Kids have 20 primary teeth, sometimes called baby teeth. That’s 10 on the top and 10 on the bottom, and most children will have the full set by age 3. These 20 teeth eventually give way to 32 permanent adult teeth over a process that starts around age 6 and isn’t fully complete until the late teens or early twenties.
The 20 Baby Teeth, Broken Down
Those 20 primary teeth break down into three types: 8 incisors (the flat front teeth used for biting), 4 canines (the pointed teeth next to the incisors), and 8 molars (the wider teeth in the back used for chewing). Each type appears in matching pairs on the top and bottom jaw, so the mouth is symmetrical.
Baby teeth are smaller and whiter than adult teeth, with thinner enamel. Their roots are also shorter, which is part of why they’re able to loosen and fall out when permanent teeth start pushing up underneath them.
When Each Tooth Comes In
The first teeth to appear are usually the two bottom front teeth (lower central incisors), which typically break through between 6 and 10 months of age. The upper central incisors follow at around 8 to 12 months. From there, teeth continue filling in from front to back over the next two years.
Here’s the general timeline:
- Central incisors: 6 to 12 months
- Lateral incisors: 9 to 16 months
- First molars: 13 to 19 months
- Canines: 16 to 23 months
- Second molars: 23 to 33 months
These ranges vary quite a bit from child to child. Some babies get their first tooth at 4 months, while others don’t see one until after their first birthday. Both ends of that spectrum are normal. By around age 3, most kids will have all 20 teeth in place.
When Baby Teeth Start Falling Out
Baby teeth generally fall out in the same order they came in. The lower central incisors go first, typically around age 5 or 6, followed by the upper central incisors. After that, the lateral incisors loosen, then the first molars, canines, and finally the second molars. This process stretches over several years, so kids spend a long time with a mix of baby and adult teeth in their mouth.
The shedding happens because permanent teeth developing beneath the gums gradually dissolve the roots of the baby teeth above them. As the root gets shorter, the baby tooth loosens until it falls out on its own (or with a little help from a curious kid).
The Jump to 32 Adult Teeth
Permanent teeth start replacing baby teeth around age 6, but the full set of 32 adult teeth won’t be complete until the late teens or even early twenties, when wisdom teeth come in. Adults end up with 8 incisors, 4 canines, 8 premolars, and 12 molars. Premolars are a new category that doesn’t exist in the baby tooth set. They fill in between the canines and molars.
One detail that surprises many parents: the first permanent teeth to arrive don’t actually replace a baby tooth at all. Around age 6, four molars (called “6-year molars”) erupt behind the last baby teeth, in spots where no baby tooth existed. Because they don’t push anything out, they can show up without parents realizing a permanent tooth has come in. These molars are important to keep an eye on since they’ll be in your child’s mouth for life and are especially prone to cavities in those early years.
Caring for Baby Teeth
It’s tempting to think baby teeth don’t matter much since they’re going to fall out anyway. But primary teeth hold space in the jaw for the permanent teeth developing underneath. If a baby tooth is lost too early to decay or injury, neighboring teeth can drift into the gap, crowding out the adult tooth that’s supposed to come in later. Cavities in baby teeth can also cause pain, infection, and problems with eating and speech development.
The American Academy of Pediatric Dentistry recommends scheduling a child’s first dental visit within 6 months of the first tooth appearing, and no later than 12 months of age. That first visit is mostly about checking development and getting parents set up with good brushing habits for their child. Until kids develop the coordination to brush well on their own (usually around age 6 or 7), they’ll need a parent’s help to do a thorough job.