Molars

1. Maxillary Second Molar
Calcification begins 3 years
Crown completed 7-8 years
Eruption 12 years
Root completed 14-16 years

2. Permanent Maxillary Second Molar - Occlusal
 Crown outline from this view will usually be that of a rhomboid. The
mesiolingual line angle and distofacial line angles are obtuse. The
distolingual line angle and mesiofacial line angles are acute. This
rhomboidal form presents four well developed functional cusps on its
occlusal surface.
 The central groove extends mesially from the central pit in the central fossa to
the mesial pit in the mesial triangular fossa.
 The distal oblique groove extends from the distal pit in the distal triangular fossa
in a lingual direction parallel to the oblique ridge. It continues onto the lingual
surface as the lingual groove.
 The mesial contact area is located facial to the faciolingual bisector. The distal
contact area is centered faciolingually.
The maxillary 2nd molar has similar occlusal anatomy to the maxillary 1st molar with the
following exceptions:
 Rarely has fifth or Carabelli’s Cusp.
 The distolingual cusp is smaller. In some specimens, it is quite small giving this
tooth a “heart shaped” appearance which is more characteristic of a third molar
crown. The primary cusp triangle characteristic of all maxillary molars is
identifiable since it does not include the distolingual cusp.
 This “heart” type is still considered to have four cusps although at least one
textbook considers this tooth to have only three functional cusps.
 When the distolingual cusp is small in size, the oblique ridge and the distal
marginal ridge often become difficult to distinguish as separate landmarks.
 In some specimens, the triangular ridge of the distofacial cusp and the distal
cuspal ridge of the mesiolingual cusp do not exactly meet and the transverse
groove of the oblique ridge is quite deep.
 When compared to the first molar, the maxillary second molar usually has more
secondary grooves.
M
D

3. Permanent Maxillary Second Molar - Occlusal
 Crown outline from this view will usually be that of a rhomboid. The
mesiolingual line angle and distofacial line angles are obtuse. The distolingual
line angle and mesiofacial line angle are acute. This rhomboidal form presents
four well developed functional cusps on its occlusal surface.
 The central groove extends mesially from the central pit in the central fossa
to the mesial pit in the mesial triangular fossa.
 The distal oblique groove extends from the distal pit in the distal triangular fossa
in a lingual direction parallel to the oblique ridge. It continues onto the lingual
surface as the lingual groove.
 The mesial contact area is located facial to the faciolingual bisector. The distal
contact area is centered faciolingually.
The maxillary 2nd molar has similar occlusal anatomy to the maxillary 1st molar with the
following exceptions:
 Rarely has fifth or Carabelli’s Cusp.
 The distolingual cusp is smaller. In some specimens, it is quite small giving this
tooth a “heart shaped” appearance which is more characteristic of a third molar
crown. The primary cusp triangle characteristic of all maxillary molars is
identifiable since it does not include the distolingual cusp.
 This “heart” type is still considered to have four cusps although at least one
textbook considers this tooth to have only three functional cusps.
 When the distolingual cusp is small in size, the oblique ridge and the distal
marginal ridge often become difficult to distinguish as separate landmarks.
 In some specimens, the triangular ridge of the distofacial cusp and the distal
cuspal ridge of the mesiolingual cusp do not exactly meet and the transverse
groove of the oblique ridge is quite deep.
 When compared to the first molar, the maxillary second molar usually has more
secondary grooves.
M
D

