1. Department of Health Sciences, University of Jyväskylä, Oulu, Finland,
2. Department of Physical and Rehabilitation Medicine, Jyväskylä Central Hospital, Jyväskylä, Finland,
3. Medical Research Center Oulu, Oulu, Finland,
4. Oulu University Hospital and University of Oulu, Oulu, Finland,
5. Institute of Dentistry, University of Eastern Finland, Kuopio, Finland,
6. Oral and Maxillofacial Department, Kuopio University Hospital, Kuopio, Finland,
7. Department of Prosthetic Dentistry and Stomatognathic Physiology, Institute of Dentistry, University of Oulu, Oulu, Finland,
8. Oral and Maxillofacial Department, Oulu University Hospital, Oulu, Finland, and
9. Department of Psychology, Faculty of Social Sciences, University of Jyväskylä, Jyväskylä, Finland