By age 3, most children have all 20 of their baby teeth. The last teeth to arrive are the second molars, the broad flat teeth at the very back of the mouth, which typically push through between 23 and 33 months old. So at 3 years old, your child is likely finishing up teething rather than just starting a new round of it.
The Second Molars: The Final Baby Teeth
The second molars are the last of the 20 primary teeth to come in. Lower second molars tend to appear between 23 and 31 months, while upper second molars follow closely at 25 to 33 months. That means some children will have these teeth fully in place well before their third birthday, while others may still be waiting for one or two to break through right around age 3.
These molars sit behind the first molars your child got around 13 to 19 months of age. They’re the widest teeth in a toddler’s mouth and do the heavy lifting when it comes to chewing food. Because of their size, they can be more uncomfortable coming in than the smaller front teeth were.
Teething Symptoms at This Stage
Even though your child is older now, second molars can still cause classic teething discomfort. Common signs include red or swollen gums at the back of the mouth, increased drooling, fussiness, difficulty sleeping, loss of appetite, and an urge to bite or chew on things. Some children sail through with barely a complaint. Others have a rough few days each time a molar pushes through.
A slight increase in temperature is normal during teething, but a true fever above 100.4°F (38°C) is not caused by teething. If your child develops a high fever, something else is going on.
Cold washcloths to chew on, chilled (not frozen) teething rings, and gentle gum massage with a clean finger can all help ease the soreness. Most discomfort peaks in the day or two before a tooth breaks the surface and fades quickly after.
The Full Set: What 20 Teeth Look Like
Once those second molars are in, your child’s mouth holds a complete set of 20 baby teeth: 10 on top and 10 on the bottom. Each half of the mouth, upper and lower, contains four incisors (the front biting teeth), two canines (the pointed teeth next to the incisors), and four molars (two first molars and two second molars).
This is the set of teeth your child will use for the next several years. No new teeth will appear until the first permanent molars and lower front teeth start coming in around age 6 or 7, though some children begin losing baby teeth as early as age 4 or as late as age 8.
Why Gaps Between Baby Teeth Are a Good Sign
If you notice spaces developing between your 3-year-old’s teeth, that’s actually something to welcome. Baby teeth are smaller than the permanent teeth that will eventually replace them. As your child’s jaw grows, gaps naturally open up between the primary teeth. These spaces are the body’s way of making room for the larger adult teeth that will arrive later. A toddler or preschooler whose baby teeth are tightly packed together with no gaps may actually face more crowding issues down the road.
Caring for a 3-Year-Old’s Teeth
With a full set of teeth now in place, dental care becomes more important than ever. The American Academy of Pediatric Dentistry recommends checkups and cleanings every six months for most children, though kids at higher risk for cavities may benefit from visits every three months. At these appointments, the dentist will check your child’s developing bite, clean the teeth, and may apply sealants to cavity-prone molars.
At home, brush your child’s teeth twice a day with a rice-grain-sized smear of fluoride toothpaste (moving to a pea-sized amount once they can reliably spit it out, usually around age 3 to 4). Pay extra attention to those back molars. Their broad, grooved surfaces trap food easily, and young children lack the coordination to reach them on their own. Most kids need help brushing until around age 6 or 7.
Diet matters too. Frequent snacking on sticky or sugary foods, and sipping juice or milk throughout the day, bathes baby teeth in sugar and promotes cavities. Baby teeth have thinner enamel than adult teeth, so decay can progress quickly once it starts.
What Comes After the Baby Teeth
Once those 20 teeth are in, your child gets a long break from teething. The next dental milestone comes around age 6 or 7, when the first permanent teeth start appearing. Typically the lower front teeth loosen and fall out first, replaced by their larger adult versions. Around the same time, the first permanent molars erupt behind the last baby molars, filling in new space at the back of the jaw without replacing any existing teeth.
The transition from baby teeth to permanent teeth is gradual, stretching from roughly age 6 to age 12 or 13. In the meantime, those 20 primary teeth serve as placeholders, guiding the adult teeth into proper position. Losing a baby tooth too early to decay or injury can cause neighboring teeth to shift, potentially creating alignment problems later. That’s one reason keeping baby teeth healthy is worth the effort, even though they’re temporary.