Dental Alignment, Chewing and Swallowing in Kids

Key takeaways

Bite variation is the norm, not the exception. A meta-analysis put worldwide malocclusion prevalence at 56%, essentially unchanged from primary to permanent dentition.¹ Most of these children chew and swallow without difficulty.
The chewing evidence is real but softer than usually presented. Children with malocclusion show lower measured chewing efficiency, but the review that pooled this literature concluded it is not entirely possible to either support or deny malocclusion’s influence on chewing in healthy children, given the quality of the underlying studies.²
Two bite types have the clearest functional signature. Unilateral posterior crossbite alters jaw movement. Anterior open bite removes the front teeth’s ability to shear food.²
A bad bite is not a common cause of picky eating. The established contributors are genetic predisposition, sensory sensitivity, temperament, family feeding practices and adverse feeding experiences. Malocclusion is not among them.³
Tongue thrust is at least as likely to be a consequence as a cause. Where a gap already exists, the tongue fills it to seal the mouth for swallowing.
Early orthodontic treatment has one proven advantage, and it is not chewing. For prominent upper front teeth, early two-phase treatment reduced incisor trauma but showed no other advantage over a single course in adolescence.⁴
Straightening a bite does not prevent jaw joint problems. Research does not support the belief that a bad bite or orthodontic treatment causes TMD.⁵

56%worldwide malocclusion prevalence in a meta-analysis of 77 studies — with a 95% confidence interval running from 11% to 99%
57 of 8,192studies that survived screening in the review of how malocclusion affects chewing; 25 of them were rated low quality
13–50%the range of picky eating prevalence estimates in children, peaking between ages two and six — with no dental cause on the list

What a functional bite actually means

A functional bite describes how the upper and lower teeth meet during chewing and swallowing, and how the jaw travels to get there. Teeth that look straight in a photograph can still meet poorly, and teeth that look crowded can function well.

Malocclusion is the umbrella term for variation from an idealized bite.

Type	What it looks like	Functional relevance
Class I	Molar relationship is normal; there may still be crowding, spacing or rotation	Most common by a wide margin; usually little functional impact
Class II (overjet)	Upper front teeth sit well forward of the lower	Mainly a trauma-risk and appearance issue; shearing with the front teeth can be affected at the extreme
Class III (underbite)	Lower teeth sit ahead of the upper	Can affect biting through food; often skeletal and monitored over growth
Deep overbite	Upper front teeth overlap the lower excessively	Usually well tolerated; can cause contact with the palate at the extreme
Anterior open bite	Front teeth do not meet when the back teeth are together	The clearest functional effect — the child cannot bite through with the front teeth
Posterior crossbite	Upper back teeth sit inside the lower	The clearest effect on jaw movement, especially when it is on one side only

Two terms parents meet and should not confuse: overbite is vertical overlap, and some is normal. Overjet is horizontal protrusion, which is what most people mean by “buck teeth.”

How common are bite problems?

Common enough that “your child has a malocclusion” on its own tells you very little.

A systematic review and meta-analysis of 77 studies put worldwide malocclusion prevalence at 56%, with the highest rates in Africa (81%) and Europe (72%), followed by the Americas (53%) and Asia (48%). The prevalence score did not change between primary and permanent dentition, holding at around 54%.¹

The confidence interval is the part worth knowing. That pooled 56% carries a 95% confidence interval running from 11% to 99%.¹ A range that wide is not really an estimate of how common malocclusion is; it is a measure of how differently studies define and count it. Which is the same point from a different direction: a bite finding on its own, without a functional difficulty attached to it, does not mean much.

What misalignment actually does to chewing

The most thorough synthesis on this question screened 8,192 studies and included 57, looking at maximum bite force, chewing muscle activity, jaw movement and chewing efficiency in healthy children. What it found:

In the baby teeth, children with malocclusion showed similar maximum bite force but lower chewing efficiency than controls
In mixed and adult teeth, they showed lower bite force, lower muscle activity and lower chewing efficiency
In one-sided posterior crossbite specifically, jaw movement showed a larger opening angle and more reversed chewing cycles than in children without a crossbite

That reads as a clear picture until the authors’ own conclusion, which is the part that rarely gets quoted. Of the 57 studies, nine were high quality, 23 moderate and 25 low. Given those limitations, it is not entirely possible to either support or deny the influence of malocclusion on bite force, muscle activity, jaw movement or chewing performance in healthy children.² They also found only a low to moderate level of evidence on whether orthodontic treatment restores normal jaw function.²

The honest summary: measurable differences exist in the studies we have; whether they add up to a child who cannot manage a meal is not established. Which matches what you see — most children with a malocclusion eat normally.

