incisor /insī″zər/ , one of the four anterior teeth in each dental arch. Primary incisors appear during infancy and are replaced during childhood by secondary incisors. The crown of each incisor is chisel shaped and has a sharp cutting edge. Its labial surface is convex, smooth, and highly polished; its lingual surface is concave and, in many individuals, is marked by an inverted V-shaped basal ridge near the gingiva of the maxillary arch. The neck of an incisor is constricted, and the root is single, long, and conic. The upper incisors are larger and stronger than the lower and are directed downward and forward. Compare canine tooth, molar, premolar.
