Mesial

Mesial is a directional term meaning "toward the midline of the face." Each tooth has a mesial surface (facing the front of the mouth) and a distal surface (facing the back). For example, the mesial surface of an upper first molar faces the second premolar, while its distal surface faces the second molar. Mesial and distal are essential when documenting cavities, planning crown contacts, and describing tooth movement in orthodontics — a tooth that drifts forward into the space of a missing neighbour is said to have undergone mesial drift.