1. Oral Medicine Unit Sheba Medical Center Tel‐Hashomer Israel
2. Oral Medicine Unit, Department of Maxillofacial Surgery Tel Aviv Sourasky Medical Center Tel‐Aviv Israel
3. Central Virology Laboratory Ministry of Health, Sheba Medical Center Tel‐Hashomer Israel
4. Department of Oral Medicine & Pathology and Hospital Dentistry, School of Dentistry National and Kapodistrian University of Athens Athens Greece
5. School of Dental Medicine Tel‐Aviv University Tel‐Aviv Israel