Where the functional argument is strongest

Unilateral posterior crossbite
The malocclusion most worth taking seriously functionally, because it does not only change how the teeth meet — it changes how the jaw moves, producing a wider opening angle and more reversed chewing cycles.² It often comes with a functional shift, where the jaw deviates to one side to find a comfortable bite. That is a real reason to chew on one side, and it is the finding that most often justifies treating early.
Anterior open bite
When the front teeth do not meet, the child cannot shear food with them and compensates by pushing food back with the tongue or tearing with their hands. This one is mechanically obvious rather than statistically subtle, and it is the malocclusion most strongly linked to prolonged thumb and pacifier habits — see when thumb sucking becomes a problem.
Severe Class II or Class III
At the extremes, biting through food becomes genuinely awkward. Mild versions rarely cause functional trouble, and mild is far more common.

Where it is weakest: crowding, rotation, mild deep bite and mild Class II are common, largely cosmetic in childhood, and poor explanations for a child who will not eat.

Bite, feeding and picky eating

This is the part of the page that most needed changing, because the earlier version made a claim the evidence does not support and that sends worried parents down the wrong path.

Picky eating is common and its known causes are not dental. A narrative review of the literature from 2015 to 2025 put prevalence estimates at 13% to 50%, with peak incidence between ages two and six, and listed the contributing factors as genetic predisposition, sensory sensitivities, temperament, family feeding practices, environmental influences, and adverse feeding experiences.³ Malocclusion does not appear among them.

What this means practically. If your child eats fewer than about fifteen foods, gags on textures, or refuses anything wet or mixed, the first place to look is sensory processing, not the bite. Our overview of sensory processing differences in children covers the profile, and dental signs of sensory processing differences covers what shows up in the dental chair specifically.

When feeding difficulty is more than pickiness. Where restriction is causing nutritional deficiency, growth impairment or significant family strain, the relevant frameworks are avoidant/restrictive food intake disorder and pediatric feeding disorder, which carry greater risk than picky eating and have their own pathways.³ That is a conversation with a pediatrician and a feeding team, not an orthodontist. Our page on how to spot oral development delays early covers how to get that assessment.

Where the bite genuinely can contribute. A child with an open bite who tires visibly during meals, or a child with a crossbite and a jaw shift who chews only on one side and avoids tough textures specifically. The pattern to look for is mechanical avoidance of hard or chewy foods while soft foods are accepted normally — not refusal across all textures, which points elsewhere.

Tongue thrust: cause or consequence?

The earlier version of this page listed tongue thrusting as something misalignment causes. The orthodontic literature treats the direction of causation as genuinely unresolved, and a good part of the argument runs the other way: where an overjet or open bite already exists, it is hard to seal the front of the mouth during swallowing, so the tongue moves forward to do it — which makes the thrust a result rather than a cause.

The related argument is about duration. Tooth position responds to light, continuous force far more than to brief, intermittent force, and a swallow is brief. On that reading, resting tongue posture is the more plausible contributor and the swallow itself is the less plausible one.

Why this matters for a parent. Therapy aimed at the swallow is aiming at the mechanism with the weakest case. Work aimed at resting posture, or treatment aimed at the structural problem itself, has a better rationale. Our page on tongue posture and jaw development works through this in more depth.

