Compact Silicon Carbide Bio Glass Graft Material for Bone Augmentation.

Background: The significant clinical demand for bone augmentation and the reported complications with the current biomaterials make it an essential area of research. Using a rat model, the study explores the role of dense bioactive silicon carbide (SiC) ceramic and evaluates its integration to long bone.

Materials and methods: SiC cylinders were made at the dimension of 5×3×5 mm using SiC particles size 40 μm and were fabricated by exposing SiC particles to 15% NaOH for 15 minutes before they were mixed with the smaller SiC particles. Thereafter, they were heated to 650 °C for 5 hours. The biocompatibility and osteogencity of the SiC-compacted cylinders were then evaluated in vitro. After being cultured on the surface of SiC compact cylinders, mesenchymal stromal cells (MSCs) were evaluated for cell viability and differentiation using semi-quantitative RT-PCR, quantitative Alkaline Phosphatase (ALP) expression, and scanning electron microscopy. The material was then tested in vivo on 18 rats. After 12 weeks, the transplanted tissues were removed and subjected to mechanical, radiograph, and histologic analysis, including immunohistochemistry for osteopontin and S100.

Results: Osteogenic potential and SiC biocompatibility were noted. More radio-opacity that was indistinguishable from the cortical native bone was observed on cone-beam computed tomography for the samples; no radiolucent space was visible, indicating integration with bone. In comparison to the control group, the grafted long bone group exhibited a statistically significant greater Maximum Load and a high mechanical flexural strength compared with non-operated bone (P<0.001). Histologically, SiC integration was observed; mixed lamellar and woven bone is shown in the native bone, and osteoblastic cells were present at the edges of SiC. This was verified by positive osteopontin staining at the interface area. Moreover, positive staining at the interface area for S100 antibody indicates the innervation of the newly formed bone.

Conclusion: The tested construct made of compact SiC has potential to osteointegration into native bone, making it a suitable material for bone augmentation.