An open bite is a malocclusion where a vertical gap exists because the upper and lower teeth fail to meet when the mouth is closed. This condition can affect a person’s ability to bite, chew, and speak clearly, making its correction a common goal in orthodontics. Orthodontists use a variety of methods, ranging from specialized appliances to surgical procedures, to close this gap and restore proper dental function. The approach chosen depends entirely on the location and underlying cause of the malocclusion.
Defining the Condition and Identifying Causes
Open bites are categorized as either anterior or posterior, based on where the teeth fail to connect. The more common anterior open bite involves a space between the front upper and lower teeth when the back teeth are touching. A posterior open bite is rarer, occurring when the back teeth (molars or premolars) do not meet.
The origin of an open bite is either dental or skeletal. A dental open bite is caused by environmental factors and habits, such as prolonged thumb-sucking or tongue thrusting, which prevent normal tooth eruption. A skeletal open bite results from abnormal jaw growth, often involving excessive vertical growth of the upper jaw. This type is genetically influenced and involves a structural discrepancy between the upper and lower jaws.
Non-Surgical Orthodontic Closure Methods
For open bites caused primarily by dental factors, non-surgical orthodontic methods are often effective. Traditional braces and clear aligners are used to exert controlled forces, aiming to intrude the posterior teeth further into the jawbone. This intrusion allows the lower jaw to rotate upward, closing the anterior gap.
Specialized appliances are frequently incorporated to aid in this vertical control. These include vertical elastics, worn between the upper and lower arches, and bite turbos, which temporarily disengage the back teeth to reduce biting force. The most powerful tool for non-surgical vertical control is the use of Temporary Anchorage Devices (TADs). TADs are small titanium screws placed temporarily into the jawbone, serving as stable anchors from which the orthodontist applies precise forces to intrude the molars.
Surgical and Advanced Treatment Options
When an open bite is caused by a severe skeletal discrepancy, orthognathic surgery is required. This intervention is reserved for adult patients whose jaw growth is complete and whose open bite cannot be corrected by orthodontics alone. The complex procedure involves repositioning the maxilla (upper jaw) or mandible (lower jaw), or both, to achieve proper alignment.
The most common surgical approach involves impacting the maxilla, moving the upper jaw upward, especially in the posterior region. This movement reduces the excessive vertical dimension and allows the front teeth to meet naturally. The overall timeline for surgical correction spans 18 to 30 months, beginning with pre-surgical orthodontics to align the teeth within each jawbone. Following surgery, post-surgical orthodontics are used to fine-tune the bite and settle the teeth into their final corrected positions.
Managing Habits and Retention After Treatment
Achieving open bite correction requires careful management of underlying habits and diligent retention, as the tendency for relapse is higher than with many other malocclusions. Retention is maintained using devices like fixed retainers bonded to the back of the front teeth or removable retainers worn nightly.
Habit correction is particularly important when the open bite was caused by tongue thrusting. Myofunctional therapy is a specific program of exercises designed to retrain the tongue to rest and swallow correctly against the roof of the mouth. This therapy addresses the underlying muscle function that applies constant pressure to the teeth, preventing relapse.
For patients with a history of thumb-sucking or prolonged pacifier use, behavioral modification techniques are implemented. These often involve the use of specialized habit-breaking appliances to eliminate the habit. Addressing these environmental factors is crucial, as a corrected bite will quickly reopen if the cause is not permanently resolved.