The effect of recasting commercially pure titanium on the marginal fit of cast restorations.

Abstract

OBJECTIVE: The purpose of this study was to investigate the effect of recasting of commercially pure titanium on the marginal accuracy of complete cast crowns and 3-unit fixed partial dentures (FPDs). MATERIAL AND METHODS: Commercially pure titanium was used to cast 18 single crowns and 18 3-unit FPDs. Three casting protocols were established in relation to the proportion of new and reused commercially pure titanium, namely as-received metal; 1:1 ratio of new to reused metal (50%) and 100% reused metal. A measuring traveling microscope was used to measure marginal gaps. Two and 1-way ANOVA were used to find the effects of the applied techniques on the marginal discrepancies. RESULTS: The as-received metal demonstrated significantly smaller marginal fit discrepancies than the 50% reused and the 100% reused metals when utilized to cast 3-unit FPDs (P<0.018). However, the marginal fit discrepancies were in the clinically accepted range (<100 im) except for 100% reused. Single crown fit was significantly better than 3-unit FPD (P<0.0001). CONCLUSION: The results of this in-vitro study indicate that recasting as-received metal demonstrated acceptable marginal fit. While, the 100% reused commercially pure titanium may produce unacceptable marginal fit.