Overbite Vs Underbite

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Overbite vs underbite – what are the similarities, what are the differences, which is worse, and what are the best available treatment options for both?

Smiling does a lot of wonders; it doesn’t only make someone exude positive energy, but it also triggers the release of hormones that reduces stress, lower blood pressure, and even strengthens the immune system. However, many people refuse to smile simply because they don’t feel confident showing their teeth. Study shows that about two-thirds of American adults suffer from clinically meaningful malocclusions that require medical treatment, specifically, orthodontic intervention. The problem is that 36% of Americans are afraid to go to their dentist. But what are these malocclusions? Overbite vs. underbite, which one is more difficult to treat? Are there serious health risks associated with misaligned teeth?

If you are thinking of getting cosmetic or orthodontic treatment, you may hear your dentist talk about fixing your bite. This means treating your malocclusion. Malocclusion is the term that is described as a type of misaligned bite. You may have heard about buck teeth, crowded, or crooked before; these are actually types of malocclusions. Two of the most common types of malocclusions are the overbites and underbites, along with crossbites, overcrowding, spacing, open bite, overjet, and diastema.

This entry will talk about these different malocclusions, specifically overbite vs underbite, their causes, effects on the body, and the different ways to treat them, to help you come up with the best solution for your type of malocclusion.

Overbite vs. Underbite: Differences Between the Two

It is actually quite easy to differentiate the two; overbite refers to the upper set of teeth, while underbite is described for the lower set of teeth. In both scenarios, the teeth extend too far past their opposing biting partner. This causes a bite problem since the upper and lower teeth do not meet right in the middle

Overbite and underbite are two very different malocclusions. The former happens when the upper teeth extend and overlap too far from the lower teeth when the mouth is closed. Underbites, on the other hand, are when the lower teeth extend too far out than the top teeth, resulting resembling a bulldog-like look on the face. These differences are very important, as many people mistake the two for each other.

Understanding Overbite

It is completely normal for the upper teeth to extend past the lower teeth a little bit, this is called a slight overbite. In some cases, however, the overlap is too pronounced resulting in an overbite, also called a closed bite or deep bite.

Overbites are more common than underbites. In overbites, the teeth overlap may look straight or jetted outward at an angle. Overbites also differ in severity. While mild cases can be fixed with simple orthodontic treatments like at-home clear aligners, severe overbites may require complex treatment plans such as in traditional braces or Invisalign.

Generally, a bite is considered overbite if the upper set of teeth extends 4mm to 10mm over the lower set of teeth. Some dentists will even classify a difference of 2mm as an overbite.

The good news is this type of malocclusion can be easily fixed using conventional treatment options. It is even easier to correct in young children, since their bones, especially the jaw bone, have not fully fused yet.

Causes of Overbite

Overbite usually happens when the lower jaw is smaller or shorter relative to the upper jaw. This is because when the lower jaw is shorter than the upper jaw, it causes bite alignment problems. The bottom teeth may grow upwards until they hit the upper back teeth or even the roof of the mouth. As the lower teeth grow all the way up, they usually cause overcrowding too.

Other common causes of overbite include:

• Bad oral health habits during childhood (thumb sucking, lip sucking, tongue thrusting or pushing the upper baby teeth out using the tongue)

• Overly developed bite muscles (those who frequently clench their jaw or grind their teeth)

• Genetics (inherited condition)

Why you need to correct an overbite?

If left untreated, moderate to severe cases of overbite can cause serious health complications, most of which usually start as oral problems, such as irreparable damage to the teeth due to abnormal teeth and jaw position. Moreover, a misaligned bite can also lead to chronic jaw pain, such as temporomandibular joint disorder (TMJD or simply known as TMJ.

Other health complications caused by overbite include:

• Cavities and tooth decay due to worn enamel

• Gum disease

• Severe and recurring headaches

• Jaw pain

• Discomfort while eating

• Difficulty speaking

• Difficulty with fully opening or closing of the mouth

• Low self-esteem

• Sleep apnea

Severe cases of overbite can also alter the facial structure, leading to mental and emotional problems that stem from low self-esteem. Moreover, severe overbites during childhood can worsen, causing further deterioration of teeth and jaw later on or as early as pre-pubescence.

Overbites treatments

Overbite treatments usually take between six months to 24 months with braces. Surgeries can be faster. Basically, it boils down to the specifics of your condition. The experience of the orthodontist also plays a big role.

Braces

Braces are widely considered the gold standard of orthodontic treatment. It can treat a wide range of malocclusions, from mild to severe. There are also many different types of braces out there, from traditional metal braces, self-litigating braces, ceramic braces, and lingual braces, to clear aligners like Invisalign. Regardless of the type, the idea of braces is simple, they provide consistent pressure to the teeth to force them to gradually move to the desired direction and position, which eventually straightens the teeth and aligns the bite.

Metal and ceramic braces are the common choices for overbites. Ceramics look nicer as they are more discreet than their metal counterparts.

Splint therapy

Also known as a repositioning splint, this dental appliance is worn on the bottom teeth to push the mandible (lower jaw) forward, reducing the gap between the lower and upper teeth, and eventually fixing the overbite.

This treatment is often considered a short-term solution. If the problem is not fixed, orthodontists may move on to more comprehensive and complex treatment.

