An anterior open bite is a type of bite misalignment where the upper and lower front teeth don’t overlap or touch when the mouth is closed, even though the back teeth come together normally. If you smile and your front teeth have a visible gap between them top to bottom, that’s an open bite. It affects anywhere from 0.6% to 16.5% of people in the United States, depending on age and ethnic background.
What It Looks Like and How It’s Classified
In a normal bite, the upper front teeth slightly overlap the lower front teeth vertically. With an anterior open bite, that overlap is missing entirely. You can often see a clear space between the upper and lower front teeth even when biting down fully on the back teeth. The size of the gap varies from person to person, though there’s no universally agreed-upon measurement that separates “mild” from “severe.”
Orthodontists generally distinguish between two types. A dental open bite is limited to the teeth themselves and the surrounding bone, with no deeper structural problem in the jaw. A skeletal open bite involves a mismatch in how the upper and lower jaws have grown vertically, which shows up on X-rays as a disharmony between the facial bones. The skeletal type is typically harder to treat because the problem goes beyond tooth position.
Common Causes
The most recognized triggers are childhood habits. Prolonged thumb sucking, pacifier use, and tongue thrusting all apply mechanical forces to the front teeth during critical growth periods, gradually pushing them apart. Non-nutritive sucking habits and tongue-thrust swallowing are significant risk factors for developing an open bite in preschool-age children.
Tongue position plays an especially important role. Children normally transition from an infantile swallowing pattern to a mature one around age four. If that shift doesn’t happen, the tongue continues to press forward against or between the front teeth during swallowing and at rest. This constant, low-grade pressure is enough to prevent the teeth from coming together properly. Even in people who didn’t have childhood habits, a forward resting tongue posture can maintain or worsen an open bite over time.
Genetics matter too. Some people inherit a facial growth pattern where the lower jaw grows more vertically than forward, naturally creating a tendency toward an open bite. And in some cases, the open bite appears later in life as a consequence of joint disease rather than habits or growth patterns.
How It Affects Eating, Speaking, and Jaw Health
Because the front teeth can’t meet, biting into food becomes difficult. People with an anterior open bite have roughly half the bite contact area and less than half the maximum clenching force of people with normal bites. In one study, participants with an open bite reported difficulty eating significantly more types of food than the control group (about 7 problematic foods versus fewer than 1). Despite these chewing difficulties, the body appears to compensate: the same study found no measurable difference in how quickly the stomach processed a solid meal, suggesting adaptive mechanisms partially make up for the reduced chewing.
Speech is often affected. An open bite disrupts the airflow needed for certain sounds, particularly fricative sounds like “s,” “z,” “f,” and “ch.” Of these, the “ch” sound shows the strongest association with open bite, likely because it requires the tongue tip to contact the area right behind the upper front teeth, which is harder to do when there’s a gap.
The relationship between an anterior open bite and jaw joint problems is more complicated than most people assume. An open bite has long been listed as a possible risk factor for temporomandibular joint disorders. But the connection often runs in the opposite direction: degenerative joint disease can actually cause an open bite rather than result from one. When the jaw joint breaks down, particularly from osteoarthritis or a condition called idiopathic condylar resorption, the joint surfaces collapse and shorten the jaw, pulling the front teeth apart. This is sometimes called an “acquired open bite.” If you notice your bite changing gradually or suddenly, especially with jaw pain or clicking, the joint itself may be the source of the problem.
Treatment Options
Treatment depends on whether the open bite is dental or skeletal in origin, the patient’s age, and whether growth is still occurring.
For children and teenagers who are still growing, the first step is usually breaking the habits that caused or maintain the open bite. Orthodontists may use habit-correcting appliances like palatal cribs, which physically block the tongue or thumb from pressing against the front teeth. Functional appliances can also redirect jaw growth in younger patients whose bones are still developing.
In adults with a dental open bite, orthodontic approaches focus on moving the teeth into better positions. Techniques include using mini-screws (small temporary anchors placed in the jawbone) to push back teeth upward and allow the bite to close, or using specialized archwire techniques. A treatment framework gaining traction combines three elements: mini-screw anchorage for vertical control, habit correction through oral muscle therapy, and strategic tooth extraction with elastics when needed.
Oral myofunctional therapy, which retrains the tongue and facial muscles, is increasingly recognized as an important part of treatment. Since the tongue’s resting position and swallowing pattern often contribute to the problem, correcting tooth position without addressing muscle habits tends to produce unstable results.
Skeletal open bites in adults who are no longer growing often require surgery. The most common procedure is a Le Fort I osteotomy, where the upper jaw is repositioned upward to close the gap. This may be combined with lower jaw surgery depending on the severity. Surgery is also considered when the open bite is associated with airway problems like sleep apnea, significant jaw joint disorders, or speech impairments that orthodontics alone can’t resolve.
Why Relapse Is a Real Concern
Anterior open bites have one of the highest relapse rates of any orthodontic problem. Studies report that about 25% to 38% of cases relapse after orthodontic treatment alone, with extraction-based approaches faring somewhat better (about 26%) than non-extraction approaches (about 38%). Even with more advanced techniques using bone-anchored plates, relapse rates of 11% to 18% are reported within one to four years. Over 10 years, roughly 30% of treated open bites show some degree of instability.
The main culprits behind relapse are familiar: tongue habits that were never fully corrected, inconsistent retainer wear, continued facial bone growth after treatment, and the persistent pressure of lip and tongue muscles working against the corrected tooth positions. This is precisely why addressing the underlying muscle patterns through myofunctional therapy, not just moving teeth, is considered essential for long-term success. Wearing retainers as prescribed after treatment is equally critical, since teeth will drift back toward their original positions if left unsupported.