10 Smart Facts About Wisdom Teeth

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Like puberty and your first heartbreak, the painful process of getting your wisdom teeth removed is one of those cumbersome coming-of-age rituals that many people are forced to endure. But why do we have wisdom teeth when they seem to only cause problems? Read on to find out more about the humble third molar—the last tooth many of us get as adults.

1. THEY HAVEN’T SERVED ANY PURPOSE FOR HUNDREDS OF THOUSANDS OF YEARS.

Imagine, for a moment, that you’re a prehistoric man or woman. You subsist largely on raw meat, roots, and leaves. You’d need some pretty powerful chompers to cut up your food, right? That was where your third molars—also known as wisdom teeth—came in. Today, our palates are a little more refined, and we prefer softer foods (think avocado toast and smoothies). Plus, modern cooking tools have put our wisdom teeth out of business.

They’re not just pointless, though—they’re also problematic. Wisdom teeth are a “scar of human evolution,” according to Princeton University researcher Alan Mann. About 800,000 to 200,000 years ago, early humans’ brains started growing at a rapid pace—so much so that they ballooned to three times their original size. When that happened, it changed the shape of the braincase (the back part of the skull) and its position relative to the dental arcade (rows of teeth). The dental arcade shortened, and suddenly there was no longer enough room for third molars. And since the genes that determine the makeup of our teeth evolve separately from those that control brain development, humans were stuck dealing with the consequences of a crowded mouth, according to Live Science.

2. NATURE MAY EVENTUALLY SORT IT OUT, THOUGH.

On the bright side, scientists say evolution may eventually take care of the problem, meaning that people in the future would not develop wisdom teeth. It’s anyone’s guess as to when this will occur, though. “On the evolutionary scale, if I had to predict down the road—centuries probably—wisdom teeth are going to be one of the things that humans probably won’t have anymore,” Dr. William McCormick, assistant clinical professor at West Virginia University’s School of Dentistry, tells Mental Floss.

3. THE NUMBER OF WISDOM TEETH VARIES FROM PERSON TO PERSON ...

It’s possible that you have one, two, three, four, or none at all. Another possibility, although it’s rare, is to have more than four wisdom teeth, which are called supernumerary teeth. “In my career, I have seen two cases where patients have had fourth molars—or two sets of wisdom teeth,” McCormick says. (Comparatively, humans’ ancestors had quite the mouthful, with 12 wisdom teeth in total.)

According to McCormick, genetic factors like jaw size might determine the number of wisdom teeth that a person has. Your lineage may also have something to do with it. Practically no Aboriginal Tasmanians have third molars, but almost 100 percent of indigenous Mexicans have at least one wisdom tooth. African Americans and Asian Americans are also more likely than people of European descent to have fewer than four wisdom teeth. This variation can be attributed to a random genetic mutation that arose thousands of years ago, thereby preventing the formation of wisdom teeth. This mutation is more prevalent in certain populations.

4. ... AS DOES THE NUMBER OF ROOTS THAT EACH TOOTH HAS.

The roots are the part of the tooth that form first, and then push the bud (the part that's visible in your mouth) through your gums. While wisdom teeth typically have two or three roots, they can have more. McCormick says he personally removed his wife’s wisdom teeth in the ‘70s and was surprised to see that one of them had five roots. “It looked like a spider. It was not a pleasant extraction,” he says.

For that reason, if wisdom teeth need to be removed, it’s easier to do so before the roots start to take hold. “When the roots are totally formed, they’re anchored like a tree that’s been in your backyard for 100 years,” says Dr. Ron Good, an orthodontist in southwestern Pennsylvania who runs a family practice with his brother, Dr. Bob Good. On the other hand, surgeons want some roots to grab hold of, because removing a tiny tooth bud is “like extracting a marble,” Dr. Ron tells Mental Floss.

