A posterior open bite is a dental malocclusion where the back teeth do not make contact when the mouth is closed. A visible gap remains between the upper and lower posterior teeth, even if the front teeth meet. This condition can occur on one or both sides of the mouth. Addressing it involves understanding its causes and implementing targeted treatment strategies.
Understanding Posterior Open Bite
A posterior open bite is characterized by the absence of vertical overlap between the upper and lower back teeth when the jaw is closed. This lack of contact can significantly impact chewing efficiency and may contribute to speech difficulties. Factors contributing to this condition are diverse, often involving genetic predispositions and environmental influences.
Genetic factors can play a role, as individuals may inherit jaw growth patterns that contribute to this condition. Differences in the growth rates of the upper and lower jaws can lead to misalignment. Certain habits developed during childhood are also frequent causes. Prolonged thumb sucking or pacifier use, for example, can exert pressure on developing teeth, pushing them out of alignment.
Tongue thrusting, where the tongue pushes against the teeth during swallowing or speaking, can also prevent the posterior teeth from coming together. Issues with tooth eruption, such as a tooth failing to emerge fully or being obstructed, can result in a localized open bite.
Non-Surgical Treatment Approaches
Non-surgical methods are frequently employed to correct posterior open bites, particularly in growing patients or those with less severe malocclusions. Orthodontic treatments reposition teeth and influence jaw development. Traditional braces, consisting of brackets and wires, are a common and effective method, gradually moving teeth into proper alignment over 18 months to three years depending on severity.
Clear aligners, such as Invisalign, offer a discreet alternative for mild to moderate cases. These custom-made, removable aligners progressively shift teeth into place, with treatment times typically ranging from 12 to 18 months. While aligners provide comfort and hygiene advantages, careful monitoring is needed to prevent or address open bite development during treatment.
Beyond conventional braces and aligners, other non-surgical techniques target specific causes. Palatal expanders widen the upper jaw, creating more space and aiding in bite correction. Habit appliances counteract detrimental oral habits like tongue thrusting, retraining muscle patterns that contribute to the open bite.
Temporary Anchorage Devices (TADs), small implants placed into the bone, offer additional anchorage for precise tooth movement. TADs are valuable for intruding posterior teeth, allowing the jaw to rotate and close the open bite, providing a less invasive alternative to surgery in some cases.
Surgical Interventions
For complex cases of posterior open bite, especially those stemming from significant skeletal discrepancies, surgical intervention may be necessary. Orthognathic surgery, commonly known as jaw surgery, repositions the jaws to achieve proper alignment and improve the bite. This approach is typically considered when non-surgical orthodontic methods alone are insufficient to address the underlying skeletal issues.
Surgical procedures often include osteotomies, which are precise cuts made in the jawbone. These may involve repositioning the upper jaw (maxilla) or the lower jaw (mandible). Such procedures allow oral and maxillofacial surgeons to move the jaws into a more functional and aesthetically balanced position. Orthognathic surgery is often performed in conjunction with orthodontic treatment, with braces or aligners used both before and after surgery to refine tooth positioning and ensure optimal results.
The recovery period following orthognathic surgery can vary, typically lasting several weeks to months for full healing. While it involves significant downtime, surgery is effective for correcting severe open bites and substantial jaw discrepancies. This approach aims to resolve the underlying skeletal issues that contribute to the malocclusion, leading to improved chewing function, speech, and overall oral health.
Post-Treatment Care and Long-Term Considerations
After the active phase of posterior open bite treatment, whether non-surgical or surgical, post-treatment care is important for maintaining the corrected bite and preventing relapse. Retention is a key component, involving the use of retainers to hold the teeth in their new positions. Different types of retainers are available, including fixed retainers bonded to the back of the teeth, and removable retainers such as Hawley or clear Essix-type retainers.
For posterior open bites, Essix-type retainers are often recommended. The duration of retainer wear varies but is often long-term, sometimes indefinitely, to ensure stability. Consistent use of retainers is important, as relapse, where teeth shift back towards their original positions, can occur, especially with open bite corrections.
Continued monitoring by an orthodontic professional is also important to address any lingering habits or subtle shifts. In cases where habits like tongue thrusting were a contributing factor, addressing these behaviors through myofunctional therapy or habit appliances can be part of the long-term strategy. The overall goal of post-treatment care is to achieve a stable and functional bite that lasts for many years, preserving the investment made in correcting the posterior open bite.