With the microstructure being the dominant factor on crack initiation and propagation during the fabrication process, the objective was to identify the relationship between the microstructural characteristics and damage created during machining which could compromise clinical performance. Conventional milling operations were performed on a polished surface of 30 specimens of each microstructure. Strength, measured by microhardness indentation, was determined before and after machining. A computer vision system was employed to visualize surface damage. Grain size and shape, volume fraction of second phase, machining force measurements, surface finish, and density of surface cracking were recorded.
Surface cracking is easier to control with lower forces.
Contributions of this study are the establishment of a set of comprehensive performance indices specifically tailored for evaluating machinability of dental materials, the procedure of carrying out the machinability assessment, and a suggested architecture of machinability database for dental materials. This study was supported by NIDR 1 PO1 DE10976-01A1.