Abstract
Retention forces of super-elastic Ti-Ni alloy castclasps were studied, in comparison with other conventional dental alloys, such as cobalt-chromium alloy, gold-silver-palladium alloy and titanium.Retention forces were measured by repeated setting-removal test of the Akers type castclasps with a tooth model.Considering from retentive force-displacement curves, the retentive force of Ti-Ni alloy castclasps showed little change during the 1, 000 cycles of the test, with either the 0.25 and 0.50mm undercut.On the other hand, retention forces of conventional dental alloy clasps decreased obviously with both a 0.25 and 0.50mm undercut with increasing number of setting and removal.Ti-Ni having th super-elastic property could be applied to castclasps with much deeper undercut than other dental alloys conventionally used in designing castclasps in prosthodontics.Futhermore, the super-elastic property could prevent castclasps made of Ti-Ni alloy from being broken.
