An underbite is more than just a cosmetic concern.
It can affect how your teeth function, how your jaw grows, your facial profile, and even long-term oral health.
One of the most common questions patients ask is :
How do you fix an underbite and how long does it take?
At Ortho Co, Dr Doreen and the specialist orthodontic team treat underbites across all ages, from children and teens through to adults, using modern, evidence-based orthodontics and, when required, surgical collaboration.
This guide explains :
- What an underbite is and what causes it
- How to fix mild, moderate, and severe underbites
- Treatment options for children vs adults
- How long underbite treatment takes
- When surgery may (or may not) be needed
What Is an Underbite?
An underbite (also called a Class III malocclusion) occurs when the lower teeth sit in front of the upper teeth when biting together.
In a balanced bite :
- Upper teeth slightly overlap the lower teeth
- The jaws work together harmoniously
In an underbite :
- The lower jaw may be too far forward
- The upper jaw may be underdeveloped
- Or a combination of both
This can affect chewing, speech, tooth wear, jaw comfort, and facial balance.
What Causes an Underbite?
Underbites are usually multifactorial, meaning several factors contribute.
Common causes include :
- Genetics (jaw size and growth patterns)
- Upper jaw growth deficiency
- Lower jaw overgrowth
- Early childhood habits (thumb sucking, prolonged dummy use)
- Mouth breathing or airway issues
- Missing or misaligned teeth
- Early loss of baby teeth
- Habits
- Cleft lip and palate
In toddlers and young children, jaw growth is still adaptable — which is why early orthodontic assessment is so valuable.
Why Fixing an Underbite Is Important
Leaving an underbite untreated may lead to :
- Excessive tooth wear and chipping
- Gum recession and dental damage
- Jaw joint (TMJ) strain
- Speech difficulties
- Facial profile imbalance (chin prominence)
- Reduced smile confidence
- Jaw asymmetries and asymmetrical facial growth
Correcting an underbite is not just about aesthetics — it’s about function, long-term dental health, and quality of life.
How to Fix an Underbite
There is no single approach to fixing an underbite. The best treatment depends on :
- Age
- Severity (mild vs severe)
- Growth potential
- Jaw position
- Patient goals
Treatment options may include :
1. Braces or Aligners
For mild to moderate underbites :
- Teeth braces
- Invisalign or clear aligners
- Rubber bands (elastics)
2. Growth Modification (Children)
- Upper jaw expanders
- Palate expanders
- Functional appliances to guide jaw growth
3. Combined Orthodontics and Surgery (Adults with severe underbite)
- Orthodontics + jaw surgery
- Known as orthognathic surgery
Each plan is carefully tailored, and surgery is not always required, even for adults.
Underbite Treatment by Age
How to Fix an Underbite in a Child
Early treatment can dramatically reduce severity, and it is best to see an orthodontist from the age of 7 years old especially if there is an underbite tendency.
In children :
- The jaws are still growing, and the bone is mouldable
- The upper jaw can often be guided forward
- Growth modification appliances are most effective
Common tools include :
- Upper jaw expander
- Palate expander
- Facemasks (reverse pull headgears)
- Braces with elastics
Early treatment may prevent the need for jaw surgery later.
How to Fix an Underbite in Adults
Adults often ask:
“How do you fix an underbite in adults if growth has finished?”
Options include :
- Braces or Invisalign treatment for mild cases
- Aligners with elastics
- Braces to prepare for jaw surgery in severe cases
Underbite surgery is considered when :
- The jaw discrepancy is large
- Function or facial balance is significantly affected
Many adult underbites can still be improved without surgery, depending on severity.
How Long Does Underbite Treatment Take?
This is one of the most common questions.
How long does it take to fix an underbite?
- Mild underbite : ~12–18 months
- Moderate underbite : ~18–24 months
- Severe underbite (with surgery) : ~24–36 months
How long does an underbite take to fix with braces?
Braces alone may take :
- 12–24 months, depending on complexity
Every case is different, personalised planning is essential.
Risks and Side Effects of Underbite Treatment
Orthodontic treatment is very safe when managed by a specialist orthodontist.
Possible risks include :
- Temporary discomfort
- Mild jaw soreness
- Root shortening (rare)
- Relapse without proper retention
When surgery is involved, risks are discussed thoroughly in collaboration with an oral and maxillofacial surgeon.
When to See an Orthodontist
You should see an orthodontist if :
- A child’s lower teeth sit in front of the upper teeth
- There is difficulty biting or chewing
- The facial profile appears unbalanced or asymmetrical
- Teeth are wearing unevenly
- You’re wondering how to fix a slight or severe underbite
Early assessment does not always mean early treatment, but it allows timely, informed decisions.
📍 Book an assessment with a specialist orthodontist :
How to Prevent an Underbite from Worsening
While genetics cannot be changed, progression can sometimes be limited by :
- Early orthodontic monitoring
- Managing oral habits
- Addressing airway and breathing issues
- Timely removal of baby teeth when indicated
- Growth-guided orthodontic appliances
There is no proven way to naturally fix an underbite without orthodontic care, especially in moderate to severe cases.
Frequently Asked Questions About Underbite Correction
1. How to fix a slight underbite?
Mild underbites may be treated with braces or Invisalign and elastics.
2. How to fix a severe underbite?
Severe underbites may require orthodontics combined with jaw surgery.
3. How to fix class 3 underbite?
Class III underbites are managed based on age and severity using braces, aligners, growth appliances, or surgery.
4. How to fix an underbite jaw naturally?
There is no reliable evidence that exercises or home remedies can correct jaw position.
5. Can Invisalign fix an underbite?
Invisalign treatment may be suitable for selected mild to moderate underbites after specialist assessment.
Final Thoughts from Dr Doreen
Underbites are complex, but highly treatable with the right expertise and timing.
As trusted orthodontist in parramatta, we specialise in guiding jaw growth in children, correcting bites in adults, and creating stable, healthy smiles using modern orthodontics and careful planning.
If you or your child has an underbite, the most important step is an assessment with a specialist orthodontist who understands both dental movement and jaw growth.
We’re here to guide you every step of the way.
