My child has an underbite — when should I consider treatment?

My child has an underbite — when should I consider treatment?

13 August 2025

Underbites (Class III bites) range from a single front tooth in crossbite to a true jaw mismatch. When considering underbite treatment for children, knowing when to start is crucial, as the right timing depends on what’s causing it and how your child is growing. Here’s a parent-friendly guide with answers to the questions I’m asked most.

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What exactly is an underbite?

An underbite is when the lower front teeth sit ahead of the upper. It can be:

• Dental/functional (pseudo-Class III): the teeth bite edge-to-edge or there’s a forward “slide” of the lower jaw because of how the teeth meet.
• Skeletal: the upper jaw is small/positioned back, the lower jaw is big/forward, or both.

Why this matters: Dental problems are usually quick to fix. Skeletal problems need growth-aware treatment, and in some teens/adults, surgery is the predictable solution.

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When should my child be seen?

Age 7 is the universal “first check”, so we can spot problems early and decide whether to treat or watch carefully. American Association of Orthodontists

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My child is 7-9 and has one or two teeth in a crossbite. Treat now?

Often, yes. Early correction of a simple anterior crossbite (the “functional slide”) in the mixed dentition helps normalise the bite and guides growth in a healthier direction. Treatment is usually brief (weeks to a few months) with simple appliances. Nature

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What if it’s a true jaw problem (skeletal Class III)?

For a child with maxillary retrusion (small/back upper jaw), early maxillary protraction is the standard interceptive option:

• RME + facemask (sometimes with Alt-RAMEC protocols): aims to bring the upper jaw forward during the pre-pubertal years, improving the bite and reducing the chance of jaw surgery later. Results are best before the adolescent growth spurt. NatureScienceDirectPMC
• Bone-anchored maxillary protraction (BAMP/mentoplate/Hyrax-facemask): uses small titanium anchors instead of relying on teeth. Evidence shows more skeletal change and less unwanted tooth movement than traditional facemasks in appropriate patients (often ages ~10–14). PMC+1PubMed

Important to know: growth is individual. Early gains can relapse if mandibular growth “catches up” strongly in the teen years, which is why long-term follow-up matters. ScienceDirect

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Are there non-surgical options for teenagers?

Sometimes. If the jaw mismatch is mild to moderate, we can use:

• Camouflage orthodontics (braces/aligners, sometimes with extractions or mini-screws) to line up the teeth and make the bite functional, without changing the jaws.
• Class III elastics/TADs in select cases.

Your orthodontist should balance bite function, facial profile, and long-term stability when advising whether camouflage is sensible or whether to hold for surgery.

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When is jaw surgery (orthognathic surgery) considered?

If the underbite is moderate–severe or growth makes it worse, surgery is the predictable, stable fix once growth is nearly finished. Typical timing: ~16–18+ in girls and 18–21+ in boys, combined with braces/aligners before and after surgery. Mayo ClinicChildren’s Hospital of Philadelphia

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What treatments might be used at different ages?

• Ages 8–9 (early–mixed dentition)
  • Correct simple anterior crossbites/functional shifts.
  • Consider RME + facemask if the upper jaw is retrusive. Nature
• Ages 10–14 (late mixed–early permanent)
  • Facemask or BAMP for maxillary protraction, closely timed around growth status.
  • Ongoing monitoring to see how the mandible grows. PMC+1
• Ages 15+ (late teen–adult)
  • Camouflage if the discrepancy is mild and the facial balance is acceptable.
  • Orthognathic surgery if the discrepancy is moderate–severe or aesthetics/function demand it. Mayo Clinic

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Can exercises or “myofunctional training” fix an underbite?

No. There is no high-quality evidence that tongue/lip/cheek exercises can cure or reverse a skeletal underbite. Myofunctional therapy may help specific functions (e.g., swallowing habits) alongside orthodontic care, but it does not move jaws or reliably correct Class III malocclusion. NCBIFigshare

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What results should we realistically expect from early treatment?

• Functional crossbite: usually corrected quickly and stably.
• Skeletal Class III: Early protraction (around the age of 10) can improve the bite and sometimes reduce future surgery need, but it’s not a guarantee against surgery; growth can outpace early correction. NatureScienceDirect

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Red flags that mean “book an assessment”

• Family history of underbite or facial/jaw disproportions
• Front teeth are already biting edge-to-edge or reversed
• Difficulty biting/chewing, speech concerns, or wear on front teeth
• A chin that looks increasingly prominent year-to-year

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The bottom line

• Age 7 is the ideal first orthodontic check. American Association of Orthodontists, but it does not mean a treatment will start
• Treat early (around 9-10 years of age) when there’s a functional crossbite or a retrusive upper jaw that would benefit from protraction. Nature
• Teen years decide the final path: camouflage for milder cases or surgery after growth for predictable correction of larger discrepancies. Mayo Clinic
• Exercises don’t fix underbites. NCBI

If you’d like to book your child for an assessment, do not hesitate to reach out by clicking here to discuss your concerns further.

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