The American Association of Orthodontists recommends screening children at age 7 to check for bite problems that are best treated early. Among these problems include having a “crossbite” of the permanent molars.
What is a crossbite?
This bite problem exists when an upper tooth/teeth fits on the inside of the lower teeth when biting down. (The upper teeth should be on the outside of the lower teeth.) A crossbite can exist involving the front or back teeth. Front teeth (anterior) crossbites can be corrected through braces, headgear, or other appliances, depending on what your orthodontist determines to be the cause of the crossbite. Back teeth (posterior) crossbites may be corrected with braces, but if the cause of the problem is diagnosed to be skeletal in origin, a palatal expander is the best treatment.
An expander is an appliance made by a dental lab with a screw that goes across the palate. The appliance works by using a key to turn a screw inside the middle of the expander. This turning is prescribed by your orthodontist and is usually done by a parent. Opening the expander with the key will push the arms of the appliance and widen the bones of the palate when done in patients whose upper jaws are still growing (approximately ages 7-13). The expander has to be left in for 3-6 months after expansion is complete to allow bone to fill in the gap created between the upper jaw bones, making the treatment a permanent and stable correction.
What kinds of problems does treating a posterior crossbite prevent?
People with crossbites often shift their lower jaw to one side in order to fully bite down. If this pattern of biting off to one side continues throughout childhood and early adolescence, this shift often becomes permanent. As we all know, children are very adaptable and resilient! The lower jaw can actually grow asymmetrically to accommodate for a crossbite. The earlier a shift or crossbite is detected, the more time your child’s body will have to grow properly and symmetrically.
Asymmetrical mandibular growth causes varying degrees of facial and chin asymmetry, which can be disfiguring. It can also put unequal stress on the temporomandibular joint (TMJ), contributing to joint clicking, popping, or pain, often when combined with clenching, grinding, and/or stress.