Deflection of superstructure and stress concentrations in the IMZ implant system.

The finite element method was used to model a 4.0 x 13.0-mm IMZ implant restored with a cast gold crown to examine the relationship between deflection of the prosthetic superstructure and stress concentrations in the retaining screw using both the polyoxymethylene intramobile element and the analogous titanium element under various loading conditions. A strong correlation was observed between the peak stresses in the screw and the deflection of the superstructure. Deflections and stress concentrations generally increased with increases of either the load magnitude or the load angle. Greater deflection and stress concentrations within the coronal retaining screw were predicted with the use of the resin IME than with the titanium element.