In Vitro Comparative Study of Different Technologies for Metal Denture Frameworks Fabrication - Direct Metal Laser Sintering, Machine Milling and Hybrid Technology

Introduction: Nowadays the additive manufacturing technologies become more and more popular as they suggest good reproducibly and fast production process. One of the most generally used approach is a fabrication of a pattern, that is later replaced by casting. Modern concept usually utilizes materialized CAD models, that are milled by CAM or 3D printed and later those patterns are invested and casted. It is important for practice to be clarified whether this production method is competitive to the rapid manufacturing and subtractive fabrication methods. Materials and Methods: A STL-file with bar framework retained by four implants is used for fabrication of four group of objects. Each group of frameworks is fabricated by different technology as follows: Direct Metal Laser Sintering, Milling and hybrid technology with different investment materials (WiroFine? and Bellavest? SH). All the implant analogs are fixe into a stone plate, scanned and imported in Dental Designer, 3Shape? software. Once the frameworks are ready, they are used as a matrix for attachment and repositioning of the implant abutments according to their configuration. Then the analogs are fixed into the same stone base, which is scanned, as its image is merged to the one before the realignment procedure. The discrepancies are observed. Results: The most accurate reproduction is achieved by DMLS technology, followed milled framework. The hybrid technology shows less accuracy than contemporary methods. Therefore by using an investment material with higher expansion coefficient its accuracy is improved and makes it an alternative method to rest which are observed. Conclusion: Nowadays these contemporary technologies still remain expensive. At the same time the suggested modification of conventional casting process allows better accuracy to be achieved at lower price.