Jaw Surgery

Severe cases of overbites may require complex treatment like jaw surgery. The procedure is about modifying the size of the jaw to move it to the right position. This is usually used for misaligned jawbones.

Surgery involves splitting the upper jawbone to remove some bone, before moving it to align with the lower jawbone. Bone plates, wires, and screws are then used to hold the jaw together.

Understanding Underbite

An underbite happens when the lower front teeth extend farther and out relative to the upper set of teeth. This causes the upper and lower rows of teeth not to meet when the mouth is closed, affecting the teeth’s biting pattern.

In many cases, this is a jaw repositioning issue, as the lower jaw extends farther than the upper jaw. IN cases like this, the lower teeth have a tendency to jet outward or protrude more on what seems to be a “prominent” jaw.

Causes of Underbite

An underbite is usually caused by the upper jaw being underdeveloped, having too small of an arch, or the lower jaw being overdeveloped relative to the upper jaw. As with overbites, underbites can run in the family too.

Other causes of underbite include;

• Bad oral health habit (thumb sucking, tongue thrusting against the teeth, using feeding bottles and pacifiers for too long, particularly after the age of 3)

• Tumor in the jaw bone

• Trauma or facial injury

• Mouth breathing

Why you need to correct an underbite?

Whatever the exact cause, severe cases of underbite must be treated immediately to avoid oral health complications, such as:

• Difficulty chewing and swallowing

• Trouble cleaning the teeth properly

• Increased risk of dental problems (cavities, tooth decay, gum disease)

• Jaw strain, wear and tear of the jaw joint (TMJ), teeth, and facial muscles

• Headaches

• Earaches

• Bad breath

Underbite treatments

The treatment option for underbite largely depends on the complexity and severity of the case. Braces for underbites may last up to two years, while reverse-pull face mask averages around one year.

Braces

Like in overbites, braces are also widely used for straightening teeth and aligning the lower jaw to the upper jaw. Braces constantly apply pressure to the protruding teeth, gradually forcing the teeth to move in their desired direction and position.

Almost all types of braces can be used for treating underbites. Traditional braces are the common choice for young patients, while adults often opt for aesthetically pleasing or more discreet options such as ceramic, lingual braces, or even clear aligners like Invisalign.

Reverse-full face mask

In severe cases of underbites where the lower jaw is developing faster than the upper jaw, a reverse-pull face mask is used to slow down the growth of the lower jaw and allows the upper jaw to catch up. It fixes the malocclusion by pushing the top jaw forward, reducing the space between the upper and lower jaw. This is why this treatment option is ideal for children whose jawbones are still growing and developing.

This special mask is made up of a metal bar wrapped around the head, and soft pads that rest on the chin and forehead. The metal frame is connected to the upper front teeth and upper back teeth.

Upper Jaw Expander

This method is exactly what it sounds like – it aims to expand the upper jaw to match the shape and size of the lower jaw for proper bite alignment.

The device if fitted across the palate adjusts and widens at intervals throughout treatment time. This means with time, the upper teeth extend outwards, aligning them with the lower teeth.

Tooth extraction

In some cases, especially among children, dental professionals determine that the jaw is too small to accommodate the growing number of teeth. Tooth extraction leaves more room for the permanent teeth to grow correctly and avoid overcrowding which often results in underbites.

Jaw surgery

Surgery for underbite is usually done to lengthen the upper jaw or shorten the lower jaw. Surgeons need to break the jaw open and remove some bone tissues, and then reposition it to make proper bite alignment.

There are two common types of jaw surgery for underbite, regular orthognathic surgery, and Le Fort osteotomy. The former is done by extracting a part of the jaw bone for an optimal position. The latter on the other hand, repositions the orbit, cheeks, and top of the jaw to correct severe cases of an underbite.

Frequently Asked Questions

Q. Is overbite better than underbite?

A. Both have no advantages or benefits of some sort over each other. While overbites are more common than underbites, moderate to severe cases of the two comes with lots of challenges and risks to oral and overall health.

Q. Does overbite worsen with age?

A. Yes. Over time, the space between your upper and lower teeth increases, making the overbite worse. Thus, it is best to address it as soon as possible to minimize or even prevent long-term effects. Severe cases left untreated may require more complex (more expensive) orthodontic treatments.

For children, underbites usually worsen with age, especially during the child’s growth spurt years (9 to 14 years). After this, the growth of the jaw bone becomes stable, and usually stops around mid-teenage years.

Overbite vs. Underbite: which is worse?

So you might be wondering, which malocclusion is the worse? Well, both issues create a long list of problems that need to be addressed. Both can cause pain and affect your daily life, be it for aesthetics or proper teeth and jaw functions. Moreover, both can cause oral health problems that may lead to serious health concerns in the long run, and affect one’s self-esteem.

Thankfully, there are plenty of treatment options out there for correcting malocclusions like overbite and underbite. Talk to your dentist or orthodontist today and get that bright and beautiful smile you deserve!

Dr Febin Mary George - Editor

With more than 10 years as a dental surgeon, Dr Febin Mary George is passionate about educating consumers around the world to help look after their teeth.

She completed her Bachelor of Surgery at the Century Institute of Dental Science and Research Centre in 2010.

Alongside editing the International Journal of Dental Clinics she has also written for major publications including Thrive Global.