An open bite is a specific type of malocclusion where a vertical gap exists between the upper and lower teeth when the back teeth are closed together. This condition most frequently affects the anterior teeth, meaning the front teeth do not overlap or touch, leaving an opening even when the jaws are fully closed. Correction is pursued primarily to restore proper oral function, which is often compromised. An open bite can interfere with the ability to bite and chew food, and it may also cause difficulties in speech, such as a lisp, due to altered tongue position and airflow.
Defining the Types and Causes of Open Bite
The approach to correcting an open bite depends on whether the issue is primarily dental or skeletal in origin. A dental open bite is caused by the incorrect positioning or eruption of the teeth themselves, typically in an otherwise normally structured jaw. This type often results from persistent habits that push the teeth out of alignment.
In contrast, a skeletal open bite results from an underlying structural misalignment of the jaw bones, where the vertical growth pattern of the maxilla and mandible is disproportionate. Patients with this type often exhibit an increased lower facial height. Common causes for both types include persistent childhood habits like thumb sucking or prolonged pacifier use, which physically obstruct the teeth from meeting. Another factor is a tongue thrust, where the tongue pushes against the front teeth during swallowing or rest, along with abnormal jaw growth patterns that are often genetic.
Non-Surgical Orthodontic Correction Methods
For most cases that are primarily dental or mild to moderate skeletal issues, non-surgical orthodontic methods provide an effective path to correction. Traditional braces and archwires are commonly used to apply continuous, gentle forces that reposition the teeth and close the vertical gap. Clear aligners, such as those used in systems like Invisalign, are also used, offering a more aesthetic option for many adult patients. These aligners can correct mild to moderate open bites by leveraging anterior extrusion and posterior intrusion.
The aligners cover the posterior teeth, which creates a slight “bite block” effect. This prevents the back teeth from erupting further while simultaneously encouraging the front teeth to move downward. For more complex dental open bites, orthodontists often employ intrusion mechanics. This involves pushing the posterior teeth back into the bone, which allows the lower jaw to rotate upward and forward, effectively closing the open bite.
Temporary Anchorage Devices (TADs), which are small, temporary titanium screws placed into the jaw bone, act as fixed anchor points. Strong, specific forces can be applied from TADs to intrude the molars. This molar intrusion triggers the counter-clockwise rotation of the mandible, which contributes to open bite closure.
Specialized appliances are also used, such as fixed or removable tongue cribs. These serve to physically block the tongue from thrusting forward against the teeth. These appliances help eliminate the adverse pressure that prevents the front teeth from coming together, often playing a role in stabilizing the long-term result.
Surgical Intervention for Severe Open Bites
When the open bite is classified as a severe skeletal discrepancy, orthognathic surgery is typically the necessary intervention. This procedure is required when the extent of the misalignment is too great to be corrected by tooth movement alone. The surgery aims to reposition the jaws into a correct relationship with the rest of the facial skeleton.
The surgical process, often called corrective jaw surgery, is performed by an oral and maxillofacial surgeon. For open bite correction, the procedure often involves moving the upper jaw, or maxilla, to reduce the vertical dimension in the back of the mouth. The surgeon makes precise cuts in the jawbones, reshapes bone segments, and then stabilizes the jaw in its new position using small surgical plates and screws.
The surgical phase is always part of a combined approach, with comprehensive orthodontic treatment taking place both before and after the operation. Pre-surgical orthodontics aligns the teeth within their respective jaws so they will fit together correctly once the jaws are repositioned. Following the surgery, follow-up orthodontics is used to fine-tune the final bite alignment.
Early Intervention and Habit Correction
For young patients whose open bite is still developing due to an environmental cause like a habit, early intervention is beneficial. Addressing the underlying cause before the permanent teeth fully erupt can guide the natural growth of the jaws and teeth, sometimes eliminating the need for later, more complex treatment. A primary focus is on the cessation of detrimental habits, such as prolonged thumb or finger sucking and the use of pacifiers beyond the toddler years.
Myofunctional Therapy is a program of exercises designed to retrain the muscles of the tongue, lips, and face. This therapy focuses on correcting improper swallowing patterns and establishing a correct resting posture for the tongue, which should naturally rest against the palate, not against or between the front teeth.
Phase I orthodontics, also known as interceptive orthodontics, utilizes specific appliances to manage growth and eliminate habits in children, often between the ages of six and ten. Appliances like palatal expanders or fixed habit breakers, such as a palatal crib, can be used to physically block the tongue or finger from interfering with the bite. This early guidance and the removal of disruptive habits can lead to spontaneous correction of the open bite as the permanent teeth emerge.