How to Fix an Underbite: Treatment Options for All Ages

Editorially reviewed by the Dental.me Editorial Team · Updated July 2026

An underbite can make chewing awkward, wear down your teeth unevenly, and change the balance of your face. The good news is that it is treatable at almost any age, and how to fix an underbite depends heavily on two things: how old you are and whether the problem lives in your teeth or in your jawbones. A young child, a teenager, and an adult with the same-looking bite often need very different plans. This guide explains what an underbite is, why correcting it matters, and the full range of options from simple aligners to corrective jaw surgery.

What Is an Underbite?

An underbite, known in dentistry as a Class III malocclusion or mandibular prognathism, is a bite in which the lower front teeth sit in front of the upper front teeth when you close your mouth. In a normal bite the upper teeth slightly overlap the lower ones; in an underbite that relationship is reversed. It can range from a mild edge-to-edge overlap of a millimeter or two to a pronounced protrusion where the entire lower jaw juts forward.

Underbites fall into two broad categories, and telling them apart is the single most important step in treatment. A dental underbite means the jaws are roughly the right size but some teeth are tipped or positioned wrong. A skeletal underbite means the jawbones themselves are mismatched, usually a lower jaw that grew too long, an upper jaw that is underdeveloped, or both. Underbites are one of several common bite problems; if you want the wider picture, our overview of overbite, underbite, and crossbite explains how each one differs.

What Causes an Underbite?

Most underbites are largely genetic. The size and shape of your jaws are inherited traits, so a lower jaw that outgrows the upper one often runs in families. Because the problem is built into how the bones grow, a skeletal underbite tends to become more noticeable during childhood and adolescent growth spurts rather than staying static.

Other contributors include:

• Childhood habits such as prolonged thumb sucking, tongue thrusting, or pushing the lower jaw forward, which can nudge teeth and jaw development off track.
• Early or premature loss of baby teeth, which lets neighboring and permanent teeth drift into poor positions.
• Airway and mouth-breathing patterns that alter resting jaw and tongue posture over years.
• Injury or, rarely, jaw tumors or cysts that change how the lower jaw sits or grows.

Why Fixing an Underbite Matters

An underbite is more than a cosmetic concern, though appearance is a valid reason many people seek treatment. Left uncorrected, it can cause real functional problems that tend to compound with time:

• Chewing and biting difficulty, because the front teeth do not meet properly to shear food.
• Speech issues, since tooth and jaw position affect how certain sounds form.
• Jaw and TMJ strain, as the joints and muscles work around a misaligned bite, which can lead to soreness, clicking, or headaches.
• Uneven tooth wear and chipping, because contact forces land where they should not, accelerating enamel damage.

Because a skeletal underbite can worsen as the jaw keeps growing, catching it early often means a simpler, less invasive fix than waiting until adulthood.

How Age Changes the Treatment Plan

Age is decisive because a growing skeleton can be guided, while a finished one usually cannot. Orthodontists think about underbites very differently depending on how much growth is left.

Young children

In kids, early or “interceptive” orthodontics can take advantage of active jaw growth. A reverse-pull (protraction) facemask gently pulls an underdeveloped upper jaw forward, a palatal expander widens a narrow upper jaw, and in select cases a chin cap is used to influence lower-jaw growth. Guiding growth while it is happening is far easier than moving finished bone, which is exactly why early evaluation matters so much.

Teens and adults with mild dental underbites

When the jaws are proportionate and the problem is mostly tooth position, moving teeth can be enough. This is where braces or clear aligners shine. If you are weighing your options, our comparison of Invisalign vs braces breaks down which tends to suit different cases, and plenty of grown-ups pursue this route, as our guide to adult braces explains.

Adults with skeletal underbites

Here is the hard truth: a moderate-to-severe skeletal underbite in an adult, where the jawbones are genuinely mismatched in size, usually cannot be corrected by moving teeth alone. Braces or aligners can tip teeth to camouflage a small discrepancy, but they cannot reposition a jawbone. Correcting the underlying bone typically requires orthognathic (corrective jaw) surgery combined with braces.

Treatment Options at a Glance

Most underbite plans draw from a handful of tools, often in combination:

• Braces to align and detail tooth position; the workhorse for both dental cases and the orthodontic phase around surgery.
• Clear aligners for mild, primarily dental underbites where teeth need modest movement.
• Growth-guiding appliances (facemask, expander, chin cap) for children while the jaws are still developing.
• Tooth extraction in some crowding cases, to create room so the remaining teeth can be aligned into a stable bite.
• Orthognathic surgery plus orthodontics for severe skeletal cases, where a surgeon repositions the jaw and braces align the teeth before and after.

Diagnosis, Timeline, and Cost

How the orthodontist decides

A recommendation only makes sense after a proper workup. Your orthodontist will gather records, including photographs, digital scans or impressions, and X-rays such as a panoramic and a cephalometric (side-profile) image. From these they answer three questions: Is the underbite dental or skeletal? How severe is the size mismatch? And how much growth is left? A child with years of growth ahead may be a candidate for growth guidance, while an adult with a large skeletal discrepancy is steered toward a combined surgical plan. This diagnosis is what separates a case fixable with aligners from one that needs surgery.

Timelines and retainers

Timelines vary with complexity. A mild dental correction with aligners or braces might take roughly 12 to 24 months. Early growth-guidance in children often runs in phases and may be followed later by a second round of braces once the permanent teeth are in. Surgical cases usually involve braces for some months before surgery, the jaw procedure itself, and further orthodontic finishing afterward, stretching the total to two years or more. In every scenario, retainers are essential once treatment ends, because teeth and jaws tend to drift back toward their old positions without them.

What it costs

Cost tracks closely with complexity. Aligner or braces-only cases fall within typical orthodontic fee ranges, while cases involving corrective jaw surgery cost substantially more because they add a surgeon, an operating facility, and anesthesia. Many medical plans treat jaw surgery differently from routine orthodontics, so it is worth confirming coverage early.

Can an underbite be fixed without surgery?

Often, yes, but it depends entirely on the diagnosis. Mild dental underbites can frequently be corrected without surgery using braces or aligners, and in children, growth-guiding appliances can steer development so surgery is never needed. What cannot reliably be fixed without surgery is a severe skeletal underbite in an adult, because no amount of tooth movement will lengthen or reposition a jawbone. Anyone promising to fully correct a large skeletal underbite with aligners alone is overselling what teeth-only treatment can do.

When to See an Orthodontist

The best time to get an evaluation is earlier than most parents expect. Orthodontists recommend a first checkup around age 7, when enough permanent teeth have arrived and jaw growth patterns are visible but still guidable. Catching a Class III bite at this stage opens the door to simpler, growth-based options. Adults are never too late to be helped either, even if the menu shifts toward braces, aligners, or surgery. If you notice your or your child’s lower teeth sitting in front of the upper ones, book a consultation and let a specialist tell you whether it is dental, skeletal, and what the most efficient path forward looks like.

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