The first maxillary molars (16 and 26 using the FDI terminology) have the largest occlusal table of all the teeth in the mouth and erupt at around 6 years of age - the first permanent molars to do so.They have 4 cusps, the mesial-lingual being the largest, the distal-lingual is the smallest. The mesial and distal buccal cusps are about the same size. Sometimes a 5th cusp (cusp of Carabelli) can also be seen coming off the mesial lingual cusp. The cusps contain triangular ridges. There are also marginal ridges on the distal and mesial part of occlusal table and cuspal ridges.
There is a buccal groove that runs from the central pit to the buccal aspect above the height of contour. The lingual groove (also called the disto-lingual groove) runs from the distal pit adjacent and distally to the oblique ridge and down the lingual aspect of the tooth - crossing the height of contour. The oblique ridge crosses the occlusal width of the tooth from the mesial-lingual cusp to the buccal-distal cusp.
The occlusal table has a rhomboidal shape.
There are 3 roots. The lingual root is the largest, followed by mesial-buccal and the smallest is the distal-buccal.
Video explanation of maxillary molar anatomy from the Michigan School of Dentistry.
