No abstract

Glass caused a revolution in health care when Bioglass was discovered by Larry Hench. It was the first material to bond with bone, rather than be encapsulated by fibrous tissue, launching the field of bioactive ceramics. Bioglass is also biodegradable. Almost 50 years on from its discovery that revolution continues. Bioactive glasses stimulate more bone regeneration than other bioactive ceramics, which is attributed to their dissolution products stimulating cells at the genetic level. This second discovery has changed the way clinicians, scientists, and regulatory bodies think about medical devices and the concept of bioactivity. The original 45S5 Bioglass has only recently found really widespread use in orthopedics, having regenerated the bones of more than 1.5 million patients. Its full potential is still yet to be fulfilled. This article takes the reader from Hench's Bioglass 45S5 to its clinical uses and products, before giving examples of nonsurgical products that now use Bioglass, from consumer products, such as toothpaste, to cosmetics. Other glasses have also found important health care applications, such as borate‐based glasses that heal chronic wounds. The revolution looks set to continue as new health care applications are being found for bioactive glasses, contributing to extending the glass age.

The authors declare no conflict of interest. N ovaMin ® is the trade name for a calcium sodium phosphosilicate bioactive glass that has been developed for use in oral health care. Originally developed for the treatment of hypersensitivity by the physical occlusion of dentinal tubules, recent studies have demonstrated a potential for this material to prevent demineralization and/or aid in remineralization of tooth surfaces. The mode of action of this material results from interactions with aqueous solutions. When introduced into the oral environment, the material releases sodium, calcium, and phosphate ions, which then interact with oral fluids and result in the formation of a crystalline hydroxycarbonate apatite (HCA) layer that is structurally and chemically similar to natural tooth mineral. This article will focus on the mechanisms of action of NovaMin and present results from a series of in vitro and in situ studies demonstrating the potential of this material in the areas of remineralization and caries prevention.

Melt derived 45S5 Bioglass(R) has been studied for more than 25 years. Bioglass(R) has excellent biocompatibility, and its surface reactivity has contributed to its clinical success over the past 10 years. Recently, porous bioactive glasses have been derived through sol-gel processing in an attempt to increase the specific surface area, and, thus, the surface reactivity and degradability of the material. This allows the material to be replaced ultimately by natural tissue while it stimulates bone regeneration. In this work, the processing and properties of these sol-gel bioactive glasses are discussed, and a new drying method and treatment is described to make homogeneous particulate and monoliths on a production scale.

A class of melt‐quenched silicate glasses, containing calcium, phosphorus and alkali metals, and having the ability to promote bone regeneration and to fuse to living bone, creating strong implants with less danger of interfacial instability than previous materials, is produced commercially as Bioglass® and sold under the brand names of PerioGlas®, NovaBone® and NovaBone‐C/M®. We have collected the first high energy X‐ray and neutron diffraction data, on this important material in the hope of providing more direct experimental insight into the glass structure. Similarly, the first solid state MAS (magic angle spinning) 29Si, 31P, and 23Na NMR data on the material is presented. The diffraction data has been modeled using the reverse Monte Carlo (RMC) method to allow the identification of the atomic‐scale structural features present; the solid state NMR data is used explicitly within the model‐building process as a constraint on the connectivity of the network. The 29Si NMR suggests that the host silica network primarily consists of chains and rings of Q2 SiO4 tetrahedra, with some degree of cross linking as represented by the presence of Q3 units. The diffraction‐based RMC model suggests a Na–O distance of 2.35 Å and a corresponding coordination of ∼ 6; the coordination number is supported by the 23Na NMR data presented here which reveals that the likely sodium environment is six‐coordinate in pseudo‐octahedral arrangement. The RMC model provides evidence for the non‐uniform distribution of Ca, which is in line with previous molecular dynamics simulation results, and the data is also suggestive of CaO as the associated structural motif within the high calcium content regions of the glass.