3- The buccal roots are about the same length. They are more nearly parallel and are inclined distally more than those of maxillary first molar. So, the end of the distobuccal root is slightly distal to the distal extremity of the crown and the apex of mesiobuccal root is on a line with the buccal groove of the crown instead of the tip of the mesiobuccal cusp as in the maxillary first molar.
4-The palatal root is the longest root (1mm longer than the buccal roots).
1- The distolingual cusp is smaller than that in the maxillary first molar.
2-Part of the distobuccal cusp may be seen mesial to the distolingual cusp (through the sulcus between the mesiolingual and distolingual cusps).
3-No fifth cusp is evident.
4-The apex of the lingual root (palatal root) is in line with the distolingual cusp tip instead of the lingual groove as was found in the maxillary first molars.
3-The distal cusps (distobuccal and distolingual cusps) are smaller and less developed than those in the maxillary first molar.
4 -No fifth cusp.
5-It is not uncommon to find more supplemental grooves as well as pits on the occlusal surface than are usually found on the maxillary first molar.
Maxillary Third Molar
The third molar supplements the second molar in function, and its fundamental design is similar. all third molars, mandibular and maxillary show more variation in development than any of the other teeth in the mouth.