When trauma affects an immature permanent tooth, it can hinder blood supply and root development, resulting in what is essentially a “dead” tooth. Until now, the standard of care has entailed a procedure called apexification that encourages further root development, but it does not replace the lost tissue from the injury and causes root development to proceed abnormally.

New results from a clinical trial, jointly led by Songtao Shi of the University of Pennsylvania and Yan Jin, Kun Xuan and Bei Li of the Fourth Military Medicine University in Xi’an, China, suggest that there is a more promising path: using stem cells extracted from the patient’s baby teeth. Dr. Shi and colleagues have learned more about how these dental stem cells, called human deciduous pulp stem cells (hDPSC) work and how they could be safely employed to regrow dental tissue, known as pulp.

The Phase 1 trial, conducted in China, enrolled 40 children who had each injured one of their permanent incisors and still had baby teeth. Thirty were assigned to hDPSC treatment and 10 to the control treatment, apexification. Those who received hDPSC treatment had tissue extracted from a healthy baby tooth. The stem cells from this pulp were allowed to reproduce in a laboratory culture, and the resulting cells were implanted into the injured tooth. Upon follow-up, the researchers found that patients who received hDPSCs had more signs than the control group of healthy root development and thicker dentin, the hard part of a tooth beneath the enamel, as well as increased blood flow. At the time the patients were initially seen, all had little sensation in the tissue of their injured teeth. A year following the procedure, only those who received hDPSCs had regained some sensation.

While using a patient’s own stem cells reduces the chances of immune rejection, it is not possible in adult patients who have lost all of their baby teeth. Dr. Shi and colleagues are beginning to test the use of allogenic stem cells, or cells donated from another person, to regenerate dental tissue in adults. They are also hoping to secure FDA approval to conduct clinical trials using hDPSCs in the United States. Eventually, they see even broader applications of hDPSCs for treating systemic disease, such as lupus.