[1] Univ Salamanca, Fac Med, Dept Surg, Salamanca 37008, Spain
[2] Alfonso X El Sabio Univ, Fac Hlth Sci, Dept Endodont, Madrid 28691, Spain
[3] Alfonso X El Sabio Univ, Fac Hlth Sci, Dept Implant Surg, Avda Univ 1, Villanueva De La Canada 28691, Spain
[4] Cruces Univ Hosp, Maxillofacial Surg, Baracaldo, Spain
[5] Cruces Univ Hosp, Resp Div, Sleep & Ventilat Unit, Baracaldo, Spain
[6] Univ Oviedo, Fac Med, Dept Surg & Med Surg Specialties, Area Orthodont, Oviedo, Spain