Little kids have 20 baby teeth, also called primary teeth. These 20 teeth start appearing around 6 months of age and are usually all in place by age 3. That full set of 20 stays intact until around age 6, when children begin losing them to make room for the 32 permanent teeth that will eventually replace them.
The 20 Baby Teeth, Broken Down
Your child’s 20 primary teeth come in matched pairs, evenly split between the upper and lower jaws. Here’s what makes up the full set:
- 8 incisors: Four on top and four on the bottom, right in the front of the mouth. These are the flat, sharp teeth used for biting into food. The two in the center (central incisors) typically come in first, followed by the ones on either side (lateral incisors).
- 4 canines: Two on top and two on the bottom, sitting just next to the incisors. These are the pointed teeth that help tear food.
- 8 molars: Four on top and four on the bottom, toward the back of the mouth. Kids get a set of first molars and then a set of second molars. These are the wide, flat teeth built for chewing and grinding.
Notice there are no premolars in a child’s mouth. Those only appear as part of the permanent set later on, which is one reason adults end up with 32 teeth instead of 20.
When Each Tooth Comes In
Teeth don’t all show up at once. The process stretches over roughly two and a half years, and it follows a fairly predictable pattern, though the exact timing varies from child to child.
The lower central incisors are usually the first to break through, arriving around 6 to 10 months. The upper central incisors follow shortly after, typically between 8 and 12 months. Lateral incisors fill in next, followed by the first molars around 13 to 19 months. Canines tend to come in between 16 and 23 months. The second molars, way in the back, are the last to arrive, usually showing up between 23 and 33 months.
By age 3, most children have all 20 teeth. Some kids run a few months ahead or behind this schedule, and that’s completely normal. If your child hasn’t gotten any teeth by 12 months, it’s worth mentioning to a dentist, but late teethers usually catch up without any issues.
How Baby Teeth Differ From Adult Teeth
Baby teeth aren’t just smaller versions of adult teeth. They have some distinct physical characteristics that matter for your child’s dental health. Their enamel, the hard outer coating that protects against cavities, is only about 0.5 mm thick, roughly half the thickness of enamel on permanent teeth. That thinner enamel means cavities can develop faster and penetrate deeper in less time.
Primary teeth also appear whiter than adult teeth because they contain more water. Their crowns are more bulbous and wider relative to their height, giving them that characteristic stubby look. The roots spread apart more than adult tooth roots do, which creates space underneath for the permanent teeth developing in the jawbone. These structural differences are why baby teeth that get cavities need prompt attention. Decay can reach the inner nerve more quickly than it would in an adult tooth.
When Kids Start Losing Teeth
Around age 6, children begin losing their baby teeth in roughly the same order they came in. The lower central incisors typically fall out first, followed by the upper central incisors. This process is gradual. Most children lose their last baby teeth (usually the second molars or canines) between ages 10 and 12.
During this transition, kids have a mix of baby teeth and permanent teeth in their mouth at the same time. This “mixed dentition” phase can look a bit chaotic, with gaps, size mismatches, and teeth at different stages of growth. It’s a normal part of development. The permanent teeth gradually push the roots of the baby teeth out as they move into position, which is why baby teeth get wiggly before they fall out.
What If the Count Is Off
Most children develop exactly 20 primary teeth, but some don’t. A small percentage of kids are congenitally missing one or more teeth, a condition called hypodontia. Studies estimate this affects somewhere between 2% and 10% of people, depending on the population studied. On the other end, some children develop extra teeth. This is less common in the primary set but does occur. In rare cases (under 1%), a child can have both missing and extra teeth simultaneously.
If your child seems to have fewer or more teeth than expected, a dentist can take X-rays to see what’s developing beneath the gums and determine whether any intervention is needed down the road.
Caring for Those 20 Teeth
The American Dental Association recommends scheduling your child’s first dental visit after the first tooth appears, and no later than their first birthday. That’s earlier than many parents expect, but it establishes a baseline and catches any issues when they’re easiest to address.
For daily brushing, the recommended amount of fluoride toothpaste depends on age. Children under 3 should use a smear about the size of a grain of rice. From ages 3 to 6, a pea-sized amount (roughly 0.25 grams) is appropriate. These small quantities provide cavity protection while minimizing the amount swallowed, since young kids haven’t mastered spitting yet.
Because baby tooth enamel is so thin, what seems like a minor cavity can become a serious problem quickly. Baby teeth also serve as placeholders, keeping the spacing correct so permanent teeth can come in straight. Losing a baby tooth too early to decay or injury can cause neighboring teeth to drift, potentially leading to crowding when the permanent teeth try to emerge.