faculty of Dentistry, Dental Materials Section, University of Granada, Colegio Máximo de Cartuja s/n, 18071 Granada, Spain
3. Bioscience Research Center, College of Dentistry, University of Tennessee, Health Science Center, 875 Union Avenue, Memphis, Tennessee 38163