Influence of Thread Geometry and Bone Density on Stress Distribution in Dental Implants: A Finite Element Study

Area of Science:

• Biomaterials Engineering
• Biomechanics
• Dental Implantology

Background:

• Optimal stress distribution at the implant-bone interface is crucial for dental implant success.
• Thread design and bone density significantly influence stress distribution.
• Square and trapezoidal thread designs are underexplored compared to V-shaped and buttress designs.

Purpose of the Study:

• To compare the stress distribution patterns of square and trapezoidal dental implant thread designs.
• To analyze stress distribution in varying bone densities using three-dimensional finite element analysis (FEA).

Main Methods:

• Eight 3D finite element models were created combining square and trapezoidal thread designs with four bone densities.
• A mandibular first molar implant model was subjected to a 100 N axial load.
• Von Mises stresses were analyzed in the implant and bone tissues using FEA software.

Main Results:

• Trapezoidal threads generated higher implant stresses (7.16-18.83 MPa) than square threads (5.21-15.08 MPa), especially in low-density bone.
• Square threads transferred more stress to the cortical bone (3.69-9.60 MPa) compared to trapezoidal threads (2.73-7.98 MPa).
• Stress concentrations varied based on bone density, being localized at thread crests in dense bone and dispersed in low-density bone.

Conclusions:

• Square threads reduce implant stress but increase cortical bone load; trapezoidal threads minimize cortical stress at the expense of higher implant stress.
• Square threads may be preferable for dense bones, while trapezoidal designs might enhance stability in low-density bones.
• Preoperative bone density assessment is critical for selecting the optimal thread design to ensure long-term dental implant success.