What Is an Underbite, Overbite, or Crossbite — And Does It Need to Be Fixed?

Terms like overbite, underbite, and crossbite come up often in dental and orthodontic conversations, but many patients are not entirely sure what each one means or whether their particular bite issue is something that needs to be fixed. Here is a plain-language explanation of each type of bite problem and what is typically involved in addressing them.

What is an overbite?

An overbite is when the upper front teeth extend too far down over the lower front teeth when the jaw is closed. Some degree of vertical overlap between the upper and lower front teeth is completely normal. The problem arises when the overlap is excessive. A deep overbite can cause the lower front teeth to bite into the roof of the mouth, contribute to excessive wear on the front teeth, and in some cases be associated with jaw discomfort or TMJ issues.

What is an underbite?

An underbite is when the lower front teeth sit in front of the upper front teeth when the jaw is closed. In a properly aligned bite, the upper teeth slightly overlap the lower ones. An underbite reverses that relationship. It can be caused by a lower jaw that has grown too far forward, an upper jaw that is too far back, or a combination of both. Underbites can affect chewing, speech, and facial appearance, and they range from mild to significant.

What is a crossbite?

A crossbite is when one or more upper teeth bite inside the lower teeth rather than outside them. This can occur at the front of the mouth (anterior crossbite) or at the sides (posterior crossbite). A posterior crossbite is often associated with a narrow upper jaw. Crossbites can cause uneven wear on the teeth, shift the jaw to one side over time, and contribute to asymmetric jaw development in children if left unaddressed during growth.

Does every bite problem need to be fixed?

Not necessarily, and the answer depends on the severity of the problem and whether it is causing or likely to cause functional issues. A mild overbite with no symptoms and no significant wear may simply be monitored. A crossbite that is shifting the jaw, causing wear, or affecting a child's jaw development is more likely to benefit from treatment.

In children, addressing bite problems during active growth allows the jaw to be guided more gently and less invasively than treatment in adults. In adults, the options shift toward orthodontics, restorative correction, or in more significant structural cases, a combination with surgical input.

If you have questions about your bite or your child's bite, an evaluation at Wonder Family Dental and Dentures will give you a clear picture of what is going on and what, if anything, should be done about it.