Abstract
Various glass-ceramics were used until today in several fields of biomedical applications as e.g. in orthopaedics, dentistry or ENT. Their main benefits are assumed to be their biocompatibility or bioactivity. Sometimes also an addititional machinability is of interest. On the other side, the strength properties of this type of materials are restricted, and frequently it is not clear how they may be influenced by external influences as e.g. by the environment or the state of the surface. Thus,in the following study an attempt is made to characterize a specific group of such glass-ceramics with respect of some of these aspects.