For people who hate trips to the dentist (so, pretty much everyone), some good news: New research in Science Translational Medicine shows that lasers can help to regrow parts of broken teeth. One day, perhaps, lasers could make fillings, crowns, and other painful reasons to visit your dentist things of the past.
Earlier research suggested lasers could help regenerate heart, skin, lung, and nerve tissues. The reason is that low levels of laser light can apparently trigger chemical reactions that promote wound healing, reduce inflammation, and treat pain, among other effects. For instance, red light can accelerate hair growth.
For this new study, scientists at Harvard University and their colleagues focused on dentin, the tissue that makes up the bulk of human teeth. Dentin is harder than bone but softer than the enamel that coats teeth. When a tooth is damaged, dentists protect it with fillings, crowns, and veneers made of ceramics and other synthetic materials. But the scientists wanted to coax dental stem cells into regenerate dentin.
Rather than implanting modified dental stem cells into people or injecting chemicals to control dental stem cells in patients, the researchers wanted to find out whether they could activate proteins known as growth factors that are already in the body and use them to manipulate dental stem cells. The solution, of course, was lasers.
Laser light generates chemicals known as reactive oxygen species, the researchers think, and those chemicals activate a growth factor called transforming growth factor beta-1 (TGF-b1) in the body. This molecule in turn can stimulate dental stem cells to repair teeth. TGF-b1 is a member of a family of growth factors that is present in many other tissues, such as the skin and bone. That means it's possible that lasers could be used for regeneration here as well.
In experiments, the investigators used drills to damage molars in rats, removing pieces of dentin. They next shone lasers on the tiny, exposed teeth and the soft pulp underneath them, and applied temporary caps on the molars. Twelve weeks later, high-resolution x-ray imaging and microscopy confirmed enhanced formation of dentin.
And they didn't stop with rat studies. In experiments with adult dental stem cells extracted from human teeth, low levels of laser light activated TGF-b1 and led to the generation of dentin-forming cells. The scientists now aim to take their work to human clinical trials.