作者单位:Ramon Dominguez Biomed Res Fdn, Methodol & Stat Unit, Lugo, Spain[1]Hosp Monforte Lemos, Galician Hlth Serv, Organizat Struct Integrated Management EOXI Lugo, Lugo[2]Univ Santiago de Compostela, Sch Med & Dent, Dept Stomatol, Santiago De Compostela, Spain[3]