Stem cells extracted from baby teeth were able to regenerate dental pulp (shown, with fluorescent labeling) in young patients who had injured one of their adult teeth.                       Photo courtesy of University of Pennsylvania

Young children can be full of life.

For parents that bubbly energy can be fun to observe and enjoy, but in other instances when they trip and fall, or do something that causes trauma to their mouth – their teeth can take a hit. Unfortunately when that trauma affects an immature permanent tooth, it can also hinder blood supply and root development, resulting in what is essentially a “dead” tooth.

Until recently the only treatment option was apexification, a procedure which encourages root development but doesn’t always fix the lost tissue. In fact, it’s been known to cause abnormal root development.

So what is a parent to do?

Turn to a clinical trial.

New results of a clinical trial, jointly led by Songtao Shi of the University of Pennsylvania, who has also previously received funding from CIRM, and researchers at the the Fourth Military Medicine University in Xi’an, China, suggest that there is a more promising path for children with these types of injuries: using stem cells extracted from the patient’s baby teeth.

The work was published in the journal Science Translational Medicine.

“This treatment gives patients sensation back in their teeth. If you give them a warm or cold stimulation, they can feel it; they have living teeth again,” says Shi, professor and chair in the Department of Anatomy and Cell Biology in Penn’s School of Dental Medicine. “So far we have follow-up data for two, two and a half, even three years and have shown it’s a safe and effective therapy.”

The Phase I 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 receive a treatment of human dental pulp stem cells (hDPSC) and 10 to the control treatment, apexification.

Those that received hDPSC treatment had tissue extracted from a healthy baby 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. Blood flow increased as well. A year following the procedure, only those who received hDPSCs had regained some sensation. Examining a variety of immune-system components, the team found no evidence of safety concerns.

As further support of the treatment’s effectiveness, the researchers had the opportunity to directly examine the tissue of a treated tooth when the patient re-injured it and had to have it extracted. They found that the implanted stem cells regenerated different components of dental pulp, including the cells that produce dentin, connective tissue, and blood vessels.

But this is just a first step. While using a patient’s own stem cells reduces the chances of immune rejection, it’s not possible in adult patients who have lost all of their baby teeth.

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.