Signs worth a closer look

Genuinely worth investigating

The jaw visibly deviates to one side on closing — the classic sign of a crossbite with a functional shift, and the most actionable finding on this list
Front teeth that do not meet when the back teeth are closed
Consistent avoidance of hard and chewy foods specifically, while soft foods are eaten normally
Visible fatigue during meals — stopping from tiredness rather than fullness, or meals taking dramatically longer than a sibling’s
Frequent choking or gagging on food, especially where the pattern has changed
Trauma to the front teeth, particularly with a large overjet, which carries genuinely elevated risk⁴

Commonly over-read

Chewing on one side
A side preference is common and by itself is not evidence of a problem. It becomes meaningful alongside a visible crossbite or jaw shift, or when it is new. The earlier version of this page answered “no, that is not normal” to this question, which is stronger than the evidence supports.
Drooling in toddlers and early preschoolers
Developmentally common, and not usually a bite sign. Persistent drooling in a school-aged child is a different matter and warrants evaluation — but as a neuromuscular or airway question more than an alignment one. See nighttime drooling in children.
Crowded-looking baby teeth
Spacing in the baby teeth is a good sign rather than a bad one; crowding at that stage is worth monitoring but is not an emergency.

If a child has speech concerns alongside bite findings, the relationship is narrower than commonly assumed — see baby teeth and speech development and, for frontal lisps specifically, our guide to lisps.

What early treatment does and does not do

This is where the earlier version was most likely to lead a family into treatment they did not need.

The Cochrane review. Twenty-seven randomized trials with 1,251 participants compared early two-phase treatment for prominent upper front teeth against a single course in adolescence. Early treatment reduced the incidence of trauma to the front teeth. But once both groups had finished, there was no evidence of a difference in the final result, and the authors concluded that there appear to be no other advantages of providing early treatment compared with late treatment.⁴

Read the scope of that carefully

The review covers Class II — prominent upper front teeth — not early orthodontics in general. It does not say early treatment is never worthwhile for anything. It says that for this problem, the advantage is trauma protection and not the other things early treatment is often sold on.

So: if your child has a large overjet and plays contact sports, early treatment has a defensible rationale, and it is about protecting the front teeth. If the pitch is that early treatment will improve chewing or prevent later orthodontics, the evidence is not there.

On jaw joint problems. The National Institute of Dental and Craniofacial Research states that research does not support the belief that a bad bite or orthodontic treatment such as braces causes TMD, and that because evidence for many TMD treatments is limited, experts recommend conservative treatment and avoiding anything that permanently changes the jaw joints, teeth or bite.⁵ It adds that there is insufficient evidence that occlusal treatments — crowns, grinding down teeth, moving teeth orthodontically — work for TMD, and that in some cases they make the problem worse.⁵ Straightening a bite therefore cannot be offered as TMD prevention. See jaw clicking and TMJ in children.

Where early treatment has a stronger case. Posterior crossbite with a functional shift is the classic reason to act early, because you are correcting an active asymmetry during growth rather than pre-empting a future cosmetic result. Ask your orthodontist which specific problem is being treated and what happens if you wait. A good one will answer both without defensiveness.

The intervention menu, honestly rated

Orthodontic correction of a specific functional problem
Reasonable where there is an identified problem — crossbite with a shift, open bite affecting biting, severe overjet with trauma risk. There is a low to moderate level of evidence that orthodontic treatment restores normal jaw function.² That is a genuine “maybe,” not a promise.
Myofunctional therapy
Reasonable as an adjunct where a specific problem has been identified. Not something to buy on a promise about chewing, and worth asking what outcome is being targeted and how it will be measured.
Jaw and facial muscle exercises
Frequently recommended, thinly supported for typically developing children. Where the goal is general oral function rather than a specific neuromuscular condition, this shades into the category below.
Blowing bubbles, horns and straws
A Cochrane review of non-speech oral motor treatment found three studies with 22 children in total and concluded that no strong evidence suggests these are effective for developmental speech sound disorders.⁶ Note the scope: those studies covered only the sounds /s/ and /z/, so the review says nothing about chewing either way.⁶ The reason to doubt them for chewing is separate — motor learning favors task-specific practice.
Actual chewing practice with graded textures
The most sensible thing to do at home, and the one that follows from motor learning rather than contradicting it. Graded from soft-dissolvable to soft-chewy to firm, alongside whatever else is happening.
Feeding therapy
Where the difficulty is genuinely about eating rather than about teeth. Find a pediatric occupational therapist or speech-language pathologist with feeding training through our directory.

