What Is Class III Malocclusion?
Malocclusion refers to how the upper and lower teeth fit together when you bite. Orthodontists classify bite relationships using Angle's Classification system. In a normal bite (Class I), the upper first molar sits slightly ahead of the lower first molar, and the upper front teeth overlap the lower front teeth from the outside.
In Class III malocclusion, this relationship is reversed. The lower first molar sits ahead of the upper first molar, and the lower front teeth close in front of the upper front teeth. The result is what most people recognize as an underbite.
Dental vs Skeletal Class III
A dental Class III means the teeth are in a Class III position, but the jaw bones are relatively normal in size. The lower front teeth may be tipped forward, or the upper front teeth may be tipped backward, creating the appearance of an underbite even though the jaws themselves are proportional.
A skeletal Class III means there is an actual size discrepancy between the jaws. Either the lower jaw (mandible) is too large, the upper jaw (maxilla) is too small, or both. Skeletal Class III cases are more complex and often require surgery in adults.
Pseudo Class III (Functional Shift)
Some patients have a pseudo Class III bite, where the jaws are actually normal but the patient shifts the lower jaw forward when closing because of tooth interference. When the patient bites with the jaw in a relaxed position, the teeth come together edge-to-edge or even in a Class I relationship. This type is the easiest to treat because it only requires removing the interference causing the forward shift.
What Causes Class III Malocclusion
Class III malocclusion has a strong genetic component. Jaw size and shape are inherited traits, and Class III patterns tend to run in families. The condition is more common in certain populations, with higher prevalence in East Asian populations (approximately 4 to 14 percent) compared to European populations (approximately 1 to 5 percent).
Genetics and Jaw Growth
The growth patterns of the upper and lower jaws are controlled by different genes and follow different timelines. The upper jaw completes most of its growth by age 10 to 12, while the lower jaw continues growing until age 16 to 18 (and sometimes into the early twenties in males). This growth timing mismatch is why some children with a borderline Class III bite worsen during the teen years as the lower jaw continues to grow.
Environmental and Developmental Factors
While genetics is the dominant factor, several environmental influences can contribute. Chronic mouth breathing from enlarged adenoids or allergies can affect upper jaw development. A tongue thrust swallowing pattern can push the lower jaw forward. Early loss of baby teeth can allow teeth to shift into positions that create or worsen a Class III relationship.
Treatment Options for Class III Malocclusion
The right treatment depends on three factors: the patient's age (and remaining growth potential), whether the problem is dental or skeletal, and the severity of the jaw discrepancy. Your orthodontist will take cephalometric X-rays (side-view skull X-rays) to measure jaw positions and plan treatment.
Early Treatment in Children (Ages 7 to 10)
The American Association of Orthodontists recommends that all children have an orthodontic evaluation by age 7. For children with a developing Class III bite, early intervention can take advantage of remaining jaw growth to improve the jaw relationship.
A reverse-pull headgear (face mask) is one of the most effective early treatments. It hooks to the upper teeth or a palatal expander and pulls the upper jaw forward. A palatal expander is often used simultaneously to widen a narrow upper jaw. Together, these appliances stimulate forward growth of the upper jaw while the child is still growing.
Early treatment does not always eliminate the need for braces later, but it can reduce the severity of the problem and may eliminate the need for jaw surgery in borderline cases.
Adolescent Treatment (Ages 11 to 17)
Teens with Class III malocclusion present a planning challenge because the lower jaw is still growing. If growth is nearly complete, braces can be started. If significant growth remains, the orthodontist may monitor with periodic X-rays and delay full treatment until growth slows.
Class III elastics (rubber bands from the lower back teeth to the upper front teeth) are commonly used with braces to help correct the bite relationship. In mild to moderate cases, braces with elastics may be sufficient. In severe skeletal cases, the orthodontist may plan for eventual surgery after growth is complete.
Adult Treatment Options
In adults, jaw growth is complete, so the options are either orthodontic camouflage or orthognathic surgery. The choice depends on severity.
Camouflage treatment uses braces or aligners with elastics to tip the teeth into positions that compensate for the jaw discrepancy. This works for mild skeletal Class III cases (2 to 4 mm of discrepancy) and most dental Class III cases. The jaw positions stay the same, but the teeth are moved to create the best possible bite within the existing jaw framework.
For moderate to severe skeletal Class III cases, orthognathic surgery is usually the recommended treatment. This involves braces before and after surgery, with the surgeon repositioning one or both jaws to achieve a correct bite and balanced facial proportions.
Recovery and Long-Term Stability
Recovery depends on the type of treatment received. Braces-only treatment has no surgical recovery period. Jaw surgery recovery is more involved and is covered in detail in our orthognathic surgery guide.
After Braces-Only Treatment
Once braces are removed, you will wear a retainer to maintain your results. Class III corrections are considered less stable than Class I or Class II corrections because the lower jaw's natural growth tendency is forward. Lifelong retainer wear is particularly important for Class III patients.
If you had camouflage treatment (teeth compensated for the jaw discrepancy), the compensation makes the teeth more prone to relapse. Your orthodontist will design a retention plan with this in mind.
Growth Monitoring in Young Patients
Children and teens who receive early treatment for Class III malocclusion need ongoing monitoring until growth is complete. If the lower jaw continues to grow forward significantly, the original correction can be lost. Your orthodontist will track growth with periodic X-rays and clinical exams to determine whether a second phase of treatment or surgery is needed.
Cost of Class III Malocclusion Treatment
Treatment costs depend on the approach and complexity. All costs vary by location and provider.
- Phase 1 early treatment (expander + face mask): $3,000 to $5,000
- Full braces (camouflage treatment): $4,000 to $8,000
- Braces combined with orthognathic surgery: $20,000 to $50,000 total (including surgical fees, hospital costs, and orthodontic treatment)
- Dental insurance with orthodontic coverage may reimburse $1,000 to $3,000 for braces. Medical insurance may cover a portion of jaw surgery if it is deemed medically necessary.
Insurance Coverage for Jaw Surgery
Orthognathic surgery is often covered by medical insurance (not dental) when it is documented as medically necessary to correct a functional problem such as difficulty chewing, breathing obstruction, or TMJ dysfunction. Your orthodontist and oral surgeon will work together to submit documentation to your insurance company. Pre-authorization is typically required.
When to See an Orthodontist
Early evaluation is especially important for Class III malocclusion because treatment timing can significantly affect outcomes. See an orthodontist if you or your child has any of the following:
- Lower front teeth that close in front of the upper front teeth
- A lower jaw that appears to protrude forward
- Difficulty biting into food with the front teeth
- A family history of underbites or Class III malocclusion
- Speech difficulties related to jaw position
- Jaw pain or clicking when opening and closing
The Importance of Age 7 Evaluation
The AAO recommends all children see an orthodontist by age 7, but this is especially critical for children showing signs of a Class III bite. Early treatment between ages 7 and 10 can modify jaw growth in ways that become impossible after growth is complete. Missing this treatment window may mean the difference between braces alone and braces with jaw surgery later.
Find an Orthodontist for Underbite Treatment
Class III malocclusion treatment requires careful diagnosis and planning. An experienced orthodontist will evaluate the skeletal and dental components of your bite, assess growth potential (in children and teens), and develop a treatment plan that addresses both function and appearance.
Use our directory to find an orthodontist near you who treats Class III malocclusion. If surgery may be needed, look for orthodontists who work closely with oral and maxillofacial surgeons.
Search Orthodontists in Your Area