[1] Univ G dAnnunzio, Dept Med Oral & Biotechnol Sci, Chieti, Italy
[2] Univ Cattolica Sacro Cuore, Fdn Policlin Univ A Gemelli IRCCS, Inst Dent & Maxillofacial Surg, Rome, Italy
[3] Univ Complutense Madrid, EFP Program Periodontol, Madrid, Spain
[4] Univ Bologna, Dept Biomed & Neuromotor Sci, Unit Oral & Maxillofacial Surg, Bologna, Italy
[5] UCL, Eastman Dent Inst, Unit Periodontol, London, England