Underbite and overbite describe different relationships between the upper and lower teeth and jaws. In an underbite, the lower front teeth sit in front of the upper front teeth when biting. Overbite refers to vertical overlap of the upper front teeth over the lower front teeth; some overlap is normal, but excessive overlap can become a deep bite.
People sometimes use “overbite” when they actually mean overjet, which is the horizontal projection of the upper teeth.
At a glance
| Point | Underbite | Overbite |
|---|---|---|
| Direction | Lower teeth/jaw forward relative to upper | Excess vertical coverage by upper incisors |
| Common causes | Jaw-growth pattern, genetics, tooth position, missing teeth or functional shifts | Tooth eruption/angulation, jaw pattern, habits and vertical facial development |
| Appearance | Prominent lower jaw/chin may occur in skeletal cases | Upper teeth cover much of lower teeth; lower incisors may contact palate in severe cases |
| Treatment | Orthodontics, growth modification in selected growing patients, orthognathic surgery for some skeletal adults | Orthodontic intrusion/levelling, bite opening and other mechanics; surgery only for selected severe skeletal cases |
| Best timing | Depends on growth and severity | Depends on age, eruption and severity |
Underbite
A bite relationship where lower anterior teeth sit ahead of upper anterior teeth, often associated with dental or skeletal Class III patterns.
Overbite
The vertical overlap of upper incisors over lower incisors; a certain amount is normal, while excessive overlap is called deep bite.
Dental vs skeletal bite problems
A bite can look similar for different reasons. If the jaw bones are well positioned but teeth are tipped, orthodontics may correct the relationship. If the underlying jaws differ substantially in size or position, orthodontics alone may camouflage rather than fully correct the skeletal relationship.
Why growth matters
Children and adolescents still have facial growth potential. Some treatments aim to guide or take advantage of growth, although not every skeletal pattern can be changed predictably with appliances.
Adults with severe skeletal discrepancies may need combined orthodontics and jaw surgery if functional or aesthetic goals cannot be met with tooth movement alone.
Overbite vs overjet
Overbite is vertical overlap. Overjet is horizontal distance between upper and lower front teeth. A person can have both, one without the other, or a normal measurement of one with an abnormal measurement of the other.
Important note
An orthodontic examination and imaging, when appropriate, are needed to determine whether a bite problem is dental, skeletal or both.
Frequently asked questions
Is some overbite normal?
Yes. The term itself does not automatically mean a problem.
Can braces fix an underbite?
Many dental or mild cases can be improved orthodontically; severe skeletal adult cases may need surgery for full correction.
Do underbites cause jaw pain?
They can affect function in some people, but jaw pain has many causes and bite alone does not explain every TMJ symptom.
When should a child be evaluated?
Dentists or orthodontists can assess bite development early when an underbite/crossbite or unusual jaw growth is noticed.
Sources and further reading
KnowDifferences Editorial Team
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