Facial: It is the most prominent tooth in the mouth. It has a nearly straight incisal edge and a gracefully curved cervical line. The mesial presents a straight outline; the distal aspect is more rounded. Mamelons are present on freshly erupted, unworn central incisors.
Lingual: The lingual aspect presents a distinctive lingual fossa that is bordered by mesial and distal marginal ridges, the incisal edge, and the prominent cingulum at the gingival.
Proximal: Mesial and distal aspects present a distinctive triangular outline. This is true for all of the incisors. The incisal ridge of the crown is aligned on the long axis of the tooth along with the apex of the tooth.
Incisal: The crown is roughly triangular in outline; the incisal edge is nearly a straight line, though slightly crescent shaped.
Contact Points: The mesial contact point is just about at the incisal, owing to the very sharp mesial incisal angle. The distal contact point is located at the junction of the incisal third and the middle third.
Right and Left: Viewed from the labial, the distal incisal angle is more rounded that the mesial. In many specimens, a cross-section mid-root reveals a right triangle outline. The hypotenuse is toward the mesial.
Variation: The maxillary central incisor usually develops normally. Variations include a short crown or, on occasion, an unusually long crown. This tooth is rarely absent. The Hutchinson incisor is a malformation due to congenital syphilis in utero.
An important non-metric variation of the upper incisors is the shovel shaped incisor trait. It presents with large, robust marginal ridges and a deep lingual fossa. This feature is significant in Chinese, Eskimo-Aleuts, and North American Indians. It is an important clue to population movements, especially those peoples who moved into the Americas from Siberia since the end of the Ice Age.