Why Is My Baby Grinding Their Teeth? Reasons & What to Do

Teeth grinding in babies and toddlers, known clinically as bruxism, is one of the most common oral habits in early childhood and is almost always harmless. Studies estimate that roughly a quarter of children grind their teeth at some point, with the average age of onset around five years old, though many parents first notice it much earlier, sometimes as soon as the first teeth come in. The reasons range from simple sensory exploration of new teeth to airway problems during sleep, and the list of contributing factors is longer and more interesting than most parents expect.

How Common Is Childhood Bruxism

If you hear your baby or toddler grinding their teeth at night and feel alarmed, it helps to know you’re far from alone. One large study of children referred to dental clinics found a bruxism prevalence of about 26%, with onset averaging around age five.¹ Other research puts the range anywhere from 15% to 40%, depending on how grinding is defined and who is reporting it. That wide spread reflects a real challenge in studying the habit: parents are the main source of information, and many children sleep in separate rooms where grinding goes unheard.

Sleep studies that record jaw-muscle activity reveal that some children who grind aren’t noticed by their parents, while other children whose parents report grinding don’t show the expected muscle patterns on the recording.² The grinding sound itself can be dramatic, metal-on-metal in quality, and parents often describe it as one of the most unpleasant noises they’ve encountered. But volume doesn’t track with severity. A child who grinds loudly for a few weeks and then stops on their own has had a very different experience from one who grinds quietly for years and develops visible wear on their teeth.

Airway Problems Are a Major and Underappreciated Cause

One of the most important findings in recent research is the strong link between teeth grinding during sleep and breathing difficulties. When a child’s airway is partially blocked, the jaw may shift and clench in an unconscious effort to open the passage. Enlarged tonsils, restricted tongue mobility, and nasal obstruction are the usual culprits. A systematic review found that among children with all three of those airway factors present, the prevalence of sleep bruxism was over 90%.³ That’s a striking number, and it suggests that for many children, grinding isn’t a standalone habit but a symptom of a breathing problem.

A study of 98 children aged three to six who were brought in specifically because of bruxism found that 70% of them had obstructive sleep apnea syndrome on polysomnography, a formal overnight sleep study. Other sleep disorders identified in that group included parasomnias, circadian rhythm problems, and insomnia.⁴ This is one of the reasons dentists and pediatricians have become more attentive to grinding. It may be the most visible clue that a young child is struggling to breathe well during sleep, especially if the child also snores, breathes through their mouth during the day, or has restless sleep.

Stress, Anxiety, and Emotional Changes

Adults who grind their teeth are often told it’s related to stress, and the same connection exists in children, though it looks different at younger ages. A baby doesn’t have work deadlines, but they do experience overstimulation, separation anxiety, changes in routine, and the stress of developmental leaps. Older toddlers and preschoolers can begin grinding in response to family upheaval, a new sibling, starting daycare, or other life transitions.

Research on the stress-bruxism link in young adults found that people experiencing acute national stress showed higher frequencies of clenching and teeth grinding compared to those who weren’t, and that individuals diagnosed with adjustment disorder were particularly affected.⁵ While that study focused on adults, the underlying mechanism, an overactivated stress response driving jaw muscle tension, applies across ages. Resilience mattered too: people with a higher ability to bounce back from stressful events were more likely to keep their jaw muscles relaxed. For children, this translates into the common parental observation that grinding gets worse during stressful periods and calms down once the child adjusts.

Sensory Exploration in Babies and Toddlers

For babies specifically, the most benign explanation is often the right one. When teeth first erupt, typically between six and twelve months, the sensation is brand new. Babies explore every new thing with their mouths, and two hard surfaces that can rub against each other are irresistible. Many babies who start grinding shortly after their first teeth appear are simply experimenting with the feeling and the sound. They grind for a few weeks, lose interest, and stop.

This kind of grinding tends to happen during the day as well as at night, and it often has a playful quality. The baby might grind, pause, look at you, and grind again. Daytime grinding in an otherwise healthy baby who has recently cut new teeth rarely signals anything medical. It’s the nighttime grinding that persists past the initial teething window, especially if it’s accompanied by snoring or mouth breathing, that warrants closer attention.

