Stem cell-driven biomedical technologies for tooth regeneration: engineering scaffolds, organoid models, and...

Tooth loss remains a major unmet clinical challenge, and current prosthetic approaches cannot restore the biological complexity, sensory function, or regenerative capacity of natural teeth. Recent progress in stem cell biology, developmental engineering, and regenerative biomaterials has opened new possibilities for biological tooth regeneration. This review integrates advances across three major research domains that together define the current landscape of translational regenerative dentistry. First, we discuss stem cell-based, scaffold-guided strategies for tooth regeneration. These approaches combine dental and nondental stem cells, including DPSCs, SCAPs, PDLSCs, SHED, and iPSC-derived lineages, with bioactive materials such as HA/TCP ceramics, dentin-derived extracellular matrix scaffolds, and natural or synthetic polymers to promote odontogenic differentiation, vascularization, and periodontal attachment. Second, we summarize emerging tooth organoid and bioengineered tooth germ technologies that recapitulate epithelial-mesenchymal interactions and enable controlled reconstruction of dentin-pulp and periodontal compartments for modeling human odontogenesis. Third, we highlight molecular regulation-driven therapeutic strategies, focusing on the modulation of Wnt, BMP, FGF, TGF-β, and USAG-1 pathways to stimulate endogenous tooth regeneration and correct developmental defects. Despite marked progress, challenges remain, including stable neurovascular integration, optimization of stem cell-material crosstalk, precise control of spatiotemporal signaling, and long-term functional stability in vivo. Finally, we outline future directions involving smart biomaterials, gene- and protein-based molecular targeting, organoid-guided regeneration, and iPSC-enabled personalized therapies, which may further accelerate the clinical translation of stem cell-based tooth regeneration.