Bioactive glass has a long history of scientific investigation and clinical use. It consists of elements naturally existing in the body including Si, Na, Ca and P. When in contact with body fluids, bioactive glass undergoes a series of chemical reactions attracting the cells and proteins necessary for bone growth. Specifically, the surface reaction results in the formation of a silica gel layer which attracts calcium phosphate (CaP) that then crystallizes to form a hydroxyapatite (HA) layer which is similar in composition and structure to that found in bone. Osteoblasts become encased in a collagen and HA matrix which enables direct bonding with new bone. Vitrium is gradually resorbed and replaced by new bone during healing. Many of these processes can be observed in Figure 1.
The perceived brittleness of bioactive glass has limited its use to enhancing the bioactivity of other materials or as non-structural particles suspended in putties. Vitrium is the first bioactive glass material to be used as a standalone implant. Its physical properties, including pore size, percent porosity, compressive strength and compressive modulus can be engineered to meet specific applications.
Vitrium is produced by sintering bioactive glass fibers into a three-dimensional structure resembling that of cancellous bone. Pore formers are utilized to create macropores ranging from 100 to 600 microns to provide pathways for propagation of new, healthy bone. The pore formers are vaporized during the patented sintering process, rendering the final material composition 100% bioactive glass.