Human Teeth Overview
Your teeth aren’t all the same. When you look at your dental records or hear your dentist talk, you may notice several different names for your teeth.
Teeth come in four main types. Each type sits in a certain part of your mouth and plays a unique role.
Teeth also change over time as baby teeth fall out to make room for adult ones. Then after all the baby teeth fall out and the permanent ones come in, you might still go through another change. Around this time, many people have surgery to remove their wisdom teeth.
Although you may not think about them often, your teeth help you smile, speak, and chew food. Here are some details about your teeth you may or may not have considered.
What Are the Types of Teeth and Their Functions?
You have four types of teeth:
There are eight incisors -- four on top and four on bottom. These sharp teeth sit at the front of your mouth, and you use them to take your first bite into a piece of food. They also cut food into smaller pieces to make it easier to chew. These “front teeth” help you talk, especially to pronounce letters such as “t” and “l.” They also play a big part in your smile.
Next, you have four cuspids -- also called canines -- two on top and two on the bottom. These pointed teeth at the front corners of your mouth resemble the teeth in meat-eating animals such as wolves and tigers. You use them to rip and tear food. They are your longest teeth.
Further back in your mouth are eight premolars -- four on top and four on bottom. These flat, ridged teeth sit behind your canines on the sides of your mouth. Also known as “bicuspids,” they tear and crush food.
Finally, your molars line the back of your mouth where they chew and grind food. They’re your largest teeth and have a flat surface with ridges. Also known as “6-year molars” or “12-year molars,” they tend to come in around those two ages. Their main use is to crush food until it’s small enough to swallow.
There’s another type of molar called wisdom tooth. You have four that come in last at the back corners of your mouth. For some people, they crowd the mouth and cause problems with the gums or jawbone. Sometimes, these are “impacted,” which means they can’t break through the gums and there’s no room for them in the mouth. Many people have surgery to remove these teeth in their later teen years or early 20s.
Your Two Sets of Teeth
You have two sets of teeth. The first is called primary and grows in by the age of 2. The second set are called permanent teeth. These are the teeth that grow in between the ages of 6 and12. You start with 20 primary teeth and end with 32 permanent teeth, including the four wisdom teeth.
The incisors are typically the first to arrive when babies turn 6 months old. The permanent molars are usually the first to come in when kids are 6. They emerge behind the last primary teeth. Most adult teeth come in by age 12. Wisdom teeth grow in between ages 17 and 25.
How Many Teeth Do Humans Have?
You may notice that your dentist or hygienist counts your teeth or looks at a chart that has numbers on it. The American Dental Association created a numbering system that assigns a number from 1 to 32 to permanent teeth (including wisdom teeth) and a letter from A to T to primary teeth.
Number one is the top right molar in back. The numbers go around the top of the mouth so that the top left tooth in back is number 16. Number 17 is the bottom left molar. The numbers continue around the bottom and end with 32.
What Are the Structures of Teeth?
Your teeth have several parts as well:
- The crown is the visible part of your tooth.
- The enamel is the protective layer on the crown.
- The dentin is inside the tooth and is not visible. Still, though, it is the largest part of your tooth.
- The pulp contains nerve endings and blood.
- The root is under your gums. It anchors your tooth to your jawbone.
Dental Health Foundation of Ireland: “Tooth types.”
Advantage Career Institute Medical & Dental School: “The Five Types of Human Teeth & Their Function.”
KidsHealth.org: “Your Teeth.”
American Dental Association: “Glossary of Dental Clinical and Administrative Terms.”