Editorial: Bioceramics and Bioactive Glasses for Hard Tissue Regeneration

Since the 1980s, bioceramics (BCs) and bioactive glasses (BGs) have been used promisingly in orthopedics and dentistry to repair or replace damaged tissues. These biomaterials comprise a broad range of calcium phosphates (CaPs) based on their compositions and Ca/P molar ratio [e.g., amorphous calcium phosphates (amorphous-CaP, Ca/P: 1.2–2.2), α-tricalcium phosphate (α-TCP, Ca/P: 1.5), β-tricalcium phosphate (β-TCP, Ca/P: 1.5), hydroxyapatite (HAp, Ca/P: 1.67)], calcium silicates, glasses, and glass-ceramics (Rahaman, 2014). The initial use of these materials as fillers in bone defects has progressively extended to broader therapeutic applications in tissue engineering. Their specific chemical compositions and topographical features have promising effects on cellular response to enhance hard tissue regeneration through cell attachment, migration, proliferation, and differentiation in a three-dimensional (3D) micro-/ nano-environment. Furthermore, appropriate mechanical performance and biocompatibility of these materials are two critical issues for their possible and successful clinical translation. Therefore, there is a requirement to provide collective information and future perspectives or research directions on novel ideas and concepts to synthesize and characterize BCs and BGs, with emphasis on their chemical and structural characteristics, design of new compositions of BCs and BGs, their ease of processing with desired surface characteristics or topographies, and their mechanical and cellular responses in regulating cell fate in a 3D micro-/nano-environment for hard tissue regeneration. Tissue engineering (i.e., hard tissue regeneration) involves the combination of functional biomaterials and cells, including biomolecules and growth factors. Here, these bioactive materials have the ability to react with physiological fluids for making a firm bonding with living tissue through the formation of apatite layers that lead to an effective interaction with the biological system and attachment of bone tissue with the biomaterial surface (Hench, 1998; Kokubo et al., 2003; Kargozar et al., 2019). Functional biomaterials or scaffolds are highly porous structures with good pore interconnectivity and mechanical performance, and the efficacy of these properties (structure–property relationships) in biomedical applications is dependent on the fabrication technologies used (e.g., electrospinning, freeze-drying, and additive manufacturing methods) in order to achieve promising results with cells and growth factors in a biological environment (Kumar et al., 2017). Therefore, continuous research is expected to consider several interrelated requirements for structural and biological issues while selecting suitable BCor BG-based biomaterials for fabrication purposes. Furthermore, selection of suitable fabrication techniques is also a major challenge for obtaining scaffolds with desired properties that can mimic natural bone tissue regeneration. Although extensive research studies have already been done based on BCs and/or BGs as well as on their combinations with polymers (composites), several critical issues still remain Edited by: Masoud Mozafari, University of Toronto, Canada