[Measurements of the elastic and permanent deflection of MOD restorations during vertical loading]

In a loading device the mesio-distal deflection of mod restorations caused by different forces is measured reproducibly with inductive transducers. The accuracy of the measurements is about +/- 1 micron. Uncemented inlays of a soft gold casting alloy deflect 40 microns under load and 25 microns permanently; for an extra hard gold casting alloy the maximum values amount to 30 and 5 microns, respectively, and for a silver palladium alloy to 15 and 2 microns, respectively. Restorations of a non-gamma-2 amalgam reveal deflections within the range of accuracy near 2 microns.