Frequently Asked Questions

Does a bad bite cause feeding problems in children?

Rarely on its own. Bite variation is extremely common — a meta-analysis put worldwide malocclusion prevalence at 56% — and most of those children eat normally. Measurable differences in chewing efficiency do show up in studies, but the review that pooled them concluded it is not entirely possible to either support or deny malocclusion's influence on chewing in healthy children, given the quality of the underlying research. Two specific problems have the clearest functional effect: a one-sided posterior crossbite, and an anterior open bite.

Can a bad bite make my child a picky eater?

It is very unlikely to be the explanation. Picky eating affects an estimated 13% to 50% of children with a peak between ages two and six, and the contributing factors identified in the literature are genetic predisposition, sensory sensitivities, temperament, family feeding practices, environmental influences and adverse feeding experiences. Malocclusion is not among them. If your child gags on textures or refuses anything wet or mixed, sensory processing is the more useful place to look.

My child chews only on one side. Is that a problem?

Not by itself. A side preference is common in children who have no bite problem at all. It becomes worth investigating when it appears alongside a visible crossbite or a jaw that deviates to one side on closing, or when it is a change from how your child used to chew. The jaw deviation is the more informative sign of the two.

Does an open bite affect chewing?

Yes, more clearly than most malocclusions. When the front teeth do not meet, the child cannot shear food with them and compensates by pushing food back with the tongue or tearing with their hands. This one is mechanically obvious rather than statistically subtle, which is why it sits differently from crowding or a mild overjet.

Is tongue thrust caused by a bad bite, or does it cause one?

The direction of causation is genuinely disputed, and a good part of the argument runs from bite to thrust rather than the other way. Where an overjet or open bite already exists, it is hard to seal the front of the mouth during swallowing, so the tongue moves forward to do it. Tooth position also responds far more to light continuous force than to brief intermittent force, and a swallow is brief — which makes resting tongue posture a more plausible contributor than the swallow itself.

Should my child get early braces?

It depends entirely on what is being treated. For prominent upper front teeth, a Cochrane review of 27 trials found early two-phase treatment reduced trauma to the front teeth but showed no other advantage over a single course in adolescence. So if your child has a large overjet and plays contact sports, there is a defensible rationale, and it is about protecting the teeth. A posterior crossbite with a jaw shift is the other classic reason to act early. If the pitch is improved chewing or avoiding later orthodontics, the evidence is not there.

Is two-phase orthodontic treatment worth it?

For prominent upper front teeth specifically, the evidence says the advantage is reduced incisor trauma and nothing else measured. After both groups finished, there was no evidence of a difference in the final result. That does not make two-phase treatment wrong — it makes trauma risk the question to ask about, and it makes "it will be easier later" a claim to ask for evidence on.

Can a bad bite cause TMJ problems in my child?

The National Institute of Dental and Craniofacial Research states that research does not support the belief that a bad bite or orthodontic treatment such as braces causes temporomandibular disorders. It also notes that there is insufficient evidence that occlusal treatments work for TMD and that in some cases they make the problem worse, and recommends conservative care over anything that permanently changes the jaw joints, teeth or bite.

Do jaw exercises or blowing exercises improve chewing?

There is no good evidence for the blowing, horn and straw exercises. A Cochrane review of non-speech oral motor treatment found three studies with 22 children in total and no strong evidence of effectiveness — and those studies covered only the sounds /s/ and /z/, so they say nothing about chewing either way. Motor learning favors task-specific practice, so if the goal is chewing, graded chewing practice is the thing that transfers.

Does myofunctional therapy help swallowing?

It is reasonable as an adjunct where a specific problem has been identified, and it is not something to buy on a general promise about chewing or swallowing. Ask what outcome is being targeted, how it will be measured, and when you will review whether it is working.

When should my child first see an orthodontist?

Around age seven is the usual recommendation, because that is when the first adult molars and incisors are typically in and a crossbite, a developing open bite or a significant overjet becomes assessable. Seeing an orthodontist at seven is not the same as starting treatment at seven — for most children the answer is monitoring.

