Open Bite: Everything You Need to Know About This Malocclusion

Have you ever wondered why some people have a gap between their upper and lower teeth that prevents them from properly biting down? This dental alignment condition is known as an open bite.

Studies reveal that open bite, on average, affects approximately 16.52% of children and adolescents (5). Initially, it may seem like a minor dental alignment issue. However, if left untreated, it can gradually interfere with the development of the jaws, leading to significant changes in the facial features.

The key to addressing open bite lies in early intervention. By identifying and treating it as soon as possible, we can prevent it from worsening.

In this article:

1. What is an Open Bite?

2. The two main forms of open bite: Dental and Skeletal

3. How to differentiate between dental and skeletal open bites?

4. What Causes an Open Bite?

5. The Most Common Signs of Open Bite:

6. How is open bite treated?

7. What happens if an open bite is left untreated?

What is an Open Bite?

In a healthy bite, the upper front teeth overlap the lower teeth by about 2mm, allowing them to fit together properly when you bite. In the open bite, however, this overlap is missing, creating a space between your upper and lower teeth when you bite down.
Normal bite vs Open bite

Now, the tricky part about the open bite is that it can worsen over time if left untreated. Let me explain why.

When this malocclusion develops, the tongue will naturally be pushed forward into the gap created. This places a lot of pressure on the front teeth, causing them to shift even more out of their proper position. Moreover, carried away by the tongue's forces, the lower jaw may grow excessively long, giving a more oblong face. So, it's important to address the open bite sooner rather than later.
Tongue pushing on front teeth in an open bite

Tongue pushing on front teeth in an open bite

Open bites can occur in different areas of your mouth. The most common is the anterior open bite, which affects the front teeth in your smile zone. However, it can also occur in the back teeth, and in some cases, it may affect both the front and back teeth.
Lateral and anterior open bite

However, in children, it's crucial not to confuse an open bite with the natural eruption of permanent teeth. When children's front teeth are coming in, it's normal for there to be a gap between the two jaws. As the teeth complete their eruption, they should make contact and the bite becomes normal again.

The two main forms of open bite: Dental and Skeletal

Before we delve deeper into the topic, it's important to understand that there are two main types of open bites: dental and skeletal.

Our jaws are composed of two types of bones: the alveolar bone, which supports and holds the teeth, and the basal bone, which makes up the rest of the jaws.
Alveolar process and basal bone

In a dental open bite, the malocclusion involves only the alveolar bone. This means that treatment options, like braces, can effectively align your teeth, making the treatment relatively straightforward (2).

On the other hand, a skeletal open bite is a more complex condition involving the overall development of the jaws during childhood. This type of open bite is often attributed to genetic factors and tends to be more severe, requiring more advanced treatment (2).

Early intervention in children can take advantage of their growth potential to correct and guide jaw development. However, in adults who have completed their growth, while the alveolar bone and tooth positions can be reshaped through orthodontic treatment like braces, modifying the underlying skeletal structure (basal bone) is not possible without surgical intervention.

How to differentiate between dental and skeletal open bites?

It can be challenging to tell them apart as they are often associated with each other. To determine the nature of your malocclusion, a thorough clinical and radiological examination is needed.

In general, if the open bite is severe, involving both the front and back teeth, it is more likely to be skeletal in nature. You may also notice an increased height of the lower face.

On the other hand, if the open bite is mild and only involves the front teeth, it is more likely to be only a dental misalignment issue.

Ultimately, it's important to consult with an orthodontist who can accurately diagnose your specific malocclusion and recommend the most appropriate treatment for you.

What Causes an Open Bite?

When it comes to the causes of an open bite, they can be categorized into two main factors: genetics and functional issues. It's important to note that an open bite is often a combination of multiple factors rather than being solely attributed to one cause.

Genetic Factors:

Genetics plays a significant role in the onset of an open bite.

Individuals affected often have vertically overdeveloped jaws. This means that as the jaws grow in that direction, the teeth are also affected and move apart, leading to a noticeable gap between them.

This vertical growth pattern is strongly influenced by genetic factors (3). It's not uncommon to find that parents of patients with open bites also had or have the same issue.

Additionally, genetics determine the size and strength of facial and mouth muscles, including the tongue. An excessively large tongue can exert pressure on the front teeth, leading to an open bite.

Functional Issues:

Oral functions include all mouth activities that require the muscles to work, such as chewing, speaking, breathing, and swallowing. These play a crucial role in facial growth and maintaining proper tooth alignment.

Under normal conditions, the muscles in the mouth work in balance, exerting even pressure on the teeth to keep them in a natural position.

However, when this balance is disrupted, certain muscles may work harder than others, resulting in abnormal pressure on the teeth.

Over time, this can lead to changes in tooth position and the development of a malocclusion.

Aside from oral functions, other factors outside the mouth, such as thumb-sucking and nail-biting, can also contribute to dental alignment issues.

While these functional problems initially impact only tooth position, if they persist, they can eventually affect jaw growth, resulting in a skeletal open bite. The most common include:

1. Mouth Breathing:

When someone consistently breathes through the mouth, the tongue is placed in a low position. In addition to exerting excessive pressure on the front teeth, it causes the lower jaw to grow down and back, contributing to the open bite.

