Open Bite: Causes and How It’s Treated: Guide

Editorially reviewed by the Dental.me Editorial Team · Updated July 2026

An open bite is a type of malocclusion (a bad bite) in which the upper and lower teeth do not meet or overlap when the mouth is closed, leaving a visible gap between them. In a healthy bite, the upper front teeth rest slightly over the lower front teeth and the back teeth fit together like interlocking gears. With an open bite, some of those teeth simply never touch. It is one of the more challenging bite problems to correct, but it is very treatable once you understand what is driving it. This guide explains what an open bite is, the two main types, why it happens, the problems it causes, and how dentists and orthodontists fix it.

What is an open bite?

An open bite is defined by a lack of contact between opposing teeth when the jaws are closed. Instead of the teeth coming together, there is an open space. The size of that gap can range from a subtle few millimeters to an obvious opening you can see the tongue through. Because the teeth are not sharing the workload evenly, an open bite affects both function and appearance.

It differs from other common bite problems. An overbite, underbite, and crossbite all involve teeth that still meet but sit in the wrong position relative to one another, whereas an open bite is defined by teeth that do not meet at all. An overbite is too much vertical overlap of the front teeth; an open bite is the opposite, with too little or none.

The two main types

• Anterior open bite. The front teeth do not touch even when the back teeth are together. This is the most common and most noticeable form. When someone bites down, you can often see a gap between the upper and lower front teeth.
• Posterior open bite. The back teeth (molars and premolars) do not meet while the front teeth touch. This type is less common and less visible, but it interferes with chewing and can strain the jaw.

What causes an open bite?

Open bites usually trace back to childhood habits, the way the jaws grow, or how a person breathes. Often several factors combine.

• Thumb-sucking and pacifier use. Prolonged, forceful sucking pushes the front teeth apart and can reshape the developing bone. Learn more about thumb-sucking and your child’s teeth and why stopping the habit early matters.
• Tongue thrust and tongue posture. Resting or pushing the tongue against or between the front teeth keeps them from coming together and can hold an open bite open. Our guide to tongue thrust explains how this swallowing and resting pattern works.
• Skeletal and jaw growth patterns. Sometimes the shape and direction of jaw growth, which is often inherited, produce an open bite even without a habit. In these cases the upper and lower jaws grow in a way that leaves the teeth apart.
• Mouth breathing and enlarged tonsils or adenoids. Chronic mouth breathing, often driven by blocked nasal airways or enlarged tonsils and adenoids, changes tongue posture and can influence how the jaws develop.
• Adult contributors. In adults, jaw-joint (TMJ) problems and long-term teeth grinding or clenching can shift how the teeth meet and contribute to an open bite over time.

Problems an open bite can cause

An open bite is not just cosmetic. Because the teeth do not share the biting load properly, it affects everyday function.

• Difficulty biting and chewing. With an anterior open bite, biting into foods like a sandwich, an apple, or pizza with the front teeth is hard because those teeth never meet.
• Speech issues. Certain sounds, especially s and z, can develop a lisp when air escapes through the gap between the teeth.
• Excess wear on the back teeth. The teeth that do make contact end up doing more work, which can lead to accelerated wear and stress on those teeth.
• Jaw strain. An unbalanced bite can place uneven load on the jaw muscles and joints.
• Self-consciousness. A visible gap when smiling or speaking can make people feel self-conscious about their appearance.

How an open bite is diagnosed

A dentist or orthodontist diagnoses an open bite through a clinical exam, watching how the teeth come together when you bite down. To plan treatment they usually take X-rays and dental models or digital scans. The key question is whether the open bite is dental (the teeth are tipped or positioned wrong but the jaws are fine) or skeletal (the jaw bones themselves are the cause). That distinction, along with your age and the severity of the gap, shapes the entire treatment plan.

How an open bite is treated

Treatment depends on the cause, the patient’s age, and how severe the open bite is. The goal is always to bring the teeth into proper contact and to remove whatever is holding the bite open so the result lasts.

In children

Children have a major advantage because their jaws are still growing. Stopping the causative habit early, whether that is thumb-sucking, pacifier use, or tongue thrust, can allow a mild open bite to self-correct or be gently guided. Dentists may use habit appliances, sometimes called tongue cribs, that discourage the tongue or thumb from pushing against the front teeth. Myofunctional therapy, a program of exercises that retrains tongue posture and swallowing, is often paired with this to fix the underlying pattern.

Orthodontics

For many dental open bites, braces or clear aligners move the teeth into contact. Understanding how braces work helps explain the process: gentle, sustained pressure repositions the teeth over time, closing the gap. Aligners and braces can both be effective, and the choice depends on the case. Correcting an open bite shares principles with fixing an overbite, since both realign how the upper and lower teeth meet.

Jaw surgery for severe skeletal cases

When an open bite is severe and skeletal in an adult, moving teeth alone is not enough because the jaw bones are the source of the problem. In those cases, orthodontics is combined with corrective jaw surgery (orthognathic surgery) to reposition the jaws. This is a bigger undertaking, planned jointly by an orthodontist and an oral surgeon, and it produces stable, dramatic results for the right patients.

Addressing contributing factors

Lasting results depend on treating what caused the open bite. That may mean an ENT evaluation for enlarged tonsils, adenoids, or airway issues that drive mouth breathing, plus myofunctional therapy to correct tongue posture. If these factors are ignored, the bite is more likely to reopen.

Retention and preventing relapse

Open bites are notorious for relapsing, especially anterior ones. If an open bite is closed with braces or aligners but the tongue thrust that caused it is never corrected, the tongue can push the teeth apart again and the gap can reopen. That is why retention and habit correction are essential. After active treatment, retainers hold the teeth in place, and continued attention to tongue posture, much like preventing teeth from shifting after any orthodontic work, protects the result. Wearing retainers as directed and completing myofunctional therapy give the correction the best chance of holding.

The takeaway

An open bite, whether the front or back teeth fail to meet, usually stems from childhood habits like thumb-sucking or tongue thrust, from the way the jaws grow, or from airway problems. It causes real trouble with chewing, speech, and tooth wear, and it can affect confidence. The good news is that it is treatable: stopping the habit early, orthodontics with braces or aligners, myofunctional therapy, and, for severe skeletal cases in adults, jaw surgery. The key is addressing the cause so the bite does not relapse. If you or your child has teeth that do not meet when the mouth is closed, see a dentist or orthodontist for an evaluation. The earlier an open bite is caught, the simpler it is to correct.

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