1. Oral Medicine and Oral Surgery Laser Unit, University Centre of Dentistry, Department of Medicine and Surgery, University of Parma, 43125 Parma, Italy
2. Unit of Dentistry and Oral Surgery, Department of Surgical, Medical and Molecular Pathology and Critical Care Medicine, University of Pisa, Via Roma 67, 56126 Pisa, Italy
3. Departamento de Clínica e Odontologia Preventiva, Universidade Federal de Pernambuco, Recife 50670-901, Brazil