2. Tongue Thrusting:

Tongue thrusting is a swallowing pattern in which the tongue pushes against the front teeth instead of resting against the palate (the roof of the mouth). While it is normal and physiological in newborns, it becomes pathological if it persists after 4 years old.
This repeated pressure from the tongue can create a force that pushes the front teeth forward and contributes to an open bite.

3. Thumb Sucking:

This is a common habit among infants and young children. It's also a vital physiological reflex in newborns and can persist for up to 5 years. However, beyond this age, prolonged thumb sucking can exert pressure on the developing teeth and jaws, causing them to shift out of their proper alignment.

The Most Common Signs of Open Bite:

When it comes to identifying an open bite, there are several common signs to look out for. The most obvious sign is the inability of the upper and lower teeth to touch when biting down. However, depending on the underlying cause, there may be additional associated symptoms, including:

Increased Lower Facial Height: In cases where the open bite is skeletal in nature, there may be an increased distance between the point below the nose and the chin. This can give the face an elongated appearance.

Difficulty Closing the Lips: Individuals with an open bite often experience difficulty fully closing their lips. They may need to exert more effort and muscle contraction to do so.

Long Face Syndrome: Some individuals with an open bite may exhibit a long, narrow face and a receding chin. This condition is often associated with a narrow upper jaw and the downward and backward growth of the lower jaw. It is commonly observed in mouth breathers.

Other Signs of Mouth Breathing: Mouth breathing is often associated with open bite conditions. In addition to the physical appearance of the open bite, individuals who breathe through their mouths may display other signs, such as dark circles under the eyes, a pinched nose, an open mouth posture, and an abnormal head position with the head tilted forward.

How is open bite treated?

Treating an open bite depends on various factors such as severity, age, and underlying causes. Generally, there are three main approaches to treatment:

Removing bad habits and triggering factors
Orthodontic treatment
Jaw surgery

1. Treatment in children:

The optimal time to address an open bite is during childhood when the child is still growing. Taking advantage of the growth potential makes treatment easier and more effective. The treatment approaches for children with an open bite include:

Removing obstacles to oral functions: As mentioned earlier, oral functions such as breathing and swallowing play a crucial role in facial growth and teeth alignment. By removing obstacles that hinder proper oral functions, we can promote normal facial growth and prevent malocclusions. This may include addressing allergies, clearing the upper airways, and performing a lingual frenectomy to enhance tongue movement and posture.

Myofunctional therapy: Myofunctional therapy is a treatment approach that aims to train the muscles of the face and mouth to function correctly. Through voluntary rehabilitation exercises, the child learns to replace distorted habits with more natural and physiological ones. This therapy can address various issues, such as eliminating thumb-sucking, restoring nasal breathing, and correcting the swallowing pattern associated with tongue thrusting. Following the therapy, the brain integrates new reflexes that promote optimal dental and facial development.

Passive rehabilitation: In young children who cannot actively participate in myofunctional therapy, passive rehabilitation methods are employed. These involve using orthodontic devices to help the child get rid of his bad habit without participating in voluntary exercises. These appliances can include tongue cribs, tongue spurs, or orthodontic trainers.

Passive orthodontic device for children

By addressing obstacles and bad habits, the child's face and jaws can resume normal growth, potentially resolving the open bite (especially when baby teeth are still present) (1). If the open bite persists afterward, orthodontic treatment, such as braces, may be used to reposition the teeth correctly.

2. Treatment in adults:

In adults, the permanent teeth are fully developed, and growth has ceased, making self-correction of the open bite impossible. Treatment approaches for adult open bite include:

Removing obstacles and bad habits: In adults, it is crucial to rehabilitate oral functions as well. This involves restoring muscular balance and eliminating habits that contribute to the open bite. This ensures stable treatment results and reduces the risk of the issue returning later. The rehabilitation of oral functions in adults is achieved primarily through voluntary exercises (without the need for passive orthodontic devices).

Orthodontic treatment: Orthodontic treatment for adult open bite can be performed with or without extractions, depending on the available space in the jaw. If space is limited, extractions may be necessary. Braces or aligners such as Invisalign are then utilized to align the teeth and bring them into their correct position.

Jaw surgery: Jaw surgery, also known as orthognathic surgery, is considered in extreme cases or when the open bite is severe and skeletal. It involves repositioning one or both jaws to reduce the excessive facial height and close the open bite.

orthodontic and jaw surgery to fix an open bite

What happens if an open bite is left untreated?

Leaving an open bite untreated can have significant consequences for both your appearance and oral function. Here are some potential issues that may arise:

Aesthetic concerns: An open bite affects your smile and facial features, potentially leading to self-consciousness and decreased confidence.

Impaired daily functions: Difficulties in breathing, eating, and swallowing can arise from an untreated open bite, affecting your overall quality of life.

Progressive deterioration: An open bite is a self-sustaining condition that tends to worsen over time if not addressed. It can impact jaw growth and facial development, further exacerbating the malocclusion.

Joint problems: Misaligned teeth in an open bite can contribute to temporomandibular joint (TMJ) issues. You may experience pain, discomfort, and limited jaw movement when chewing or opening your mouth.

Oral health risks: Having an open bite increases the risk of oral health problems such as cavities, gum disease, and tooth wear. The misalignment can make proper oral hygiene more challenging, leading to potential dental complications.