When you damage a tooth, your dentist usually uses a filling or a crown to patch it up. But eventually, researchers say that your dentist might just point a laser at it, encouraging the tooth to regrow on its own. While it's no surprise that light causes reactions in the human body, some researchers have been trying to determine whether specific wavelengths of light might be able to trigger specific healing properties when focused on a certain area of the body. In this case, the researchers pointed an infrared laser at a hole drilled into a rat's tooth and found that it encouraged dentin — the material that makes up a tooth's core — to grow back more than it otherwise would have.

"It would be a substantial advance in the field."The research was led from Harvard's Wyss Institute and is being published today in Science Translational Medicine. "Lasers are routinely used in medicine and dentistry, so the barriers to clinical translation are low," David Mooney, the research team's leader, says in a statement. "It would be a substantial advance in the field if we can regenerate teeth rather than replace them."

Though the laser light was able to make stem cells turn into new dentin, it wasn't a direct change. Instead, the laser set off a chain reaction, triggering one molecule, which triggered another, which finally set the stem cells in motion. That the researchers have been able to track that reaction all the way back, they say, is critical, because it allows them to actually prove the infrared laser's efficacy, rather than adding further anecdotal evidence to the heap of literature on laser therapies for a clinical study.

The researchers believe that this method, known as low-level light therapy, has the potential to trigger cells elsewhere in the body to similar reparative results. They won't be trying that next, however: instead, they plan to move on to human trials, and they're currently working with one of the National Institutes of Health to set up safety regulations.