Contribution f Neural Crest Cells in Tooth Development and the Possibility of Tooth Regeneration '

The tooth is a vertebrate-specific organ that deve]ops through a series of reciprocal interactions between epithelium and mesenchyme. In this process, the neural crest (NC) cells participate in tooth development. NC cells are multipotent cells that are generated from the IHteral ridge of the dorsal neural tube during the early stuges of embryogenesis. NC cells migrate into various tissues, wherc they differentiate into udontoblusts, chondrocytes, osteoblasts, neurons and melanocytes, NC cells also participate in organogenesis in such organs as the teeth, mandible, heart and thymus, No tooth is observed in invertebrates, which do not have NC cells. The study of tooth development is thus useful for examining the roles of NC cells in tooth organegenesis. It has been considered that teeth can never be regenerated. However, recent progress in stem cell biology has proved the regeneration of neurons in the brain. These findings suggest the possibi]ity of tooth regeneration. Here. we review the relationships between NCLderived cel]s and tooth deve]opment, and discuss the possibility of the presence of tooth germ, dental putp cells, embryonic stem cells, und multipetent NC cellsin the peripheral tissues.