Force transmission of one- and two-piece morse-taper oral implants:: a nonlinear finite element analysis

Purpose: To compare force transmission behaviors of one-piece (1-P) and two-piece (2-P) morse-taper oral implants. Material and methods: A three-dimensional finite element model of a morse-taper oral implant and a solid abutment was constructed separately. The implant-abutment complex was embedded in a O 1.5 cm x 1.5 cm acrylic resin cylinder. Vertical and oblique forces of 50 N and 100 N were applied on the abutment and solved by two different analyses. First, contact analysis was performed in the implant-abutment complex to evaluate a 2-P implant. Then, the components were bonded with a separation force of 10(20) N to analyze a 1-P implant. Results: Von Mises stresses in the implant, principal stresses, and displacements in the resin were the same for both designs under vertical loading. Under oblique loading, principal stresses and displacement values in the resin were the same, but the magnitudes of Von Mises stresses were higher in the 2-P implant. The principal stress distributions around both implants in the acrylic bone were similar under both loading conditions. Conclusion: 2-P implants experience higher mechanical stress under oblique loading. Nevertheless, the 1-P- or 2-P morse-taper nature of an implant is not a decisive factor for the magnitude and distribution of stresses, and displacements in supporting tissues.