1. Department of Oral and Maxillofacial Surgery, Faculty of Dentistry Thamar University Thamar Yemen
2. Department of Periodontology, Faculty of Dentistry Thamar University Thamar Yemen
3. Postgraduation Program, Department of Oral and Maxillofacial Surgery, Traumatology and Prosthesis University of São Paulo São Paulo Brazil
4. Trend Research Centre Asia University Taichung Taiwan