5. YOUR WISDOM TEETH CAN ERUPT AT ANY TIME.

According to Guinness World Records, the oldest person to ever grow a wisdom tooth was 94 years old. McCormick says there's a wide variation in ages when eruption occurs; he once had a 65-year-old patient with dentures whose wisdom tooth had started to erupt (poke through the gums). “They’re crazy little beasts. You never know what you’re going to see.”

Apparently, wisdom teeth have been acting erratically for thousands of years. Aristotle documented this phenomenon in his book The History of Animals: “Cases have been known in women upwards of 80 years old where at the very close of life the wisdom-teeth have come up, causing great pain in their coming; and cases have been known of the like phenomenon in men too.”

In most cases, though, wisdom teeth erupt when you’re in your late teens or early twenties.

6. THE FIRST IMPACTED TOOTH WAS RECORDED ABOUT 15,000 YEARS AGO.

When wisdom teeth don’t have enough room to grow normally, they get stuck in the jaw and fail to erupt. These are called impacted teeth. The oldest known case of an impacted tooth was found in the skeleton of a 25- to 35-year-old woman who died some 15,000 years ago. This case cast doubt on the theory that impacted teeth are a modern ailment, caused by recent changes in our dietary habits.

7. SOME PHYSICIANS SAY THAT IMPACTED WISDOM TEETH SHOULD BE SURGICALLY REMOVED ...

Many people get their wisdom teeth removed, even if there isn’t any pain or discernible problem aside from impacting. Known as prophylactic surgery, this preventative practice is common in the U.S., but in recent years there has been some debate as to whether it’s necessary. One popular theory holds that most people either have problems with their wisdom teeth or will at some point in the future. “It’s hard to get a percentage, but probably 75 to 80 percent of people do not meet the criteria of being able to successfully maintain their wisdom teeth,” Dr. Louis K. Rafetto, who headed a task force on wisdom teeth, told The New York Times in 2011.

About 3.5 million extraction surgeries are performed each year, and according to another estimate, that adds up to be 10 million individual wisdom teeth pulled annually. Dr. Ron and Dr. Bob, of Good Orthodontics, are both of the opinion that wisdom teeth are ticking time bombs. “In our mind, we feel that wisdom teeth, in general, are of no value and are only potential problems,” Dr. Bob says. He added that third molars can interfere with your bite and cause your teeth to wear down, and in some cases, can also cause cysts, tumors, nerve damage, periodontal disease (affecting the gums and other areas around the teeth) and TMJ disorders (affecting the jaw joint). Plus, if your teeth are too crowded and you aren’t able to brush and floss them normally, it can lead to additional issues, such as gum disease and cavities.

8. ... WHILE OTHERS SAY YOU SHOULD AVOID IT.

Dental practitioners in the UK put an end to routine wisdom tooth extractions in 1998, citing a study at the University of York that reportedly found no scientific evidence to support the practice, according to the The Miami Herald.

Opposition is building in the U.S., too. Retired dentist Dr. Jay Friedman told How Stuff Works that only about 12 percent of wisdom teeth eventually cause problems. He compared that rate to the 7 to 14 percent of people who experience appendicitis, yet appendixes aren’t removed until they become a medical issue. If this seems to contradict Raffeto's statistics, it’s because there isn’t a whole lot of concrete data on the subject, and much of it is conflicting—so it really comes down to the individual physician’s and patient's preferences. “Ask three dentists the same question, and you’re going to get four different answers,” McCormick says with a laugh.

Like Friedman, McCormick doesn't support wisdom tooth removal unless there’s an infection, abscess, or other problem. “You have to weigh the surgical risk with what you’re going to try to accomplish,” he says. Like any surgery, wisdom tooth extraction poses a risk, although more serious complications, like fractured jaws and death, are extremely rare. McCormick says some possible side effects include nerve damage, infection, and dry socket (an infection of the tooth socket).

Despite the differing opinions in the dental community, McCormick, Dr. Ron, and Dr. Bob agreed that there’s no prescriptive rule for wisdom tooth removal, and that each patient should be evaluated on a case-by-case basis.