4. Permanent Maxillary Second Molar - Occlusal
 Crown outline from this view will usually be that of a rhomboid. The
mesiolingual line angle and distofacial line angles are obtuse. The distolingual
line angle and mesiofacial line angle are acute. This rhomboidal form presents
four well developed functional cusps on its occlusal surface.
 The central groove extends mesially from the central pit in the central fossa to
the mesial pit in the mesial triangular fossa.
 The distal oblique groove extends from the distal pit in the distal triangular
fossa in a lingual direction parallel to the oblique ridge. It continues onto
the lingual surface as the lingual groove.
 The mesial contact area is located facial to the faciolingual bisector. The distal
contact area is centered faciolingually.
The maxillary 2nd molar has similar occlusal anatomy to the maxillary 1st molar with the
following exceptions:
 Rarely has fifth or Carabelli’s Cusp.
 The distolingual cusp is smaller. In some specimens, it is quite small giving this
tooth a “heart shaped” appearance which is more characteristic of a third molar
crown. The primary cusp triangle characteristic of all maxillary molars is
identifiable since it does not include the distolingual cusp.
 This “heart” type is still considered to have four cusps although at least one
textbook considers this tooth to have only three functional cusps.
 When the distolingual cusp is small in size, the oblique ridge and the distal
marginal ridge often become difficult to distinguish as separate landmarks.
 In some specimens, the triangular ridge of the distofacial cusp and the distal
cuspal ridge of the mesiolingual cusp do not exactly meet and the transverse
groove of the oblique ridge is quite deep.
 When compared to the first molar, the maxillary second molar usually has more
secondary grooves.
M
D

5. Permanent Maxillary Second Molar - Occlusal
 Crown outline from this view will usually be that of a rhomboid. The
mesiolingual line angle and distofacial line angles are obtuse. The distolingual
line angle and mesiofacial line angle are acute. This rhomboidal form presents
four well developed functional cusps on its occlusal surface.
 The central groove extends mesially from the central pit in the central fossa to
the mesial pit in the mesial triangular fossa.
 The distal oblique groove extends from the distal pit in the distal triangular fossa
in a lingual direction parallel to the oblique ridge. It continues onto the lingual
surface as the lingual groove.
 The mesial contact area is located facial to the faciolingual bisector. The
distal contact area is centered faciolingually.
The maxillary 2nd molar has similar occlusal anatomy to the maxillary 1st molar with the
following exceptions:
 Rarely has fifth or Carabelli’s Cusp.
 The distolingual cusp is smaller. In some specimens, it is quite small giving this
tooth a “heart shaped” appearance which is more characteristic of a third molar
crown. The primary cusp triangle characteristic of all maxillary molars is
identifiable since it does not include the distolingual cusp.
 This “heart” type is still considered to have four cusps although at least one
textbook considers this tooth to have only three functional cusps.
 When the distolingual cusp is small in size, the oblique ridge and the distal
marginal ridge often become difficult to distinguish as separate landmarks.
 In some specimens, the triangular ridge of the distofacial cusp and the distal
cuspal ridge of the mesiolingual cusp do not exactly meet and the transverse
groove of the oblique ridge is quite deep.
 When compared to the first molar, the maxillary second molar usually has more
secondary grooves.
M
D

6. Permanent Maxillary Second Molar - Occlusal
 Crown outline from this view will usually be that of a rhomboid. The
mesiolingual line angle and distofacial line angles are obtuse. The distolingual
line angle and mesiofacial line angle are acute. This rhomboidal form presents
four well developed functional cusps on its occlusal surface.
 The central groove extends mesially from the central pit in the central fossa to
the mesial pit in the mesial triangular fossa.
 The distal oblique groove extends from the distal pit in the distal triangular fossa
in a lingual direction parallel to the oblique ridge. It continues onto the lingual
surface as the lingual groove.
 The mesial contact area is located facial to the faciolingual bisector. The distal
contact area is centered faciolingually.
The maxillary 2nd molar has similar occlusal anatomy to the maxillary 1st molar with the
following exceptions:
 Rarely has fifth or Carabelli’s Cusp.
 The distolingual cusp is smaller. In some specimens, it is quite small giving this
tooth a “heart shaped” appearance which is more characteristic of a third molar
crown. The primary cusp triangle characteristic of all maxillary molars is
identifiable since it does not include the distolingual cusp.
 This “heart” type is still considered to have four cusps although at least one
textbook considers this tooth to have only three functional cusps.
 When the distolingual cusp is small in size, the oblique ridge and the distal
marginal ridge often become difficult to distinguish as separate landmarks.
 In some specimens, the triangular ridge of the distofacial cusp and the distal
cuspal ridge of the mesiolingual cusp do not exactly meet and the transverse
groove of the oblique ridge is quite deep.
 When compared to the first molar, the maxillary second molar usually has more
secondary grooves.
M
D

