1. Division of Endodontology, Department of Preventive Dentistry, Cariology and Periodontology, University of Zurich, Plattenstrasse 11, CH-8028 Zurich, Switzerland,
2. Institute of Biomedical Engineering, ETH Zurich and University of Zurich
3. Division of Endodontology, Department of Preventive Dentistry, Cariology and Periodontology, University of Zurich, Plattenstrasse 11, CH-8028 Zurich, Switzerland