Most 15-month-olds have between four and eight teeth, though some have more and a few have less. The range is wide because tooth eruption timing varies significantly from child to child. By this age, the front teeth (central and lateral incisors) are typically in, and the first molars may be just starting to push through.
Which Teeth Are Usually In by 15 Months
The lower central incisors, the two bottom front teeth, are almost always the first to arrive, typically between 6 and 10 months. The upper central incisors follow at 8 to 12 months. That gives most 15-month-olds at least four front teeth.
The upper lateral incisors (the teeth flanking the top front two) generally come in between 9 and 13 months, and the lower lateral incisors between 10 and 16 months. Many 15-month-olds have all four lateral incisors, bringing the total to eight. Some children are still waiting on the lower lateral incisors at this age, which is perfectly normal given that the eruption window extends to 16 months.
The first molars are the next teeth on the schedule. Upper first molars erupt between 13 and 19 months, and lower first molars between 14 and 18 months. At 15 months, some children already have one or two molars breaking through, while others won’t see them for several more months. If your child does have early molars in addition to all eight incisors, the count could be closer to 10 or 12.
Why Counts Vary So Much Between Children
Genetics is the biggest factor. If you or your partner were late teethers, your child likely will be too. Beyond family patterns, research has identified several other influences on eruption timing: sex (boys tend to get certain teeth slightly earlier than girls), birth weight, gestational age, nutritional status, and overall growth rate. Premature babies often teethe later by calendar age, though when adjusted for their earlier birth, they actually tend to erupt teeth a bit sooner than full-term infants.
Certain medical conditions, particularly thyroid disorders and metabolic conditions, can also delay eruption. But in the vast majority of cases, a child with fewer teeth than average is simply on the later end of a normal curve.
When a Low Tooth Count Is Worth Checking
The normal window for a baby’s very first tooth spans from 4 to 15 months. If your 15-month-old has no teeth at all, it’s worth mentioning to your pediatrician or a pediatric dentist. Some guidelines suggest a dental evaluation if no teeth have appeared by 9 months. A complete absence of teeth at 15 months doesn’t necessarily signal a problem, but a professional can check for underlying causes like nutritional deficiencies or, rarely, a condition affecting tooth development.
If your child has at least a few teeth, even if the count seems low compared to other toddlers the same age, there’s generally no cause for concern. Children fill out their full set of 20 primary teeth by around age 3, and late starters almost always catch up.
Molar Teething at 15 Months
If your child seems fussier than usual around this age, molars may be the reason. The first molars are broader and flatter than incisors, which means they can cause more discomfort as they push through the gums. Common signs include drooling, chewing on objects, irritability, and disrupted sleep. Some children also pull at their ears on the side where a molar is erupting, which can look like an ear infection.
A chilled (not frozen) teething ring or a clean, cool washcloth to chew on can help with the discomfort. Gently rubbing the gums with a clean finger also provides counter-pressure that many toddlers find soothing.
Caring for Those Early Teeth
The American Academy of Pediatric Dentistry recommends brushing with a tiny smear of fluoride toothpaste twice a day as soon as the first tooth appears. At 15 months, use a soft-bristled, age-appropriate toothbrush with a rice-grain-sized amount of fluoride toothpaste. That small amount is safe to swallow and effective at protecting enamel.
Your child should also have had a first dental visit by now, ideally by their first birthday or within six months of their first tooth erupting. If that visit hasn’t happened yet, it’s a good time to schedule one. Early visits are brief and focused on checking that teeth and gums are developing normally, and they help your child get comfortable with the dental office before any treatment is ever needed.