Degradation of luting cements measured in vitro.

The described method of measuring degradation of luting cements in vitro, by which various media, including bacteriological, can be used, gives results indicating that degradation is a more complex process than could previously be measured. Degradation appears to be a process following a sequence of absorption, disintegration, and solution. Factors, such as cement, thickness of the cement layer, molarity, and pH of the medium, affect, mostly by interaction, the degradation speed. Though the clinical predictability of this test method is not yet determined, it gives the opportunity to measure the various stages of degradation and to appoint the different factors affecting this process. Clinical tests based on the same principle are in progress.