b. Lingual Surface. The lingual surface is scoop-like or shovel-like in
appearance and is bounded by prominent mesial and distal marginal ridges. It is
narrower than the facial surface because both proximal surfaces converge toward the
lingual. The cingulum is located in the cervical third and is slightly distal to the midline
of the crown. The incisal two-thirds is concave and the cervical one-third is convex in
c. Mesial Surface. The mesial surface is somewhat triangular in shape with the
apex of the triangle toward the incisal edge. It has a slight faciolingual convexity. The
contact area is located in the incisal third.
d. Distal Surface. The distal surface is smaller in area but similar in outline to
the mesial surface. Its contours are more convex than those of the mesial surface. The
contact is located near the junction of the middle and incisal thirds.
e. Incisal Edge. The incisal edge is fairly straight and ends in curved
mesioincisal and distoincisal angles. The distoincisal curvature is more pronounced
than is the mesioincisal curvature. The incisal edge is usually worn so that it presents a
distinct, narrow surface which usually slopes toward the lingual surface.
f. Root. The single root averages about 1 1/4 times the length of the crown.
This single root tapers gradually from about its midsection to end in a rounded apex. In
cross section, the root is egg-shaped with the narrow curvature toward the lingual
4-11. MAXILLARY LATERAL INCISOR
The maxillary lateral incisor (figure 4-21) is smaller in size than the central incisor
but has the same general appearance. It presents a generally greater convexity in its
crown portion than does the central incisor. The maxillary lateral incisor can be
compared with the central incisor in many ways.
a. Facial Surface. The facial surface is similar in appearance to the central
incisor but more convex (rounded) in form. Developmental grooves are not as
pronounced as in the central incisor.
b. Lingual Surface. The lingual surface is similar in appearance to the central
incisor. The marginal ridges are relatively broader. The lingual pit is often small, deep,
and irregular in shape.
c. Mesial Surface. The mesial surface is similar to the mesial surface of the