How does cleft lip/palate affect the teeth?

How does cleft lip/palate affect the teeth?
A cleft of the lip, gum (alveolus), and/or palate in the front of the mouth can produce a variety of dental problems. These may involve the number, size, shape, and position of both the baby teeth and the permanent teeth. The teeth most commonly affected by the clefting process are those in the area of the cleft, primarily the lateral incisors. Clefts occur between the cuspid (eye tooth) and the lateral incisor. In some cases the lateral incisor may be entirely absent. In other cases there may be a “twinning” (twin = two) of the lateral incisor so that one is present on each side of the cleft. In still other cases the incisor, or other teeth, may be present but may be poorly formed with an abnormally shaped crown and/or root. Finally, the teeth in the area of the cleft may be displaced, resulting in their erupting into abnormal positions. Occasionally the central incisors on the cleft side may have some of the same problems as the lateral incisor.