1. Department of Dentistry, Ng Teng Fong General Hospital and Faculty of Dentistry, National University Health System, Singapore
2. National Dental Research Institute Singapore, National Dental Center Singapore and Duke-NUS Medical School, Singapore Health Services, Singapore
3. School of Health and Social Sciences, Nanyang Polytechnic, Singapore
4. Department of Prosthodontics, Trisakti University, Jakarta, Indonesia
5. Department of Prosthodontics, Faculty of Dentistry, Trisakti University, Jakarta, Indonesia