b. Lingual Surface. The lingual surface is about half the size of the facial cusp.
This is because the lingual cusp is very short and because the mesial and distal
surfaces have a marked lingual convergence.
c. Mesial Surface. The mesial surface is convex in all directions. In outline, it
resembles the mesial surface of a lower cuspid with an enlarged cingulum. The contact
area is located at the junction of the middle and occlusal thirds.
d. Distal Surface. The distal surface is more convex faciolingually
than is the mesial surface. The contact area is located at the junction of the middle and
occlusal thirds near the center of the surface.
e. Occlusal Surface. The occlusal surface is round to oval in outline. A well-
developed transverse ridge runs from the tip of the facial cusp to the lingual cusp. The
facial cusp occupies about four-fifths of the occlusal surface.
f. Roots. The single root tapers gradually toward the apex. Near the crown,
the root is narrower lingually than it is facially.
4-22. MANDIBULAR SECOND BICUSPID
The mandibular second bicuspid (figure 4-32) is slightly larger, stockier, and less
rounded than the mandibular first bicuspid. It is, however, more rounded or ovoid (egg-
shaped) than the maxillary bicuspids and may have two or three cusps. The three-cusp
form has two lingual cusps and one facial cusp.
a. Facial Surface. The facial surface resembles the facial surface of the first
b. Lingual Surface. The lingual surface is similar in outline to the facial surface.
The lingual surface varies somewhat with the number and arrangement of lingual
cusps. It is markedly larger than the lingual surface of the mandibular first bicuspid.
The cusp (or cusps) is also much larger. Where two lingual cusps are present, they are
divided by a lingual groove passing from the occlusal onto the lingual surface.
c. Mesial Surface. The mesial surface has the form of a lingually inclined
parallelogram. The surface is convex with a shallow concavity sometimes present in
the cervical area. The contact area is located at the junction of the middle and occlusal
thirds and lingual to the midline of the tooth.
d. Distal Surface. The distal surface resembles the mesial surface, but is
slightly more convex.