Subtractive VS Additive Manufacturing Techniques for Fabrication of Digitally Designed Partial Dentures

Abstract

Statement of problem. Human errors are the main reason complicating the fabrication of removable partial denture (RPD) frameworks. The integration of the computer-aided design and computer-aided manufacturing (CAD-CAM) promises better outcome and improving the patient experience with the prostheses. Purpose. The purpose of this in vitro study was to evaluate the accuracy of digitally designed removable partial denture frameworks constructed by additive and subtractive methods of castable resins patterns using Comparative 3D analysis. Material and Methods. An educational maxillary model with missing second premolars and first molars bilaterally was used for this study. Scanning of the cast and designing of each component of the framework was done to produce an STL file. The STL file was used to produce twelve frameworks, six of them were milled in the form of castable resin, then casted by lost wax technique into CoCr metal framework. The other six were printed in the form of castable resin, which was casted by the same manner into CoCr frameworks. Comparative 3D analysis was used to measure the accuracy of the fabricated frameworks. Frameworks of each group were scanned then an STL file for each framework was generated. The STL files were imported into the Geomagic Control X software to be superimposed with the initial design to measure the deviation from it. Conclusions: Both techniques showed reliable results, even though subtractive manufacturing creates more accurate RPD frameworks compared to additive manufacturing.