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
4-13. MAXILLARY FIRST BICUSPID
The maxillary first bicuspid (figure 4-23) has the largest crown of the four
maxillary bicuspid teeth. It is formed from four developmental lobes--three lobes form
the facial cusp and one lobe forms the lingual cusp.
a. Facial Surface. The facial surface resembles the facial surface of the
maxillary cuspid but is not as long or as broad.
b. Lingual Surface. The lingual surface is oval in shape and convex in all
directions. It is shorter and narrower than the facial surface.
Figure 4-23. Maxillary right first bicuspid.