[1] Univ Kiel, Clin Conservat Dent & Periodontol, Sch Dent Med, D-24105 Kiel, Germany
[2] Cairo Univ, Oral Med & Periodontol Dept, Fac Oral & Dent Med, Cairo, Egypt
[3] Univ Kiel, Clin Appl Cellular Therapy, D-24105 Kiel, Germany
[4] Cairo Univ, Fac Med, Dept Clin Pathol, Cairo, Egypt
[5] Univ Kiel, Dept Oral & Maxillofacial Surg, D-24105 Kiel, Germany
[6] Charite, Dept Operat & Prevent Dent, D-13353 Berlin, Germany