Comparisons of Precision of Fit Between Cast and CNC-Milled Titanium Implant Frameworks for the Edentulous Mandible

Purpose: The purpose of this study was to investigate and compare the precision of fabrication in repeatedly produced computer numeric controlled (CNC)-milled frameworks with conventional castings, and to analyze the distortion from application of different veneering materials. Materials and Methods: Twenty identical titanium frameworks were fabricated by means of a CNC milling technique for the same master model. Five conventional frameworks were cast as a control group to the same model. The frames were measured with regard to fit in a coordinate measuring machine linked to a computer. Measurements were made during different stages of handling of the titanium framework, and after veneering materials had been applied. Results: The CNC frameworks showed a statistically better fit and precision of fabrication compared to conventional castings ( P .05). The application of veneering material did not statistically affect the fit of the titanium frameworks ( P> .05). Conclusion: It is possible to fabricate implant-supported frameworks by means of the present CNC technique with a very high precision and repeatability.