Effect of Different Surface Treatment on Hardness of Dental Alloys

Objectives: Investigate different surface treatments on hardness of specimens produced by CAD-CAM milling techniques and selective laser melting technique. Materials and Methods: Thirty disc-shaped specimens were put into three main groups. Each group has ten examples of Co-Cr metal that were made of different materials. There were three kinds of milling: hard, selective laser melting (3D printer), and soft. Everything was cut up into 15 mm wide pieces that were 3 mm thick so that they could be used for more tests. The last step was to finish them off and make their surfaces smooth with a diamond grinder. A scanning electron microscope (SEM) was used to look at one example from each group and figure out how the surface of the metal frame was made. We tested how hard specimens were. We used the independent sample one-way ANOVA to determine differences. Results: Hardness tests for all test groups in the study showed that 3D printing usually gave the best hardness in the control and sandblast groups. Hard cutting gave the most hardness in the Laser group. We used One- and Two-way ANOVA and Levene's test to look at the data statistically. All the tests had p-values of 0.001, which means that the hardness values for each milling type are very different from one another. Conclusion: 3D printing generally resulted in the highest hardness values, and the control and sandblast groups hard milling showed superior hardness in the Laser group.