Titanium versus magnesium plates for unilateral mandibular angle fracture fixation: biomechanical evaluation using 3-dimensional finite element analysis

Abstract

Objectives: The aim of the study was to compare the stress distribution of magnesium alloy and titanium fracture fixation plates using 3 different designs of fixation plates (Straight plate with interval, Straight plate without interval, and Circular bar) used in simple unilateral mandibular angle fracture and to analyze the stresses acting within the screws used to stabilize the plates. Methods: Finite element models of 3 fixation screw designs (Straight plate with interval, Straight plate without interval, and Circular bar) were developed to simulate the biomechanics of mandibular fixation devices. Material properties of mandibular bone, magnesium and titanium alloy (Titanium alloys) was incorporated. Fracture lines were created on the angle of mandible and loads of 100–500 N were applied in sequence on the mandibular premolar/molar region of the normal side. Von Mises stresses and the magnitude of displacement on the fixation plates and screws were calculated. Results: For 300 N of applied load the straight plate with interval showed stress values in the range of 2.3 MPa–505 MPa (Magnesium alloys) and 3 MPa–533 MPa (Titanium alloys). The straight plate without interval showed Von Mises stress values in the range of 0.9 MPa–431 MPa (Magnesium alloys) and 2.3 MPa–460 MPa (Titanium alloys). However, the Von mises stress values for Circular bar were in the range of 3 MPa–345 MPa (Magnesium alloys) and 3 MPa–353 MPa (Titanium alloys). The displacement of the fixations plates for all the designs were less than 1 mm. The von mises stress values for Circular bar showed less stresses acting within the prosthesis compared to the straight plate with interval, and straight plate without interval.

Keywords

• Magnesium
• Titanium
• Finite element analysis
• Mandibular angle fracture
• Biomechanics