Numerical investigations of the loading behaviour of a prefabricated non-rigid bar system

The aim of this study has been to systematically evaluate the loading behaviour of a novel pre-fabricated chair-side SFI-Bar® bar system supported by two implants using finite element (FE) analysis. Two series of FE models were created of the bar placed on two idealised implants and embedded in idealised bone segments using CAD data. In the first series, the inter-implant distance varied from 10 to 26 mm; the second series consisted of a bar with a fixed implant distance of 26 mm and varying horizontal fitting inaccuracy from 0.0 to 0.3 mm. The bar was loaded vertically at 500 N. In all simulations, the regions with the greatest amount of stress were concentrated on the connecting elements of the bar and the bar itself. A slight increase in stress was observed with decreasing inter-implant distance. With a non-zero fitting inaccuracy, no clear correlation was observed between the amount of play and the stress distribution in the system. For a perfect fit, an obvious increase in stress was found in the implant and strain in the implant bed. With respect to the excessive static loading performed in our simulations and the resulting loading behaviour, we conclude that the SFI-Bar is a system suitable for clinical application.