Why Do Mouth Wounds Heal So Quickly?

Why is it that a cut on your finger seems to last for days, but a cut in your mouth is usually healed by morning? There are a lot of factors at play, but 2017 research found one intriguing answer that could benefit more than just your mouth: There's a molecule in your saliva that can help grow new cells.

Scientific Spit-Take

Scientists already knew that saliva contains a peptide called histatin-1 that fights off bacteria and aids in wound healing. For a 2017 study published in the FASEB Journal, Chilean researchers set out to discover exactly how the little molecule helped heal wounds. In a series of experiments, they added histatin-1 to chicken embryo cells and several types of human blood-vessel cells and watched what happened.

There are many steps that have to happen for a wound to heal. New skin cells have to form and migrate from the wound's edges little by little to cover the whole thing like a Band-Aid. Active cells called fibroblasts move in, too, helping to produce collagen, elastin, and other proteins that the new skin will need. The body also starts regrowing blood vessels, which boosts blood flow to the wound and makes it heal even faster.

It turns out that histatin-1 does all of that. Not only does it make new skin cells migrate and attach themselves to the wound, but it actually helps to grow new blood vessels.

Should You Kiss It And Make It Better?

So if saliva heals wounds, should you lick yours? Probably not. For one thing, your mouth is full of germs: Some estimates say there are 650 different species of bacteria in there. You're better off using established methods: Clean the wound with a mild solution and keep it covered with a bandage. 

No, the most important thing to come from this research into saliva's healing powers is in the world of biotechnology. The Chilean researchers hope to use histatin-1 molecules to create new materials and implants that could help speed up wound healing. "The clear results of the present study open a wide door to a therapeutic advance," FASEB Journal editor in chief Thoru Pederson, Ph.D. said.

Correction 8/26/2019: A previous version of this article mentioned a 2016 study about "maternal kisses...alleviating minor childhood injuries." That study turned out to be fake, and the mention has been deleted.

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For more answers to deceptively complex science questions, check out "Ask a Science Teacher: 250 Answers to Questions You've Always Had About How Everyday Stuff Really Works" by Larry Scheckel. We handpick reading recommendations we think you may like. If you choose to make a purchase, Curiosity will get a share of the sale.

Written by Ashley Hamer August 28, 2017

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