Effect of recasting Ti-6Al-4V alloy on the internal and marginal accuracy of complete cast crown.

Abstract

The purpose of the study was to investigate the effect of recasting Ti-6Al-4V on the marginal accuracy and internal fit of complete cast crowns. Ti-6Al-4V was used to cast 18 single crowns, six of each group. Three groups of Ti-6Al-4V ingots were tested. The first group was as received from manufacturer, second group was a mixture (1:1 ratio) of as received and the alloy that was once used and the last group was an alloy used once (recast). A travelling microscope was used to measure the marginal and internal gaps between the metal die and the casting. The fitting discrepancies were analyzed with a 1-way ANOVA and Tukey’s multiple range (α=.05). The lowest mean marginal gap was recorded for the as-received (36.87im) and the highest was for the 100% reused (39.24im). However, these differences were not statistically significant (P=0.192). For the internal fitting, no significant difference was shown between as-received and 50% reused groups (P>0.91). Yet, the alloys in both the groups showed gaps that were significantly smaller than the 100% reused alloy (P<0.002). Used Ti-6Al-4V metals could be melted and utilized again for casting single crowns. As-received and 50% reused metals demonstrated better internal fit than the 100% reused metals.