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Aims &Objectives: To evaluate Marginal discrepancy and Surface roughness of CAD-CAM Milled and 3D Printed provisional crowns after subjecting them to thermocycling. Materials and Methods: A stainless-steel metal die with ANSI/ADA specifications had been fabricated for the study. It was scanned with an intraoral scanner and the data was sent to VHF S5M CAD CAM milling and R3Pro printing machine. A total of 10 samples Milled Group A(n=10) and 10 Printed Group B(n=10) provisional crowns were fabricated from PMMA material using the scanned data. The temperatures for thermocycling are 37ºC and 60ºC. Each group is subdivided into two subgroups(n=5) based on thermocycling temperatures. The timeduration selected for Thermocycling was 7,14 and21 days. Marginal discrepancy was measured by using Stereomicroscope and Surface roughness was measured with Profilometer. Results: Marginal discrepancy values were greater in CAD CAM milled crowns(141.47 µm) than in Printed crowns(109.87 µm) at 60ºC after a time-period of 21days.Surface roughness values were higher in Milled crowns(3.915µm) than in CAD CAM Printed crowns(3.817µm) at 60ºC for a given time duration of 21days. One-way ANOVA statistical analysis was done. The mean marginal gap of CAD CAM Milled crowns was statistically significant than Printed crowns(p>0.05). Conclusion: Printed provisional restorationshad better Marginal accuracythan CAD CAM Milled provisional crowns. Surface roughness was higher in CAD CAM Milled crowns than in Printed provisional restorations.
Ravella et al. (Mon,) studied this question.