1. Department of Oral and Maxillofacial Medicine and Pathology, Research and Graduate Division, Dental School, National Autonomous University of Mexico, Mexico City 04510, Mexico
2. Microbiology Laboratory, Facultad de Ciencias de la Salud, Universidad Autónoma de Baja California, Tijuana 21100, Mexico
3. Department of Oral Public Health, School of Superior Studies, National Autonomous University of Mexico, León 37684, Mexico