Cessation of Fgf10 signaling, resulting in a defective dental epithelial stem cell compartment, leads to the transition from crown to root formation.

Mouse, rat and human molars begin to form root after the completion of crown formation. In these teeth, fibroblast growth factor (Fgf) 10 disappears in the transitional stage from crown formation to root. By contrast, rodent incisors and vole molars demonstrate continuous growth, owing to the formation and maintenance of a stem cell compartment by the constant expression of Fgf10.