Crossbite Explained: Types and Causes

A crossbite can be serious depending on its extent and position. Posterior crossbites create uneven bite forces that may increase wear on individual teeth, strain the jaw joints, and cause asymmetric jaw growth in children. Anterior crossbites — where upper front teeth bite behind the lower — can damage enamel and gum tissue over time. Not all crossbites are equally significant, but a clinical assessment is advisable to understand the implications for your specific bite pattern.

Clear aligners can treat some crossbites, particularly where the cause is tooth position rather than jaw size. Posterior crossbites involving one or two teeth that need tipping or rotation are often manageable with aligner treatment. Skeletal crossbites — where the underlying jaw width is the cause — often require fixed appliances, expanders, or in adults potentially surgical correction. A specialist orthodontist can advise which approach is appropriate after a clinical examination.

Crossbites can worsen gradually if untreated. The bite forces from an uncorrected crossbite may cause ongoing tooth wear, jaw asymmetry, and discomfort over years. In children, jaw development can be affected by the abnormal bite loading. In adults, while the jaw is no longer growing, teeth continue to drift and bite forces continue to load asymmetrically. Early correction is generally easier and more stable than treating a crossbite that has been present for many years.

Treatment time for a crossbite depends on the type, the number of teeth involved, and whether the bite also needs correcting across both arches. A simple single-tooth anterior crossbite may resolve in 3–6 months with braces or simple appliances. Posterior crossbites needing palatal expansion typically involve 3–6 months of active expansion followed by alignment, with complete treatment in a teenager including alignment taking around 12–18 months in total. Complex skeletal cases, particularly in adults, can take longer and may involve surgical planning.

Crossbites most commonly result from a mismatch between upper and lower jaw width, or individual teeth sitting inside the opposing arch. In growing children, habits such as thumb sucking or mouth breathing can contribute. In adults, crossbite is often a structural issue that has been present since the permanent teeth emerged.

Some crossbites cause uneven loading of the jaw joints and muscles, which can contribute to jaw discomfort or asymmetric jaw movement over time. Not all crossbites cause symptoms, but those that do may be helped by orthodontic correction. A clinician can assess whether your bite pattern is contributing to jaw symptoms during a full examination.