[1] Univ Milan, Dept Hlth Sci, Dent Clin, Milan, Italy
[2] Univ Milan, WHO Collaborating Ctr Milan Epidemiol & Community, Milan, Italy
[3] Univ Milan, Unit Obstet & Gynecol, L Sacco Dept Biomed & Clin Sci, Milan, Italy
[4] Univ Milan, Ctr Fetal Res Giorgio Pardi, Milan, Italy
[5] Univ Sassari, Gynecol & Obstet Clin, Dept Surg Microsurg & Med Sci, I-07100 Sassari, Italy
[6] Univ Sassari, Dept Surg Microsurg & Med Sci, Dent Clin, I-07100 Sassari, Italy
[7] Univ Roma La Sapienza, Dept Oral & Maxillofacial Sci, Prevent & Community Dent Unit, Rome, Italy