Types of crossbite
Posterior crossbite
The upper molars and premolars close inside the lower teeth. This is mostly linked to a narrow upper jaw. When it occurs on one side, the lower jaw may shift to one side when closing; during growth, this shift can contribute to facial asymmetry.
Anterior crossbite
One or more upper front teeth close behind the lower front teeth. This can result from a single tooth erupting in the wrong direction, or it can be a sign of a skeletal problem such as an underbite or an underdeveloped upper jaw.
Causes
- A narrow upper jaw and palate
- Mouth breathing, prolonged thumb sucking or dummy use
- A permanent tooth erupting in a different direction because a baby tooth was lost late
- Skeletal mismatch between the lower and upper jaws
- Hereditary factors
Why should it be detected early?
In children, a crossbite – especially one that makes the lower jaw shift to one side when closing – is one of the problems that are recommended to be corrected during growth. At this age, the upper jaw is easier to widen, and removing the shift can support symmetrical jaw development. In an anterior crossbite there is a risk of wear and gum recession on the lower front teeth. That is why the first orthodontic check-up is recommended at around age 7.
Treatment options
Palatal expansion
For a posterior crossbite caused by a narrow upper jaw, rapid palatal expanders are often used during growth. For details, see the palatal expansion page.
Clear aligners
For crossbites caused by the teeth, and in suitable cases, correction can be achieved with clear aligners by widening the dental arch or moving individual teeth. In children, Invisalign First can be used for this purpose.
Brackets and elastics
For single teeth in crossbite or cases needing comprehensive treatment, brackets and cross elastics may be used.
Skeletal crossbite in adults
In adults who have finished growing, the midpalatal suture has fused, so skeletal expansion is limited. In marked cases, mini-screw-assisted or surgically assisted expansion may be considered.