Orthodontics: Single tooth crossbites

When there is a crossbite of a single tooth or in some cases a couple of teeth, this is called a dental crossbite as opposed to a skeletal crossbite. Skeletal crossbites usually involve the palate bone and are discussed elsewhere on this Web site.

Here are a series of photos to illustrate how we correct single tooth crossbites which can and usually do cause severe tissue problems as well as abnormal wear of the tooth structure. We want to discuss the use of a clear lower "bite plate" retainer to keep the teeth apart during correction of the crossbite.

First let's talk about what is a single tooth crossbite of a front tooth. Note the upper tooth is crossed over behind the lower tooth and is 'locked' behind the lower teeth.
To keep the front teeth apart while we move the upper teeth back across the lower teeth, the child wears a thicker than normal lower retainer which is built-up in the back to keep the front teeth apart while the back teeth touch. This photo shows the retainer before it is seated all the way down on the teeth.
Here, we can see the lower retainer in all the way down in place on the bottom teeth. Now you can see how the retainer keeps the front teeth apart so the upper central can move forward with the help of the braces once they are placed. Placing braces is essential to accomplishing the movement of the teeth.
The single tooth being moved forward with braces to eliminate the crossbite.
Correction of the crossbite after only two weeks! Once the upper central travels across the lower teeth, the natural overlap of the teeth will hold the position. The next step is to place a removable retainer in the upper and then deal with the crowding of the lower teeth.
On another patient, both upper cuspids (the teeth on the sides) are in crossbite and we can see the lower retainer is in place and the braces have just been placed. Note the wires are weaving through the brackets and there is elastic material called power-chain attached from the 'nickel titanium thermal' wire to the teeth on both sides. The wire and power-chain gradually pull the teeth over from the improper position.
A closer look at the tooth in crossbite "without" the lower retainer so you can see how the teeth would be 'locked' behind the lower teeth if the retainer was not in place during this phase of treatment. Usually this correction occurs quickly and takes from 2 to 8 weeks.
With the clear lower retainer in place the upper teeth are free to move across because the lower retainer keeps the teeth apart.

Single Tooth Cross-bites and orthodontics