Mechanical effects of taper angles in implant-abutment connection: a finite element study.

Abstract

<h4>Purpose</h4>To analyze how the taper angle (defined here as the half‑angle per side) influences the mechanics of the implant-abutment connection using finite element analysis.<h4>Methods</h4>Three‑dimensional finite element models (implant body, abutment, and screw) with taper angles of 8°, 15°, 18°, and 22° were established in ABAQUS/CAE. All components were modeled as linearly elastic Ti‑6Al‑4 V (E = 110 GPa, ν = 0.35). Frictional contact (μ = 0.3) was assigned at the taper and screw interfaces. A bolt load of 605 N (equivalent to 35 Ncm) was applied and then released to assess the press‑fit retention. Under the maintained preload, 100-N vertical and horizontal loads (unidirectional and bidirectional) were applied for five cycles. The primary outcomes are the abutment axial displacement, implant von Mises stress, bolt load change, and microgap size.<h4>Results</h4>Smaller taper angles (8°, 15°) retained press‑fit after preload release, whereas larger angles (18°, 22°) lost press‑fit contact. As the taper angle decreased, the abutment axial displacement, implant stresses, and bolt load loss increased. The effect of the loading direction follows the order: vertical < horizontal (unidirectional) < horizontal (bidirectional). Microgaps decreased with smaller taper angles and cycling.<h4>Conclusion</h4>Taper angle differences affect press-fit, abutment axial displacement, screw loosening, stress distribution, and microgap formation.