1 Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland; Department of Ear and Oral Diseases, Tampere University Hospital, Tampere, Finland; Faculty of Health Sciences, Institute of Dentistry, University of Eastern Finland, Kuopio, Finland; Department of Oral and Maxillofacial Diseases, Kuopio University Hospital, Kuopio, Finland. Electronic address: timo.peltomaki@tuni.fi.