Contrary to what many believe, the term “overbite” does not refer to the upper front teeth sticking out too far, nor does it mean misalignment of the teeth. The term actually refers to the amount of vertical overlap between the upper and lower front teeth. Normal overbite is about 3mm. Overbite is often confused with overjet, which is the horizontal distance between the upper and lower front teeth.
Excess overbite is called “deep overbite” or “deep bite.” In this case there is too much vertical overlap between the upper and lower front teeth, and in severe cases the lower teeth may be completely hidden behind the upper front teeth. Deep overbite can cause excessive wear and is unhealthy for the bite. It can lead to TMJ (jaw joint) problems as well as gum irritation or recession behind the upper front teeth.
Correction of a deep overbite requires orthodontic treatment involving either braces or Invisalign. An orthodontist may also use a bite plate, which is a piece of acrylic that fits up into the roof of the mouth to protect the gums and open the bite. Alternatively, he/she may use bite turbos – little metal platforms glued to the tongue-side of the upper front teeth which stop the lower front teeth from biting down all the way.
Lack of overbite is referred to as “open bite.” In this case the front teeth do not overlap and all. People with an open bite are often embarrassed about their smile and have difficulty biting into sandwiches and pizza with their front teeth. Open bites may be caused by a number of different factors, including jaw position, thumb-sucking habits, and tongue-thrusting habits.
If the open bite is related to a thumb or tongue habit, cessation of the habit often leads to at least some natural correction of the open bite. Habit appliances, which are placed in the roof of the mouth, can help stop a difficult habit. Braces or Invisalign is usually needed to fully correct the open bite and align the front teeth. In the case of a severe jaw problem, jaw surgery may be required to correct the open bite.