Reconstruction of Segmental Mandibular Defects Restored by Prosthesis with Support and Porous Structure: A Biomechanical Study / 医用生物力学

ABSTRACT

Objective To design a personalized titanium mandibular prosthesis with porous and support structure, and analyze its stress distribution characteristics through finite element analysis, so as to evaluate clinical value and prospect of the prosthesis. Methods The fourth mandibular premolar and molar from the right mandible of Beagle dogs were removed. The spiral CT was taken after three-month healing, and the three-dimensional (3D) model of the mandible was established. Resection of 3 cm mandible with simulated surgical procedure and reconstruction with personalized restoration were conducted. The prosthesis consisted of abutment, pillar, solid unit, porous unit and retention unit. A personalized titanium mandibular prosthesis finite element model A was established, to analyze the prosthesis stress under loading, and further study was proceeded when the maximum stress of each part constituting the prosthesis was smaller than yield strength of its material. The finite element model B with the assembly of the prosthesis, mandible and screw was constructed and loaded with the mastication force, and the stress, strain and displacement distributions of the mandible were recorded. Results When the abutment was under 100 N vertical loading, the peak stress of the prosthesis with solid structure and porous structure was 147.03 and 75.36 MPa, respectively, which was smaller than yield strength of its material; the peak stress of the cortical bone and cancellous bone was 53.713, 4.216 7 MPa, and the strain was 3.753 6, 3.562 5, respectively; the maximum displacement of the restoration was 338.3 μm. ConclusionsTaking the canine mandible as an example, the personalized prosthesis with porous and support structure shows the uniform stress distribution and good mechanical properties through finite element analysis. The results provide a new method for the design of prosthesis for repairing mandibular defects.