Comparison of the failure between conventional PMMA and milled PMMA full arch maxillary interim prosthesis fixed on 4 implants: An In Vitro Study

Objectives: The principal objective of this study was to compare the failure load between the conventional heat polymerized PMMA and the CAD/CAM milled PMMA interim full arch implant prostheses. The secondary aim was to evaluate the success of the distal extension of the temporary PMMA prosthesis. Methods: A metallic edentulous upper arch model with 4 Straumann screw-retained abutment digital analogs was used to create 15 specimens for each of the 2 groups: Conventional and milled. Failure load was measured on 5 different regions on the left and right side of each specimen with the YLE universal testing machine: Anterior, premolar, and molar. Results: The maximum force supported before breaking was noted for each region (N). The medians of failure load were statistically analyzed. Significant differences were observed between the 2 groups and among each region in the 2 groups. The posterior cantilever was the weakest sector in both groups followed by the anterior then the premolar regions. Conclusions: The interim milled PMMA prosthesis are a better choice due to their improved mechanical stability.