1. Tor Tegnander Dental Clinic, Tollbugata 10, 8006 Bodø, Norway
2. Polish-Norwegian Medical Consultants, ul. Mickiewicza 5, 44-100 Gliwice, Poland
3. Department of Engineering Materials and Biomaterials, Faculty of Mechanical Engineering, Silesian University of Technology, ul. Konarskiego 18a, 44-100 Gliwice, Poland
4. Materials Research Laboratory, Faculty of Mechanical Engineering, Silesian University of Technology, ul. Konarskiego 18a, 44-100 Gliwice, Poland