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Home » Posterior Open Bite: What Is It?

Posterior Open Bite: What Is It?

A posterior open bite is a type of dental problem in which the back teeth on the opposite jaws do not touch each other while chewing food. There is a visible gap between the two arches of teeth.

It is the opposite of an anterior open bite, in which the front teeth of the opposite jaws do not meet.

Although it has not been studied as vastly as other dental problems, dental professionals believe it contributes to the following:

  • Defective speech
  • Chewing inefficiency
  • Low secretion of saliva
  • Ineffective swallowing
  • Impaired growth
  • Facial asymmetry

In this article:

  • Types of posterior open bite
  • What causes a posterior open bite
  • Treatments
  • FAQs

Types of posterior open bite

1. Bilateral posterior open bite

A bilateral open bite occurs when both jaws do not fully develop, causing the back teeth to be spaced apart. 

2. Unilateral posterior open bite

This type of open bite occurs when only one jaw is deficient. The lower jaw is usually shorter than the upper jaw, causing the back teeth on that side to protrude.

Based on the source of abnormality, the posterior open bite may be of two different types:

Dental open bite: The jaw has no problem, but the teeth are not fully grown or misaligned.

Skeletal open bite: There is no problem with the teeth, but the jaws are misaligned, not fully developed, or not expectedly grown.

9 Leading Causes of a Posterior Open Bite

1. Tooth Ankylosis

If you have this condition, the root of your primary tooth remains permanently connected to your jaw. The tooth should be removed to prevent the permanent tooth’s eruption. If not, you may have a posterior open bite.

2. Eruption disorder

Your permanent teeth may not fully grow or erupt even if your primary teeth are extracted. The condition is rare and may affect both primary and permanent teeth. It mostly affects the teeth at the back of the mouth.

3. Genetic factors

Genetics can play a role in the presence of an open bite. If one or both parents have a history of dental problems, their children are more likely to have them.

4. Injury or illness

Injury to the lower jaw can cause it to move away from its normal position. The result can be an open bite. Also, certain illnesses can cause the lower jaw to shrink, leading to this type of bite.

5. Dental problems

If the upper and lower jaws don’t grow evenly, it can lead to an open bite. The crowding of teeth, or uneven teeth, can cause this problem.

6. Injuries to the jawbone

Jawbone injuries can also lead to an open bite. A severely injured lower jaw can prevent the back teeth from coming into contact with their opposite teeth.

7. Neurological problems

Conditions such as cerebral palsy can also affect the growth of the lower jaw and lead to an open bite.

8. Tumors or cysts in the jawbone

Tumors or cysts in the jawbone can lead to a shrunk lower jaw and a posterior open bite.

9. Skeletal abnormalities

These can be of two kinds:

  • Pathological skeletal abnormalities.
  • Non-pathological skeletal abnormalities.

Both are related to abnormal growth of the bone and can cause posterior or anterior open bites.

6 major symptoms of a posterior open bite

1. Difficulty chewing

If the back teeth are not in contact, it can be hard to chew food properly. This can cause people to eat softer foods that may not provide enough nutrients.

2. Speech problems

An open bite can also cause speech problems due to the alignment of the teeth. This can make it difficult to form certain words correctly.

3. Misaligned teeth

Misaligned teeth are another common symptom of a posterior open bite. When the back teeth are not in contact, it can cause the teeth on either side of the open space to move out of place.

4. Jaw pain

Jaw pain is another common symptom of an open bite. This can be due to misaligned teeth or the extra effort needed when chewing.

5. Facial asymmetry

Having a posterior open bite may mean the patient’s jaws are not correctly aligned to each other. That may give the patient’s face an unusual shape. This is the aesthetic part of the problem.

6. Tooth erosion

A posterior open bite can result in tooth erosion or fracture. There will be a tendency in the patient to bring the teeth together to chew food properly. That will impact the teeth that are already correctly aligned and touch their opposite teeth.

Can a posterior open bite be fixed?

