In fact these cells are destined to become any one of more than 200 different types of tissue cells in the body, such as muscle cells, blood cells, nerve cells and even new teeth.
Science and technology has developed so much that in the recent years scientists hope to use these cells to develop new tissues, treatments and potentially even organs for transplanting into a patient. First and foremost argument made by the scientific community is that human stem cell research is said to promise new life changing treatments and possible cures for many devastating diseases and injuries, such as Parkinson's disease, diabetes, heart disease, multiple sclerosis, burns and spinal cord injuries (Young 2-16).
There are a number of sources for obtaining human stem cells. The first is IVF (In Vitro Fertilization) treatment, where surplus embryos (and unfertilized eggs for creating embryos) are donated for research with the consent of the donor rather than being destroyed following treatment. The second source is aborted tissues, which are used as stem cells taken from the aborted fetus. Another is umbilical cord blood, rich in stem cells. These cells are harvested following the baby's birth.
The most controversial is perhaps therapeutic cloning, where cells are created for research that is genetically identical to the donor (patient). This is done by removing the nucleus of an egg and fusing this egg with any enucleated cell from the donor. This will create an embryo genetically identical to the donor. Cells can then be harvested from this embryo for treatment. Being an exact replica, there is potentially less chance of rejection following transplantation.
The US President's Council on Bioethics recently published a whole white paper on Alternate Sources of Human Pluripotent Stem Cells (www.bioethics.gov). Sometimes these cells could be taken from the recipient patients themselves, avoiding any immune-rejection difficulties. At other times they are taken from donors. There are even proposals to create new non-embryonic organisms which can produce human stem-cells. What all these 'adult' stem-cells have in common is that they are derived from people without harming anyone. Umbilical cord blood, the placenta and even the amniotic fluid have in fact been found to be rich in stem-cells (McGuckin et al 245-255). Stem-cells have also been found in all the tissues found in our bodies such as the brain, pancreas, liver, skin, fat, muscle, blood, bone marrow, lungs, nose and tooth pulp. This paper discusses the importance of stem cell research in the dental field.
At this point of time it is important to understand the how the tooth is formed and what are the fundamental cells involved in this process. The process of tooth formation begins with the interactions between epithelial and dental papilla cells. This interaction promotes tooth morphogenesis by stimulating a subpopulation of mesenchymal cells to differentiate into odontoblasts. These odontoblasts are finally destined to form the primary dentin. If we look into the morphology of odontoblasts, these are columnar polarized cells with eccentric nuclei and long cellular processes aligned at the outer edges of dentin (Smith et al. 273-280).
Once the tooth erupts, reparative dentin is formed by