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

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.

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.

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.

Taper angle differences affect press-fit, abutment axial displacement, screw loosening, stress distribution, and microgap formation.