Overbite, Underbite, Crossbite & Open Bite: Types of Malocclusion Explained
Malocclusion is the dental term for a bad bite, meaning the teeth or jaws do not line up correctly when the mouth closes. The most common types are overbite, underbite, crossbite, and open bite. Most are treatable with braces or clear aligners, and the best age to catch them is early, though adults can be treated too. This guide explains each type, what causes it, and how orthodontists fix it.
What is malocclusion?
Malocclusion is a misalignment between the upper and lower teeth when the jaw is closed. In plain terms, it is a bad bite. It is extremely common, ranges from mild to severe, and can be cosmetic, functional, or both. A mild case may only affect appearance, while a significant one can make chewing, speaking, or cleaning the teeth harder and can wear teeth down over time.
Orthodontists group malocclusions by how the teeth and jaws relate to each other. The four you hear about most are overbite, underbite, crossbite, and open bite, often alongside crowding or spacing. The table below sums them up at a glance, and the sections after it go deeper on each.
| Type | What it looks like | Common causes | Usual treatment |
|---|---|---|---|
| Overbite | Upper front teeth overlap the lower ones too much | Genetics, jaw growth, thumb sucking | Braces or aligners, sometimes elastics |
| Underbite | Lower teeth sit in front of the upper teeth | Lower jaw overgrowth or upper jaw undergrowth | Braces, growth appliances, sometimes surgery |
| Crossbite | Some upper teeth bite inside the lower teeth | Narrow upper jaw, tooth position | Expander, braces or aligners |
| Open bite | Front teeth do not touch when the back teeth close | Thumb or tongue habits, jaw growth | Braces, habit appliances |
| Overjet | Upper teeth stick out forward horizontally | Jaw relationship, thumb sucking | Braces or aligners, elastics |
Overbite
An overbite is when the upper front teeth overlap too far down over the lower front teeth. A small overlap is normal and healthy. It becomes a problem, sometimes called a deep bite, when the overlap is excessive. Overbites are usually caused by genetics, the way the jaw developed, or childhood habits like prolonged thumb sucking. Most overbites are corrected without surgery using braces or clear aligners, often with elastics to guide the bite.
Underbite
An underbite is when the lower teeth sit in front of the upper teeth when the mouth is closed. It usually comes from the lower jaw growing too far forward, the upper jaw being underdeveloped, or both. Underbites can cause jaw strain and uneven tooth wear. Milder cases respond to braces or aligners, cases caught during childhood growth can be guided with appliances, and severe skeletal underbites sometimes need jaw surgery combined with orthodontics.
Crossbite
A crossbite is when one or more upper teeth bite on the inside of the lower teeth instead of outside. It is a sideways, or horizontal, misalignment and can affect the front teeth, the back teeth, or both. A common cause is a narrow upper jaw. Left untreated, a crossbite can lead to uneven wear, gum problems, and a jaw that shifts to one side. Treatment often uses a palatal expander to widen the upper jaw, followed by braces or aligners.
Open bite and overjet
An open bite is when the front teeth do not touch even though the back teeth are closed, leaving a visible gap. It is often linked to thumb sucking or tongue thrusting habits, especially in children. Overjet is different: it is when the upper front teeth stick out horizontally over the lower teeth, sometimes called buck teeth, as opposed to the vertical overlap of an overbite. Both are typically treated with braces or aligners, and habit appliances can help stop the behavior driving an open bite.
Worth knowing: Bite problems rarely fix themselves, and they can slowly worsen as teeth drift and wear. Catching them early keeps treatment simpler, which is why orthodontists recommend a first check-up by age seven.
How orthodontists treat malocclusion
Most malocclusions are treated by moving teeth into a better position with braces or clear aligners, sometimes helped by other appliances. The right approach depends on the type and severity, and on whether a child is still growing. A specialist exam, usually with X-rays, is what determines the plan. Common tools include the following.
- Braces or clear aligners to move teeth into correct alignment, the backbone of most treatment.
- Elastics, or rubber bands, to correct how the upper and lower jaws meet.
- Palatal expanders to widen a narrow upper jaw, most effective in growing children.
- Growth-guiding appliances that use a child’s development to correct jaw relationships.
- Jaw surgery combined with orthodontics, reserved for severe skeletal cases in adults.
When to see an orthodontist
See an orthodontist if you notice teeth that do not meet properly, difficulty chewing, jaw pain or clicking, mouth breathing, or front teeth that stick out or do not touch. An evaluation is often free and puts a name and a plan to whatever you are seeing. For children, the recommended first visit is by age seven, and you can read more in our guide on the right age to see an orthodontist.
Find and compare orthodontists near you, including which practices are board certified and independently owned, and get your bite evaluated.
Search orthodontists near me →This article is general information, not medical or dental advice. Every bite is different; always confirm diagnosis and treatment with a licensed orthodontist.
