Biomechanical comparison of magnesium bioresorbable and titanium lag screws for mandibular symphysis fracture fixation: A finite element analysis.

Objective: This study evaluates the biomechanical performance of magnesium bioresorbable lag screws compared to conventional titanium screws for mandibular symphysis fracture fixation using finite element analysis (FEA).

Material & methods: A 3D mandible model was created using MIMICS software from high-resolution CT data. Fracture lines were simulated, and Mg and titanium screws were designed in SolidWorks and virtually implanted. Meshing was performed using 3-matic software to represent geometry accurately. FEA was conducted using ABAQUS under masticatory forces of 150 N (incisor load) and 550 N (molar load). Stress distribution, displacement, and fracture stability were assessed, with material properties derived from established data.

Results: Mg screws exhibited lower von Mises stress (VMS) compared to titanium screws under both loading conditions. For incisor loading, Mg screws recorded 44.71 MPa compared to 56.94 MPa for titanium, with the lowest stress in Mg screws (25.73 MPa). Similarly, under molar loading, Mg screws showed reduced stress (48.35 MPa vs. 61.53 MPa for titanium). Mandibular stress (22.158-23.14 MPa), screw deformation (0.230-0.255 mm), and fracture displacement (0.278-0.310 mm) were comparable across materials.

Discussion: Mg screws demonstrated comparable biomechanical stability to titanium screws while significantly reducing stress concentrations, effectively transmitting loads within bone healing limits. Their bioresorbable nature eliminates the need for secondary surgeries, offering a promising alternative for mandibular fracture fixation and enhancing clinical outcomes.