Abstract
An internal fixation plate is used to repair a mandible damaged owing to injury or tumor resection. In the clinical use of the plate, a surgeon must bend a conventional flat plate to fit the shape of the mandible, however, the bending process requires a long time and the dimensional accuracy is insufficient for fixation. In this study, the authors constructed a numerical simulation model of the mandible, examined various factors affecting the deformation and stress state of the mandibular fixation plate, and then investigated the effects of the process parameters of additive manufacturing on the mechanical properties and corrosion resistance of prototype plates, and the biological safety. As a result, the following was found. (1) The mechanical properties and corrosion resistance of fabricated commercially pure titanium (C.P.Ti) plates are the same as those of conventionally wrought C.P.Ti and they can be used as internal fixation plates for mandibular bone defects. (2) We designed and fabricated a prototype fixation plate for a resected mandible, and confirmed that it could be fixed on the mandible model with good compatibility. (3) The additively manufactured plate was acid heat-treated and implanted in the rat skulls to confirm osseointegration. The resulting bonding forces were sufficient for assisting the fixation force of screws.
