1. School of Dental Technology, Taipei Medical University, Taipei, Taiwan
2. School of Dentistry, Taipei Medical University, Taipei, Taiwan
3. Division of Prosthodontics, Department of Dentistry, Taipei Medical University Hospital, Taipei, Taiwan
4. Department of Oral Biology & Engineering, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima City, Hiroshima, Japan.