1. Department of Periodontology, Oral Pathology, Oral Medicine and Radiology, Faculty of Dentistry, University of Sana’a, Sana’a, Yemen
2. Department of Periodontology, Faculty of Dentistry, Khartoum University, Khartoum, Sudan
3. Department of Preventive Sciences—Periodontology, Faculty of Dentistry, Jazan University, Jazan, Saudi Arabia
4. Substance Abuse Research Center (SARC), Jazan University, Jazan, Saudi Arabia