1. Department of Restorative Dentistry, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia
2. Department of Periodontology, Faculty of Dentistry, University of Babylon, Babylon, Iraq
3. Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur, Malaysia
4. Department of Oral and Craniofacial Sciences, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia