The first maxillary molar is the most significant teeth from the maxillary molar teeth. This tooth has a rhomboid shape, and its mesiodistal length is a bit smaller than the buccolingual. The buccal mesiodistal length of the first maxillary molar is narrower than the same palatal length. The cervical distobuccal line angle is concave and rounded, and it is a common site for plaque retention. The buccal surface is flatter than the palatal, as the palatal surface tends to be more convex.

This tooth presents with four cusps:

• Mesiolingual (the largest one)

• Mesiobuccal

• Distobuccal

• Distolingual

The first maxillary molar is known as the only tooth of the maxillary molars, which sometimes have a 5th cusp called the cusp of Carabelli. Usually, it has a connection with the mesiolingual cusp, and if this happens, the 5th cusp groove is present.

The first maxillary molar contains an oblique ridge, also called the transverse ridge, connecting the mesiolingual and distobuccal cusps. 

The height of contour of the first maxillary molar is as follows:

• Facial - in the cervical third;

• Lingual - near or in the middle third;

• Buccal - often called the buccal cervical ridge or simply the cervical ridge.

The first maxillary molar has three roots - mesiobuccal, distobuccal, and lingual. The largest and also the longest is the lingual root. The lingual root contains a lingual root depression, but the mesiobuccal root presents with mesial and distal root depressions. This characteristic can result in a 4th root canal on the mesiobuccal root.

Overall, roots are divergent, and they can spread out of the periphery of the crown part.