Child Grinding Teeth at Night: Normal, Worms or Night Guard?
Clinically reviewed by Dr. Abinaash Kaur, DDS, RCDSO, on 2026-11-09. Dr. Kaur is a general dentist in Toronto (Bloor West Village) registered with the Royal College of Dental Surgeons of Ontario.
Most children who grind their teeth at night stop on their own, and most don't need a night guard. Worms aren't the cause, and the studies that went looking for them mostly came back empty.
The sound of a child grinding in the next room is loud, and it's unnerving the first time you hear it. The Canadian Dental Association notes that with sleep grinding, "it's not uncommon for a partner, spouse or parent to hear it first" (Canadian Dental Association). You're the parent in that sentence.
Have no fear. In more than 20 years of seeing families in Bloor West Village, I've heard this question more times than I can count, and the answer is almost always calmer than the noise suggests. (If you're the one grinding, our post on how to stop grinding your teeth at night is the adult version, and the evidence there is different.)
How many kids grind their teeth, and do they grow out of it?
Pretty much every count comes from parents, and the numbers are all over the map.
One systematic review pooled 22 studies and found grinding reported in anywhere from 3.5% to 40.6% of children, with "a commonly described decrease with age and no gender differences" (Journal of Oral Rehabilitation via PubMed). A 2024 scoping review from the Université de Montréal put the range at 5% to 50% "depending on the age range and on the SB diagnosis" (Journal of Oral Rehabilitation via PubMed). SB is the researchers' shorthand for sleep bruxism, the clinical name for night grinding.
So somewhere between one child in twenty and one in two. That's the honest state of the counting.
The best Canadian numbers come from Quebec. Mothers of 1,946 children answered sleep questions from age one and a half to seven, and 55.5% of the children fell into the group that never ground their teeth at any point (Sleep via PubMed). Read that the other way: close to half of those children ground at some stage.
That's a lot of normal.
Does it stop? Mostly, yes. The American Academy of Pediatric Dentistry's guidance says "Evidence indicates that juvenile bruxism is self-limiting and does not persist in adults" (American Academy of Pediatric Dentistry). A French review describes it peaking "at 10-14 years of age, after which it drops until adulthood" (Archives de Pédiatrie via PubMed).
Mostly isn't always. One Brazilian study followed children for three to five years and found the grinders "remained with this behaviour and showed higher dental wear over the years" (Journal of Oral Rehabilitation via PubMed). So expect it to fade, and keep an eye on the teeth in case it doesn't.
Why do kids grind their teeth in their sleep?
Most people think a child grinds because something is wrong with the teeth. Here's what the research points to instead: sleep.
The Montreal review describes childhood grinding as multifactorial and "arousal associated," with snoring, sleep apnoea, nightmares, allergies and mouth breathing on its list of risk factors (Journal of Oral Rehabilitation via PubMed). A meta-analysis of 14 studies in children up to age 12 found the sleep behaviours tied to grinding were snoring, mouth breathing, restless sleep, drooling, sleeping on the stomach, and not getting enough sleep (Sleep and Breathing via PubMed).
The CDA's own causes list is shorter: "Anxiety and/or stress", "Interrupted sleep", and "Crooked, misaligned and/or missing teeth" (Canadian Dental Association).
What about worry? In the Quebec study, preschoolers whose separation anxiety climbed through the early years "had almost double the risk of presenting sleep bruxism at age 7," though the two patterns were only weakly linked overall (Sleep via PubMed). Stress plays a part, and a smaller one than the adult grinding advice would have you believe.
New teeth matter for toddlers who grind while awake. In 144 children aged 4 to 36 months, 16.7% of parents reported daytime grinding, and children with more erupted molars and canines ground less, which the authors read as a possible "adaptive behaviour" (Journal of Oral Rehabilitation via PubMed).
A toddler testing new teeth against each other is doing something normal.
Screens and sugar are the newest suspects. In 440 children aged 4 to 8, grinding rose as screen time and added sugar rose (Sleep Medicine: X via PubMed), and a small trial of 48 children found that cutting TV time and added sugar went along with less grinding (Journal of Oral Rehabilitation via PubMed). A hint, not a rule.
Is it worms?
No. This one has been tested, and it's the oldest grinding myth there is.
A Brazilian team examined 57 children aged 6 to 11 and checked three stool samples from each. Parasites turned up in 30% of the grinders and 41% of the non-grinders, "but no statistically significant association was observed," and the authors concluded their findings "do not support the existence of an association" (Journal of Dentistry for Children via PubMed).
Two studies did find a link. In Isfahan, Iran, parasites were found in 11 of 50 grinders and 8 of 50 non-grinders aged 3 to 6 (Dental Research Journal via PubMed). In rural Egypt, among 450 children aged 3 to 10, reported grinding was more frequent in those who tested positive for intestinal parasites (BMC Oral Health via PubMed).
