An open bite is a type of misalignment where certain upper and lower teeth don’t touch when your mouth is fully closed. It affects roughly 3% of the general population, though prevalence varies by age and background. While it can be subtle enough to go unnoticed, a significant open bite creates real problems with eating, speaking, and long-term dental health.
Anterior vs. Posterior Open Bite
The most common form is an anterior open bite, where the front teeth don’t meet even though the back teeth come together normally. If you have one, you can usually see a visible gap between your upper and lower front teeth when you bite down. This is the type most people picture when they hear “open bite.”
A posterior open bite is less common and harder to spot. In this case, the premolars and sometimes the molars fail to make contact, while the front teeth may touch just fine. You might not notice it visually, but it can make chewing inefficient because food doesn’t get ground properly between the back teeth.
What Causes an Open Bite
Open bites develop from a combination of habits, anatomy, and airway issues. In children, the most familiar culprit is prolonged thumb or finger sucking. If the habit continues past age 5, the steady pressure can push the front teeth apart and reshape the developing jaw. The Mayo Clinic notes this is the age at which changes to the teeth and palate become more likely.
Tongue thrusting is closely linked. A child who develops an open bite from thumb sucking often starts pushing the tongue forward into the gap to create a seal while swallowing. This reinforces the problem even after the sucking habit stops. A second pattern, sometimes called the “teeth apart” swallow, develops when chronic nasal congestion or enlarged tonsils force a child to breathe through the mouth. The lower jaw drops to make room for the tongue, and the tongue pushes forward during every swallow, gradually separating the front teeth.
Skeletal factors also play a role. Some people inherit a jaw structure where the upper and lower jaws grow at slightly different rates or angles, creating a gap that no habit caused. In one orthodontic screening population, skeletal open bites accounted for about 5% of cases. These tend to be more difficult to correct because the issue is in the bone, not just the tooth position.
How It Affects Speech and Eating
When your front teeth don’t meet, biting into food becomes difficult. Think of trying to tear a piece of bread or bite through a sandwich: your incisors can’t do their job, so you compensate by using the side of your mouth or tearing food with your hands. Chewing can also feel less efficient with a posterior open bite, since fewer teeth share the grinding work.
Speech problems are common, particularly lisps. Sounds like “s” and “z” require the tongue to press close to the roof of the mouth just behind the front teeth. With an open bite, the tongue slips into the gap instead, producing a “th” sound. Consonants like “d” and “t,” which depend on tongue-to-tooth contact, can also come out unclear.
Long-Term Risks of Leaving It Untreated
An untreated open bite doesn’t just stay the same. According to the American Association of Orthodontists, an anterior open bite forces the back teeth to absorb all the biting pressure without support from the front teeth. Over time, that extra load increases the risk of gum problems, tooth mobility, and even fractures in the molars and premolars. Swallowing difficulties can persist, and the jaw joints may become strained from the uneven mechanics.
Treatment With Braces or Aligners
Correcting an open bite starts with addressing whatever caused it. If tongue thrusting or a remaining sucking habit is still active, those need to be managed alongside orthodontic treatment, or the bite will reopen after the braces come off.
Traditional braces remain a standard option. They can pull the front teeth downward (extrusion) or push the back teeth upward into the bone (intrusion) to close the gap. Small titanium screws called temporary anchorage devices are sometimes placed in the jawbone to provide a fixed point for these movements, giving the orthodontist more control than rubber bands alone.
Clear aligners have become a viable alternative for many adults with anterior open bites, particularly in cases that don’t require tooth extraction. Aligners work through the same principles of extruding front teeth or intruding back teeth, and they offer obvious cosmetic advantages during treatment. They do require disciplined wear, though. Less consistent use can push treatment well beyond the typical timeline.
For mild alignment issues, treatment may wrap up in 6 to 12 months. More complex bite corrections, including significant open bites, often take 18 months or longer, with severe cases sometimes reaching 30 months.
When Surgery Is Needed
Skeletal open bites, where the problem is in the jaw structure rather than just the teeth, sometimes can’t be fully corrected with orthodontics alone. In these cases, jaw surgery (orthognathic surgery) repositions the upper jaw, the lower jaw, or both to bring the teeth into proper alignment. An oral surgeon typically works alongside an orthodontist: braces or aligners align the teeth before and after surgery, while the surgery itself moves the bone.
Surgery is generally reserved for adults whose jaws have finished growing, usually around age 16 to 18. Recovery involves several weeks of a modified diet and gradual return to normal activity, followed by continued orthodontic treatment to fine-tune the bite. The results tend to be stable because the underlying skeletal mismatch has been addressed rather than compensated for.
Prevention in Children
Most pediatric open bites are preventable or at least reducible. Gently discouraging thumb sucking before age 5 is the single most impactful step, since the jaw is still soft and growing during those years. If the habit stops early enough, mild open bites in baby teeth often self-correct as permanent teeth come in.
Chronic mouth breathing deserves attention too. If your child consistently breathes through their mouth, snores, or seems congested even without a cold, it’s worth having their airway evaluated. Enlarged tonsils or adenoids can set off the chain of tongue posture changes that lead to an open bite. Treating the airway issue early removes the mechanical trigger before permanent damage sets in.