Teeth and their supporting tissues have a very limited capacity for self-repair, so current dental treatments mostly replace lost tissue rather than regenerate it. Tissue engineering offers an alternative, but the oral environment makes it hard to keep cells and materials in place and to monitor them. Magnetic nanoparticles, mainly iron oxides such as magnetite and maghemite, can be controlled remotely by an external magnetic field and detected by magnetic resonance imaging. This review first summarises their structure, superparamagnetic behaviour, characterization, synthesis routes and surface coatings. It then discusses their advantages for tissue engineering: magnetically guided cell assembly, mechanobiological stimulation, responsive scaffolds, cell tracking and theranostics, injectable systems that can be controlled on demand, and an established safety record. Their applications are reviewed tissue by tissue. They include pulp–dentin regeneration with magnetic scaffolds and dental pulp stem cell spheroids, periodontal repair with graded scaffolds, labelled stem cells and field-responsive hydrogels, enamel engineering through magnetic cell-sheet assembly, occlusion of dentinal tubules for dentine hypersensitivity, and enhanced bone formation around magnetised implants. Across these studies, magnetic nanoparticles promote cell adhesion and odontogenic or osteogenic differentiation, especially under a static magnetic field. However, the evidence comes mostly from cell cultures and short-term rodent models, and particle properties and magnetic exposure vary widely between studies. Standardised reporting, larger animal models and long-term safety data are needed before these approaches can help dentistry move from replacing lost tissues towards regenerating them.