This refers to where the lower front teeth are biting in front of the upper teeth.
While it may be due to upper front teeth leaning inwards, it may also be a combination of a smaller upper jaw size and/or larger lower jaw size.
Why does an Underbite need to be corrected?
One of the more common causes of an underbite is a smaller upper jaw size. There is a window of time where the upper jaw bones and their connections have not hardened and an underbite can be treated predictably by moving the upper jaw forwards. This age limit is approximately 10 years in “bone age”, though with newer technologies, this upper age limit can be a bit older. The more severe the underbite, the better it is to be seen and treated earlier.
After this window of time has passed, it is not as effective in moving the upper jaw forwards.
Treatment is then aimed at addressing any narrow upper jaw that may be present.
In late teens and adults, jaw guidance plates do not work well to correct jaw problems and braces treatment is sometimes delayed at this age, till the jaws have fully grown.
Mild and moderate underbites can still be treated with braces alone. With severe underbites, improvements in one’s smiles and facial appearance are often achieved with a combination of braces or Invisalign and jaw surgery.
What are the treatment options?
In a child, treatment is usually a fixed upper custom expander worn full time, and a removable facemask that is worn at nights and sleep time wear.
Narrow upper jaws are corrected with a fixed upper expander.
In late teens and adults, mild or moderate underbites are generally treated with upper & lower braces or Invisalign.