The Comparison of Retention Between Overdenture Copings Manufactured by DMLS, CAD and Conventional Casting Techniques

Aims: To compare the retention of copings produced by Direct Metal Laser Sintering (DMLS), Hard metal CAM (Computer Assisted Milling) and conventional casting techniques. Materials and Methods: An implant abutment was used as an ideal model which was scanned by 3D scanner and 8 copings of each group were fabricated from a single STL file. Each specimen was seated, luted, and mounted on a vertical column universal testing machine for a pull-off test. Dislodgement readings were recorded and statistically analyzed with ANOVA test and Duncans multiple range test. Results: Significant difference was found between the studied groups in retention. The laser-sintered group showed the highest force required for dislodgement followed by conventional casting group then by the hard metal milling group. Conclusions: within the limitations of this study, Laser sintered group has the superior retention above the other two groups