1. Department of Paediatric Dentistry; Faculty of Dentistry; The University of Hong Kong; Pokfulam; Hong Kong
2. Department of Pedodontics and Preventive Dentistry; Narayana Dental College and Hospital; Nellore; Andhra Pradesh; India
3. Department of Dental Material Science; Faculty of Dentistry; The University of Hong Kong; Pokfulam; Hong Kong
4. School of Dentistry; Oral Health Centre of Western Australia; University of Western Australia; Perth; Australia