An open bite is a malocclusion where the upper and lower teeth do not overlap vertically when the mouth is closed. Fixing this issue is crucial not only for aesthetics but also for proper chewing, swallowing, and speech function. Successful correction requires a precise diagnosis and a tailored plan based on the underlying cause and the patient’s age.
Defining the Condition and Common Causes
An open bite is a lack of vertical overlap between the upper and lower dental arches. It is categorized by location: an anterior open bite occurs when the front teeth do not meet, and a posterior open bite occurs when the back teeth fail to contact, impairing chewing.
The underlying cause classifies the issue as dental or skeletal. A dental open bite is localized to the teeth and often results from habits that impede tooth eruption. A skeletal open bite involves an abnormal growth pattern of the jawbones, such as excessive vertical development of the face.
Common contributing factors include prolonged thumb-sucking or pacifier use, which pushes developing teeth out of alignment. Tongue thrusting is another frequent cause, where the tongue pushes forward between the teeth during swallowing or speaking, preventing the teeth from meeting.
Treatment Strategies Based on Patient Age
The timing of intervention determines the success and complexity of open bite correction. Treatment strategies are structured around whether the patient is still growing, utilizing interceptive or comprehensive approaches.
Interceptive Treatment (Phase I)
Interceptive treatment, or Phase I, is typically recommended for children around age seven. This early phase focuses on guiding jaw growth and eliminating harmful oral habits, such as thumb-sucking or tongue thrusting.
Habit correction often uses simple removable appliances. Removing the source of the force allows the teeth to erupt naturally, which can simplify or self-correct the open bite.
Comprehensive Treatment (Phase II)
Comprehensive treatment, or Phase II, is reserved for adolescents and adults whose jaw growth is complete. The focus shifts to the precise movement of established teeth and correction of stabilized skeletal issues.
If the open bite has a significant skeletal component, treatment is more complex. This phase relies on moving the teeth into the correct position or, in severe cases, surgically repositioning the jawbones.
Orthodontic and Surgical Correction Methods
Open bite closure involves various mechanical methods tailored to the diagnosis. For dental open bites or mild skeletal cases, non-surgical orthodontic methods move the teeth vertically. Traditional braces and clear aligners are effective, with aligners showing success in managing the vertical dimension by facilitating the intrusion of back teeth.
A primary orthodontic mechanism for closing an anterior open bite is the intrusion of the posterior teeth. This allows the mandible to rotate slightly forward and upward, naturally closing the gap. Movement can be achieved by placing specialized appliances, such as a tongue crib, to block the tongue from thrusting.
Temporary Anchorage Devices (TADs)
More advanced non-surgical techniques incorporate Temporary Anchorage Devices (TADs), which are small titanium screws placed into the jawbone. TADs serve as an immovable anchor point to apply constant, precise force to intrude the posterior molars.
This method bypasses the need for patient compliance and is effective when combined with clear aligners. Using TADs can often correct moderate skeletal discrepancies that previously required surgery.
Orthognathic Surgery
For severe skeletal open bites in adults, orthognathic surgery is necessary to achieve a stable result. This procedure, often a bimaxillary osteotomy, involves surgically repositioning the upper jaw (maxilla) and sometimes the lower jaw (mandible).
The most common surgical approach is a Le Fort I osteotomy with differential posterior impaction. This moves the back part of the upper jaw upward, causing the mandible to rotate counter-clockwise, closing the open bite and improving the facial profile.
Maintaining Correction and Preventing Relapse
Open bite correction carries a notable risk of relapse, as teeth and jaws are prone to shifting back due to persistent muscular forces. This necessitates a strict and often long-term retention phase, which begins immediately after active tooth movement is complete.
The choice of retainer is influenced by the original problem and correction method. Removable Essix-style retainers with full posterior coverage are frequently used, as the plastic material maintains intrusive pressure on the back teeth.
Fixed retainers, which are thin wires bonded to the back of the front teeth, may also be used with removable appliances for additional passive support.
Addressing underlying soft tissue dysfunction is paramount for stability. Residual habits, particularly tongue thrusting, exert constant pressure that can push the teeth apart again.
Orofacial myofunctional therapy (OMT) is often recommended alongside orthodontic retention. OMT involves exercises to retrain the tongue and facial muscles to swallow correctly and maintain a high resting posture, stabilizing the corrected bite over time.