9. THEY’RE CALLED LOVE TEETH IN KOREAN.

In English, the name wisdom tooth conveys the idea that third molars come in later than other teeth, at a time when you’re older and (hopefully) wiser. Other languages don’t follow the same convention. In Korean, for example, the poetic name for third molars translates to “love teeth,” because it's around this time (late teens and early 20s) that one typically experiences their first love. The Japanese language also has a creative word for it: oyashirazu, or “unknown to parents,” since most people have already moved away from home by the time their wisdom teeth come in.

10. THEY’RE USED IN STEM CELL RESEARCH.

It turns out wisdom teeth aren't all bad. Although some of the research is still in the experimental phase, scientists are studying dental stem cells—which were discovered in 2003—to see if they can potentially be used to repair and regenerate tissue.

One study on mice, at the University of Pittsburgh’s School of Medicine, found that stem cells taken from wisdom teeth could someday be used to repair corneas that have been scarred by infection or injury. Any clinical applications for humans would require more research, though.

"There are studies with dental pulp cells being used to treat neurological disorders and problems in the eye and other things,” Dr. Pamela Robey, of the National Institute of Dental and Craniofacial Research, told CNN. “The problem is, these studies have really not been that rigorous ... the science needs a lot more work.”

10 Products for a Better Night's Sleep

Amazon/Comfort Spaces
Amazon/Comfort Spaces

Getting a full eight hours of sleep can be tough these days. If you’re having trouble catching enough Zzzs, consider giving these highly rated and recommended products a try.

1. Everlasting Comfort Pure Memory Foam Knee Pillow; $25

Everlasting Comfort Knee Pillow
Everlasting Comfort/Amazon

For side sleepers, keeping the spine, hips, and legs aligned is key to a good night’s rest—and a pain-free morning after. Everlasting Comfort’s memory foam knee pillow is ergonomically designed to fit between the knees or thighs to ensure proper alignment. One simple but game-changing feature is the removable strap, which you can fasten around one leg; this keeps the pillow in place even as you roll at night, meaning you don’t have to wake up to adjust it (or pick it up from your floor). Reviewers call the pillow “life-changing” and “the best knee pillow I’ve found.” Plus, it comes with two pairs of ear plugs.

Buy it: Amazon

2. Letsfit White Noise Machine; $21

Letsfit White Noise Machine
Letsfit/Amazon

White noise machines: They’re not just for babies! This Letsfit model—which is rated 4.7 out of five with nearly 3500 reviews—has 14 potential sleep soundtracks, including three white noise tracks, to better block out everything from sirens to birds that chirp enthusiastically at dawn (although there’s also a birds track, if that’s your thing). It also has a timer function and a night light.

Buy it: Amazon

3. ECLIPSE Blackout Curtains; $16

Eclipse Black Out Curtains
Eclipse/Amazon

According to the National Sleep Foundation, too much light in a room when you’re trying to snooze is a recipe for sleep disaster. These understated polyester curtains from ECLIPSE block 99 percent of light and reduce noise—plus, they’ll help you save on energy costs. "Our neighbor leaves their backyard light on all night with what I can only guess is the same kind of bulb they use on a train headlight. It shines across their yard, through ours, straight at our bedroom window," one Amazon reviewer who purchased the curtains in black wrote. "These drapes block the light completely."

Buy it: Amazon

4. JALL Wake Up Light Sunrise Alarm Clock; $38

JALL Wake Up Light Sunrise Alarm Clock
JALL/Amazon

Being jarred awake by a blaring alarm clock can set the wrong mood for the rest of your day. Wake up in a more pleasant way with this clock, which gradually lights up between 10 percent and 100 percent in the 30 minutes before your alarm. You can choose between seven different colors and several natural sounds as well as a regular alarm beep, but why would you ever use that? “Since getting this clock my sleep has been much better,” one reviewer reported. “I wake up not feeling tired but refreshed.”

