This tooth assists the maxillary first molar in function, and it has the same from with some varioations.
- The crown is a little shorter cervico-occlusally (by about 0.5mm) narrower
mesiodistally (by 1mm), but of the same measurement bucco-lingually.
- The buccal groove is located further distally, with a resultant larger and longer mesiobuccal cusp, and a shorter, smaller and sharper distobuccal cusp.
- The buccal roots
are about the same length. They are more nearly parallel ad are inclined distally more than those of the maxillary first molar so that the end of the distobuccal root is slightly distal to the distal extremity of the crown.
- The apex of the mesiobuccal
root is on a line with the buccal groove of the crown instead of the tip of the mesiobuccal cusp as found on the first molar.
- The mesilingaul cusp is smaller and not well developed
as in the first maxillary molar. No fifth cusp is present.
- The distolingual cusp is smaller.
- The buccal cusps may be seen between the lingual cusps.
- The apex of the lingual root is in line with the distolingual cusp instead of the
lingual groove as was found on the first molar.
- There is no developmental groove on the palatal root.
No tubercle of Carabelli. It shows less divergent roots (being
within the confines of buccolingual crown outline). In addition the cervical concavity is not present.
It is similar to the mesial except that the distobuccal cusp is smaller than in the first
molar. The apex of the lingual root is in line with the distolingualcusp.
The crown is more constricted mesiodistally and has no tubercle of Carabelli. There are two major types of crown from:
- Rhomboidal form which is most frequent type resembling the maxillary first molar except that:
- The rhomboid form is more accentuated.
- The acute angle is less acute, and the obtuse angles are greater.
- The distobuccal and distolingual
cusps are smaller.
- Heart shaped form resemble the maxillary third molar. The distolingaul cusp being poorly developed or sometime missing.
It is common to find supplemental grooves as well as grooves and pits on the occlusal
surface of the maxillary second molar which make the surface more wrinkled.
It is similar to the first maxillary molar both in the mesiodistal and buccolingual cross sections. It is not common to
find two root canals in the mesiobuccal root.