Evaluation of passive fit of screw-retained digital fixed/detachable denture fabricated from poly-ether-ether-ketone material using conventional and digital methods (in-vitro study)

Abstract Aim: The aim of this in-vitro study was to evaluate the passive fit of screw-retained fixed/detachable digital denture framework fabricated from poly-ether-ether-ketone (PEEK) material using conventional and digital methods and comparing it with a denture framework fabricated from cobalt-chrome (Co-Cr) alloy. Material and methods: One readymade mandibular completely edentulous epoxy resin model covered with silicon resilient was used. Four implant analogs were placed at zero tilt on each cast multiunit abutments (MUA) and scanned with the epoxy resin cast by extra oral scanner and 3D virtual copy model was made. Outputting stereolithography (STL) file was saved and used as reference cast. The epoxy resin model with silicon was duplicated and poured in type IV stone that scanned and saved as STL file. Fourteen frameworks were designed as a duplication of the single ideal model and saved as STL file. Half of the frameworks were fabricated digitally from Co-Cr and the other half from PEEK. Passive fit was assessed for all dentures framework by conventional method and digital method. In conventional assessment of passive fit one screw was tightened on one side and the marginal fit was evaluated on the other sides by measuring the gap between the edge of MUA and the framework. Digital assessment of passive fit was made by using computer-aided design/computer-aided manufacturing software program and superimposition was made with the software demonstrating the amount of deviations between the prostheses and reference cast. Results: The result of this in-vitro study showed a significant difference between the two different material frameworks (PEEK and Co-Cr) regarding the gap between MUA and framework. However, the gap value was less in PEEK than Co-Cr. Conclusions: It was concluded that denture framework fabricated from PEEK has better passive fit compared to denture framework fabricated from Co-Cr using conventional and the digital evaluation.