The distortion of cast cobalt-chromium alloy partial denture frameworks fitted to a working cast.

PURPOSE: This in vitro study examined the distortion of 10 identically designed cast cobalt-chromium alloy frameworks, individually constructed, and adjusted by 10 technicians to fit one of 10 replicated stone working casts. MATERIAL AND METHODS: The distortion was measured with a specially developed strain gauge apparatus when the frameworks were seated on the maxillary metal analog, the stone working cast, or a stone duplicate cast. RESULTS: A statistically significant difference between the distortion of each of the frameworks was observed. A significant difference in the distortion was also observed for the frameworks when placed on each of the three casts. The distortion was the least when the frameworks were seated on the stone working cast and the greatest when seated on the metal analog. CONCLUSION: This study demonstrated that the distortion of a framework is not related to its closeness of fit as observed by the presence or absence of gaps between the framework components and the teeth.