7. Permanent Maxillary Second Molar - Occlusal
 Crown outline from this view will usually be that of a rhomboid. The
mesiolingual line angle and distofacial line angles are obtuse. The distolingual
line angle and mesiofacial line angle are acute. This rhomboidal form presents
four well developed functional cusps on its occlusal surface.
 The central groove extends mesially from the central pit in the central fossa to
the mesial pit in the mesial triangular fossa.
 The distal oblique groove extends from the distal pit in the distal triangular fossa
in a lingual direction parallel to the oblique ridge. It continues onto the lingual
surface as the lingual groove.
 The mesial contact area is located facial to the faciolingual bisector. The distal
contact area is centered faciolingually.
The maxillary 2nd molar has similar occlusal anatomy to the maxillary 1st molar with the
following exceptions:
 Rarely has fifth or Carabelli’s Cusp.
 The distolingual cusp is smaller. In some specimens, it is quite small giving
this tooth a “heart shaped” appearance which is more characteristic of a
third molar crown. The primary cusp triangle characteristic of all
maxillary molars is identifiable since it does not include the distolingual
cusp.
 This “heart” type is still considered to have four cusps although at least one
textbook considers this tooth to have only three functional cusps.
 When the distolingual cusp is small in size, the oblique ridge and the distal
marginal ridge often become difficult to distinguish as separate landmarks.
 In some specimens, the triangular ridge of the distofacial cusp and the distal
cuspal ridge of the mesiolingual cusp do not exactly meet and the transverse
groove of the oblique ridge is quite deep.
 When compared to the first molar, the maxillary second molar usually has more
secondary grooves.
M
D

8. Permanent Maxillary Second Molar - Occlusal
 Crown outline from this view will usually be that of a rhomboid. The
mesiolingual line angle and distofacial line angles are obtuse. The distolingual
line angle and mesiofacial line angle are acute. This rhomboidal form presents
four well developed functional cusps on its occlusal surface.
 The central groove extends mesially from the central pit in the central fossa to
the mesial pit in the mesial triangular fossa.
 The distal oblique groove extends from the distal pit in the distal triangular fossa
in a lingual direction parallel to the oblique ridge. It continues onto the lingual
surface as the lingual groove.
 The mesial contact area is located facial to the faciolingual bisector. The distal
contact area is centered faciolingually.
The maxillary 2nd molar has similar occlusal anatomy to the maxillary 1st molar with the
following exceptions:
 Rarely has fifth or Carabelli’s Cusp.
 The distolingual cusp is smaller. In some specimens, it is quite small giving this
tooth a “heart shaped” appearance which is more characteristic of a third molar
crown. The primary cusp triangle characteristic of all maxillary molars is
identifiable since it does not include the distolingual cusp.
 This “heart” type is still considered to have four cusps although at least one
textbook considers this tooth to have only three functional cusps.
 When the distolingual cusp is small in size, the oblique ridge and the distal
marginal ridge often become difficult to distinguish as separate landmarks.
 In some specimens, the triangular ridge of the distofacial cusp and the distal
cuspal ridge of the mesiolingual cusp do not exactly meet and the transverse
groove of the oblique ridge is quite deep.
 When compared to the first molar, the maxillary second molar usually has more
secondary grooves.
M
D

9. Permanent Maxillary Second Molar - Occlusal
 Crown outline from this view will usually be that of a rhomboid. The
mesiolingual line angle and distofacial line angles are obtuse. The distolingual
line angle and mesiofacial line angle are acute. This rhomboidal form presents
four well developed functional cusps on its occlusal surface.
 The central groove extends mesially from the central pit in the central fossa to
the mesial pit in the mesial triangular fossa.
 The distal oblique groove extends from the distal pit in the distal triangular fossa
in a lingual direction parallel to the oblique ridge. It continues onto the lingual
surface as the lingual groove.
 The mesial contact area is located facial to the faciolingual bisector. The distal
contact area is centered faciolingually.
The maxillary 2nd molar has similar occlusal anatomy to the maxillary 1st molar with the
following exceptions:
 Rarely has fifth or Carabelli’s Cusp.
 The distolingual cusp is smaller. In some specimens, it is quite small giving this
tooth a “heart shaped” appearance which is more characteristic of a third molar
crown. The primary cusp triangle characteristic of all maxillary molars is
identifiable since it does not include the distolingual cusp.
 This “heart” type is still considered to have four cusps although at least one
textbook considers this tooth to have only three functional cusps.
 When the distolingual cusp is small in size, the oblique ridge and the distal
marginal ridge often become difficult to distinguish as separate landmarks.
 In some specimens, the triangular ridge of the distofacial cusp and the distal
cuspal ridge of the mesiolingual cusp do not exactly meet and the transverse
groove of the oblique ridge is quite deep.
 When compared to the first molar, the maxillary second molar usually has more
secondary grooves.
M
D