None of these studies was done in Canada, and none gave children deworming medicine and watched the grinding stop. Please don't do that at home either. If your child has stomach pain, itching, or a change in appetite or stools, that's a conversation for your family doctor, grinding or not.
Grinding is a sleep question, not a stomach question.
Do kids grind more when they're sick?
Parents tell me the grinding gets louder when a cold is going through the house. Wait? Is there anything to that?
I searched for a study that tested colds and grinding directly and couldn't find one. What the research has instead is a nose story.
In 60 children with blocked noses seen at an ear, nose and throat clinic, grinding was present in 65.22% (International Journal of Pediatric Otorhinolaryngology via PubMed). In 140 children aged 4 to 12 with large tonsils and adenoids, grinding was reported by questionnaire in 25.7% before surgery to remove them and 7.1% afterward (International Journal of Pediatric Otorhinolaryngology via PubMed).
That second study had no comparison group, so hold it loosely.
The reviews are cautious too. A 2024 systematic review of 29 studies concluded "there is an association between SB and SBD in children. However, the level of evidence is low" (Oral Diseases via PubMed), where SBD means sleep-breathing disorders. A scoping review found the link to sleep apnea in children "seems plausible" with "currently insufficient supportive evidence" (Sleep via PubMed).
So a stuffed-up child who breathes through their mouth at night may well grind more. Plausible, not proven.
Whatever you do, don't reach for tape. Our post on mouth taping for sleep explains why that's a bad idea for anyone and a worse one for a child, and our older post on breathing for life covers why nasal breathing matters for a growing face.
Is grinding a sign of autism?
Grinding is not on the list of autism signs published by the Public Health Agency of Canada, which centres on eye contact, babbling, and how a child plays and connects with others (Public Health Agency of Canada). I'm a dentist, not a developmental specialist, so I'll stick to what the research says.
It does say something. In a study of 150 autistic preschoolers and 150 matched children in Riyadh, teeth grinding was the most common oral habit in the autistic group, at 54.7% (Pakistan Journal of Medical Sciences via PubMed). A 2022 meta-analysis pooled 15 such studies covering 3,850 people, found the autistic group more likely to grind, then rated the certainty of that evidence "very low" and concluded: "It is uncertain whether individuals with ASD are more likely to have bruxism than healthy controls" (Special Care in Dentistry via PubMed).
Those studies run in one direction: they start with children already diagnosed and ask what habits they have. Your question runs the other way, and a habit that close to half of all children have at some point can't sort children into groups on its own.
I wrote the same thing about whether thumb sucking is a sign of autism, and the logic hasn't changed.
If anything about your child's development worries you, the Public Health Agency of Canada says to speak to your healthcare provider about an assessment (Public Health Agency of Canada). You don't need a grinding habit as your reason.
What do I look for in the chair?
Four things, and none of them takes long.
First, the baby canines, the pointy teeth beside the front four, because grinding tends to flatten them. A meta-analysis of 22 studies found canine wear in 84.13% of children who ground, with headache in 52.85%, at "low to very low" certainty (Sleep Medicine Reviews via PubMed). Another review was blunter: "Tooth wear was not found to be a major sign of SB in children" (Frontiers in Oral Health via PubMed).
So I look, and I don't over-read what I see.
Second, chips. A baby tooth with a flaked edge, or a filling that keeps breaking, tells me the forces at night are real.
Third, the airway: tonsil size, whether the lips rest apart, and how your child breathes while I'm working.
Fourth, the bite and the jaw joints. A child whose jaw clicks gets the same careful look an adult does, and our post on jaw clicking explains what that noise means.
Some days the schedule pushes me, and even then a nervous seven-year-old gets to count my instruments before I count their teeth.
When is it worth a visit, or a call to your doctor?
Grinding on its own, with a happy kid and intact teeth, is something we watch at regular checkups. That can be the whole plan.
Book a dental visit sooner if your child wakes with a sore jaw or sore teeth, has morning headaches, chips a tooth, or the edges of the teeth look flatter. A scoping review found an association between sleep grinding and both migraine and tension headache in children and adolescents (Journal of Oral and Facial Pain and Headache via PubMed), so headaches plus grinding is a combination I want to hear about.
Once the adult teeth are in and still wearing, the conversation changes, because those teeth have to last.
Call your family doctor or paediatrician about the breathing, not me. The Canadian Paediatric Society's advice to parents is plain: "If your child regularly snores loudly or seems to stop breathing for a short time, then gasps, this can be a sign of a problem" (Canadian Paediatric Society, Caring for Kids). I can notice big tonsils. I can't diagnose a sleep problem, and no blog post can either. Our post on sleep apnea mouthguards and bite changes explains why the dental side of airway care starts with a physician.
Does my child need a night guard?
Usually not, and this is the question parents arrive with.
