Stem cells are unspecialized cells, which have the capacity to self-renew and generate differentiated cell types. They hold great promises in regenerative medicine, which has the potential to revolutionize our approach to treat diseases and alleviate problems caused by trauma and aging. The dental field has been an active area for researching stem cell based therapies and a great effort has been made to develop strategies for utilizing embryonic stem cells (ESCs), adult dental stem cells and more recently, induced pluripotent stem (iPS) cells in tooth regeneration. In this review, we focus on these three main sources of stem cells, describe findings that have laid the foundation for using these cells in tooth regeneration, and discuss the potential as well as challenges of tooth bioengineering in clinical application.