Yes, spit is gross.
It’s also pretty amazing – and critical to oral health. It helps wash away food particles and decay-causing microbes. It dilutes acid, helping keep the oral pH neutral or slightly alkaline. It provides calcium and phosphate to help remineralize and strengthen tooth enamel.
What’s more, research published late last year in Applied and Environmental Microbiology shows that compounds in saliva seem to actively protect the teeth from S. mutans, the main microbe involved in tooth decay.
Specifically, the researchers found that salivary mucins – a kind of protein that makes mucus, well, mucus-y (which is to say thick and gel-like) – provide a kind of natural defense system for the teeth. They don’t do it by killing bacteria. They trap and suspend them in fluid, keeping them from attaching to the teeth and colonizing.
[Lead author Erica Shapiro] Frenkel says their findings suggest boosting the body’s natural defences might be a better way to prevent tooth decay than relying on external agents like sealants and fluoride treatments.
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Frenkel also points out that the oral microbiome – the collection of friendly bacteria in the mouth – is better preserved when naturally present species are not killed. “The ideal situation,” she adds, “is to simply attenuate bacterial virulence.”
In fact, that’s the essence of oral hygiene. A sterile mouth is impossible, and killing “bad bugs” always necessarily involves killing good ones, too. Rather, brushing and flossing and the rest are means of controlling bacteria, not getting rid of them all together. As professor of oral microbiology Dr. Phillip Marsh has put it,
Pushing to have an ultraclean mouth isn’t beneficial to us; we should be trying to maintain our natural microbiota at levels compatible with oral health in order to preserve their beneficial activities.
For more on how to maintain good saliva flow, see our previous post on dry mouth.
Image by GG Puentes, via Flickr