There's a reason why so many people find these clips extremely disturbing and strangely satisfying at the same time.

Amanda MacMillan
September 26, 2017

First, it was pimple-popping, next it was removing a callus at home with a razor and then salivary-stone extraction. Now, there’s a new viral video trend depicting a super gross hygiene habit: “extreme dental cleanings" that remove visible layers of tartar and plaque from patients’ teeth.

Even if you’re not one to get squeamish in the dentist’s chair, these videos start out pretty disturbing. One clip that’s racked up nearly 3 million views since it was posted in 2014 states that the patient has never had her teeth cleaned before—and it shows. Another, with more than 900,000 views, zooms in closely as a hygienist aggressively scrapes at the buildup between teeth.

No one likes to get their own teeth cleaned. But it’s clear that many people enjoy watching it happen to other people. One commenter even wrote about a “strange feeling of satisfaction” after watching one of these clips.

So why do we like to gross ourselves out with videos like this? Daniel R. Kelly, PhD, author of Yuck! The Nature and Moral Significance of Disgust, says it has to do with the jolt of raw emotion they provide.

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“It’s the same reason people like horror movies or bungee jumping,” says Kelly, who’s also a professor of philosophy at Purdue University. “You get to experience the thrill of having these extreme emotions—like disgust or fear—but in these contrived situations, you get to have these experiences without actually being under threat.”

In this case, “under threat” may be in the dentist’s chair, which can be scary enough. But it may also have to do with all that nasty brown tartar we see in the videos, which our brains associate with sickness and bad hygiene. (It is, after all, a big cause of gum disease and tooth decay.) “Some of the most potent elicitors of disgust have to do with poison or contamination—stuff that can kill you,” says Kelly.

That definitely includes bodily fluid, he adds. “When you think about the pimple-popping videos, they’re oozing pus—and now with these teeth-cleaning videos, it’s very centered on the mouth and all the fluids going on there.”

The disgust angle may be one reason we not only watch these videos, but we share them with our friends, as well. “There’s this weird thing that if something disgusts you, you’re more likely to tell other people about it,” says Kelly. That makes sense from an evolutionary perspective, he adds. “You don’t want your group to get infected by whatever this threat is, so you need to keep track of it and spread the word.”

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Then again, these videos all end with clean, sparkly, white(ish) teeth, as well as the vanquishing of an unsightly zit or other skin blemish, so maybe that’s the real pull. “There’s probably some catharsis there,” says Kelly. “When someone pops a zit or when their teeth are finally clean, they experience some relief—the threat is no longer present.”

Of course, not everyone experiences this strange draw or enjoys watching these videos. “I’m only speaking from a theoretical perspective—not a personal one,” says Kelly. “I don’t feel whatever it is that other people feel when it comes to this nasty stuff.”