Yes, a posterior open bite can be fixed. This can be done in a few different ways, depending on the cause. Below we’ll discuss some of the most common treatments.

Periodontal therapy

This may include:

  • Oral hygiene instructions
  • Scaling (removing toxins and buildup from teeth)
  • Root planing (preventing the building from returning)

Orthodontic treatment

This treatment is often necessary to correct a posterior open bite. This may involve braces or surgery to move the teeth into the correct position.

  • Jaw surgery

In most cases, a patient needs jaw surgery to correct the jaw. The surgery, named orthognathic surgery, restores the proper alignment of the teeth.

It involves separating the lower jawbone into two pieces and realigning the bone segments. The procedure requires the application of anesthesia.

The recovery time after posterior open bite surgery will vary based on the individual and the extent of the surgery. Most people will require time off from work to recover and may experience some swelling and discomfort following surgery. Full recovery typically takes several weeks.

  • Speech therapy

A speech therapist may help overcome issues like chewing or speaking difficulties resulting from the open bite. An open bite often causes misaligned teeth that affect speaking. Such a therapist works with a dental professional.

Cosmetic Procedures

Apart from the jaw surgery, the following dental cosmetic procedures and appliances may be useful to correct posterior open bites:

Face Lift

Face Lift is a non-surgical treatment for the posterior open bite. Instead of adjusting the jaw’s position to have an optimum bite, as with jaw surgery, it allows the jaw to move to an optimum position and adjusts the bite.

In other words, it uses the VENLAY bite restoration system to improve the size of the teeth to close the gap between the two opposite arches.

Nickel-Titanium Archwires

In an extreme case of surgical treatment, the following can help to force the jaws to come together:

  • Nickel-titanium archwires
  • Extrusion bands
  • Stainless steel archwires with T-loops

How to prevent a posterior open bite from developing?

You can do several things to prevent an open bite from developing. Here is an inexhaustible list:

Brushing and flossing teeth regularly

Having good oral health is essential for preventing dental problems that can lead to an open bite.

Seeing a dentist for regular check-ups

Going to the dentist for regular check-ups can help detect and treat any issues before they have a chance to cause an open bite.

Correcting bad habits

If you have bad habits such as thumb sucking or tongue thrusting, fixing these habits can help prevent an open bite from ever forming.

Using a mouthguard

If you participate in sports or activities that may cause trauma to the teeth, a mouthguard can help protect them from damage.

Eating a healthy diet

Eating a healthy diet can help ensure that you get the nutrients your body needs. This can help reduce the risk of future dental problems that can lead to an open bite.


Can wearing a nightguard fix a posterior open bite?

No, wearing a nightguard will not fix a posterior open bite. Nightguards protect teeth from damage caused by nighttime grinding and clenching. They are not designed to correct alignment problems or dental issues that may lead to an open bite. Instead, treatment for an open bite will usually involve orthodontic treatment or Face Lift.

What happens if a posterior open bite is not treated?

If a posterior open bite is not treated, it may worsen over time. There can be difficulties chewing and speaking and dental problems such as tooth decay and gum disease. A severe open bite can even cause the jaw to misalign. Therefore, it is wise to seek treatment for an open bite as soon as possible.

Which surgery corrects posterior open bite?

The surgery that corrects a posterior open bite is called orthognathic surgery. It aims to fix irregularities in the jawbones and realigns them, so that opposite arches meet when chewing food. The surgery requires a qualified professional, such as a maxillofacial, oral surgeon, or plastic surgeon. The surgeon receives help from an orthodontist. The surgery needs 1-3 hours to finish and about six weeks to heal.

What is the difference between posterior and anterior open bites?

In a posterior open bite, the teeth of the opposite arches do not meet when chewing food. An anterior open bite is its opposite. In it, the front teeth of the opposite arches do not come in contact with each other when chewing food.

Final Word

An open bite can cause many problems, both dental and functional. However, there are many treatments available to correct the alignment of the teeth and restore proper function. Treatment is most successful when started early, so it is wise to seek help if you think you may have an open bite.


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