Teeth may be poorly aligned because the dental arch is too small and/or the teeth are too large. The bone and gums over the roots of extremely crowded teeth may become thin and recede as a result of severe crowding. Impacted teeth (teeth that should have come in, but have not), poor biting relationships, and undesirable appearance may all result from crowding.
Crowded teeth are very difficult to clean, brush and floss, thus causing a dull, discoloured appearance.
Upper front teeth that protrude horizontally beyond the normal contact with the lower front teeth are prone to injury, often indicate a poor bite of the back teeth (molars), and may indicate an unevenness, or lack of harmony, in jaw growth. Usually, protruded upper teeth are often associated with a lower jaw that is too short in proportion to the upper jaw. Thumb and finger sucking habits can also cause protrusion of the upper incisor teeth and/or retrusion (tipping backwards) of the lower front teeth.