What is an Underbite & How is it Fixed?

The jaws in human are divided into two parts. They are called lower jaw or mandible, and upper jaw or maxilla. Normally, these two parts are placed in such a way that the chin gets a good shape. The positions of the two jaws also help to bite the foods properly. An underbite is a condition, when a person’s lower jaw or mandible extends forward or protrude out to some extent. Let us know the causes, problems and treatments to fix it.

What is an Underbite

What is an Underbite?

Underbite is a condition wherein the lower jaw of a person protrudes forward from the upper jaw. It makes the chin and lower teeth more prominent, which is not found normally. This condition is also known as mandibular prognathism. In some severe forms of underbite, the affected person’s speech can also be distorted, and shape of the face may look quite unusual. These types of cases are called skeletal malocclusions. An underbite or mandibular prognathism is abbreviated as Class III malocclusion or “bad bite.”

What are the Causes of an Underbite?

There are different reasons behind underbite. Some of the most obvious reasons are as follows:

  • Hereditary problems like Crouzon syndrome, or Basal Cell Nevus syndrome.
  • Thumb-sucking regularly and constantly.
  • Poor chewing habit that is disorderly and too fast.
  • Inborn misalignment of lower jaw.

What are the Problems Related to Underbite?

An underbite leads to multiple problems, even some lifestyle issues. There always remains a risk of developing serious jaw problems. Some common problems related to underbite include the following ones:

  • Misalignment of the lower jaw may lead to jaw pain (TMJ), headache and earache.
  • As bites fall irregularly in underbite, there remains a chance of wear and tear on enamel and high risk of tooth decay.
  • Chances of periodontal disease (gum disease) increase by manifold.
  • Chances of mouth breathing, halitosis, and bacterial infection also increase by manifold due to underbite.
  • An affected person may have problems in speaking due to underbite. Sometimes, the problem could exist for a longer time.
  • Underbite may lead to sleep apnea, and snoring.
  • Underbite can change the structure of the face and mouth.

What are the Treatments to Fix Underbite?

Numerous procedures exist for adjusting an underbite. Such treatment procedures range from jaw surgery to the uses of numerous types of orthodontic appliances. In critical condition, surgery remains the only option. If detection of the problems and proper steps are taken at a young age, the problem could be solved with the help of the right appliances. As per the experts, orthodontic screening is important at an early age of 5 to 7 years.

The two common treatment procedures of underbite that are normally followed for rectifying the defect in the children and teenagers are as follows:

  • Wired-frame Braces for Underbite: A device made of wire-frame is fixed across the patient’s palate. An orthodontist does the treatment and imparts relevant advice to the patient. Every day at night, a special key linked to the wire-frame is used to expand it in small quantities. The procedure slowly causes the upper jaw to expand until the lower jaw no more closes outside of the upper jaw. A patient needs to stay in touch with the orthodontist, who takes all responsibilities to adjust the wire-frame and provide medical support to the patient whenever required. This device is to be used for a year, and then it is to be replaced with a retainer.
  • Reverse-pull Face Mask for Underbite Treatment: Another process of correcting an underbite in a child is to apply a “reverse-pull” face mask. It looks like a catcher’s mask from outside. It requires to be worn for a few hours each day. This is generally used when the wire-frame expander treatment procedure doesn’t work effectively. In some cases, an orthodontist may advise to use the mask in combination with the chin cap. Orthodontic braces sometimes work quite effectively.

In case of adults, surgery is the only option to correct an underbite. The following steps are followed when the orthodontic decides to undertake a surgery:

  • Step 1: An X-ray reveals the actual position of the two jaws, and how much adjustment is required.
  • Step 2: The process of neuromuscular dentistry may be used to reduce temporomandibular joint pain. It also helps to improve jaw functions to some extent.
  • Step 3: Minimum 2 years before the surgery, the patient is asked to use a brace throughout this period.
  • Step 4: During the surgery, the lower jaw is pushed back and the upper jaw is pulled forward to adjust them with each other.

Cosmetic Treatment for Underbite

It is comparatively a new method of rectifying an underbite. Cosmetic dentistry is a perfect remedy for the mild cases of underbites, and the patients can avoid complicated surgery in this way. This procedure helps to reshape the lower teeth to adjust with the upper teeth, and then veneers are fitted to the upper teeth. This procedure makes it possible to adjust the teeth accordingly, so that the disadvantages of an underbite are avoided altogether. This doesn’t fix the problem physically, but only increases jaw functionality that gives the jaws and chin the right shape, and also helps to improve the functionality of the jaws.


Underbite is to be corrected as early as possible. The problem in the children can be solved with 100% accuracy, but in case of adults, complete adjustment is not possible. One needs to undergo a long-term treatment procedure, and in most of the cases, certain lifestyle changes may be required to adjust with the treatment procedures. Experts ask the parents to take their children to the orthodontics at least once, so that any problem of underbites, if existing may be detected at the earliest. Timely treatment will improve all visible problems slowly, and it will also be cost effective.

Pramod Kerkar, M.D., FFARCSI, DA
Pramod Kerkar, M.D., FFARCSI, DA
Written, Edited or Reviewed By: Pramod Kerkar, M.D., FFARCSI, DA Pain Assist Inc. This article does not provide medical advice. See disclaimer
Last Modified On:May 13, 2022

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