1. Department of Prosthodontics, Aristotle University of Thessaloniki, Faculty of Health Sciences, School of Dentistry, 54124 Thessaloniki, Greece
2. Aristotle University of Thessaloniki, Faculty of Health Sciences, School of Medicine, 54124 Thessaloniki, Greece
3. Department of Prosthodontics, University of Otago, School of Dentistry, Dunedin 9054, New Zealand
4. Aristotle University of Thessaloniki, School of Engineering, Department of Mechanical Engineering, Physical Metallurgy Laboratory, 54124 Thessaloniki, Greece
5. Division of Graduate and Postgraduate Prosthodontics, Department of Prosthodontics, Tufts University School of Dental Medicine, Boston, MA 02111, USA