Large oral bone defects require grafting of bone blocks rather than granules to give physically robust, biocompatible and osteoconductive regeneration. Bovine bone is widely accepted as a source of clinically appropriate xenograft material. However, the manufacturing process often results in both reduced mechanical strength and biological compatibility. The aim of this study was to assess bovine bone blocks at different sintering temperatures and measure the effects on mechanical properties and biocompatibility. Bone blocks were divided into four groups; Group 1: Control (Untreated); Group 2: Initial boil for 6 h; Group 3: Boil 6 h followed by sintering at 550 °C for 6 h; Group 4: Boil 6 h followed by sintering at 1100 °C for 6 h. Samples were assessed for their purity, crystallinity, mechanical strength, surface morphology, chemical composition, biocompatibility and clinical handling properties. Statistical analysis was performed using one-way ANOVA and post-hoc Tukey’s tests for normally distributed and Friedman test for abnormally distributed quantitative data from compression tests and PrestoBlue™ metabolic activity tests. The threshold for statistical significance was set at p < 0.05. The results showed that higher temperature sintering (Group 4) removed all organic material (0.02% organic components and 0.02% residual organic components remained) and increased crystallinity (95.33%) compared to Groups 1–3. All test groups (Group 2–4) showed decreased mechanical strength (MPa: 4.21 ± 1.97, 3.07 ± 1.21, 5.14 ± 1.86, respectively) compared with raw bone (Group 1) (MPa: 23.22 ± 5.24, p <0.05), with micro-cracks seen under SEM in Groups 3 and 4. Group 4 had the highest biocompatibility (p < 0.05) with osteoblasts as compared to Group 3 at all time points in vitro. Clinical handling tests indicated that Group 4 samples could better withstand drilling and screw placement but still demonstrated brittleness compared to Group 1. Hence, bovine bone blocks sintered at 1100 °C for 6 h resulted in highly pure bone with acceptable mechanical strength and clinical handling, suggesting it is a viable option as a block grafting material.

Bone loss resulting in large bony defects presents a significant challenge for surgeons. In cases requiring reconstruction, bone “block” grafts that have the key attributes of both physical robustness and biocompatibility are required to facilitate bone healing and regeneration. Current technologies employed for the development of block grafts often result in constructs with suboptimal strength and integration. This study aimed to develop a bovine‐derived bone block graft using the process of supercritical fluid (SCF) extraction to maintain mechanical strength and biocompatibility. Bone blocks were prepared from the condyles of bovine femurs. After optimization, the blocks were divided into six groups; Group 1: Raw bone, Group 2: SCF–CO₂, Groups 3: SCF–CO₂–H₂O₂, and Group 4: SCF–CO₂–H₂O₂ + Pepsin. Characterization of the constructs included analysis of organic material (thermogravimetric analysis, TGA), crystallinity using x‐ray diffraction (XRD), surface topography with scanning electron microscopy (SEM), and chemical composition using Fourier‐transform infrared (FTIR) spectroscopy. Mechanical strength was assessed using compression testing, and clinically relevant handling was investigated with a bench‐top drill test. Biological testing was carried out in vitro using human bone marrow‐derived mesenchymal stem cells (hBMSCs). The SCF‐treated bone blocks showed promising results with enhanced mechanical strength (raw bone [mean = 23.01 8.9 MPa], SCF–CO₂–H₂O₂ [mean = 48.9 ± 11.6 MPa], p < 0.0001) reduced organic content (raw bone = 17.6%, SCF–CO₂–H₂O₂ + Pepsin = 12.4%), and significantly higher hBMSCs' metabolic activity on the SCF–CO₂ and SCF–CO₂ + H₂O₂ compared to Bio‐Oss at 24, 48, 72, and 96 h (p < 0.05). SEM photomicrographs showed reduced debris in trabecular structures with open pores after SCF–CO₂ treatment, especially in SCF–CO₂–H₂O₂ + Pepsin blocks. Moreover, the bench‐top clinical handling test demonstrated the ease of block fixation with surgical screws. Overall, the SCF–CO₂ and posttreatments of bovine block grafts showed potential for clinical application.