The promise of injectable hydrogels in dental bone regeneration

Injectable hydrogels are considered to be a minimally invasive approach for the regeneration of the dental bone, providing a number of benefits over traditional surgical procedures. These three-dimensional networks can be given in liquid form and undergo in situ gelation, which keeps their high-water content and structural integrity while enabling them to conform to irregular bone defects. This review focuses on the current state of injectable hydrogel systems for dental bone regeneration, strategies of synthesis, and biological performance, focusing on the design of the material and clinical translation. Injectable hydrogels can be broadly classified into two categories: natural polymer-based systems and synthetic polymer-based systems. Natural polymer-based systems include materials such as chitosan, alginate, hyaluronic acid (HA), and protein-based formulations. Synthetic polymer-based systems include polyethylene glycol (PEG), polyvinyl alcohol (PVA), and thermosensitive polymers. Hybrid composite systems combine the mechanical flexibility of synthetic polymers with the bioactivity of natural polymers. Both physical crosslinking techniques (ionic interactions, thermogelation, and hydrogen bonding) and chemical crosslinking techniques (enzymatic catalysis, Schiff base reactions, photoinitiation, and thiol-disulfide exchange) are included in the synthesis and gelation mechanisms, and each has unique benefits concerning mechanical characteristics, degradation kinetics, and biocompatibility. Advanced fabrication methodologies, including fibre integration, bioprinting, and integration of nanotechnology, have enhanced the functional properties of injectable hydrogels. These systems promote osteogenesis, angiogenesis, immunomodulation, and infection control by acting as flexible carriers for growth factors, bioactive ceramics, extracellular vesicles (EVs), and antimicrobial agents. Growth factor-loaded hydrogels have accelerated bone healing and periodontal regeneration in human subjects, according to clinical trials with encouraging results. However, despite the progress, there are limitations in improving the mechanical properties for the oral environment, establishing uniform regulatory frameworks for clinical translation, preserving bioactivity during degradation, and reaching regulated biodegradation rates. Future research should concentrate on building a dual-functional system that combines regenerative qualities and antimicrobial qualities. Large-scale manufacturing under Good Manufacturing Practice (GMP) conditions and the design of patient-specific scaffolds using artificial intelligence and computational modelling are critical for successful clinical translation.