Artificial bone grafting is widely used in current orthopedic surgery for bone defect problems. Unfortunately, surgeons remain unsatisfied with the current commercially available products. One of the major complaints is that these products cannot provide sufficient mechanical strength to support the human skeletal structure. In this study, we aimed to develop a bone scaffold with better mechanical property and good cell affinity by 3D printing (3DP) techniques. A self-developed 3D printer with laser-aided gelling (LAG) process was used to fabricate bioceramic scaffolds with inter-porous structures. To improve the mechanical property of the bioceramic parts after heating, CaCO₃ was added to the silica ceramic slurry. CaCO₃ was blended into a homogenous SiO₂-sol dispersion at weight ratios varying from 0/100 to 5/95 to 9/91 (w/w). Bi-component CaCO₃/SiO₂-sol was prepared as a biocomposite for the 3DP scaffold. The well-mixed biocomposite was used to fabricate the bioceramic green part using the LAG method. The varied scaffolds were sintered at different temperatures ranging from 900 to 1500°C, and the mechanical property was subsequently analyzed. The scaffolds showed good property with the composite ratio of 5:95 CaCO₃:SiO₂ at a sintering temperature of 1300°C. The compressive strength was 47 MPa, and the porosity was 34%. The topography of the sintered 3DP bioceramic scaffold was examined by SEM, EDS and XRD. The silica bioceramic presented no cytotoxicity and good MG-63 osteoblast-like cell affinity, demonstrating good biocompatibility. Therefore, the new silica biocomposite is viable for fabricating 3DP bone bioceramics with improved mechanical property and good cell affinity.

Zirconia (ZrO₂) has been widely used in clinical applications, such as bone and dental implantation, because of its favorable mechanical properties and resistance to fracture. However, the poor cell affinity of ZrO₂ for bone regeneration and tissue binding, as well as its shrinkage due to crystal phase transformation during heat treatment, limits its clinical use and processing plasticity. This study aims to investigate an appropriate ZrO₂–SiO₂ composite recipe for ceramic 3D printing processes that can strike a balance between the mechanical properties and cell affinity needed in clinical applications. Specimens with different ZrO₂–SiO₂ composite recipes were fabricated by a selective laser gelling method and sintered at temperatures ranging from 900 to 1500 °C. The S5Z5 composite, which consists of 50 wt% ZrO₂, 35 wt% SiO₂ and 15 wt% SiO₂ sol, showed an appropriate compressive strength and bending strength of 82.56 MPa and 55.98 MPa, respectively, at a sintering temperature of 1300 °C. The shrinkage rate of the S5Z5 composite was approximately 5% when the sintering temperature was increased from 900 to 1500 °C. All composites exhibited no cytotoxicity after 144 h of MG63 cell incubation, and the S5Z5 composite exhibited the most obvious cell affinity among the composite recipes. From these results, compared with other composites, the S5Z5 composite was shown to possess mechanical properties and a cell affinity more comparable to those of natural human bone.

Slurry concentration and wire speed affect the yield and machining quality of ceramics (Al₂O₃) that are produced using wire-saw machining (WSM). This study determines the effect of slurry concentration and wire speed on the material removal rate (MRR), the machined surface roughness (SR), the kerf width, the wire wear and the flatness for swinging and non-swinging WSM. The experiments show that swinging WSM results in a higher machining efficiency than non-swinging WSM. WSM with swinging also achieves a peak MRR at a medium slurry concentration (25 wt%) and a higher wire speed (5.6 m/s) using the cutting conditions for the experimental region. However, slurry concentration and wire speed have no significant effect on the machined SR, the kerf width, the wire wear or the flatness for WSM with swinging mode.