Tooth grinding in a 9-month-old is almost always a normal part of development. Babies who have recently gotten their first teeth often grind them simply because the sensation is new and interesting. It sounds alarming, but at this age, it rarely signals a problem and typically requires no treatment.
Why Babies Grind New Teeth
Most babies get their first teeth between 6 and 10 months, and grinding often starts shortly after. Your baby is discovering that these hard little surfaces exist in their mouth, and pressing them together is a sensory experiment. It’s the same impulse that drives babies to chew on everything they can reach. The grinding may come and go as new teeth emerge and your baby adjusts to the changing landscape inside their mouth.
Some babies also grind when they’re teething because the pressure on sore gums feels relieving, similar to how biting down on a teething ring helps. If your baby seems fussier than usual or is drooling heavily alongside the grinding, teething discomfort is a likely contributor.
Grinding During Sleep
If you notice the grinding mostly at night, it’s worth paying attention to how your baby breathes while sleeping. Research has found a strong link between sleep grinding and airway issues in children. In one study, children with enlarged tonsils, restricted tongue movement, or nasal obstruction had a 90.9% rate of sleep grinding. A narrow upper airway, even without full obstruction, can contribute to the problem.
The mechanism works like this: when a child’s airway narrows during sleep, the body responds by shifting the jaw forward and clenching, which helps keep the airway open. Grinding is essentially a side effect of your baby’s body trying to breathe more easily. Snoring frequently occurs alongside sleep grinding in children for the same reason.
If your baby grinds primarily during sleep and also snores, breathes through the mouth, or seems to pause breathing momentarily, mention it to your pediatrician. These patterns can point to issues like enlarged tonsils or adenoids that are worth evaluating, especially as your child grows.
When Grinding Is Just a Phase
For the vast majority of babies, grinding stops on its own. Toddlers who grind are exploring the feel of their new teeth, and most children outgrow the habit entirely by the time their adult teeth come in. At 9 months, your baby has only a few teeth, and the grinding will likely taper off as the novelty wears off or as more teeth fill in and the bite becomes more stable.
There’s no mouthguard or dental appliance recommended for babies this young. The American Academy of Pediatric Dentistry recognizes bruxism as one of several common oral habits in infants but doesn’t recommend aggressive intervention at this stage. Baby teeth are designed to handle some wear, and the grinding pressure from a 9-month-old is relatively light.
Signs That Deserve a Closer Look
While grinding itself is usually harmless, keep an eye on your baby’s teeth for visible changes. White spots on the tooth surface can indicate enamel breakdown. A light brown discoloration may signal an early cavity. If your baby seems to have pain while eating, pulls away from cold or warm foods, or becomes unusually fussy during meals, the teeth may need a professional check.
These signs are more commonly related to decay than to grinding alone, but persistent, forceful grinding over many months could theoretically wear down enamel on baby teeth. At 9 months, you’re unlikely to see this kind of damage. It becomes more relevant if the habit continues intensely into the toddler years.
What You Can Do Now
You don’t need to stop your baby from grinding during the day. Redirecting with a teething toy can help if the sound bothers you, but the habit isn’t hurting anything. Cold teething rings or a chilled washcloth give your baby something else to press their gums against, which may reduce the grinding if teething pain is driving it.
For nighttime grinding, focus on breathing quality rather than the grinding itself. Make sure your baby’s nose is clear before bed, especially during colds or allergy season. A cool-mist humidifier can help if dry air is contributing to nasal congestion. If snoring or mouth breathing is a regular feature of your baby’s sleep, bring it up at your next well-child visit so your pediatrician can check the tonsils and adenoids.
Your baby’s first dental visit is recommended by age one, and that appointment is a good time to mention the grinding. A pediatric dentist can look for any early signs of wear and confirm that the teeth are developing normally.