The most distal teeth are molars. Most humans have three molars, but many — especially in America — have their third molars (called wisdom teeth) extracted. Some people do not develop third molars at all, or they never erupt into occlusion. Molars have three or more cusps, and are used as grinding teeth.
The upper molars are typically labeled with superscript numbers M1, M2, and M3, the lowers with subscript numbers M1, M2 and M3. Hence, the left lower first molar becomes LM1.
Teeth have different directional terminology, referring specifically to the tooth row and the mouth. The direction toward the center front of the tooth row is mesial, and toward the rear of the tooth row is distal. For molars and premolars, the direction toward the cheek is buccal, and in toward the tongue is lingual.
The two incisors, one canine, two premolars and three molars on both top and bottom are called the human dental formula. We write a dental formula as follows:
2 1 2 3