Mechanism of bone formation Bond Apatite®
Case 1 - Bond Apatite® Histology 3 months post op
Is a composite bone graft cement, which is made of pure Biphasic calcium sulfate cement and Hydroxyapatite (HA) particles, in a 2:1 ratio.
- The HA particles (PSD) are specifically designed and packaged to consist of various sizes, ranging from 90 microns to 1mm.
- The HA particles were designed to serve two primary functions: 1. To slow down the overall resorption rate of the graft. 2. To maintain the graft volume. In doing so, the HA particles are able to be used in a wide variety of grafting procedures, ranging from small and simple bone deficiencies to larger and more complex bone defect treatments.
- The physiologic bone formation mechanism is entirely different from that of conventional particulate bone grafting. The fundamental difference between traditional grafting materials and that of Bond apatite has to do with the integration of the particles. With conventional grafting materials, there is a physical integration of the graft particles, resulting in only 20-25% of vital bone formation. In contrast, with Bond apatite® there is absolutely no integration between the newly formed bone, allowing the HA particles to be completely resorbed. As a consequence of this mechanism, the graft is completely transformed into the patient’s native bone. No graft is left behind; only the patient’s newly formed vital bone with 100% regeneration..
- In being a composite graft, this material has two different resorption modes:
- Biphasic Calcium sulfate – Comprises of 2/3 of the graft material and resorbs relatively quickly, within 4 to 10 weeks.
- HA Particles – Due to the unique controlled PSD, the particles resorb over a period of a few months.
- The small- and medium-sized HA particles resorb in 3-4 months. In contrast, the larger size particles, which comprise of less than 10%, will remain for a prolonged period of time, fully resorbing after eight months – at which time the particles have almost entirely disappeared and been replaced by vital host bone.
Case 2 - Bond Apatite® Histology 8 months post op
Core for histology was harvested 8 months post op
How does it work
Immediately following the placement of Bond apatite® graft cement into the bony defect, a degradation process of the biphasic calcium sulfate components initiates.
- Calcium sulfate (CS) does not simply resorb. Rather, there is an interaction and a biological effect between the calcium sulfate dissolution and the bone growth. This interaction significantly stimulates bone formation – therefore categorizing Bond apatite® as a bioactive material.
- • As CS dissolves and recedes, a vast number of calcium ions are released. In a biological process, the calcium then precipitates into hydroxyapatite-like calcium phosphate mineral latticework, which acts as an osteoconductive trellis for new bone formation. This becomes incorporated into new bone and then remodels as the bone matures over time.
- The HA particles occupy 1/3 of the composite graft components, and are intended to slow down the overall resorption rate of the graft. The particles differ in both size and shape, ranging from 90 microns to 1mm. They do not integrate with the bone. Instead, during their resorption process, they are first encapsulated by connective tissue, then resorbed, and then the connective tissue undergoes ossification.
- Thus, 12 weeks post op, nearly 90% of the graft is replaced by the patient’s own bone, while eight months post-op, almost no remnants of the graft can be seen due to the complete transformation of the graft into new vital