A study on biocompatibility and implant stability of 3D printed alumina/magnesium silicate composite ceramic bone screws.

Abstract

To address the requirements of moderate strength, high osseointegration, and low bone damage for bone screws applied in non - weight - bearing sites such as ligament reconstruction and bone defect repair, this study designed and fabricated alumina - magnesium silicate (Al₂O₃/MgSiO₃) composite ceramic bone screws using digital light processing (DLP) 3D printing technology. Mechanical compression test results showed that when the doping amount of magnesium silicate (MS) reached 15 wt% (MS15 group), the compressive strength was 222.9% higher than that of the pure alumina (MS0 group). In vitro mineralization experiments and cell experiments indicated that the MS15 group exhibited the most excellent performance in inducing mineralization and stimulating the proliferation and differentiation of osteoblasts. Results of simulated working condition tests showed that the failure torque of the ceramic bone screws reached 3.42 ± 0.42 N m, the pull-out force reached 428.47 ± 10.80 N. Finite element simulation results demonstrated that the shallow thread design effectively reduced stress concentration, verifying the rationality of the structural design. Based on the existing experimental investigations and finite element simulation results, the Al₂O₃/MgSiO₃ composite ceramic bone screws fabricated in this study exhibit favorable performance adaptability and promising application prospects in non-weight-bearing site scenarios, in comparison with their metallic and polymeric counterparts.