Who of us doesn’t like a wide full smile? Many people seek orthodontic treatment because they have “narrow smiles” and because they show too much “dark corridors” between their cheeks and teeth when they smile. This is actually caused by narrow jaws and may or may not cause problems other than the undesirable appearance. If the bite is acceptable then narrow arches are mostly a cosmetic problem that can be managed if the individuals elects to.

On the other hand, narrow arches may result in what is so called “posterior crossbites”, in which one or more of the upper posterior (back) teeth bite “inwards” relative to the bottom teeth. Posterior crossbites at an early age may result in functional jaw shifts resulting in a deviation in jaw growth and possible jaw asymmetry. Narrow arches and crossbites can be corrected with braces with or without palatal expanders than make the jaw arches wider. Expansion is easier in children and young adolescents since the bone is still flexible and easier to expand.