Most people don’t actually “have to” get their wisdom teeth out. But the majority eventually do because human jaws have shrunk over evolutionary time, leaving too little room for these late-arriving molars to grow in properly. About 24% of adults have at least one impacted wisdom tooth, meaning it’s trapped fully or partially beneath the gum line. When that happens, the tooth can cause infections, damage neighboring teeth, or develop cysts. Even when wisdom teeth come in without symptoms, cross-sectional studies of older adults in the U.S. and Finland have found that up to 80% of wisdom teeth still present after age 74 show signs of disease like decay or gum infection.
Why Your Jaw Doesn’t Have Room
Wisdom teeth are your third set of molars, and they typically try to push through between ages 17 and 25. The problem is architectural: over thousands of generations, the human jaw has gotten smaller while the number of teeth has stayed the same. Early humans ate tougher, more abrasive diets that wore down teeth and stimulated more jaw growth. Modern diets don’t do that, so many people simply run out of space in the back of their mouth before these last teeth arrive.
When there isn’t enough room, a wisdom tooth can come in at the wrong angle, get stuck partway through the gum, or never emerge at all. These are all forms of impaction, and they’re categorized by the direction the tooth is pointing. The most common type is mesial impaction, where the tooth tilts forward toward the rest of your teeth. A tooth can also lie completely on its side (horizontal impaction), angle toward the back of the mouth (distal), or sit mostly upright but still be unable to fully break through (vertical). Each position creates its own set of problems.
Infections Under the Gum Flap
The single most common reason wisdom teeth cause trouble is a condition called pericoronitis. When a tooth is only partway through the gum, a flap of tissue called an operculum forms over part of the exposed crown. Food, bacteria, and debris get trapped underneath that flap, and the area becomes infected. Symptoms include swollen, painful gums around the back of your mouth, difficulty opening your jaw, and sometimes a bad taste from pus draining near the tooth.
Pericoronitis can be mild and resolve with cleaning and saltwater rinses, but it tends to come back. Repeated episodes are one of the clearest signals that the tooth needs to come out. In more serious cases, the infection can spread into the jaw or throat, which requires urgent treatment.
Damage to the Teeth Next Door
An impacted wisdom tooth doesn’t just sit there harmlessly. If it’s angled toward the neighboring second molar, it can press against that tooth’s root with enough force to cause root resorption, a process where the outer layer of the root is physically broken down. Think of it as the wisdom tooth slowly eroding the foundation of the tooth in front of it. In severe cases, the pressure can destroy enough of the root that the second molar has to be extracted too, meaning you lose two teeth instead of one.
Even without direct root damage, a wisdom tooth wedged against its neighbor creates a tight pocket that’s nearly impossible to keep clean. Bacteria accumulate in that gap, leading to cavities on the back surface of the second molar or bone loss from chronic gum disease around both teeth.
Cysts and Other Growths
Every tooth develops inside a small sac of tissue. When a wisdom tooth stays buried in the jawbone, that sac can fill with fluid and form a cyst. A study of nearly 5,500 impacted third molars found cysts in about 2.2% and tumors in about 1.2% of cases. While those percentages sound low, a cyst that goes undetected can grow large enough to hollow out a section of jawbone or damage the roots of adjacent teeth. Malignant tumors are rare (0.05% in that same study) but possible, which is one reason dentists monitor retained wisdom teeth with periodic X-rays.
When Removal Is Actually Recommended
The American Association of Oral and Maxillofacial Surgeons takes a nuanced position: wisdom teeth that already show disease, or that are at high risk for developing it, should be surgically removed. But teeth that are disease-free and at low risk can be monitored instead. Removal is also favored when the tooth will never be functional (it has no opposing tooth to chew against), when it’s blocking the second molar from coming in properly, or when jaw surgery is planned.
For teeth that currently look fine, the decision involves weighing the likelihood of future problems against the risks of surgery. Your dentist or oral surgeon will consider the angle of impaction, how deep the tooth sits, your age, and how easy it would be to keep the area clean long term. There’s no universal rule that says every wisdom tooth must come out.
Why Age Matters for the Procedure
If removal is the plan, earlier is generally easier. In your late teens and early twenties, the roots of wisdom teeth are still forming and haven’t fully anchored into the jawbone. The bone itself is less dense at that age, and healing tends to be faster. As roots grow longer and the surrounding bone hardens with age, extraction becomes more technically difficult and the risk of complications rises.
That said, “earlier is easier” doesn’t mean “now or never.” Plenty of people have wisdom teeth removed in their 30s, 40s, or later without major issues. The recovery may take a bit longer and the procedure might be more involved, but it’s routine surgery at any adult age. What matters most is not ignoring a tooth that’s causing problems just because you missed the ideal window.
What Happens if You Keep Them
Some people keep their wisdom teeth for life without any complications. If your teeth came in fully, are positioned correctly, aren’t crowding your other teeth, and you can reach them with a toothbrush and floss, there may be no reason to remove them. The key word is “can reach them.” Wisdom teeth sit so far back in the mouth that many people simply can’t clean them well, which makes decay and gum disease almost inevitable over decades.
If you and your dentist decide to keep your wisdom teeth, active surveillance is important. That means regular dental visits with X-rays to check for cysts, bone loss, or changes in the tooth’s position. A wisdom tooth that looks fine at 25 can start causing problems at 40. The AAOMS notes that patients should understand a retained, disease-free wisdom tooth might never cause trouble, but also that delaying removal until problems appear means dealing with a harder extraction and a higher complication rate later.