Adults have 32 permanent teeth, split into four types: incisors, canines, premolars, and molars. Each type has a distinct shape, sits in a specific spot along your jaw, and handles a different job when you chew. Here’s a complete guide to identifying every tooth in your mouth.
Incisors: Your Eight Front Teeth
Incisors are the flat, thin teeth right at the front of your mouth. You have eight total: four on top, four on the bottom. The two in the very center of each jaw are your central incisors, and the ones flanking them on each side are lateral incisors. Their flat, narrow edges work like a blade, slicing into food when you take a bite. These are the teeth you use when you bite into an apple or cut through a piece of bread.
Central incisors are the first permanent teeth most children get, typically appearing between ages 6 and 8. The upper central incisors are the widest teeth in your mouth and the most visible when you smile.
Canines: The Four Pointed Teeth
Just past your incisors on each side sit your canines, sometimes called cuspids or “eye teeth.” You have four: one in each corner where the front teeth meet the side teeth. Canines are the sharpest teeth in your mouth, with a single pointed tip designed for gripping and tearing food, especially meat and crunchy vegetables.
Canines also have the longest roots of any tooth, which anchors them firmly and gives them strength for tearing. They’re among the last front teeth to come in, typically erupting between ages 10 and 13.
Premolars: The Eight Transitional Teeth
Behind each canine sit two premolars (also called bicuspids), giving you eight total. Premolars are a hybrid between canines and molars. They have a broader chewing surface than canines but aren’t as large as molars, and they help you tear, crush, and grind food into smaller pieces.
Most premolars have two cusps, the raised bumps on the biting surface. Your upper first premolars typically have a split root, while the rest usually have a single root. Mandibular (lower) second premolars have the largest chewing surfaces of all the premolars and can sometimes have three cusps instead of two. Premolars arrive between ages 9 and 12, replacing the baby molars that children lose around the same time.
One important note: children don’t have premolars at all. Kids have only 20 primary teeth, which include incisors, canines, and molars but skip premolars entirely. The eight premolars are unique to your adult set.
Molars: Your Twelve Back Teeth
Molars are the large, powerful teeth at the back of your mouth. You have 12 in total: three on each side, top and bottom. They’re your primary chewing teeth, built for crushing and grinding food down before you swallow. Their broad, flat surfaces have four or five cusps, giving them the textured landscape they need to break food apart efficiently.
Your first molars are the biggest and strongest. Upper first molars typically have four major cusps plus a small extra bump, while lower first molars have five well-developed cusps. Upper molars generally have three roots, while lower molars have two. Your second molars, just behind the first, are slightly smaller but similarly structured, with four cusps each.
First molars erupt around ages 5 to 7, making them some of the earliest permanent teeth. Second molars follow between ages 11 and 13.
Wisdom Teeth: The Third Molars
Your third molars, better known as wisdom teeth, are the very last teeth at the back of each arch. They typically emerge between ages 17 and 25, and they’re the most variable teeth in your mouth. Their roots tend to be fused together and irregularly curved, unlike the neatly separated roots of your other molars.
About 10 million wisdom teeth are removed each year in the U.S., but not all of them actually need to come out. Roughly 50% of upper wisdom teeth classified as impacted are actually developing normally and will erupt on their own if given time. Only about 12% of truly impacted wisdom teeth cause problems like cysts or damage to neighboring teeth. The discomfort most people feel as wisdom teeth come in is similar to teething and usually resolves once the tooth fully emerges. Infection of the gum tissue around a wisdom tooth occurs in fewer than 10% of cases, and most of those infections can be treated without removing the tooth.
What’s Inside Every Tooth
Regardless of type, every tooth shares the same internal structure. The outer layer you can see is enamel, the hardest substance in your body. It’s made almost entirely of a tightly packed mineral that forms a protective shield. Beneath the enamel sits dentin, a strong but slightly softer layer that makes up the bulk of the tooth. At the very center is the pulp, a soft tissue containing blood vessels and nerves. This is the part that senses temperature and pain. Below the gum line, a thin layer of cementum (similar to bone) covers the root surface and helps anchor the tooth into your jawbone.
How Dentists Number Your Teeth
When your dentist says something like “number 19 has a cavity,” they’re using the Universal Numbering System, which assigns each permanent tooth a number from 1 to 32. The count starts at your upper right wisdom tooth (number 1), moves along the upper arch to your upper left wisdom tooth (number 16), then drops down to your lower left wisdom tooth (number 17), and follows the lower arch back to your lower right wisdom tooth (number 32).
Here’s how the numbers map to each tooth type:
- 1-3 and 14-16 (upper), 17-19 and 30-32 (lower): Molars, with 1, 16, 17, and 32 being wisdom teeth
- 4-5 and 12-13 (upper), 20-21 and 28-29 (lower): Premolars
- 6 and 11 (upper), 22 and 27 (lower): Canines
- 7-10 (upper), 23-26 (lower): Incisors, with 8-9 and 24-25 being your central incisors
Outside the U.S., many dentists use the FDI system instead. This uses a two-digit code where the first digit identifies the quadrant (1 for upper right, 2 for upper left, 3 for lower left, 4 for lower right) and the second digit identifies the tooth position from the center outward (1 for central incisor through 8 for wisdom tooth). So tooth “14” in the FDI system means upper right first premolar, while “36” means lower left first molar. Children’s teeth use quadrants 5 through 8 with positions 1 through 5.
When Each Tooth Arrives
Baby teeth typically fall out in roughly the same order they came in. The lower central incisors go first, followed by the upper central incisors, then lateral incisors, first molars, canines, and second molars. The permanent teeth that replace them follow a slightly different schedule:
- Ages 5-7: First molars (these erupt behind the baby molars, not replacing any tooth)
- Ages 6-8: Central and lateral incisors
- Ages 9-12: Premolars (replacing baby molars)
- Ages 10-13: Canines
- Ages 11-13: Second molars
- Ages 17-25: Third molars (wisdom teeth)
These ranges vary quite a bit from child to child. Girls tend to get their permanent teeth slightly earlier than boys, and some people never develop certain teeth, particularly wisdom teeth, at all.