The evidence is thin in a way that matters. An umbrella review of the systematic reviews on childhood grinding concluded "there is currently insufficient evidence to make recommendations for specific treatment options" (Brazilian Oral Research via PubMed). One meta-analysis of treatments found 10 usable papers and a total of 94 children, and called the data "limited" (Cranio via PubMed).
A scoping review of interventions reminds dentists that "bruxism is not considered a disorder in otherwise healthy individuals" (European Journal of Pediatrics via PubMed).
My own reasoning is simpler. A child's mouth changes every few months: baby teeth loosen, adult teeth arrive, the jaw grows. A guard fitted this spring won't fit by next spring, and I'm not keen on a rigid appliance over a bite that's still finding its shape. Adults are a different case, which is why our night guard guide exists.
There are exceptions. An older teen with a full set of adult teeth, visible wear, and morning jaw pain gets the "case-by-case approach, taking into account the specificities of each young patient" that the French review recommends (Archives de Pédiatrie via PubMed).
A sports mouthguard is a different appliance for a different job, and our post on mouthguards with braces and Invisalign covers that one.
What helps at home?
Try this:
- Protect the hour before bed. The Canadian Paediatric Society says "No screens for 1 hour before sleep" and no tablets, televisions or games in the bedroom (Canadian Paediatric Society, Caring for Kids). It's the cheapest experiment you can run.
- Keep bedtime the same. Not enough sleep sat on the risk-factor list in the meta-analysis of 14 studies (Sleep and Breathing via PubMed).
- Check the nose. Watch your child sleep for a minute. Mouth open, snoring, or restless flipping around? Mention it at the next doctor's visit.
- Ease off the evening sugar. The small trial that cut sugar and TV saw grinding ease (Journal of Oral Rehabilitation via PubMed).
- Don't wake them, and don't mention it at breakfast. They can't hear themselves, and they can't stop it on purpose.
Frequently Asked Questions
Q: Is it normal for a child to grind their teeth at night? Yes, it's common. Reviews of parent surveys put the share of children who grind anywhere from 3.5% to 50% depending on age and how grinding was defined (Journal of Oral Rehabilitation via PubMed, Journal of Oral Rehabilitation via PubMed), and most children stop on their own as they grow.
Q: Does teeth grinding in kids mean they have worms? No. In a study of 57 children that tested stool samples directly, parasites were found in 30% of the grinders and 41% of the non-grinders, with no statistically significant association (Journal of Dentistry for Children via PubMed). Two studies from Iran and Egypt did find a link (Dental Research Journal via PubMed, BMC Oral Health via PubMed), but none showed that treating parasites stops grinding. Don't give deworming medicine for grinding.
Q: Why does my child grind their teeth more when they're sick? Nobody has tested colds and grinding directly. Grinding was present in 65.22% of one clinic sample of children with blocked noses (International Journal of Pediatric Otorhinolaryngology via PubMed), and a 2024 systematic review found an association between grinding and sleep-breathing problems in children while rating the evidence low (Oral Diseases via PubMed). A congested mouth-breather may grind more. Plausible, not proven.
Q: Is teeth grinding a sign of autism? Grinding isn't on the Public Health Agency of Canada's list of autism signs (Public Health Agency of Canada). A 2022 meta-analysis of 15 studies found grinding more common in autistic children but rated the certainty of that evidence "very low" and called the question uncertain (Special Care in Dentistry via PubMed). Grinding is common in all children, so on its own it can't tell you anything about your child. Talk to your family doctor or paediatrician about any developmental concern.
Q: Does my child need a night guard? Usually not. An umbrella review of the research on childhood grinding found "insufficient evidence to make recommendations for specific treatment options" (Brazilian Oral Research via PubMed), and a growing mouth outgrows a rigid appliance quickly. We watch the teeth at checkups and talk about a guard case by case, usually once the adult teeth are in and showing wear.
Q: When should I worry about my child's grinding? See your dentist for morning jaw or tooth pain, headaches, a chipped tooth, or teeth that look flatter. See your family doctor or paediatrician if your child "regularly snores loudly or seems to stop breathing for a short time, then gasps," which the Canadian Paediatric Society flags as a sign of a problem (Canadian Paediatric Society, Caring for Kids).
Reviewed by Dr. Abinaash Kaur, DDS (University of Western Ontario), who has practised general and family dentistry in Bloor West Village for more than 20 years. This article is general oral health information, not a diagnosis or a substitute for an examination. Questions about your child's breathing, sleep or development belong with your family doctor or paediatrician.
Hearing grinding from the next room and not sure what it means? Bring your child in and we'll check the teeth, look at the bite and the airway, and tell you plainly whether there's anything to do. We're at 750 Annette Street in Bloor West Village, serving the Junction, High Park, and Baby Point. Book a visit with The Village Dentist and we'll take it from there.
