Glass-ceramics in dentistry: Fundamentals, technologies, experimental techniques, applications, and open issues

Dental glass-ceramics (DGCs) are developed by controlled crystallization of oxide glasses and form an important group of biomaterials used in modern dentistry. They are also of great importance to scientists studying the fundamentals of crystallization. DGCs must meet strict requirements for restorative prostheses and to streamline the workflow for dentists and increase patient comfort. Considerable research has been devoted to developing new DGCs using advanced technologies, such as CAD/CAM or 3D printing, and to improve material properties. DGCs are designed to have exceptional aesthetics, translucency, high strength, chemical durability, wear resistance, biocompatibility, low thermal conductivity, and hardness similar to that of natural teeth. Some are also bioactive to stimulate a favorable response from the tooth and supporting bone. This allows treatment of hypersensitivity, regeneration of alveolar bone, and healing of periodontal tissues. In this comprehensive and critical review, we compare (inert) restorative prostheses and bioactive GCs. We elaborate on the relevant theoretical fundamentals of crystallization in oxide glasses and explain key technologies to fabricate DGCs. Advanced experimental techniques to unveil the details of crystallization in DGCs are thoroughly discussed. Finally, we propose a strategy for adopting advanced technologies, characterization tools, theoretical insights, and computer models to advance this important field.