1. Department of Endodontics, School of Dentistry, Showa University, 2-1-1, Kitasenzoku, Ohta-ku, Tokyo 145-8515, Japan
2. Center for Oral Biology, School of Dentistry, Karolinska Institutet, PO Box 4064, S-14 104 Huddinge, Sweden
3. Biora AB, Medeon Science Park, Malmö, S-205 12, Malmö, Sweden
4. Biora AB, Medeon Science Park, Malmö, S-205 12, Malmö, Sweden, Clinical Research Laboratory, Faculty of Dentistry, University of Oslo, PO Box 1109, Blindern, N-0317 Oslo, Norway,