1. Central Institute of Biomedical Engineering, Department of Biomaterials, University of Ulm, 89081 Ulm, Germany, Hacettepe University, Faculty of Dentistry, Department of Prosthodontics, 06100 Sıhhiye, Ankara, Turkey, and Hacettepe University, Chemical Engineering Department, and Bioengineering Division, and TUBITAK−Center of Excellence-BIYOMUH, 06532, Beytepe, Ankara, Turkey