Chapter 19. Bioactive Silicate Glass in Implantable Medical Devices: From Research to Clinical Applications

Abstract

Melt-derived silicate bioactive glasses have excellent osconductivity. However, due to insufficient mechanical properties, bioactive glasses as such are not suitable for load-bearing. This chapter reviews two fundamentally different approaches to complement medical devices with bioactive glass. We discuss metallic implants coated with bioactive glass and fiber-reinforced composite implants which rely on bioactive glass as an ostreoconductive component. Significant efforts have been made in coating load-bearing metallic implants with bioactive glasses. The problems with typical coating methods like spray-coating, enameling and immersion casting include scaling of the substrates at the elevated temperatures, loss of the compositional control, transport of unwanted ions from the substrate into the glass and difficulties in matching the thermal expansion coefficients of the glasses and metals. Therefore, novel coating methods (laser cladding, enameling by direct laser treatment and electrophoretic deposition) were introduced. However, no workable solution has been found. In addition, metallic implants as such are not devoid of drawbacks, and could be replaced by modern fiber-reinforced composite implants. In load-bearing applications, these implants are still in the preclinical testing phase, whereas a major breakthrough occurred in the application of non-load-bearing bioactive glass containing fiber-reinforced composite implants for the treatment of patients with calvarial defects.