Overbite vs Underbite: How Are They Different?
If your upper or lower jaw sits further forward than the other, and your top and bottom teeth don’t meet the way they should, you may be looking at an overbite or an underbite.
The two are often confused, but they’re opposite problems with different causes and different treatments. We see overbites and underbites regularly at Orthodontics at Parramatta. Here’s what separates the two, and what treatment can involve.
In Summary
- An overbite is when the upper front teeth overlap more than 4mm, and an underbite is when the lower teeth sit in front of the upper teeth.
- Complications might include jaw pain, uneven wear, hygiene issues and general discomfort.
- Both issues can be treated with braces, Invisalign and, in severe cases, jaw surgery.
- It’s important to seek advice from specialist orthodontic care to find the right treatment path for you.
What is an overbite?
An overbite occurs when the upper front teeth overlap significantly over the lower front teeth vertically. This causes the top jaw to sit further forward on the face than the lower jaw.
In a ‘normal’ bite, the upper teeth might overlap the lower teeth by about 2-3mm. It’s considered an overbite when the vertical overlap exceeds this amount.
What is an underbite?
An underbite refers to when the lower teeth sit in front of the upper teeth when biting down. This causes the lower jaw to sit further forward on the face. Underbites are typically less common, but often more noticeable.
Overbites vs underbites vs ‘normal’ teeth
| Overlap | Effect | |
| Overbite | Vertical overlap of 4mm or more | Risk of jaw pain, enamel wear and gum damage |
| Underbite | Lower teeth overlap upper teeth externally | Risk of TMJ, severe dental issues and difficulty chewing and speaking |
| Normal bite | Vertical overlap of 2-3mm | Protects enamel and promotes clear speech |
What causes an overbite?
- Genetics and jaw size
- Childhood habits e.g. thumb sucking or prolonged dummy use
- Nail biting
- Tongue thrusting
- Tooth spacing issues
What causes an underbite?
- Genetics and jaw size
- Childhood habits e.g. thumb sucking and prolonged dummy use
- Trauma or injury
- Cleft lip or palate
- Skeletal components
Why treatment matters
An underbite or overbite presents more than just cosmetic challenges. They can cause many ongoing dental, hygiene and comfort issues that treatment can further alleviate:
- Uneven tooth wear
- Jaw pain
- TMJ issues
- Difficulty chewing
- Facial asymmetry (in severe cases)
By seeking the advice of an orthodontist, you can explore your treatment options and prevent long-term issues by resolving the underbite or overbite with specialist care.
How overbites and underbites are corrected
There are a number of treatment pathways for patients with overbite and underbite. In childhood cases, in particular, early intervention means that treatment is more likely to be effective and will produce better outcomes that prevent the need for more complex intervention later.
Can braces fix an overbite or underbite?
Metal or ceramic braces are an effective solution for both an underbite and overbite. The fixed bracket braces use alignment wires to shift the teeth into the correct position.
Can Invisalign fix an overbite or underbite?
In more mild cases, Invisalign may fix an overbite and underbite. The clear plastic aligners can gradually shift the teeth, provided the issue is caused by the teeth position rather than the jawbone.
Jaw surgery for severe cases
In more severe cases, particularly in complex underbites, jaw surgery may be necessary. This is applicable if the problem stems from the jawbone structure rather than the teeth position.
Why see a specialist orthodontist
To diagnose your case in an accurate, timely and compassionate manner, consult a specialist orthodontist. Our team at Orthodontics at Parramatta has a deep understanding and experience of complex underbite and overbite cases, and will be able to advise on the best course of treatment for you.
Come and see us for a consultation
Our team of compassionate specialists can offer guidance to help you find the right treatment plan for you. Book an appointment online, or you can call us on 02 7803 7803 to discuss your treatment pathways.
FAQs
The main difference lies in which set of teeth protrudes:
- Overbite: a vertical misalignment where the upper teeth overlap the lower teeth.
- Underbite: A misalignment where the lower jaw/teeth sit forward, biting in front of the upper teeth.
No, an overbite or underbite cannot fix itself without treatment. Both cases are structural and dental misalignments, and may worsen over time without orthodontic intervention.
Invisalign is a common treatment pathway for mild and moderate cases of both overbite and underbite.
It’s ideal to assess and treat an overbite or underbite by age 7. This allows for early intervention before permanent teeth come through and jaw patterns become clear.
The severity depends entirely on each case. However, an underbite is generally considered more complex and difficult to treat than an overbite because they involve skeletal growth mismatches.
In some cases of mild or moderate overbite and underbite, you may not need braces. However, your orthodontist may recommend fixed braces as an effective solution.
Yes, if left untreated, an underbite can frequently cause jaw pain. This is due to the uneven stress placed on your jaw joints and muscles.
