Low-power laser triggers stem cells to repair teeth

Ranking among the X-Men probably isn't all that it's cracked up to be, but who wouldn't want their uncanny ability to regenerate lost bone or tissue? New research into tooth repair and stem cell biology, from a cross-institution team led by David Mooney of Harvard's Wyss Institute, may bring such regeneration one step closer to reality or at the very least, give us hope that we can throw away those nasty dentures.

The researchers employed a low-power laser to trigger human dental stem cells to form dentin, a hard bone-like tissue that is one of four major components of teeth (the others being enamel, pulp, and cementum). This kind of low-level light therapy has previously been used to remove or stimulate hair growth and to rejuvenate skin cells, but the mechanisms were not well understood, results varied, and evidence of its efficacy was largely anecdotal.

The new work is the first to document the molecular mechanism involved, thus laying the foundations for controlled treatment protocols in not only restorative dentistry but also avenues like bone regeneration and wound healing. "The scientific community is actively exploring a host of approaches to using stem cells for tissue regeneration efforts," said Wyss Institute Founding Director Don Ingber. "Dave [Mooney] and his team have added an innovative, noninvasive, and remarkably simple but powerful tool to the toolbox."

To test the team's hypothesis, Praveen Arany, an assistant clinical investigator at the National Institutes of Health, drilled holes in the molars of rats and mice, then treated them with low-dose lasers and temporary caps. Around 12 weeks later, tests confirmed that the laser treatments triggered enhanced dentin formation.

Performing dentistry on rat teeth takes extreme precision and is actually harder than the same procedure on human teeth (Image: ames Weaver, Harvard's Wyss Institute)

Further experiments were conducted on microbial cultures in the laboratory, where they found that a regulatory cell protein called transforming growth factor beta-1 (TGF-1) was activated in a chemical domino effect that in turn caused the stem cells to form dentin. The good news there is that TGF-1 is more or less ubiquitous, with key roles in many biological processes such as immune response, wound healing, development, and malignancies.

This means we could one day see the technique used to do far more than help repair teeth. But first it needs to clear planned human clinical trials, so for now you'll have to make do with dentures, canes and all manner of other prosthetics while the likes of Wolverine prance around with self-healing bodies.

A paper on the research was recently published in the journal Science Translational Medicine.

Source: Wyss Institute at Harvard

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Low-power laser triggers stem cells to repair teeth