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This One Ingredient Naturally Whitens Coffee-Stained Teeth, New Study Says

Scientists used a high-precision method to find this on-trend, holistic formula is actually effective.

If you're one of the 80% of people who sip coffee most every day, there's probably a good chance you've studied the mirror to see whether your favorite drink is discoloring your smile. If you're concerned about coffee stains—but not so sure about frequently using whitening products with peroxide—check out what ingredient brightened things up after scientists soaked a set of teeth inside coffee for nearly a week straight.

A team of dental researchers at Iran's Shahid Beheshti University of Medical Sciences recently published an intriguing study in the peer-reviewed Dental Research Journal. To start, the research team allowed 30 teeth to sit inside a 98.6-degree coffee solution for five days. They used an electronic wavelength device to measure the color of the teeth, as well as an instrument for measuring the surface of the teeth.

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Then, they split the teeth into three groups of 10. Science suggests charcoal's abrasive nature helps slough foreign material away from surfaces, and its chemical composition binds to absorb toxins away from the source, like coffee stains on otherwise healthy teeth. So, one group of teeth was cleaned with an Iranian brand of charcoal-based toothpaste, another with a charcoal-based Irish brand, and the third with a whitening formula of Colgate (as a control to compare its effects against the two charcoal toothpastes).


The scientists measured out each toothpaste to 20 grams (just under one ounce) and combined that with two tablespoons of water. They used a "brushing machine" to clean the teeth with 100 motions per minute for a total of 2,000 strokes. Why these exact numbers? They explain this would be equal to brushing three times a day for a month and half.

After all this attention to detail, the scientists re-measured the color and surface profile of the teeth. They state that "the differences between the toothpastes were not significant," but that "all the three used toothpastes have the abrasive and whitening effect on the samples significantly." 

Fortunately, your own method of teeth-whitening might not have to be as rigorous as this study was! Based on the results, it sounds like if you're a coffee drinker who's looking for a more natural way to whiten your teeth, charcoal toothpaste products may be worth a try.

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Krissy Gasbarre
Krissy is a senior news editor at Eat This, Not That!, managing morning and weekend news related to nutrition, wellness, restaurants and groceries (with a focus on beverages), and more. Read more about Krissy
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