1. Unit of Biostatistics and Research Methodology, School of Medical Sciences, Universiti Sains Malaysia, Health Campus, Kubang Kerian, Kelantan, Malaysia
2. Medical Faculty, Universiti Sultan Zainal Abidin, Medical Campus, Kuala, Terengganu, Malaysia
3. School of Dental Sciences, Universiti Sains Malaysia, Health Campus, Kubang Kerian, Kelantan, Malaysia
4. Orthodontic Unit, Kota Bharu Dental Clinic, Jalan Mahmood, Kota Bharu, Kelantan, Malaysia