Scientists have come up with a bright way to whiten the smile.
They say their concept of using laser light to entice the body's own stem cells into action may offer enormous promise beyond dentistry in the field of regenerative medicine.
The researchers used a low-power laser to coax dental stem cells to form dentin, the hard tissue similar to bone that makes up most of a tooth, demonstrating the process in studies involving rats and mice and using human cells in a laboratory.
They did not regenerate an entire tooth because the enamel part was too tricky, but getting dentin to grow could end root canal treatment, the painful procedure to remove dead or dying nerve tissue and bacteria from inside a tooth, they said.
"I'm a dentist by training. So I think it has potential for great impact in clinical dentistry," researcher Praveen Arany, a United States National Institutes of Health researcher said.
Arany expressed hope that human clinical trials could get approval in the near future.
Harvard University bioengineering professor David Mooney said: "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."
Using existing regeneration methods, scientists must take stem cells from the body, manipulate them and put them back into the body. This technique more simply stimulates stem cells that are already in place.
Scientists had long noticed the capacity of low-level laser therapy to stimulate biological processes but were not sure how.
Arany noted the importance of finding the right laser dose, saying: "Too low doesn't work and too high causes damage."
The researchers found that laser exposure of the tooth prompted certain molecules to activate a cell protein known to be involved in development, healing and immune functions.
Arany said he hoped the method could be used in healing wounds, regenerating cardiac tissue, dealing with inflammation issues and fixing bone damage, among other applications.
The study appears in Science Translational Medicine.