Comparison of CAD-CAM and traditional chairside processing of 4-unit interim prostheses with and without cantilevers: Mechanics, fracture behavior, and finite element analysis

Statement of problem How processing by computer-aided design and manufacturing (CAD-CAM) or traditional chairside fabrication techniques affects the presence defects mechanical properties interim dental prostheses is unclear. Purpose The purpose this in vitro study was to compare effects CAD-CAM versus material on fracture biomechanical behavior 4-unit with without a cantilever. Material methods Two types were fabricated abutments first premolar mandibular molar, one from prefabricated block polymer-monomer autopolymerizing acrylic resin (n=10). Both groups assessed compressive strength testing additionally cantilevered second molar using universal machine 5-kN load cell. A finite element model (FEM) built scanning both prosthesis designs. Finite analysis (FEA) replicated experimental conditions evaluate stress distribution through prostheses. Results Interim fixed manufactured showed significantly higher mean loading values (3126 N 3136 N) than for conventionally made (1287 1390 (P=.001). cantilever decreased (1954 2649 N), although did not influence (1268 1634 N). highest von Mises stresses recorded FEA occlusal surface, design, at transition region (connector) between prosthetic teeth. Conclusions partial produced had those traditionally. negatively affected prostheses, structures still revealed high homogenous loading.