Optimal Design And Biomechanical Investigations Of Customized 3D Fixation System For Mandibular Fracture

Mandibular fracture has a bad influence on maxillofacial aesthetic,chewing,speaking and so on,which highly lowers the patient's living standards.Mandibular angle is one of the most common sites for fractures,accounting for 25% of all cases of mandibular fractures.Although most of the mandibular fractures can be cured successfully by 2D fixation plates and bioabsorbable plates,obsolete fracture and special fracture still need new fixation plate with more advantages.The customized fixation system with favourable biomechanical properties and special 3D shape to match the bone surface can reduce the operational time,improve the initial stability,accelerate the bone healing,and reduce or eliminate the possibility of bone resorption and failure,finally improving the success rate of the operation.This study reconstructed the mandible model and the biomechanical model by the medical processing software.Then,new design technique based on the topological optimization for customized fixation system was proposed and researched.Take mandibular angle fracture for example,the customized plate with “V” shape was designed by the new design technique.And both finite element analysis and experimental testing were carried out to compare and analyze the biomechanical behavior of “V” plate and common plates.Ultimately,the results show apparently that the “V” plate is equipped with better biomechanical properties than common plates,which can prove that new optimal design technique is feasible and effective to acquire customized 3D fixation system for mandibular fractures.(1)Finite element modeling solutions for mandibular biomechanical simulation were investigated.After comparing the modeling solutions based on the triangular mesh andparametric surface,this study shows that the former method is more appropriate to reconstruct the mandible with complex shape and structure.(2)One design technique based on topological optimization of customized 3D fixation system for mandibular fracture was proposed,and one customized plate with “V” shape was designed for mandibular angle fracture.(3)The mandibular biomechanical model with various muscles was reconstructed,and the biomechanical behaviors of different fixation systems under three static loading conditions were analyzed.The results from finite element analysis show that the average maximum stress of “V” plate(98MPa)decreased 73.37% compared to one-plate system(368MPa)and36.77% compared to two-plates system(155MPa).And the numerical results have been proved by experimental results.(4)The biomechanical testing platform was set up,and the mandible model with personalized condyle restricting devices and articular discs was fabricated by 3D printing technique.And the biomechanical behaviors of customized fixation plate and common plates were compared and analyzed.