1. ETEP (Etiology and Therapy of Periodontal and Peri-Implant Diseases) Research Group, Faculty of Dentistry, Complutense University, 28040 Madrid, Spain
2. Department of Periodontology, Faculty of Dentistry, University of Porto, 4200-393 Porto, Portugal
3. Department of Anatomy and Embryology, Faculty of Optics, Complutense University, 28040 Madrid, Spain