A bite problem, which dentists call a malocclusion, means the upper and lower teeth do not meet the way they ideally should. It is extremely common. Reviews of children and adolescents put the overall prevalence of some form of malocclusion anywhere from around 39 percent to over 90 percent depending on the population and how it is measured. Most cases are mild and never cause trouble, but some affect chewing, speech, tooth wear, and confidence, and benefit from treatment.
This guide explains the four bite types people ask about most: overbite, underbite, crossbite and open bite. It covers what each one is, why it can matter, and the options for fixing it.
Key takeaways
- A malocclusion simply means the teeth or jaws do not line up ideally. It is very common and often mild.
- Overbite is vertical overlap of the front teeth, deep bite means too much. Increased overjet is the upper teeth sitting too far forward.
- Underbite is the lower teeth sitting in front of the upper teeth.
- Crossbite is one or more teeth biting on the wrong side of the opposing teeth, and open bite is a gap where teeth should meet.
- Treatment ranges from aligners and braces to growth-guiding appliances in children, and jaw surgery for severe adult cases.
One idea that makes bite problems easier to understand
Think of a bite in two directions. Vertical describes how much the front teeth overlap up and down, which gives you deep bite or open bite. Horizontal describes how the teeth line up front to back and side to side, which gives you overjet, underbite and crossbite. Almost every bite issue is a variation in one of those two directions.
Overbite and overjet
An overbite is the normal vertical overlap of the upper front teeth over the lower ones. A small overlap is healthy. A deep bite means the upper teeth cover too much of the lower teeth, sometimes enough for the lower teeth to bite into the gum behind the upper teeth. Deep bite is reported in roughly one in five people. Overjet is different: it is how far forward the upper teeth sit, the classic protruding front teeth look, and increased overjet is also common. Both can be improved with braces or aligners, and in growing children with appliances that guide the jaws.
Underbite
An underbite is when the lower teeth sit in front of the upper teeth. It is the least common of the main bite problems, recorded in roughly 5 percent of people, and is often linked to the lower jaw being larger or more forward than the upper jaw. Mild dental underbites can be corrected with braces or aligners. Cases driven by jaw size, especially in adults, may need a combination of orthodontics and jaw surgery for a stable result. Catching it early in childhood gives the most options.
Crossbite
A crossbite means a tooth, or group of teeth, bites on the inside or outside of where it should against the opposing teeth. A front crossbite affects the incisors, a posterior crossbite affects the back teeth, and it can cause the jaw to shift to one side when closing. Posterior crossbite is reported in roughly 9 percent of people. Because an uncorrected crossbite can wear teeth unevenly and load the jaw asymmetrically, it is one of the bite problems most worth assessing, and in children a simple expander often resolves it quickly.
Open bite
An open bite is a gap between the upper and lower teeth when the back teeth are together, most often at the front. It affects roughly 5 percent of people. Common causes include prolonged thumb sucking or dummy use in childhood, and tongue habits. Stopping the habit early can let a child's bite recover on its own. Established open bites in teenagers and adults usually need orthodontics, and sometimes surgery in severe cases.
How bite problems are treated
| Bite type | Typical first-line options | Severe or jaw-based cases |
|---|---|---|
| Deep bite / overjet | Braces or aligners, growth appliances in children | Combined orthodontics and surgery |
| Underbite | Braces or aligners for dental cases | Orthodontics plus jaw surgery |
| Crossbite | Expander in children, braces or aligners | Surgically assisted expansion in adults |
| Open bite | Stop the habit early, braces or aligners | Orthodontics plus surgery |
For most people, modern braces or clear aligners handle the job well. Our guides to straightening crooked teeth and aligner options explain the everyday choices, and a braces guide covers what treatment is like day to day.
Why a bite problem is worth assessing
Many bites are fine left alone. The ones worth treating are those causing uneven tooth wear, jaw discomfort, difficulty cleaning crowded teeth, speech or chewing trouble, or appearance concerns that affect confidence. An assessment will tell you whether yours is in the watch-and-leave group or the worth-treating group. We do not publish our own fees here. For a plan and a written quote, see our offers page or get in touch.
Frequently asked questions
Does every bite problem need braces?
No. Many are mild and cause no harm. Treatment is recommended when the bite affects function, cleaning, tooth wear, or confidence.
What is the best age to fix a bite?
Childhood and the early teens offer the most options because the jaws are still growing, but adults can be treated successfully too, often with aligners.
Can clear aligners fix a crossbite or open bite?
Aligners can manage many mild to moderate cases. Complex or jaw-based bites may need braces or a combined surgical plan. An assessment decides.
Will a bite problem get worse over time?
Some are stable for life, others cause progressive tooth wear or jaw strain. That is why having it assessed once is worthwhile, even if you choose not to treat it.
Is jaw surgery always needed for an underbite?
No. Mild dental underbites are corrected with braces or aligners. Surgery is reserved for cases driven by significant jaw size differences, usually in adults.
The takeaway
Overbite, underbite, crossbite and open bite are the main bite problems, and most are easier to understand once you split them into vertical and horizontal. Many are harmless, but the ones that affect wear, function or confidence respond well to modern orthodontics. If you are unsure which group yours is in, our team at Lumi Dental can assess it and provide a written quote. Start on our offers page or read about retainers after treatment.
This article is general information and not a substitute for an individual orthodontic assessment.
