d. Distal Surface. The distal surface resembles the mesial but it is more
convex. It is shorter occlusocervically.
e. Occlusal Surface. The occlusal surface has four cusps. Each cusp is
named according to its position on the tooth (for example, mesiofacial, mesiolingual,
and mesioocclusal). Each cusp is developed from a single developmental lobe. An
oblique ridge is formed by a continuation of enamel ridges from the mesiolingual and
the distofacial cusps. Three pits are formed on this surface--the mesial, the central, and
the distal pits. These pits are found in corresponding fossae. A distolingual groove
runs from the distal pit onto the lingual surface. A facial groove runs from the central pit,
between the two facial cusps, to the facial surface.
f. Roots. The roots divide into three separate roots in its cervical (gingival)
third. Each root is named according to its position on the tooth--mesiofacial, distofacial,
and lingual. The lingual root is larger and longer than the facial roots. The mesiofacial
root is larger than the distofacial root.
4-16. MAXILLARY SECOND MOLAR
The maxillary second molar (figure 4-26) is very similar to the maxillary first
molar. There are some differences. It is smaller in all dimensions than the first molar.
The fifth cusp is seldom present. The distolingual cusp is proportionally smaller. The
mesiofacial and distofacial roots are occasionally fused.
Figure 4-26. Maxillary right second molar.