What is an Underbite?

Class III Malocclusion

An underbite refers to a dental condition when the lower jaw is pushed forward when you close your mouth, causing the lower jaw and teeth to be located in front of the upper front teeth and jaw.

If you have a normal bite, your front teeth will overlap your lower teeth (the top front teeth will slightly overlap the bottom teeth), while in an underbite, your upper and lower teeth do not align when you are biting.

Dental underbite causes the lower teeth to protrude past the upper teeth, resulting in a misaligned jaw. Underbites are class III orthodontic malocclusions (prognathism) and may affect only about 5% to 10% of people. Overbites, crossbites, gap teeth, crooked teeth, teeth crowding and overlapping teeth are considered other types of malocclusions.

An underbite can cause both cosmetic issues for the person and pain and discomfort. If the person suffers from severe underbite, they may feel self-conscious and have low self-esteem.

Underbites range from mild cases to severe cases:

Mild underbite cases: are hardly noticeable, and the person can easily live with the condition. Besides, no jaw surgery is needed to fix a mild underbite. Sometimes an X-Ray is needed to notice mild cases of underbites.

Severe underbite cases: are when the lower teeth extend too forward, and the lower jaw extends beyond the upper jaw. In addition to pain and discomfort, severe cases of underbites may cause serious oral health problems for the person, including chewing difficulties, speaking problems, excessive tooth wear, an increased risk of chipping or breakage of the front teeth. (wear and tear on your front teeth)

  • Malocclusion refers to teeth misalignment.
  • An underbite can be caused by genetics or environmental factors.
  • Either jaw malformation or teeth misalignment may cause an underbite or even both.
Class III malocclusion

What causes underbites?

The following could be among the main causes of underbites:


Whether you like what you are reading, you can inherit your tooth shape and size from your parents! Genetic factors play an essential role in the shape and size of a person’s jaw and teeth. So, you may have inherited underbites from your parents! Prevention?! No chance!

Childhood habits

Unfortunately, some cute innocent childhood habits can interfere with the proper shape of your teeth and jaw and lead to orthodontic issues as the person grows older. If you have an underbite, it may be due to some of these bad habits you used to do when you were a child.

Injury to the jaw

Facial and jaw injuries have the potential of causing permanent damage to the jawbones. While surgery can correct your jawbone, the upper and lower jaws may not fit together properly even after the surgery, and this can cause misaligned teeth and lead to developing underbites.


A misaligned jaw or a protruding jaw may be due to a jawbone tumour or even a tumour in your mouth, which can result in underbites.

Common underbite Symptoms and Complications

Can a dental underbite cause oral health problems, or are they just a cosmetic issue?

Aside from causing self-esteem issues for the person, an underbite can lead to several dental problems and pain and discomfort and needs to be addressed. Here are some of the most common complications that arise from an untreated underbite:

  • Chronic mouth breathing
  • Bad breath
  • sleep apnea
  • Heavy snoring
  • Teeth-grinding at night
  • Worn-away enamel
  • Temporomandibular joint disorders (TMD)
  • Chronic jaw pain
  • Mouth and face pain because of a misaligned jaw
  • Difficulty chewing food
  • An increased risk of tooth decay and gum disease
  • An increased risk of jaw surgery
  • Altered face shape
  • Low self-confidence
Class III malocclusion

Underbite correction treatments

Underbite correction methods and treatments

Despite popular belief, most people are not born with perfectly aligned teeth. Having a set of aligned and healthy teeth requires you to practise good oral hygiene, but sometimes you need to seek help from dental treatments like orthodontic treatment to achieve that goal.

Underbites cannot be left untreated and require professional treatment to be fixed. Your age and the severity of your misalignment will usually determine the best treatment plan.

It’s best to correct an underbite and seek orthodontic treatment at an early age to lower the risk of the need for jaw surgery. It’s easier to correct underbite in childhood because the jawbone malleability is at its peak and can be guided into the correct position easier.

If your child’s underbite is mild and hardly noticeable, you can put off the treatment until they turn seven years old because, at this age, their permanent teeth begin to erupt.

Children will start to lose their baby teeth between ages six to seven and grow permanent teeth.

Common treatment options for a dental underbite may include:

Orthodontic treatment or surgical treatment

An upper jaw expander

If you have a small upper jaw, your orthodontist may suggest using an upper jaw expander to align the upper and lower jaws and correct an underbite. The orthodontist will place this wire-frame device in your upper jaw across your palate, so the jaw can gradually widen nightly. As a result of using an upper jaw expander, your lower teeth will match with the upper teeth-the lower and upper teeth will move into their proper position over time. The treatment process with an upper jaw expander will typically take about a year. An upper jaw expander can be used for kids and pre-teenagers, and it may be removable or fixed.

Reverse-pull face mask

Reverse pull face masks are one of the treatment options to correct an underbite for younger children by pulling the upper jaw forward. They look like brace headgears, wrap around your child’s head, and pull their upper jaw forward into the desired position using metal bands fixed to the back upper teeth.

A chin cap

A chin cap is an oral appliance that prevents the growth of the lower jaw in children.

The elastic bands of a chin cap will fit over the crown of your child’s head and prevent the lower jaw from growing by applying moderate force.

Invisalign (Clear Aligners)

Clear aligners are used as underbite correction methods if the patient does not have a severe underbite. These removable clear aligners will move the teeth into their proper position and be used for both children and adults. For more severe cases of underbite, clear aligners should be used with jaw surgery.

Traditional braces

Orthodontists will typically recommend using traditional dental braces as effective underbite correction treatments. Dental braces are fixed orthodontic appliances and cannot be removed during treatment.

Your child needs to see their orthodontist every four to eight weeks so the orthodontist can ensure everything is going according to their treatment plan. A complete treatment of underbites with dental braces may take eighteen months to three years.

Your child may need to wear retainers after correcting their underbites with braces.

Tooth extraction

Removing some teeth can sometimes correct some mild to moderate cases of underbite. Tooth extraction can decrease overcrowding and relax the jaw a little. The orthodontist may decide to remove some teeth before treating underbites with dental braces to create more space for braces.

Orthognathic jaw surgery

For severe cases of underbites, the only feasible treatment option may be jaw surgery. An orthognathic surgery cost may be high, probably up to $40,000. Jaw surgery involves the administration of general anesthesia and then repositioning the jaw by the oral surgeon. The oral surgeon will reposition the jawbone during jaw surgery by pulling the upper jaw forward or pushing the lower jaw back to correct an underbite. Jaw surgery will usually be performed for adults. After having jaw surgery, the complete healing process may be within one to three weeks, though it is different from person to person.

Do you need more information? Please do not hesitate to contact our experienced Brisbane kids dentists at Pure Dentistry in Brisbane on 07 3343 4869.