Load bearing capability of three-units 4Y-TZP monolithic fixed dental prostheses: An innovative model for reliable testing

In this work, three-units monolithic fixed dental prostheses (FDPs) have been analysed and a novel model for reliable testing has been proposed. Such model is based on a new design of the polymeric base of the FDP, realised via additive manufacturing (AM) - a solution that conveys at the same time quick manufacturability, low cost, custom-ability, and design freedom. By means of this new model, the load-bearing capability of three-units monolithic FDPs has been thoroughly tested; in particular, three different analyses were performed: (i) analytical with a beam-like model, (ii) numerical, using non-linear three-dimensional Finite Elements (FE) models and (iii) experimental, by static bending test. The FDPs considered in this work were manufactured using a fourth-generation zirconia, namely 4Y-TZP. The findings demonstrated the undoubted advantages of the new base configuration, which minimized the effect of the base (which as a matter of fact is absent in in-vivo conditions) on the stress state of the connectors in the FDPs, and increased the repeatability and reliability of the experimental bending tests, able to determine the load bearing capability of the 4Y-TZP FDPs.