Calcium sulfate-based load-bearing bone grafts with patient-specific geometry

The treatment of bone defects with complex three-dimensional geometry presents challenges in terms of bone grafting and restoration. In this paper, we propose a rapid and effective method that uses 3D printing, ceramic casting, and the incorporation of mesh reinforcement to create load-bearing bone grafts with patient-specific three-dimensional geometry. Using two types of facial bones as examples, we show that this fabrication method has a high degree of geometrical fidelity. We also experimentally study the fracture behavior of six different architectures designed for the treatment of mandibular defects, one of the principal load-bearing facial bones. These design configurations include un-reinforced calcium sulfate samples, and samples reinforced with one or two layers of stainless steel, poly (lactic acid), and poly (L-lactic acid). The results suggested a trade-off between energy dissipation and maximum load based on the position of the metal mesh in the sample. Samples reinforced with one layer of metallic mesh at their lowermost margin exhibited a 17% higher stiffness and a 21.3% higher peak load, while samples with a layer of metal mesh embedded within dissipated 16% more energy. Samples with two layers of metallic mesh demonstrated the highest improvements among all samples, dissipating 5767.85% more energy and exhibiting a peak load 145.6% higher compared to plain CS. The improvements in stiffness for SD, SL, and S2 were 3%, 21.3%, and 21.9% respectively compared to the plain ceramic. In contrast, PLA mesh improved energy dissipation by 96.71% but reduced the peak load by 29.18%, while PLLA mesh decreased both the peak load and the dissipated energy by 13.05% and 35.31%, respectively. While PLA mesh reduced stiffness by 11% compared to plain CS, PLLA mesh-reinforced samples were slightly stiffer than pure CS by 1.6%.