Influence of buccal cusp reduction when using porcelain laminate veneers in premolars. A comparative study using 3-D finite element analysis.

OBJECTIVES Based on a maxillary premolar restored with laminate veneer and using the 3-D finite element analysis (FEA) and μCT data, the aim of this study was to evaluate the influence of different types of buccal cusp reduction on the stress distribution in the porcelain laminate veneer and in the resin luting cement layer. METHODS Two 3-D FEA models (M) of a maxillary premolar were built from μCT data. The buccal cusp reduction followed two configurations: Mt - buccal cusp completely covered by porcelain laminate veneer; and Mp - buccal cusp partially covered by porcelain laminate veneer. The loading (150 N in 45°) was performed on the top of the buccal cusp. The finite element software (Ansys Workbench 10.0) was used to obtain the maximum shear stress (τ(max)) and maximum principal stress (σ(max)). RESULTS The Mp showed reduced the stress (σ(max)) in porcelain laminate veneer (from -2.3 to 24.5 MPa) in comparison with Mt (from -5.3 to 27.4 MPa). The difference between the peak and lower stress values of σ(max) in Mp (-6.8 to 26.7 MPa) and Mt (-5.3 to 27.4 MPa) was similar for the resin luting cement layer. The structures not exceeded the ultimate tensile strength or the shear bond strength. CONCLUSIONS Cusp reduction did not affect significant increase in σ(max) and τ(max). The Mt showed better stress distribution (τ(max)) than Mp.