Ti-15Mo Alloy Decreases the Stress Concentration in Mandibular Angle Fracture Internal Fixation Hardware

Area of Science:

• Biomaterials Science
• Orthopedic Surgery
• Mechanical Engineering

Background:

• Mandibular angle fractures often require internal fixation with plates and screws.
• Commercially pure titanium (cpTi) is a common material, but its stiffness can lead to stress shielding.
• Alternative alloys are being investigated to improve mechanical stability and reduce stress shielding.

Purpose of the Study:

• To compare the mechanical stability of 2.0 plates made of cpTi versus a titanium-molybdenum (Ti-15Mo) alloy.
• To evaluate two internal fixation methods for mandibular angle fractures using 3D finite element analysis.
• To assess the stress distribution in the bone and fixation hardware.

Main Methods:

• Four groups were analyzed: cpTi and Ti-15Mo alloy plates with either one (Eng 1P) or two (Eng 2P) fixation configurations.
• A 100 N compressive load was applied to the mandibular first molar.
• Three-dimensional finite element analysis was used to evaluate von Mises equivalent stress, maximum/minimum principal stresses, and maximum principal strain.

Main Results:

• The Ti-15Mo alloy group showed a 10.5% decrease in plate stress and a 29.0% decrease in screw stress (one plate).
• With two plates, the Ti-15Mo alloy group exhibited a 28.5% reduction in screw stress.
• No significant differences in stress or strain were observed in the mandibular bone between the groups.

Conclusions:

• The Ti-15Mo alloy significantly reduces stress concentration in fixation screws and plates compared to cpTi.
• This reduction in stress shielding between the hardware and bone is clinically relevant.
• Using Ti-15Mo alloy may enhance the healing outcome for mandibular angle fractures treated with internal fixation.