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An underbite, a type of teeth misalignment, occurs when the lower teeth protrude beyond the upper front teeth. It ranges from mild, affecting only teeth, to severe, involving the jaw. Causes include genetics, developmental issues, or habits like thumb-sucking or prolonged pacifier use. Underbites can cause chewing and speaking difficulties, increased tooth wear, and sometimes jaw pain and headaches. Treatment typically involves orthodontics and, in severe cases, surgery to realign the jaw.

What is an underbite?

In an underbite, the lower teeth protrude further forward than the upper teeth, causing the lower jaw and bottom teeth to appear more prominent. This condition is relatively common, affecting approximately 5% to 10% of the population. A large proportion of underbites are due to a growth disharmony between the upper jaw (maxilla) and lower jaw (mandible).While many individuals with a mild underbite may not even be aware of it, in severe cases, the gap between the lower and upper teeth is pronounced and noticeable.

What causes an underbite?

There are a few reasons why you may have an underbite.

Genetics. The shape and position of your teeth and jaw and the way they grow are largely inherited from your parents and family.

Habits in childhood. habits such as digit sucking or use of a dummy for an extended time can alter jaw growth and development.

Crowding. Crowded front teeth can move into an underbite position within the jaw.

Cleft lip and palate. An underbite is also common in children and adults with cleft lip and palate.

Injury. Facial trauma or injury can cause your facial bones or jaw to break. In some cases this can disrupt the position of the jaw and cause an underbite.

Do I need to correct an underbite?

Not all underbites are equally severe. In very mild cases, the underbite may not be visibly detectable from the outside. However, in severe cases, the lower jaw protrudes so far forward that it becomes noticeable to others.

Underbites can have more than just cosmetic implications. Even mild cases can lead to wear and tear on the front teeth that meet in an incorrect position, making them more susceptible to chipping or breakage.

In severe cases, underbites can cause significant issues with both your teeth and jaw. These problems might include difficulty in speaking properly and challenges with chewing food when the jaw isn't aligned correctly.

Untreated underbites may cause:

  • Lack of self esteem and self confidence
  • Facial pain from strain on the jaw joints
  • Sleep apnoea
  • Speech difficulties, like lisping
  • Problems with chewing and biting food
  • Cracking and wearing down of the teeth

How to correct an underbite

Several options are available to correct an underbite and often, orthodontists may combine two or three of these treatment approaches to achieve the best results. After examining your jaw and teeth, your orthodontist will explain the treatment options and recommend the most suitable one for your specific situation.

Treatment options for underbite correction:

Tooth extraction

In some cases, having crowded teeth may result in an underbite. The orthodontist may recommend extracting one or more teeth before fitting braces to create more space for the braces to work effectively.

Extractions will be carried out by your dentist or an oral surgeon under local anaesthetic, but occasionally a general anaesthetic may be required, especially when this involves multiple teeth extractions including wisdom teeth.

Underbite jaw surgery

For severe underbite cases, jaw surgery may be necessary. Management of surgical cases requires a high level of training and expertise, you can rest assured that you will be in very capable hands at Kingston Orthodontics. You will be seen and treated by a Consultant Specialist Orthodontist and Consultant Oral and Maxillofacial Surgeon.

Underbite surgery is a common underbite treatment. If you are concerned about the result of your procedure, ask your orthodontist and surgeon  to show you before and after photos of  patients who have undergone underbite surgery.

Your orthodontist will fully assess your face and bite and if suitable, will arrange to see you jointly with an oral and maxillofacial surgeon to fully plan your treatment. Underbite surgery requires various stages of combined orthodontics and jaw surgery.

Your orthodontist will provide you with braces which will be in place before, during and after your jaw surgery. Before surgery your braces aim to realign your teeth, this will worsen your bite temporarily with the aim of full bite correction being achieved after jaw surgery.

Your oral and maxillofacial surgeon will fully plan and discuss your jaw surgery with you. This will be carried out under general anesthesia. The surgery may involve repositioning both the upper and lower jaws or may be a single jaw operation only.  Carefully planned surgical cuts are made to allow movement of the jaws in the planned direction. Small titanium plates and screws will be placed to hold the bone in position until it fully heals.

Your orthodontist and maxillofacial surgeon will fully explain the changes that you can expect. These changes will include:

There are no visible scars after underbite surgery because all incisions will be inside the mouth. Your fixed braces remain in place before, during and after your jaw surgery. After the procedure, your orthodontist will place elastics between your upper and lower braces to hold your bite in place whilst the bones heal in the right position.

After underbite surgery you will need to take four weeks off work and other activities to allow yourself time to recover.

Underbite treatment summary

Treatment option Permanent, long term or removable Duration of treatment Ideal treatment age
Upper jaw expander Removable and fixed appliances 6-12 months   Before age 13
Reverse pull face headgear Removable 6 months Before age ten
Chin cap Removable 6 months Before age ten
Underbite braces, including Invisalign Traditional braces are fixed, while others, like Invisalign, are removable 1 – 3 years When the majority of adult teeth erupt
Tooth extraction Permanent One dental visit When all adult teeth come through
Underbite surgery Permanent 1-3 years Over the age of 18

The link between underbite, cleft lip and palate

The chances of a baby born with a cleft lip and cleft palate also developing an underbite are high. This is because their upper jaw bone and upper teeth haven’t developed properly.

Generally, people with a cleft lip and palate and underbite will require underbite surgery to correct these issues. The cleft team will correct these issues over time with braces and surgery as appropriate. Orthodontists specialising in the management of cleft lip and palate are involved in the multi disciplinary care of these children.

Underbite surgery within the National Health Service

Underbite surgery is available within the national health service for children under the age of 18 diagnosed with a jaw size discrepancy. If eligible for the treatment, the NHS will provide you with the surgery and braces before and after your surgery. Unfortunately this treatment is not available within the NHS for adults.

If you need an underbite treatment, contact Kingston Orthodontics at [email protected] or 0203 002 2501 to book an appointment with our orthodontist.


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