Establishment of a Responsive Tooth‐on‐a‐Chip Platform for the Assessment of Regenerative Factors in Dental Tissue Regeneration

Tooth formation relies on reciprocal signaling between embryological dental epithelial (DE) and mesenchymal (DM) cells, orchestrating the formation of enamel, dentin, and vascularized pulp. Current regenerative strategies aim to recreate DE-DM signaling, yet responsive in vitro platforms that faithfully reconstruct this interface and enable benchmarking of candidate cues are unavailable. Herein, a tooth-on-a-chip with a reconstructed DE-DM interface was tested for cue-specific tissue maturation in vitro. The platform comprises a polydimethylsiloxane microfluidic device integrating a fibrin-based mesenchymal compartment with an overlying epithelial layer. The system was exposed to two developmental inducers, sequential fibroblast growth factor 10 (FGF10) and bone morphogenetic protein 4 (BMP4), and BMP2, as well as the clinically used enamel matrix derivative Emdogain, to emulate distinct inductive environments. The platform robustly supported interface formation and revealed cue-specific maturation trajectories with high experimental reproducibility. Notably, Emdogain induced enamel organ-like structural maturation, revealing a previously unrecognized pro-enamel (amelogenic) activity of a biomaterial that has been used clinically for over three decades. Together, these findings validated the tooth-on-a-chip system as a biologically relevant in vitro test platform, providing a translational framework for benchmarking regenerative cues and guiding the development of dental regenerative therapies.