1. Paul Johann Rau, Clinic for Conservative Dentistry and Periodontology, School of Dental Medicine, University of Heidelberg, Heidelberg, Germany
2. Thomas Pioch, Clinic for Conservative Dentistry and Periodontology, School of Dental Medicine, University of Heidelberg, Heidelberg, Germany
3. Hans-Jörg Staehle, Clinic for Conservative Dentistry and Periodontology, School of Dental Medicine, University of Heidelberg, Heidelberg, Germany
4. *Christof E Dörfer, PD Dr, Clinic for Conservative Dentistry and Periodontology, School of Dental Medicine, University of Heidelberg, Heidelberg, Germany