In the fourth year of the New Faculty award, my colleagues and I have continued work on all 3 Aims. We have made significant progress on Aim 1, which focuses on the study of mouse dental stem cells in the animal. The mouse incisor provides an excellent model for studying the processes that underlie the ability of epithelial stem cells to contribute to tissue renewal, because its continuous growth requires generation of all the necessary cell types from adult stem cells. As little is known about how this continuous growth is achieved, one of the main focuses of this CIRM grant is to understand this process. We have published several manuscripts over the past year based on the results from Aim 1, and we expect that at least one more manuscript will be prepared during the coming year resulting from the work on Aim 1. For the experiments in Aim 2, we have been developing the adult dental stem cell culture system, and we have just published a manuscript describing the system and conditions. We continue to work on experiments in Aim 3, using human fetal ameloblasts and embryonic stem cells, and have generated more data for this Aim that we intend to publish in the coming year.