1. a Department of Biomedical Engineering , W.J. Kolff Institute, University Medical Center Groningen and the University of Groningen , Groningen , The Netherlands
2. b Department of Prosthodontics, Faculty of Dentistry , University of Indonesia , Jakarta , Indonesia
3. c Department of Oral Maxillofacial Surgery and Maxillofacial Prosthetics , University Medical Center Groningen, University of Groningen , Groningen , The Netherlands
4. d Department of Oral Biology , Faculty of Dentistry, University of Indonesia , Jakarta , Indonesia