1. The mesiolingual and distolingual angles are obtuse, making up the oblique ridge (connects the mesiolingual and distobuccal cusps).
2. The largest root is the palatal root, the smallest root is the distobuccal root.
3. The mesiobuccal root often has a second canal: the MB2 canal.
4. Has the greatest faciolingual crown diameter of all teeth due to cusp of carabelli (extra cusp on the mesiopalatal line angle).
5. The occlusal shape is rhomboidal.
6. Wider mesial-distally on the facial than the lingual.
7. They have a distinct distal concavity.

Pictured here: Tooth #3

Maxillary Second Molars (#2, #15)

1. The roots are generally less divergent and have a distal inclination
2. The cervical cross section is generally triangular.
3. The molar cusp triangle (Mesiobuccal, distobuccal, mesiolingual cusps) does not include the distolingual cusp.
4. If the distolingual cusp is not present, the tooth has a heart shape appearance.

Pictured here: Tooth #2

Maxillary Third Molars (#1, #16)

1. Along with mandibular central incisors, the maxillary third molars only occlude one opposing tooth.
2. This molar is most frequently heart-shaped with 3 cusps (missing DL cusp).
3. The mesiolingual cusp is the smallest.
4. The roots are often shorter, convergent, and often fused together.
5. Keep in mind: the third molars have the most variation of anatomy of any tooth in the mouth!

Pictured here: Tooth #1