If your normal biting relationship is reversed, then you have a crossbite. This occurs when the lower teeth overlap the upper teeth and is usually caused by crowding, ectopic tooth eruption, or abnormal skeletal development. A crossbite may "lock" your lower jaw in place possibly resulting in problems such as pain, popping or clicking of your jaw joints, thin or receding gums, or abnormal wear of your teeth.

You have an anterior crossbite if your smile is similar to the one on the left. You have a posterior crossbite if your smile is similar to the one on the right.