Teeth: Names, types, and functions

Teeth are made up of different layers — enamel, dentin, pulp, and cementum. Enamel, the hardest substance in the body, is on the outside of the tooth.

The second layer is dentin, which is softer than enamel, and the deepest layer inside the tooth is the pulp, which consists of nerves and blood vessels. The cementum is on the root of the tooth and is beneath the gums.

The number and types of teeth a person has change as they age. Typically, people have two sets of teeth during their life — primary, or baby teeth, and permanent, or adult teeth. In this article, we look at the teeth that children and adults have, as well as their functions.

Humans have the following types of teeth:

Incisors

Incisors are the sharp teeth at the front of the mouth that bites into food and cut it into smaller pieces. They are flat with a thin edge. They are also called anterior teeth.

Both children and adults have eight incisors — four central incisors at the front of the mouth, two on each row, with one lateral incisor positioned on either side of them.

Canines

Canines are sharp, pointed teeth that sit next to the incisors and look like fangs. Dentists also call them cuspids or eyeteeth. Canines have the longest teeth, and people use them to tear food.

Both children and adults have four canines. Children usually get their first permanent canines between the ages of 9 and 12. The lower canines tend to come through slightly before those in the upper jaw.

Check out an interactive dental chart—it’s got both Universal and Canadian Tooth Numbering! Plus, you’ll find quick tooth info, care tips, and common issues in one spot.

Premolars

Premolars, or bicuspids, are bigger than the incisors and canines. They have many ridges and help chew and grind up food. Adults have eight premolars. The first and second premolars are the molars that sit next to the canines.

Young children do not have premolar teeth. These first appear as permanent teeth when children are 10–12 years old.

Molars

Molars are the biggest of all teeth. They have a large, flat surface with ridges that allow them to chew food and grind it up. Adults have 12 permanent molars — six on the bottom and top jaw, and children have eight primary molars.

The last molars to erupt are wisdom teeth, or third molars, which usually come through between the ages of 17 and 21. These sit at the end of the row of teeth, in the far corners of the jaw. Some people do not have all four wisdom teeth, or the teeth may stay unerupted in the bone and never appear in the mouth.

Sometimes, wisdom teeth become impacted, which means they become trapped under the gum and are unable to come through properly.

Wisdom teeth that only come through halfway or are in the wrong position can increase the risk of infection or damage to surrounding areas. If people have any issues with their wisdom teeth, they must see a dentist.

People may experience mild discomfort when their wisdom teeth start pushing through the gums, but anyone feeling a lot of pain or has swelling should see a dentist.

A dentist may need to remove wisdom teeth if a person has tooth decay, pain, or an infection. People do not need these teeth for chewing, and they are difficult to keep clean because of their position far back in the mouth.

Number of teeth

Children have 20 primary, or baby, teeth. Primary teeth first start to appear when babies are around 6 months old. Children usually get all their primary teeth by the age of 3.

These teeth gradually fall out, and 28 permanent teeth replace them. Sometimes, permanent teeth push the baby teeth out, but typically, permanent teeth come through the gums at the back of the mouth behind the last baby tooth in the jaw.

The first permanent teeth to erupt through the gums are four first, or ‘6-year’ molars, so-called because they usually come through when a child is about 6 years old.

The first baby teeth to fall out are the lower central incisors. The adult central incisors tend to erupt around the same time as the first permanent molars around age 6-7.

Usually, people have lost all of their baby teeth by around the age of 14.

Fun and Surprising Facts About Your Teeth

Incisors

• The shape of your upper central incisors can sometimes reflect your ancestry, with individuals of European descent often having larger, more pronounced upper incisors.

Canines

• Canines are sometimes known and referred to as “eye teeth” because they are located directly below the eyes and are the last to be affected by age-related wear.

Premolars

• Premolars have a unique ability to regenerate enamel in the form of a “dentin bridge,” helping them repair minor damage over time.

Molars

• Molars, especially the lower ones, can have “extra” roots called “accessory roots,” which are not always present but can sometimes be discovered during dental X-rays.

Wisdom Teeth

• Despite being called “third molars,” wisdom teeth are usually the last ones to come in and don’t always show up fully formed. Some even take years to emerge fully!