Suman Thotapalli
Aims: The ringless casting procedure is in use in clinical dentistry although there is not adequate scientific data to support its use in pattern fabrication using different die materials. The purpose of the study was to compare vertical marginal discrepancy of cast copings fabricated on two die materials cast using ringless casting technique.
Materialsand methods: Two groups of cast copings were fabricated after investing patterns in phosphate
bonded investments mixed using standard liquid/water ratio. The vertical marginal discrepancy ofnickel chromium cast copings which were cast after fabrication on two die materials (type IV die stone, Epoxy-it) using Ringless casting technique was determined and the Mean Vertical marginal Discrepancy was calculated based on measurements made with a Travelling Microscope.
Results: The mean and standard deviation for each side was calculated. One way ANOVA and paired t-testwas performed to identify statistically significant difference between the groups. The results of the study showed marginal discrepancy values of 38 μm and 37 μm for type IV die stone and Epoxy-it die materials cast using the ringless casting system.
Conclusions: The purpose of the study was to compare vertical marginal discrepancy of cast copings fabricated on two die materials cast using ringless casting technique. The results showed no statistical significance when using the two die materials and stone enhancers can be used as an alternative to improve the accuracy of cast copings.
