[1
]
Department of Prosthodontics, Propaedeutics and Dental Materials, School of Dentistry,
Christian-Albrechts University at Kiel, Germany; Department of Fixed Prosthodontics,
Faculty of Dentistry, Ain Shams University, Egypt. Electronic address: kebeid@proth.uni-kiel.de.
[2
]
Department of Prosthodontics, Propaedeutics and Dental Materials, School of Dentistry,
Christian-Albrechts University at Kiel, Germany.
[3
]
Department of Fixed Prosthodontics, Faculty of Dentistry, Ain Shams University, Egypt.