Screen Time and Sugar Consumption

A more recent area of study that surprises many parents is the association between screen time and sleep bruxism in children. Research conducted during and after the COVID-19 pandemic, when children’s screen exposure increased substantially, found that children with sleep bruxism spent significantly more time in front of screens than children without it. One study measured an average daily screen time of about 167 minutes in the bruxism group versus 135 minutes in the non-bruxism group.⁶

A separate study found strong correlations between possible sleep bruxism and both screen time and added sugar consumption, with the screen-time association being particularly robust.⁷ Neither study proves that screens cause grinding, as children who use more screens may also have worse sleep hygiene, more stimulation before bed, or other overlapping risk factors. But the association is consistent enough that reducing evening screen exposure is a reasonable, low-cost thing to try if your child grinds at night.

Nutritional Gaps That May Play a Role

Vitamin D deficiency and low calcium intake have been linked to sleep bruxism in ways that go beyond coincidence. One case-control study found that people with sleep bruxism were roughly six to seven times more likely to be vitamin D deficient and about six times more likely to have low dietary calcium intake compared to controls.⁸ A review of the broader literature on nutrition and bruxism found that deficiencies in vitamin D, magnesium, and omega-3 fatty acids can increase neuromuscular excitability and stress sensitivity, both of which could feed into grinding.⁹

This doesn’t mean that giving your child a vitamin D supplement will stop the grinding. But if your child is a picky eater, rarely drinks milk, or has limited sun exposure, it’s worth mentioning the grinding to your pediatrician, who can check vitamin D levels with a simple blood test. Correcting a deficiency is worth doing for bone health and immune function regardless, and it may help with bruxism as a secondary benefit.

The Pinworm Question

In many cultures, teeth grinding in children is widely believed to be a sign of intestinal worms, especially pinworms. This belief is persistent enough that researchers have actually tested it, and the results are mixed at best. One study of children aged three to six found a statistically significant relationship between pinworm infection and bruxism.¹⁰ But a more controlled study that actually measured bruxism severity using a device worn on the jaw found no significant correlation between pinworm infection and bruxism levels.¹¹

The honest summary is that pinworms probably don’t cause grinding in any straightforward way. It’s possible that the discomfort and itching from a pinworm infection disrupts sleep quality, which in turn worsens grinding that was already present for other reasons. But if your child is grinding, assuming worms is not a productive first step. If you have reason to suspect pinworms independently, like your child complaining of itching around the anus at night, that’s worth addressing for its own sake. Just don’t expect treating the worms to cure the grinding.

Gastroesophageal Reflux and Grinding

Another connection that many parents don’t know about is between acid reflux and sleep bruxism. Both conditions tend to occur during the night, and a systematic review found that when a reflux episode precedes a grinding episode during sleep, the combination can accelerate tooth wear. Stomach acid reaching the mouth softens tooth enamel, and grinding then strips that weakened enamel away more efficiently than either problem would on its own.¹²

For babies, reflux is extremely common in the first year. Most spit-up is normal and resolves on its own. But if your baby has been diagnosed with GERD, or if you notice signs like arching during feeds, frequent vomiting, and poor weight gain alongside grinding, the two may be related. Managing the reflux, whether through positioning, feeding changes, or medication if your pediatrician recommends it, could indirectly reduce the grinding or at least protect the teeth from the combined damage.

Neurodevelopmental Conditions

Teeth grinding is more common in children with certain neurodevelopmental conditions, including Down syndrome, cerebral palsy, ADHD, and autism spectrum disorder. A review of the evidence found that grinding and clenching were relatively frequent across all of these groups, with Down syndrome showing the highest prevalence, followed by cerebral palsy and then ADHD and autism.¹³ Children with cerebral palsy in particular tend to have higher rates of malocclusion and parafunctional oral habits, with bruxism being one of the most commonly observed.¹⁴

If your child has a known developmental condition and grinds their teeth, it’s worth bringing up with their care team, because the grinding may be more persistent and more likely to cause dental damage than in neurotypical children. Management may need to be more proactive, including dental monitoring and, in some cases, protective mouthguards once the child is old enough to use one safely.

