When your upper and lower back teeth, specifically the molars and premolars, do not make contact when your jaw is closed, this condition is known as a posterior open bite. It represents a type of malocclusion, which is any deviation from a normal, ideal bite. Instead of the typical interlocking of teeth, a visible space exists between the opposing back teeth. This gap can be present on one side (unilateral) or both sides (bilateral) of the mouth.
Understanding a Posterior Open Bite
When your upper and lower back teeth, specifically the molars and premolars, do not make contact when your jaw is closed, this condition is known as a posterior open bite. It represents a type of malocclusion, which is any deviation from a normal, ideal bite. Instead of the typical interlocking of teeth, a visible space exists between the opposing back teeth. This gap can be present on one side (unilateral) or both sides (bilateral) of the mouth.
Common Causes for Back Teeth Not Touching
The reasons behind a posterior open bite are varied, often involving a combination of factors related to jaw development, tooth eruption, and daily habits. Genetic predispositions can play a role, influencing jaw growth patterns that may lead to misalignment. Disproportionate vertical growth of the jawbones, where the upper and lower jaws grow at different rates, is a skeletal factor that can prevent the back teeth from meeting.
Dental factors also contribute to this condition. Issues with how teeth erupt can lead to a posterior open bite, such as primary failure of eruption (PFE) where teeth do not emerge fully, or mechanical failure of eruption (MFE) often due to a tooth fusing with the bone (ankylosis). Missing teeth can cause adjacent teeth to shift, creating gaps. Additionally, previous orthodontic treatments, especially clear aligner therapy, can sometimes result in a posterior open bite if there is premature contact between front teeth or issues with posterior tooth intrusion.
Habitual behaviors, particularly during childhood, are significant contributors. Prolonged thumb or finger sucking and extended pacifier use can exert pressure on developing teeth, pushing them out of alignment. Tongue thrusting, where the tongue pushes between the back teeth during swallowing or speech, can also prevent proper contact. Mouth breathing, often linked to underdeveloped jaws, can further exacerbate this issue.
Other factors include temporomandibular joint (TMJ) disorders, which can cause changes in the jaw’s position and lead to a posterior open bite due to inflammation or disc displacement within the joint. Parafunctional habits like chronic clenching might also contribute to the problem over time.
Solutions for a Posterior Open Bite
Addressing a posterior open bite typically necessitates professional dental or orthodontic intervention, as self-correction is rare, especially in adults. The diagnostic process usually begins with a comprehensive dental examination, which may include X-rays and dental impressions, to accurately assess the bite and identify the root cause.
Orthodontic treatment is a common approach, utilizing appliances like braces or clear aligners to gradually move teeth into their correct positions. Specialized orthodontic appliances, such as bite blocks or habit breakers, may also be used, particularly in growing children, to guide tooth eruption or correct detrimental habits. Elastics, or rubber bands, are often incorporated with braces or aligners to apply specific forces that help close the vertical gap.
In more severe cases, especially those with significant skeletal discrepancies, orthognathic surgery may be necessary. This involves repositioning the jawbones to achieve proper alignment and bite function. Surgical intervention is often combined with orthodontic treatment for optimal results. For certain situations where minor adjustments are needed, restorative dentistry options like crowns or onlays can be used to build up the surfaces of the teeth and establish proper contact.
Habit correction is also a component of treatment, especially when issues like tongue thrusting are identified. This might involve myofunctional therapy or specific appliances designed to retrain tongue posture and swallowing patterns. Consulting with a dentist or orthodontist is the first and most important step to determine the most appropriate treatment strategy for your unique situation.