1. 1 Department of Oral Cell Biology, University of Umeå, Umeå, Sweden, 2 Department of Oral & Maxillofacial Surgery , University of Umeå, Umeå, Sweden, 3Department of Orthodontics, University of Umeå, Umeå, Sweden, 4Department of Pathology, Huddinge Hospital, Karolinska Institutet, Huddinge, Sweden, 5Department of Clinical Chemistry, University of Lund, Lund, Sweden