Medications That Can Trigger Grinding

Certain medications have been identified as potential triggers for bruxism, both during sleep and while awake. A review of the literature found evidence or indications that several classes of medications, as well as some addictive substances, can induce or worsen grinding.¹⁵ In pediatric practice, the most relevant medications tend to be those used for ADHD and certain psychiatric conditions. Stimulant medications used for attention disorders are among the most commonly reported triggers. If your child started grinding around the same time they began a new medication, mention the timing to their prescribing doctor. Sometimes an adjustment in dose or timing can help.

How Grinding Is Actually Diagnosed

For most children, bruxism is “diagnosed” the old-fashioned way: a parent hears the grinding and mentions it to the dentist or pediatrician. This is considered the most practical clinical method, though it has obvious limitations. Children who sleep in their own room may grind undetected for months or years.² The gold standard for diagnosis is polysomnography, an overnight sleep study that records brain activity, muscle contractions, and breathing patterns. But sleep studies are expensive, require specialized facilities, and are uncomfortable for young children, so they’re generally reserved for cases where a sleep disorder like obstructive sleep apnea is suspected.

Standardized clinical screening criteria developed by the American Academy of Sleep Medicine have been found to have strong diagnostic capabilities and can serve as a useful screening tool, even though they don’t fully replace a formal sleep study.¹⁶ In practice, your child’s dentist will look for visible tooth wear, ask about grinding sounds, and check for jaw tenderness. That’s usually enough to guide the next step, which for most young children is simply watchful waiting.

What You Can Actually Do

The frustrating truth is that there’s no single fix for childhood bruxism, because there’s no single cause. But there are practical steps worth taking, depending on what seems to be driving the grinding in your child.

• Rule out airway issues: If your child snores, breathes through their mouth during the day, or seems to struggle to breathe at night, talk to your pediatrician about a referral to an ENT specialist. Enlarged tonsils and adenoids are treatable, and addressing them can dramatically reduce or eliminate grinding.
• Reduce evening screen time: Given the consistent association between screen exposure and sleep bruxism, cutting screens in the hour or two before bed is a sensible step that also improves sleep quality in general.
• Check nutrition: If your child’s diet is limited, ask your pediatrician about checking vitamin D levels. Ensuring adequate calcium and magnesium intake through food or supplements is reasonable and low-risk.
• Manage stress and transitions: For toddlers and preschoolers grinding during stressful periods, extra comfort, consistent bedtime routines, and reassurance often help. The grinding usually subsides once the child adjusts.
• Address reflux if present: If your baby has reflux symptoms alongside grinding, managing the reflux protects teeth even if it doesn’t fully stop the grinding.
• Review medications: If grinding started or worsened after beginning a new medication, flag the timing for your child’s doctor.

Mouthguards, the go-to treatment for adult grinders, are generally not appropriate for babies and young toddlers. The jaw and teeth are changing too rapidly, and a poorly fitting guard can become a choking hazard or interfere with normal dental development. For older children with permanent teeth who grind severely, a dentist may recommend a custom-fitted guard, but this is typically a conversation for school-age children, not babies.

When to Talk to Your Child’s Doctor

Most babies and toddlers who grind will outgrow it without any intervention. The habit peaks in early childhood and tends to decline as the permanent teeth come in. But certain signs warrant a conversation with your pediatrician or pediatric dentist sooner rather than later:

• Visible tooth damage: Flattened, chipped, or noticeably worn-down teeth suggest grinding that’s intense enough to need monitoring.
• Snoring or pauses in breathing: These point toward a possible airway problem, which is the most treatable and consequential cause of grinding.
• Jaw pain or headaches: Older toddlers and preschoolers may complain of pain around the jaw or ears, or have unexplained morning headaches.
• Grinding that persists past age six: By the time permanent teeth start arriving, ongoing grinding becomes more of a dental concern because permanent enamel doesn’t replace itself.
• Associated developmental concerns: If your child has a known neurodevelopmental condition, proactive dental monitoring for grinding-related wear is worthwhile.

In the study of children brought in specifically for bruxism, the majority turned out to have an underlying sleep disorder, most commonly obstructive sleep apnea.⁴ That finding is a useful reminder: grinding itself is the symptom you can hear, but the thing worth investigating is what’s behind it. For many children, treating the root cause, whether it’s enlarged tonsils, reflux, stress, or a nutritional gap, resolves the grinding as a side effect.