[A new possibility of improving the breaking strength of mineral tooth facets by ion exchange ]

A 140% increase in the breaking strength of Keradens facings may be achieved by ion exchange, i.e., by substitution of the small sodium ions in soda feldspar by the larger potassium ions, which is done by melting the soda feldspar with potassium nitrate. The temperature and the time required for optimum exchange conditions are derived from the results of the present study.