Finite element analysis to compare stress distribution of gold alloy, lithium-disilicate reinforced glass ceramic and zirconia based fixed partial denture

Aim: Clinical data indicate that veneer chipping of zirconia core is more likely than with ceramic-fused-to-metal structures. The purposes of this simulation study were to: (a) use two-dimensional finite element modeling to simulate stresses at the interface of three-unit posterior fixed partial dentures (FPDs) made with three different core materials; and (b) to investigate the influence of three different veneer thicknesses on the stress distribution within the veneer–core complex.

Methods: A mesio-distal cross-section of a three-unit FPD was digitized and used to create two-dimensional models of the teeth, supporting bone, different core materials (gold alloy, zirconia and lithia-disilicate reinforced glass ceramic), and different pontic preparation configurations (occlusal veneer thickness 1.0, 1.5, and 2.0 mm). A simulated 100 N vertical occlusal load was applied to the standardized pontic element. Compression stress and tensile stress values were calculated by finite element analysis along the veneer–core interface and compared.

Results: The veneer–core interfacial stress of zirconia-based FPD is greater than that of gold alloy and lithium-disilicate reinforced glass ceramic core. The veneer–core interface stress value decreased with increasing occlusal veneer thickness.

Conclusions: Finite element modeling revealed differences in tensile and compressive stresses between different pontic preparation configurations and core materials. In general, gold alloy and lithium-disilicate reinforced glass ceramic core provided more even stress distribution at the connector and pontic of fixed partial denture than a zirconia framework.