A recent study has shown for the first time that low-power lasers can be used to trigger stem cells in the body to form new tissue, including dentin in teeth. The study was done by a Harvard-led team that hopes their work can initiate a wave of clinical applications used to heal wounds and regenerate bones and teeth. The report for this study written by senior author and Robert P. Pinkas Family Professor of Bioengineering at the Harvard School of Engineering and Applied Sciences David J. Mooney was published in the journal Science Translational Medicine.
Dental Stem Cells
In their report, the research team describes how the low power laser triggered dental stem cells to create dentin which is the hard tissue that makes up teeth as well as the precise molecular mechanisms at play. Current procedures require scientists to remove stem cells from the body and work with them in the laboratory before they can go back in the body. The results of this type of research are difficult to translate to the clinic because of the regulatory and practical hurdles involved. The Harvard-led team hopes their laser-based method will be easier to translate to the clinic.
According to Professor Mooney, “Our treatment modality does not introduce anything new to the body, and lasers are routinely used in medicine and dentistry, so the barriers to clinical translation are low. It would be a substantial advance in the field if we can regenerate teeth rather than replace them.”
The research for this laser treatment began when Mooney and Dr. Praveen Arany, an Assistant Clinical Investigator at the National Institutes of Health (NIH), drilled holes in the molars of rats and treated the tooth pulp with low-powered laser light before sealing them with temporary caps. Dr. Arany examined the teeth using high-resolution x-ray imaging and microscopy and discovered that the lasers caused the stem cells in the tooth pulp to form dentin. The team then took the next step by experimenting with cultured tissue to investigate the molecular level activity when lasers are applied to trigger new tissue growth.
The researchers discovered that stem cells are triggered to produce dentin by a common regulatory cell protein called transforming growth factor beta-1, or TGF-B1. The TGF-B1 protein is inactive until a molecule activates it. The team discovered that the laser light causes reactive oxygen species (ROS) to activate the TGF-B1 complex which then triggers the stem cells to form dentin. This discovery scientifically confirms anecdotal reports that have circulated for years of doctors getting results from using laser light to stimulate skin and hair growth. This is also the first time scientists have identified the underlying molecular mechanisms of low power laser treatment.
“The scientific community is actively exploring a host of approaches to using stem cells for tissue regeneration efforts,” according to Don Ingber, Founding Director of the Wyss Institute that provided funding for the study. “Dave [Mooney] and his team have added an innovative, noninvasive and remarkably simple but powerful tool to the toolbox.”
Dr. Arany is currently working with a team on starting human trials and says they are “excited about expanding these observations to other regenerative applications with other types of stem cells.” Currently, fillings and dental implants are being used to repair and replace damaged teeth.