[1] Pontificia Univ Catolica Valparaiso, Fac Sci, Valparaiso 2340000, Chile
[2] Hosp Carlos Buren, Oral & Maxillofacial Surg, Valparaiso 2340000, Chile
[3] Univ Autonoma Barcelona, Dept Paediat Obstet & Gynaecol & Prevent Med, Barcelona 08193, Spain
[4] Univ La Frontera, Fac Dent, Dept Paediat Dent & Orthdnt, Temuco 4780000, Chile
[5] Univ La Frontera, Ctr Res Epidemiol Econ & Oral Publ Hlth CIEESPO, Fac Dent, Temuco 4780000, Chile
[6] Univ Chile, Fac Dent, Dept Oral & Maxillofacial Surg, Santiago 8380000, Chile
[7] Univ Chile, Fac Dent, Cochrane Associated Ctr, Santiago 8380000, Chile
[8] Hosp Clin San Borja Arriaran, Dept Oral & Maxillofacial Surg, Santiago 8320000, Chile
[9] Iberoamer Cochrane Ctr, Barcelona 08025, Spain
[10] Hosp Mar Med Res Inst, Hlth Servi Res Grp IMIM, Barcelona 08003, Spain
[11] CIBERESP, CIBER Epidmiol & Salud Publ, Madrid 28029, Spain
[12] Pompeu Fabra Univ, Dept Expt & Hlth Sci, Barcelona 08003, Spain