A 4-year-old typically has 20 baby teeth. This is the full set of primary teeth, and most children have all 20 in place by around age 3. At four, your child is in a stable window where all baby teeth have come in but none have started falling out yet.
The 20 Baby Teeth, Mapped Out
Those 20 teeth are split evenly between the upper and lower jaws, 10 on top and 10 on the bottom. Each jaw holds the same combination:
- Four incisors: the flat front teeth used for biting
- Two canines: the slightly pointed teeth next to the incisors
- Four molars: the wider teeth in the back used for chewing
If you count your child’s teeth and land on 20, everything is on track. This full set of baby teeth will serve them for the next couple of years before any begin to loosen.
What If Your Child Has Fewer Than 20?
Some children are born missing one or more baby teeth, a condition called hypodontia. It’s uncommon. Research published through the American Academy of Pediatric Dentistry puts the prevalence at less than 1% in most populations, with slightly higher rates (up to 5%) reported in Japanese children. When teeth are missing, the most commonly absent ones are the upper lateral incisors (the teeth flanking the two front teeth) and the lower front teeth.
Having fewer than 20 baby teeth doesn’t always mean permanent teeth will be missing too, but a pediatric dentist can take X-rays to check what’s developing beneath the gums.
When Baby Teeth Start Falling Out
At age 4, tooth loss is still a year or two away. Most children lose their first baby tooth around age 6, starting with the lower front teeth. The shedding process then continues gradually through about age 12, when the last baby molars are replaced.
By age 6 or 7, you can also expect the first permanent molars to appear. These don’t replace any baby teeth. Instead, they emerge behind the last baby molars, bringing the total tooth count above 20 for the first time. Some children experience sore or swollen gums, irritability, and difficulty sleeping when these molars push through, similar to what they went through during teething as infants.
Caring for a 4-Year-Old’s Teeth
Baby teeth hold space in the jaw for the permanent teeth developing underneath. Losing a baby tooth early to decay can cause the surrounding teeth to shift, potentially creating alignment problems later. That makes daily care at this age more important than it might seem.
For children between 3 and 6, the CDC, the American Dental Association, and the American Academy of Pediatric Dentistry all recommend brushing twice a day with a pea-sized amount of fluoride toothpaste (roughly 0.25 grams). The pea-sized guideline exists because children this age still swallow some toothpaste while brushing. By around age 6, the swallowing reflex is mature enough that accidental ingestion becomes much less of a concern.
Most 4-year-olds still need help brushing, especially reaching the back molars. Letting your child hold the brush first and then finishing for them is a practical way to build the habit while making sure every surface gets cleaned.
The Full Timeline at a Glance
At 4, your child sits in the calm middle stretch of dental development. The teething phase is behind them, and tooth loss hasn’t started. Here’s the broader picture:
- 6 to 12 months: first baby teeth appear
- Age 2.5 to 3: all 20 baby teeth are usually in place
- Age 4 to 5: full set of 20, no changes expected
- Age 6 to 7: first baby teeth fall out; first permanent molars arrive
- Age 12 to 13: last baby teeth shed
- Age 21: all 32 permanent teeth, including wisdom teeth, have typically erupted