Comparison between Marginal Gap of Stone and Metal Dies in a CAD/CAM System

Objective: The purpose of this study was to evaluate and contrast the zirconia crown's marginal gap on stone and metal dies in a CAD/CAM system. Materials and Methods: After preparing a melamine tooth (lower six molar) with 1.5mm occlusal reduction, 1 mm axial reduction and deep shoulder finishing line to construct metal and stone die .It was scanned with a 3D laser scanner by CAD/CAM system. Melamine tooth was milled and replicated into chrome –cobalt die and stone die. Twenty samples as a total, 10 for metal die and 10 for stone die were prepared. On the master die, marginal gaps were measured at four specific locations on each surface (mesial, buccal, distal, and lingual). Using a microscope digital camera (Dino Lite) at a magnification of 110X, the direct view technique was employed, and the measurements of the marginal gap were recorded using the image J software. Results: In the metal group the highest marginal gap was recorded while the lowest marginal gap was recorded with the stone group. Conclusion: The metal group recorded a statistically significant higher marginal gap than the marginal gap that was recorded in the stone group. Stone die was more accurate when 3D scanner is used.