[1] Univ Helsinki, Dept Oral & Maxillofacial Dis, Haartmaninkatu 8, FI-00014 Helsinki, Finland
[2] Helsinki Univ Hosp, Helsinki, Finland
[3] Univ Helsinki, Dept Otorhinolaryngol Head & Neck Surg, Helsinki, Finland
[4] Karolinska Inst, Dept Clin Sci Intervent & Technol, Div Ear Nose & Throat Dis, Stockholm, Sweden
[5] Karolinska Hosp, Stockholm, Sweden