Adults have 32 permanent teeth, and each one has a specific name based on its type and position in the mouth. These teeth fall into four categories: incisors, canines, premolars, and molars. Children start with a smaller set of 20 baby teeth before the full adult set comes in.
The Four Types of Teeth
Every tooth in your mouth belongs to one of four groups, and each group has a distinct shape designed for a specific job.
Incisors are the eight front teeth, four on top and four on the bottom. They’re shaped like small chisels with a single narrow edge that cuts into food when you bite. The two teeth right at the center of your smile are your central incisors, and the ones immediately next to them are your lateral incisors.
Canines are the four pointed teeth sitting just outside the incisors, one in each corner of your mouth. They have a sharp, pointy surface built for tearing into foods like meat and crunchy vegetables. These are the teeth that most resemble fangs.
Premolars (also called bicuspids) are the eight teeth behind the canines, two on each side of both jaws. They’re transitional teeth that help you tear, crush, and grind food into smaller pieces. Most premolars have two raised points (cusps) on their chewing surface, though some lower premolars can have three.
Molars are the twelve large, flat teeth at the back of your mouth, three on each side of both jaws. These are your main chewing teeth, designed for crushing and grinding food. Upper molars typically have four cusps, while lower first molars have five. Your third molars, the ones farthest back, are your wisdom teeth.
Every Adult Tooth by Name and Number
Dentists in the United States use the Universal Numbering System, which assigns each tooth a number from 1 to 32. The count starts at your upper right wisdom tooth, moves across the top of your mouth to the upper left wisdom tooth, drops down to the lower left wisdom tooth, and sweeps back across the bottom to the lower right wisdom tooth. Here’s every tooth in order.
Upper Teeth (Right to Left)
- 1: Upper right third molar (wisdom tooth)
- 2: Upper right second molar
- 3: Upper right first molar
- 4: Upper right second premolar
- 5: Upper right first premolar
- 6: Upper right canine
- 7: Upper right lateral incisor
- 8: Upper right central incisor
- 9: Upper left central incisor
- 10: Upper left lateral incisor
- 11: Upper left canine
- 12: Upper left first premolar
- 13: Upper left second premolar
- 14: Upper left first molar
- 15: Upper left second molar
- 16: Upper left third molar (wisdom tooth)
Lower Teeth (Left to Right)
- 17: Lower left third molar (wisdom tooth)
- 18: Lower left second molar
- 19: Lower left first molar
- 20: Lower left second premolar
- 21: Lower left first premolar
- 22: Lower left canine
- 23: Lower left lateral incisor
- 24: Lower left central incisor
- 25: Lower right central incisor
- 26: Lower right lateral incisor
- 27: Lower right canine
- 28: Lower right first premolar
- 29: Lower right second premolar
- 30: Lower right first molar
- 31: Lower right second molar
- 32: Lower right third molar (wisdom tooth)
When your dentist says something like “number 19 has a cavity,” they’re talking about your lower left first molar. The system reads as if you’re looking at the patient, so “right” and “left” refer to the patient’s own right and left sides.
How Each Tooth Type Differs in Structure
Incisors and canines are relatively simple teeth. Each one has a single root anchoring it into the jawbone. Incisors are flat and blade-like, while canines are slightly thicker with a pointed tip.
Premolars get more complex. Your upper first premolars each have a split root (two branches, one facing your cheek and one facing your tongue), while most other premolars have just one root. Their chewing surfaces have two cusps, making them effective at both tearing and grinding.
Molars are the most structurally complex teeth in your mouth. Upper molars typically have three separate roots, and the upper first molar often has a small extra bump on its chewing surface called the cusp of Carabelli, giving it five cusps total instead of four. Lower molars have two roots. Wisdom teeth are the exception to these patterns: their roots tend to fuse together into a single tapered root, and their shape is often irregular.
Wisdom Teeth
Wisdom teeth are simply your third molars, the last teeth on each side of both jaws. They usually come in between the ages of 17 and 25, well after the rest of your permanent teeth. Many people don’t have enough room in their jaw for these teeth to fully emerge, which is why they’re the teeth most commonly removed. Some people never develop all four, and a few never develop any at all.
Baby Teeth vs. Adult Teeth
Children have 20 primary (baby) teeth that start appearing around 6 months of age. This smaller set includes incisors, canines, and molars, but no premolars. The baby molars eventually fall out and are replaced by the adult premolars and molars.
By about age 12 or 13, most children have lost all their baby teeth and have 28 of their 32 permanent teeth. The final four, the wisdom teeth, arrive years later. By age 21, all 32 permanent teeth have typically erupted for those who develop a full set.
Quick Count by Type
- Incisors: 8 total (4 upper, 4 lower)
- Canines: 4 total (2 upper, 2 lower)
- Premolars: 8 total (4 upper, 4 lower)
- Molars: 12 total (6 upper, 6 lower), including 4 wisdom teeth
Each type appears symmetrically on both sides of your mouth, so whatever you have on the left, you have the same on the right. This symmetry is why dentists can quickly identify a tooth just by its number or its name combined with its position.