An underbite is an orthodontic condition in which the lower teeth and jaw extend beyond the upper teeth. It affects roughly 5–10% of people worldwide, with higher prevalence reported in some populations. For example, about 15% of individuals of Chinese descent develop an underbite compared with roughly 5% of people in the United States, which suggests genetic factors play a significant role.
When left untreated, an underbite can influence self-esteem, eating and speech, and may contribute to disturbed sleep and other health issues.
What is an underbite?
An underbite, also called mandibular prognathism or Class III malocclusion, is a type of bite misalignment in which the lower teeth sit in front of the upper teeth. In moderate to severe cases, the lower jaw may protrude enough to alter facial appearance. Beyond aesthetics, underbite is considered a serious dental and skeletal issue because it can affect oral function and overall health.
Because underbites can lead to numerous complications, early evaluation and treatment planning with a dentist or orthodontist is important.
Underbite Causes
Underbites can develop from a variety of causes, including genetic predisposition, childhood habits, injuries, tumors, and congenital conditions.
Genetic Factors
Genetics is a well-established contributor to underbite development. Certain inherited traits and syndromes are associated with mandibular prognathism. Historical examples include the Habsburg jaw seen in some royal lineages. Other hereditary conditions that can feature an underbite include Treacher Collins syndrome, nevoid basal cell carcinoma syndromes, acromegaly, Binder syndrome, Geroderma osteodysplastica, and Rabson-Mendenhall syndrome.
Childhood Habits
Some early-life behaviors can increase the risk of malocclusion, including:
- Prolonged thumb sucking
- Use of pacifiers beyond age three
- Extended bottle feeding after infancy
- Persistent tongue thrusting during toddler years
Physical Injury
Trauma that fractures the jaw may heal improperly and result in a persistent underbite, even after surgical repair.
Tumors
Benign or malignant growths in the jaw or surrounding tissues can displace bone or soft tissues and contribute to an underbite.
Cleft Lip or Palate
Individuals born with cleft lip or palate have a higher likelihood of developing an underbite due to altered growth patterns of the facial skeleton.
How to Fix Underbite
Treatment for an underbite depends on its cause and severity. Common options include:
- Orthodontic treatment
- Tooth extraction
- Tooth reshaping and veneers
- Orthognathic (jaw) surgery
- Prosthetic or restorative approaches sometimes called “facelift” dentistry
Mild dental underbites in children often respond well to orthodontics alone. When the problem is primarily skeletal, corrective jaw surgery may be necessary, particularly in older teens and adults.
1. Orthodontic treatment
Fixed braces or clear aligners can correct many mild to moderate underbites, especially when tooth position rather than jaw position is the primary issue. In growing children, orthodontic appliances such as reverse-pull face masks or palatal expanders can guide jaw development and improve bite relationships. Extractions are sometimes used to relieve crowding and create space for proper alignment.
Approximate costs:
- Braces: $2,000–$8,000
- Lingual braces: $8,000–$10,000
- Clear aligners: $4,000–$7,000
2. Tooth extraction
Removing specific teeth, most commonly lower premolars, can reduce crowding and allow the remaining teeth and jaws to align better. Extractions are often part of a broader orthodontic treatment plan.
Approximate cost: $75–$300 per tooth
3. Tooth reshaping
For mild cases, conservative reshaping of teeth combined with cosmetic restorations such as veneers can improve bite fit and appearance. Minor enamel contouring is typically painless and can also reduce areas prone to decay.
Approximate cost: $50–$300 per tooth
4. Surgery
Orthognathic surgery repositions the upper and/or lower jaws to establish a functional, balanced bite. Surgery is usually coordinated with orthodontic treatment before and after the operation. Recovery varies by procedure but often spans several weeks to a few months.
Approximate cost: $20,000–$40,000 before insurance
5. “Facelift” Dentistry
Some restorative approaches use digital jaw tracking and custom prosthetic restorations to alter bite relationships without surgery. These techniques are typically intended for adults and may shorten total treatment time for select cases, though they can be expensive and are not appropriate for every patient.
Approximate cost: $35,000 and up
Underbite Complications and Symptoms
An underbite can cause a range of functional problems, including:
- Speech difficulties
- Jaw or facial pain
- Frequent headaches
- Temporomandibular joint (TMJ) pain and dysfunction
- Earaches
- Breathing issues, mouth breathing, and snoring
- Sleep-disordered breathing, including obstructive sleep apnea in some cases
- Teeth grinding (bruxism)
- Potential effects on digestion and overall well-being
The most visible sign of an underbite is the lower jaw or lower front teeth protruding beyond the upper front teeth. Overcrowded teeth and a chronically sore jaw are common complaints. Dentists can usually identify an underbite during routine exams, even in younger children.
Underbite in Children
Traditionally, significant orthodontic intervention often begins around age seven, but early assessment as young as two to five years old can allow interceptive measures that guide growth and potentially reduce the need for more invasive treatment later. If an underbite interferes with breathing, feeding, or speech, or if it is associated with a congenital defect, earlier intervention may be necessary.
Since malocclusion can complicate oral hygiene, caregivers should monitor brushing and flossing and watch for early signs of cavities or gum disease.
Underbite vs. Overbite
An overbite (retrognathism) is the opposite condition, where the upper front teeth and jaw extend significantly over the lower teeth. Both underbites and overbites can affect appearance and function, leading to concerns about chewing, speaking, breathing, and self-confidence.
Is underbite treatment covered by insurance?
Insurance coverage varies. Many dental plans cover treatment when it is deemed medically necessary, but annual maximums on dental insurance are often limited and may not fully cover extensive orthodontic or surgical care. Orthognathic surgery is sometimes covered by medical insurance when it is required for airway or functional reasons, such as sleep apnea. Cosmetic-only procedures are less likely to be covered. Always confirm coverage with your insurer and treatment team before beginning care.
FAQs
What’s the best age to treat an underbite?
Early evaluation is beneficial. Interceptive treatment can begin in childhood, and traditional corrective treatment is commonly effective between ages five and ten. Addressing growth concerns as soon as they are identified can reduce the need for surgery later.
Can I get my underbite fixed as an adult?
Yes. Adult treatment can successfully correct many underbites, often combining orthodontics with surgery or restorative techniques depending on the underlying cause.
Does an underbite make me unattractive?
An underbite does not make someone inherently unattractive. Many people experience improved self-confidence after treatment, but appearance is only one aspect—treatment often improves function, comfort, and overall health.
Should I treat an underbite if it doesn’t seem to cause problems?
Even if symptoms are not obvious, an underbite can lead to long-term issues with teeth, jaw joints, and breathing. A dental professional can evaluate whether treatment is advisable to prevent future complications.
How will my appearance change after correction?
Outcomes vary by individual and the type of treatment. Corrective procedures that realign the jaws can produce noticeable facial changes and often improve symmetry and proportions. Your dental or surgical team can show case examples and set realistic expectations for your situation.
If you suspect an underbite for yourself or your child, consult a dental professional for a thorough evaluation and a treatment plan tailored to your needs.