الفهرس 
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Abstract
This study was conducted to evaluate the accuracy, adaptation and retention of different fabrication techniques for digitally designed kennedy class I removable partial denture frameworks.
An educational maxillary model with missing second premolars and molars bilaterally was used for this study. After rest seat preparations were done the stone model was scanned using 3shape benchtop scanner to create a resin model. The resin model was then used for the three groups.
Scanning of the resin model and designing of each component of the framework was done using the partial denture module in 3shape software to produce an STL file.
In the first group, the STL file was used to mill the design in the form of castable resin, which was sprued, invested and casted by lost wax technique into Co-Cr metal framework. In the second group, the STL file was used to mill the design from Co-Cr blank to directly produce Co-Cr frameworks.
In the third group, the STL file was used to print the design from Co-Cr powder using selective laser melting technique to produce Co-Cr frameworks. These steps were repeated to produce twenty four frameworks, eight in each group.
Comparative 3D analysis was used to measure the accuracy and adaptation of the fabricated frameworks. Frameworks of each group were scanned using the 3Shape desktop scanner, 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 regarding the accuracy. While, the STL files were imported into the Geomagic Control X software to be superimposed with the fitting surface of the resin model to measure the adaptation.
Retention was tested after applying tensile forces by using universal testing machine to simulate the insertion and removal cycles, through 5 time intervals at baseline.
The results obtained from this study revealed higher accuracy, adaptation and retention of the subtractive manufacturing methods, and this difference was statistically significant with the least values were found in group C ( Co-Cr frameworks constructed by selective laser melting).
CONCLUSION
Within the limitations of this study, it could be concluded that:
• Co-Cr partial denture frameworks fabricated by direct milling technique is the most accurate, adaptive and retentive frameworks compared to Co-Cr partial denture frameworks fabricated by lost wax and selective laser melting technique.
RECOMMENDATION
- Further future clinical research is required to explore the validity of different manufacturing techniques for removable partial denture frameworks.