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An Introduction to Bioactivity via Restorative Dental Materials
Published in Mary Anne S. Melo, Designing Bioactive Polymeric Materials for Restorative Dentistry, 2020
Mary Anne S. Melo, Ashley Reid, Abdulrahman A. Balhaddad
The concept of “bioactive” was established in the late 1960s when a young professor in the Department of Materials Science and Engineering at the University of Florida, Larry Hench, invented the material we know as Bioglass. He created an entirely new paradigm for how biomaterials research viewed the interactions between synthetic materials and the human body (Greenspan 2016). The discovered Bioglass 45S5 or calcium sodium phosphosilicate material was able to replace the defective bone by the deposition of hydroxyapatite to bind the existing bone without any signs of rejection or complications (Hench et al. 1971). In the first stage of Bioglass placement, the alkali ions on the glass surface interact with the hydrogen ions from the surrounding tissue causing hydrolysis of the silica groups and an increased pH. As a result, the silanol group formation occurs and forms a silica-gel layer at the surface of the Bioglass. The calcium and phosphate ions transferred at the silica-rich layer making the structure of the Bioglass similar to the hydroxyapatite layer, which attracts the surrounding growth factors to promote the remineralization and regeneration process (Rabiee et al. 2015; Hench 2006).
Glass Processing and Properties
Published in Debasish Sarkar, Ceramic Processing, 2019
Bioglass 45S5 is commonly referred to by its commercial name bioglass. Commercial-grade dental bioglass and bioglass ceramics have distinct compositions and exist in different phases, which results in different degrees of in vivo bonding; classical compositions are discussed in Table 8.7. Class A bioactive materials bond to both bone and soft connective tissues. The surface reactions rapidly form a hydroxycarbanate apatite (HCA) layer that binds collagen fibers of soft and hard tissues. Class B bioactive materials bond to bone via osteoconduction but do not bond to soft tissues. The surface reactions to form an HCA layer are too slow to bind the collagen fibers of soft tissues. Medical professionals can choose a suitable composition according to the patient’s health and preferences.
Ceramic Based Biomaterials
Published in Yaser Dahman, Biomaterials Science and Technology, 2019
Bioglass is currently used for various applications, such as bone plating, dental implants, spinal fusions, and bone graft studies. One of the main uses of Bioglass 45S5 is to produce bioactive bone graft products. This type of bioglass functions by undergoing a dissolution process after being implanted into the body. The dissolution process of the bioglass consists of the material releasing ions (silica, phosphate, calcium, and sodium ions) that are resorbed and replaced by bone. The process is dependent on the size and shape of the particles; materials that are smaller have a higher surface area while materials with a spherical shape will tend to be resorbed faster and release more ions (Rahaman et al., 2011). In-vitro studies have shown that bioglass 45S5 dissolution ions positively affect bone formation involved cells (Figure 4.4). The ability of the bioglass to create a bone-like mineral layer on its surface is what gives the bioactive properties to this material. In the body, the particles that begin to dissolve combine with ions from the environment to form a hydroxy-carbano-apatite (HCA) coating on the surface. The similarity between HCA and bone mineral characteristics creates the optimal surface coating for new bone formation, resulting in a chemical bond between the bioactive glass ions and the surrounding bone. Bone replacement of the bioglass will take approximately 9–12 months (Bosetti, 2005).
Preparation of layered calcium silicate organically modified with two types of functional groups for varying chemical stability
Published in Journal of Asian Ceramic Societies, 2021
Jin Nakamura, Yuna Suzuki, Ryosuke Narukawa, Ayae Sugawara-Narutaki, Chikara Ohtsuki
Calcium silicate-based materials have been important components of artificial bones since the invention of Bioglass 45S5 [1]. A fundamental characteristic of calcium silicate-based materials is their capability of hydroxyapatite formation in the body [2]. The formation of hydroxyapatite on calcium silicate-based materials leads to direct bonding to living bone (i.e., bone-bonding). This can be achieved by the dissolution of calcium ions into the surrounding bodily fluid, which increases the degree of supersaturation with respect to hydroxyapatite. The soluble products released from the calcium silicate-based materials have been known to genetically stimulate osteoblasts, leading to proliferation, differentiation, and calcification [3,4]. An inorganic layered compound calcium silicate hydrate (CSH, CaxSiyOx+2y·nH2O) is composed of sheet-like units (denoted as hetero-layer) consisting of calcium oxide polyhedral, crosslinked by chains of SiO4 tetrahedra or “dreierketten” [5,6]. We focused on the CSH as a candidate for drug delivery carriers for bone-reconstruction treatment because materials with binary CaO-SiO2 composition have bone-tissue-bonding abilities through the formation of hydroxyapatite within the body [2]. Tuning the solubility of the CSH is the key to developing novel bone-bonding biomaterials as the solubility determines the releasing rate and the bone-bonding ability of the administered drug.