Osteostimulation information

Osteostimulation is a technique attempted for improving healing of bone injuries or defects. It has not however been found to be significantly effective in increasing bone healing.^[1]

It is believed to work through the active stimulation of osteoblast proliferation and differentiation as evidenced by increased levels of DNA synthesis and of the osteoblast markers osteocalcin and alkaline phosphatase. Through an ionic exchange, Bioglass first acts as a scaffolding around and through which new bone forms. In vivo studies have demonstrated that the osteostimulative properties result in stimulation and acceleration of new bone formation in an osseous defect.^{[citation needed]}

Osseous defects, whether from trauma or surgical intervention, all follow a similar healing pattern. Within minutes of defect formation, platelets collect at the site of the injury and adhere to the exposed collagen fibers. The release of the platelet contents stimulates additional platelet aggregation and initiates clot formation.¹ This release also has a chemotactic effect and attracts various white blood cells (leukocytes) to the damaged tissues and an acute inflammatory response is initiated. Neutrophils and other leukocytes begin removing any bacteria, foreign material, and dead tissue via a process known as phagocytosis. The inflammatory response and other antigens in the wound also attract lymphocytes. These immune cells release cytokines, such as IL-1 and TNF-α,which can have multiple actions on further physiologic responses. For example, IL-1 amplifies the immune response by inducing the proliferation of T-cells, increases the phagocytic abilities of monocytes and macrophages, and induces the proliferation of fibroblasts. The disruption of the vascular supply, and the subsequent cellular reactions during the inflammatory and immune reactions, result in multiple changes in the local environment, including decreases in pH, oxygen content and the ionic concentrations for calcium, phosphorus, potassium and sodium. If these conditions persist, a chronic inflammatory response may set in, resulting in extensive tissue destruction.² With respect to implant materials, chronic inflammation and foreign body reactions are associated with the development of a fibrous capsule around the implant. The goal of a graft material is to aid in tissue healing.

By moderating pH and ionic concentration changes³, Bioglass may reduce the release or attraction of the immune cells, decreasing the time course and extent of the inflammatory response. Indirect evidence for this has been seen in recent research showing decreased TNF-α⁴ and elastase⁵ levels in the presence of Bioglass when compared to controls.