Adults have eight premolars. These eight teeth sit in pairs on each side of your upper and lower jaws, positioned between your canines and your molars. In the full set of 32 adult teeth, premolars make up exactly one quarter.
Where Premolars Sit in Your Mouth
Your teeth follow a consistent pattern from the front of your mouth to the back: incisors, canines, premolars, then molars. On each side of each jaw, you have two premolars, labeled the first premolar (closer to the front) and the second premolar (closer to the back). That gives you four premolars in your upper jaw and four in your lower jaw.
The full adult tooth count breaks down like this:
- Incisors: 8 (your front cutting teeth)
- Canines: 4 (the pointed teeth next to your incisors)
- Premolars: 8 (the transitional teeth behind your canines)
- Molars: 12 (your large back grinding teeth, including wisdom teeth)
Children Don’t Have Premolars
If you’re wondering about kids, they have no premolars at all. The primary (baby) set of 20 teeth includes incisors, canines, and molars, but no premolars and no wisdom teeth. The spaces where premolars will eventually sit are occupied by baby molars during childhood.
Premolars are exclusively adult teeth. The first premolars typically erupt between ages 10 and 11, and the second premolars follow closely between ages 10 and 12. They push out the baby molars as they come in.
What Premolars Do
Premolars are transitional teeth, both in their position and their function. Your front teeth (incisors and canines) bite and tear food. Your back teeth (molars) grind it down. Premolars handle the middle step: they crush and break food into smaller pieces before it moves to the molars for final grinding. They have a flatter biting surface than canines but aren’t as broad as molars, making them well suited for this in-between role.
First vs. Second Premolars
Your first and second premolars look similar but aren’t identical. Both have two main cusps (raised points on the biting surface), one on the cheek side and one on the tongue side. In the upper jaw, first premolars tend to have a more prominent cheek-side cusp compared to second premolars, where the two cusps are closer to equal in size. This difference is even more pronounced in the lower jaw, where first and second premolars can look quite distinct from each other.
Root structure also varies. Upper first premolars often have two roots, while upper second premolars and both lower premolars usually have a single root.
When the Count Is Off
Not everyone ends up with exactly eight premolars. Some people are born missing one or more, a condition called congenital absence. The lower second premolar is the most commonly missing one, with studies finding prevalence rates between 0.7% and 3.6% of the population. When a premolar never develops, the baby molar it was supposed to replace may stay in place well into adulthood, or the gap may need orthodontic treatment.
On the other end of the spectrum, some people develop extra (supernumerary) premolars. This happens in roughly 1 in 157 people, occurs about three times more often in males than females, and shows up more frequently in the lower jaw. Extra premolars often remain impacted beneath the gum line and are discovered on dental X-rays taken for other reasons. They sometimes need removal if they crowd or displace the normal teeth around them.
Why Premolars Are Often Extracted
Premolars are the teeth most commonly removed for orthodontic purposes. When your jaw doesn’t have enough room to align all your teeth, an orthodontist may recommend extracting one or two pairs of premolars to create space. Because premolars sit in the middle of the dental arch, removing them allows the remaining teeth to be shifted into better alignment without leaving a visible gap once braces or aligners close the space.