10. Permanent Maxillary Second Molar - Occlusal
 Crown outline from this view will usually be that of a rhomboid. The
mesiolingual line angle and distofacial line angles are obtuse. The distolingual
line angle and mesiofacial line angle are acute. This rhomboidal form presents
four well developed functional cusps on its occlusal surface.
 The central groove extends mesially from the central pit in the central fossa to
the mesial pit in the mesial triangular fossa.
 The distal oblique groove extends from the distal pit in the distal triangular fossa
in a lingual direction parallel to the oblique ridge. It continues onto the lingual
surface as the lingual groove.
 The mesial contact area is located facial to the faciolingual bisector. The distal
contact area is centered faciolingually.
The maxillary 2nd molar has similar occlusal anatomy to the maxillary 1st molar with the
following exceptions:
 Rarely has fifth or Carabelli’s Cusp.
 The distolingual cusp is smaller. In some specimens, it is quite small giving this
tooth a “heart shaped” appearance which is more characteristic of a third molar
crown. The primary cusp triangle characteristic of all maxillary molars is
identifiable since it does not include the distolingual cusp.
 This “heart” type is still considered to have four cusps although at least one
textbook considers this tooth to have only three functional cusps.
 When the distolingual cusp is small in size, the oblique ridge and the distal
marginal ridge often become difficult to distinguish as separate landmarks.
 In some specimens, the triangular ridge of the distofacial cusp and the distal
cuspal ridge of the mesiolingual cusp do not exactly meet and the transverse
groove of the oblique ridge is quite deep.
 When compared to the first molar, the maxillary second molar usually has more
secondary grooves.
M
D

11. Permanent Maxillary Second Molar - Occlusal
 Crown outline from this view will usually be that of a rhomboid. The
mesiolingual line angle and distofacial line angles are obtuse. The distolingual
line angle and mesiofacial line angle are acute. This rhomboidal form presents
four well developed functional cusps on its occlusal surface.
 The central groove extends mesially from the central pit in the central fossa to
the mesial pit in the mesial triangular fossa.
 The distal oblique groove extends from the distal pit in the distal triangular fossa
in a lingual direction parallel to the oblique ridge. It continues onto the lingual
surface as the lingual groove.
 The mesial contact area is located facial to the faciolingual bisector. The distal
contact area is centered faciolingually.
The maxillary 2nd molar has similar occlusal anatomy to the maxillary 1st molar with the
following exceptions:
 Rarely has fifth or Carabelli’s Cusp.
 The distolingual cusp is smaller. In some specimens, it is quite small giving this
tooth a “heart shaped” appearance which is more characteristic of a third molar
crown. The primary cusp triangle characteristic of all maxillary molars is
identifiable since it does not include the distolingual cusp.
 This “heart” type is still considered to have four cusps although at least one
textbook considers this tooth to have only three functional cusps.
 When the distolingual cusp is small in size, the oblique ridge and the distal
marginal ridge often become difficult to distinguish as separate landmarks.
 In some specimens, the triangular ridge of the distofacial cusp and the distal
cuspal ridge of the mesiolingual cusp do not exactly meet and the transverse
groove of the oblique ridge is quite deep.
 When compared to the first molar, the maxillary second molar usually has
more secondary grooves.
M
D

12. Permanent Maxillary Second Molar - Summary
Occlusal
 All four Four cusps: ML > MF > DF >
DL
 Wrinkled occlusal anatomy due to
more supplemental grooves
 Rhomboid crown outline
 Primary cusp triangle
 DL cusp may be quite small