Buy it: Amazon

5. Philips SmartSleep Wake-Up Light; $200

Philips SmartSleep Wake-Up Light
Philips/Amazon

If you’re looking for an alarm clock with even more features, Philips’s SmartSleep Wake-Up Light is smartphone-enabled and equipped with an AmbiTrack sensor, which tracks things like bedroom temperature, humidity, and light levels, then gives recommendations for how you can get a better night’s rest.

Buy it: Amazon

6. Slumber Cloud Stratus Sheet Set; $159

Stratus sheets from Slumber Cloud.
Slumber Cloud

Being too hot or too cold can kill a good night’s sleep. The Good Housekeeping Institute rated these sheets—which are made with Outlast fibers engineered by NASA—as 2020’s best temperature-regulating sheets.

Buy it: SlumberCloud

7. Comfort Space Coolmax Sheet Set; $29-$40

Comfort Spaces Coolmax Sheets
Comfort Spaces/Amazon

If $159 sheets are out of your price range, the GHI recommends these sheets from Comfort Spaces, which are made with moisture-wicking Coolmax microfiber. Depending on the size you need, they range in price from $29 to $40.

Buy it: Amazon

8. Coop Home Goods Eden Memory Foam Pillow; $80

Coop Eden Pillow
Coop Home Goods/Amazon

This pillow—which has a 4.5-star rating on Amazon—is filled with memory foam scraps and microfiber, and comes with an extra half-pound of fill so you can add, or subtract, the amount in the pillow for ultimate comfort. As a bonus, the pillows are hypoallergenic, mite-resistant, and washable.

Buy it: Amazon

9. Baloo Weighted Blanket; $149-$169

Baloo Weighted Blanket
Baloo/Amazon

Though the science is still out on weighted blankets, some people swear by them. Wirecutter named this Baloo blanket the best, not in small part because, unlike many weighted blankets, it’s machine-washable and -dryable. It’s currently available in 12-pound ($149) twin size and 20-pound ($169) queen size. It’s rated 4.7 out of five stars on Amazon, with one reviewer reporting that “when it's spread out over you it just feels like a comfy, snuggly hug for your whole body … I've found it super relaxing for falling asleep the last few nights, and it looks nice on the end of the bed, too.” 

Buy it: Amazon 

10. Philips Smartsleep Snoring Relief Band; $200

Philips SmartSleep Snoring Relief Band
Philips/Amazon

Few things can disturb your slumber—and that of the ones you love—like loudly sawing logs. Philips’s Smartsleep Snoring Relief Band is designed for people who snore when they’re sleeping on their backs, and according to the company, 86 percent of people who used the band reported reduced snoring after a month. The device wraps around the torso and is equipped with a sensor that delivers vibrations if it detects you moving to sleep on your back; those vibrations stop when you roll onto your side. The next day, you can see how many hours you spent in bed, how many of those hours you spent on your back, and your response rate to the vibrations. The sensor has an algorithm that notes your response rate and tweaks the intensity of vibrations based on that. “This device works exactly as advertised,” one Amazon reviewer wrote. “I’d say it’s perfect.”

Buy it: Amazon

This article contains affiliate links to products selected by our editors. Mental Floss may receive a commission for purchases made through these links.

30 Pungent Facts About Farts

This man is clearly not trying to hide the fact he just passed gas.
This man is clearly not trying to hide the fact he just passed gas.
BrilliantEye/iStock via Getty Images

Whether you openly admit it or desperately try to hide it, it’s an undeniable fact that every living and breathing human being farts. And while passing what you thought was going to be silent gas only to be wrong in certain situations can definitely be embarrassing, there’s something undeniably humorous about flatulence—no matter your age.

If you do love a good fart joke, you’re in good company. The very first recorded joke, which was written by the Sumerians and dates all the way back to 1900 BCE, was about—you guessed it—breaking wind. And some of the world's great thinkers, from William Shakespeare to J.D. Salinger, have slipped a fart joke (or 10) into their work.

In this episode of The List Show, we're sniffing out 30 fascinating facts about farts—from why humans expel gas to how often the average adult squeezes the cheese. You can watch the full episode below.

For more videos like this one, be sure to head here and subscribe.