Stem cell technology is moving forward at a tremendous rate. Recent discoveries have surprised even the most expert researchers. While every piece of new data broadens the current knowledge and contributes to this moving forward, the new data also serve as paradigm shifters of fundamental knowledge of cell biology. While the question What is a Stem Cell may now seem to basic to even discuss, there are still some discrepancies, however, between groups in terms of their functional roles. Teeth develop from the ectoderm of the first branchial arch and the ectomesenchyme of the neural crest. Deciduous teeth start to form between the sixth and eighth weeks, and permanent teeth begin to form in the twentieth weeks. Several studies have demonstrated that the pulp from both adult teeth and deciduous teeth contains dental pulp stem cells. Several factors have made them very attractive as a model system for many researchers; they are multipotent, ethically and non-controversially available in large numbers, immuno-compatible, developmentally primitive, easy to isolate and have high expansion potential in vitro. However, many controversies still exist in the field. There are several unanswered questions in the biology of dental pulp and odontoblasts. This new volume in the" SpringerBriefs in Stem Cells" series presents an evaluation of stem cells from human dental pulp as a reliable stem cell source for cell-based therapy to stimulate tissue regeneration. "

Induced Pluripotent Stem (iPS) cells are mature cells that have been genetically reprogrammed so that they return to their embryonic state. It is not yet known if iPS stem cells and embryonic stem cells differ significantly. Today many fundamental belief systems in biology are shifting towards accepting that mature body cells can be reverted to an embryonic state without the help of eggs or embryos. With their changed identities, iPS cells are then ready to serve as new tools for research in the fields of disease pathogenesis, drug discovery, oncology, and cell transplantation. One example of this would be using iPS from a patient's mature cells to repair damaged tissue; it is thought that there would be very low incidence of rejection of the 'new' tissue in these cases. For the last four years, this therapeutic promise has been studied by hundreds of researchers worldwide in an effort to understand the ability of these cells to reverse their biological clocks.