2016 Volume 59 Issue 4 Pages 351-358
Purpose: Beta-tricalcium phosphate (β-TCP) exhibits biocompatibility and osteoconductivity and has been used clinically as a bone graft material. However, conventional β-TCP degrades slowly, with residual material frequently inducing aberrant healing. We therefore developed a collagen scaffold containing β-TCP nanoparticles by applying nanoscale dispersing technology. When the nano-β-TCP/collagen scaffold was implanted into rat cranial bone, its degradation and bone augmentation were remarkable when compared with collagen sponge. Accordingly, we evaluated the bone-forming effects of nano-β-TCP/collagen scaffold on extraction sockets in dogs.
Methods: β-TCP powder (average particle size: 2.3 μm) was pulverized into nanoscale particles and dispersed into distilled water along with the surfactant sodium cholate (0.2 wt%). Collagen sponge was immersed in a dispersion (1 wt%) of β-TCP nanoparticles. This was followed by rinsing and freeze-drying to yield the nano-β-TCP/collagen scaffold. The surface of the scaffold was characterized by SEM. Subsequently, the extraction socket of a maxillary first premolar was filled with nano-β-TCP/collagen scaffold in the experimental group, while collagen sponge was applied to the socket in the control group. Radiographic images of the socket were then obtained at baseline, and at 1, 3 and 5 weeks after surgery. Histological observations were performed at 2 and 5 weeks.
Results: SEM images showed nanosized (approx. 100 nm) β-TCP particles attached to the fibers of collagen sponge. The interconnected spaces within the collagen sponge were not filled with β-TCP particles. In the experimental group, the extraction socket showed increased radiopacity when compared with the control group. Histological observation at 2 weeks revealed that new bone was present in the socket in the experimental group. In addition, ingrowth of cells and blood vessels was detected in the nano-β-TCP/collagen scaffold. In contrast, only slight new bone growth was seen in the control group. At 5 weeks in the experimental group, the scaffold had disappeared and the extraction socket was fully filled with new bone. In the control group, although new bone was detected, connective tissue and residual collagen sponge were also observed in part of the extraction socket. Newly formed bone area in the experimental group (25.1%) was significantly greater when compared with the control group (7.6%). Residual material area in the experimental group (59.1%) was significantly less when compared with the control group (81.2%).
Conclusion: Nano-β-TCP/collagen scaffold exhibited high biocompatibility and degradability. New bone formation in tooth extraction sockets of dogs was facilitated by implantation of nano-β-TCP/collagen scaffold.
