Three-dimensional Finite Element Analysis of Cantilever Fixed Partial Dentures

The replacement of a maxillary second premolar in shortened dental arch (SDA) therapy may be achieved in a number of ways including the provision of a cantilever fixed partial denture (FPD). Objectives: The purpose of this study was to investigate, by means of three-dimensional finite element analysis (3-D FEA), the biomechanics of two designs of cantilever FPD for the replacement of a maxillary second premolar in SDA therapy under different scenarios of occlusal loading. Methods: Two-and three-unit cantilever FPDs were modelled and analysed using the finite element packages PATRAN® and ABAQUS®. Displacement and maximum principal stress distributions within the prostheses, supporting structures, periodontal ligament/bone (PDL/B) and abutment/retainer (A/R) interfaces were examined under axial and lateral occlusal loading. Results: The results indicated that higher levels of displacement occurred in the two- rather than the three-unit cantilever FPD with the greatest displacement having occurred under lateral loading (0.3mm). The greatest maximum principal stresses in the PDL/B interfaces were located buccocervically, with the greatest magnitudes being observed in the two-unit FPD under lateral loading (12MPa). The greatest maximum principal stresses in the A/R interfaces were located cervically in relation to the lingual margin of the retainer adjacent to the pontic under lateral occlusal loading (22MPa). Conclusions: It was concluded that the displacement and maximum principal stresses observed in relation to the cantilever FPDs were greatest under lateral occlusal loading, notably in the two-unit cantilever FPD. The biomechanics of the three-unit cantilever FPD were more favourable than those of the two-unit cantilever FPD under similar boundary conditions and loading.