Effect of chewing and cutting condition for V-shape three-dimensional titanium miniplate for fixation of mandibular angle fractures (MAFs)

Abstract

PurposeMiniplate shapes determine the fixation stability to promote best healing and osseointegration process of mandibular fracture. In clinical treatment, the common method used two straight-type miniplate or I-shape miniplate; sometimes this method is not stable enough or limited by the fracture geometry and caused high risk of failure due to screw loosening. This paper aims to investigate a new type of miniplate called V-shape miniplate design as an alternative to the standard straight plate based on total displacement, von Mises stress, stress transfer parameter (STP) and strain energy density transfer parameters (SEDPTs) for two types of bite force condition, which is cutting and chewing condition.Design/methodology/approachThe 3D fixation models were constructed and the finite element (FE) simulation is based on the two-bite force load that ranges from 50 to 700 N based on cutting and chewing bite force condition using ANSYS Workbench 19.2.FindingsIn result comparison, the maximum loading of the V-shape miniplate can reduce deformation by 5.9%, reduce stress by 0.58% reduce strain by 8.1% in cutting condition while reducing deformation by 6.43%, reduce stress by 15.25%, reduce strain by 10.1% in chewing condition. To assess the stress transfer behavior of miniplates fixations to the mandibular bone, the STP and SEDPT were evaluated at the normal cortex screw and the locking head screw. In the simulation, the locking head screw is vertical to the bone structure while the cortex screw is 95 degrees to the bone structure, as a result, the STP value for locking head screw is 1.0073 while in cortex screw is 0.7408.Research limitations/implicationsMeanwhile, the SEDPT value for locking head screw is 2.7574 and 1.8412 for cortex screw.Practical implicationsClinically, V-shape miniplate has shown factual data that can be used for prototyping. STP and SEDTP values provide evidence of how fixation stability is better than I-shape miniplate.Originality/valueIn conclusion, the newly designed V-shape miniplate has overall better stability than the standard I-shape miniplate, and the locking head screw has the STP value closer to 1 than the standard cortex screw; it means the locking screw is better in reducing the stress shielding.