Adults have 32 permanent teeth, including wisdom teeth. Children have 20 primary (baby) teeth. In practice, many adults end up with 28 teeth because their wisdom teeth are removed or never come in at all.
Baby Teeth: The First 20
Children develop 20 primary teeth, which start breaking through the gums around 6 months of age. The lower front teeth typically appear first, between 5 and 9 months, followed by the upper front teeth at 8 to 12 months. The rest fill in gradually, with the last baby molars arriving between 20 and 30 months. By age 3, most children have a full set.
These 20 teeth include 8 incisors (the flat front teeth), 4 canines (the pointed ones), and 8 molars. Children don’t have premolars, which is one reason their set is smaller than an adult’s.
Adult Teeth: The Full 32
Permanent teeth begin replacing baby teeth around age 6 and continue arriving into the mid-twenties. A complete adult set breaks down like this:
- 8 incisors: four on top, four on the bottom. These are your front teeth, each with a thin edge designed for biting into food.
- 4 canines: one in each corner of your mouth. They’re the pointiest teeth you have, built for tearing tougher foods like meat.
- 8 premolars: sitting just behind the canines. They work as a bridge between tearing and grinding, helping crush food into smaller pieces.
- 12 molars: the broad, flat teeth in the back of your mouth, including 4 wisdom teeth. About 90% of your chewing happens on your molars.
The first permanent molars arrive around age 5 to 7, often before any baby teeth have fallen out. Incisors replace their baby versions between ages 6 and 8, premolars come in around 9 to 12, and canines between 10 and 13. Second molars show up at 11 to 13. Wisdom teeth are last, typically appearing between 17 and 25, though these timelines vary quite a bit from person to person.
Why Most Adults Have Fewer Than 32
While 32 is the textbook number, relatively few adults actually keep all of them. Wisdom teeth are the most common reason. A Harvard analysis of over 63,000 people across 92 studies found that roughly 23% of the global population never develops one or more wisdom teeth at all. Estimates range from 5% to 37% depending on the population studied. For many others, wisdom teeth grow in at an angle or crowd the existing teeth, leading to extraction.
CDC data from the National Health and Nutrition Examination Survey shows what this looks like in real life. Adults aged 20 to 34 have an average of 27 teeth. That drops to about 25.6 teeth for people aged 35 to 49, and 23.3 for those 50 to 64. Tooth loss from decay, gum disease, and injury accumulates over a lifetime, so the number trends downward with age. A healthy adult mouth with wisdom teeth removed and nothing else missing will have 28 teeth.
Extra or Missing Teeth
Some people are born with more or fewer teeth than expected, not counting wisdom teeth. Congenitally missing permanent teeth (a condition called hypodontia) affects about 4 to 5% of the population, or roughly 1 in every 10 to 12 people when you include milder cases. It’s slightly more common in women. The most frequently missing teeth are the upper lateral incisors (the ones just beside your front teeth) and the second premolars.
On the other end, some people develop extra teeth beyond 32, a condition called hyperdontia. These additional teeth most often appear near the upper front teeth or behind the molars. They’re usually spotted on dental X-rays and may need to be removed if they crowd or block other teeth from coming in properly.
What Each Type of Tooth Does
Your teeth aren’t all shaped the same because they don’t all do the same job. Incisors act like a blade, slicing through food when you take a bite. Canines grip and tear, which is why they have a single sharp point. Premolars are versatile, combining some of the tearing ability of canines with the crushing surface of molars. And molars do the heavy lifting: their wide, bumpy surfaces grind food down so you can swallow and digest it efficiently.
This division of labor is why losing certain teeth affects eating more than others. Losing a molar reduces your chewing power noticeably, while a missing incisor mostly affects biting and appearance. The arrangement also explains why your dentist pays close attention to molars, since they handle the bulk of chewing force and are harder to keep clean because of their location in the back of the mouth.