What if my child's bite looks fine but they still struggle to eat?

Then the bite is probably not the explanation, which is useful information. Look at sensory processing, at oral motor skills, and at whether the difficulty is texture-specific or global. An occupational therapist or speech-language pathologist with feeding training is the right assessment, and it is a different appointment from an orthodontic one.

Sources

Lombardo G, Vena F, Negri P, et al. Worldwide prevalence of malocclusion in the different stages of dentition: a systematic review and meta-analysis. European Journal of Paediatric Dentistry. 2020;21(2):115–122. PMID 32567942. 77 studies included after screening 450 records. “The worldwide prevalence of malocclusion was 56% (95% CI: 11-99), without differences in gender. The highest prevalence was in Africa (81%) and Europe (72%), followed by America (53%) and Asia (48%). The malocclusion prevalence score did not change from primary to permanent dentition with a common score of 54%.”
Effect of malocclusion on jaw motor function and chewing in children: a systematic review. Clinical Oral Investigations. 2022;26(3):2335–2351. PMID 34985577. 8,192 studies identified, 57 included; quality high in nine, moderate in 23, low in 25. Children with malocclusion showed lower chewing efficiency in the primary dentition and lower bite force, muscle activity and chewing efficiency in mixed and permanent dentition; unilateral posterior crossbite showed a larger jaw opening angle and higher frequency of reverse chewing cycles. “Based on the limitations of the studies included, it is not entirely possible to either support or deny the influence of dental/skeletal malocclusion traits on MOBF, EMG, jaw kinematics, and masticatory performance in healthy children.”
Decoding picky eating in children: a temporary phase or a hidden health concern? . Nutrients. 2025;17(24):3884. PMID 41470829. Narrative review of literature published 2015–2025. “Prevalence estimates of PE vary widely (13-50%), with peak incidence between ages two and six. Contributing factors include genetic predisposition, sensory sensitivities, temperament, family feeding practices, environmental influences, and adverse feeding experiences.” Distinction from avoidant/restrictive food intake disorder and pediatric feeding disorder is described as essential.
Batista KBSL, Thiruvenkatachari B, Harrison JE, O’Brien KD. Orthodontic treatment for prominent upper front teeth (Class II malocclusion) in children and adolescents. Cochrane Database of Systematic Reviews. 2018;3(3):CD003452. PMID 29534303. 27 randomized trials, 1,251 participants. “Evidence of low to moderate quality suggests that providing early orthodontic treatment for children with prominent upper front teeth is more effective for reducing the incidence of incisal trauma than providing one course of orthodontic treatment in adolescence. There appear to be no other advantages of providing early treatment when compared to late treatment.”
National Institute of Dental and Craniofacial Research. TMD (temporomandibular disorders). nidcr.nih.gov/health-info/tmd — “Research does not support the belief that a bad bite or orthodontic treatment (such as braces) causes TMDs.” “Because evidence for many TMD treatments is limited, experts recommend conservative treatments and avoiding treatments that permanently change the jaw joints, teeth, or bite, or involve surgery.” Of occlusal treatments including crowns, grinding down teeth and orthodontic repositioning: “There is insufficient evidence that these occlusal treatments work to treat TMDs, and in some cases they make the problem worse.” Checked August 29, 2026.
Lee AS-Y, Gibbon FE. Non-speech oral motor treatment for children with developmental speech sound disorders. Cochrane Database of Systematic Reviews. 2015;(3):CD009383. PMID 25805060. Three studies involving 22 children in total, covering “limited types of NSOMTs for treating children with speech sound disorders of unknown origin with the sounds /s/ and /z/”. “Currently no strong evidence suggests that NSOMTs are an effective treatment or an effective adjunctive treatment for children with developmental speech sound disorders.”

Medical disclaimer. This page is for general educational purposes and does not constitute medical advice, diagnosis, or treatment. It is not a substitute for evaluation by a qualified clinician who knows your child. A bite finding on its own is not an explanation for a feeding difficulty. If your child is not gaining weight or is losing skills they previously had, contact your pediatrician.

How Dental Alignment Affects Chewing and Swallowing in Children