The objective of this investigation was to present a novel method to facilitate and accelerate geometry acquisition/modification during the fabrication of finite element models of tooth restorations. Microcomputed tomographic data, stereolithography, and surface-driven automatic meshing were used to generate premolar finite element models with different occlusoproximal cavity preparations and corresponding composite resin restorations. Occlusal loading was simulated by nonlinear contact analysis. Cuspal widening was measured and correlated with existing experimental data for model validation. Cuspal widening during application of a 150-N load ranged from 2.7 µm for the unrestored tooth to 5 to 179 µm for the different preparations and 3.5 to 6.9 µm for the different restorations. The described method was efficient and generated detailed and valid three-dimensional finite element models. These models were used to study the effect of restorative procedures on cuspal deflection and revealed high cuspal strains associated with mesioocclusodistal preparations and restorations compared to individual two-surface preparations. This study confirmed that, whenever possible during removal of interdental decay, an intact marginal ridge should be maintained to avoid threesurface preparations such as the mesio-occlusodistal and the high cuspal strain associated with this design.