Facial (F) – the surface of a tooth closest to the cheeks or lips; this surface can also be known as the Labial Labial (La) – the surface of an anterior tooth facing the lips Buccal (B) – the surface of a posterior tooth facing the cheeks Incisal Edge [or ridge] (I) – the biting edge of anterior teeth Lingual (L) – the surface of a tooth closest to the tongue Proximal – the surface of a tooth that touches a neighboring tooth’s surface; each tooth has two proximal surfaces known as the mesial and distal surfaces. Mesial (M) – the surface of a tooth that is closest to the midline (middle) of the face