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, Faculty of Dentistry, Trisakti University, Jakarta, Indonesia