An open bite is when some of your teeth do not meet when your jaw is fully closed, leaving a visible gap. It happens most often at the front (an anterior open bite), where the upper and lower front teeth do not touch even though the back teeth do. The earlier it is picked up, especially in children, the simpler it usually is to correct.
Key takeaways
- An open bite means the upper and lower teeth do not contact when the jaw is closed, usually at the front.
- Common causes include prolonged thumb or dummy sucking, tongue thrusting, mouth breathing, and how the jaws grow.
- It can affect biting into food, speech (especially sounds like s and th), and self-consciousness about the smile.
- In young children, stopping the habit early can let the bite correct itself.
- In older children and adults, aligners, braces, appliances, or in some cases jaw surgery are used.
What an open bite is
Normally the top teeth overlap the bottom teeth slightly when you bite together. With an open bite, a gap remains. An anterior open bite affects the front teeth and is the most common type. A posterior open bite, where back teeth do not meet, is less common. Because the front teeth cannot meet, people with an anterior open bite often tear food with their side teeth or find biting into things like a sandwich awkward.
What causes an open bite
Most open bites come from pressure on the teeth over time, or from the way the jaws and teeth develop. The habits most often linked to an anterior open bite are dummy (pacifier) sucking, thumb sucking, and tongue thrust, where the tongue pushes forward against or between the front teeth when swallowing or at rest.
| Cause | How it creates an open bite |
|---|---|
| Thumb or dummy sucking | Ongoing forward and outward pressure holds the front teeth apart |
| Tongue thrust | The tongue pushes between the teeth, keeping a gap open |
| Mouth breathing | Altered tongue and jaw posture can change how teeth erupt and meet |
| Jaw growth pattern | The way the upper and lower jaws grow can leave the front teeth apart |
| Incomplete eruption | Front teeth that have not fully come through do not reach each other |
Thumb sucking deserves particular attention, because it can trigger a secondary tongue thrust that makes the problem worse. Our guides on thumb sucking and teeth and mouth breathing in children cover two of the biggest contributors in detail.
Why an open bite matters
Beyond appearance, an open bite can make it hard to bite through food with the front teeth, which shifts the work to other teeth. It can affect speech, particularly s and th sounds, because the tongue slips into the gap. Some people also notice their back teeth take more of the load, which can contribute to wear over time. For children, catching it early often means simpler treatment and a lower chance of it settling into the adult bite.
How an open bite is treated
Treatment depends heavily on age and cause. The general principle is to start with the least invasive option that addresses the underlying reason.
In young children
If a sucking habit is the cause and it stops early enough (generally before the adult front teeth are well established), the bite can improve on its own as the jaws grow. Dentists use gentle habit-breaking strategies first, such as reminders, reward charts, and encouragement. If needed, an appliance called a palatal crib can discourage thumb sucking and tongue thrusting. Combined with myofunctional therapy (exercises that retrain tongue posture and swallowing), some cases improve within a few months. Early assessment is the theme of our guide to early orthodontic treatment for children.
In older children and adults
Once the adult teeth and jaws are set, an open bite usually needs active orthodontics. Clear aligners or braces can move teeth back into contact, and small anchoring devices are sometimes used to help. If the open bite is driven mainly by jaw growth rather than tooth position, orthodontics may be combined with jaw surgery in more significant cases. Addressing an ongoing tongue thrust or mouth breathing at the same time helps stop the bite from relapsing. For a wider view of correcting how teeth meet, see our guide to overbite, underbite and crossbite, and for adult options specifically, braces versus aligners for adults.
Frequently asked questions
Can an open bite fix itself?
In young children whose sucking habit stops early, it sometimes improves as the jaws grow. Once the adult teeth are in place, it usually needs treatment.
Can clear aligners fix an open bite?
Aligners can correct many open bites, particularly milder ones driven by tooth position. Whether they are suitable for your case depends on an assessment.
Is an open bite caused by genetics?
Jaw growth patterns can be inherited and contribute, but habits like sucking, tongue thrust, and mouth breathing are often involved too. Most cases have more than one factor.
Does an open bite cause speech problems?
It can affect certain sounds, especially s and th, because the tongue moves into the gap. Correcting the bite often helps, and speech therapy can complement treatment.
What happens if an open bite is left untreated?
It will not usually improve on its own in adults, and it can contribute to uneven tooth wear and ongoing difficulty biting. Treatment is elective, but many people choose it for function and comfort.
The takeaway
An open bite is a common and treatable difference in how the teeth meet. In children, early attention to habits can make a big difference and sometimes avoids braces altogether. In adults, aligners, braces, or a combined approach can close the gap. The best first step is an assessment to find the cause. To discuss options, the team at Lumi Dental is happy to help, and you can see current offers on the current deals page.
This article is general information and not a substitute for personalised advice from your dentist.
