When the dentist examines your teeth and finds decay you may hear some designations that mean nothing to you but seem a little frightening. The dentist may refer to a number of surfaces. These are like directions on a compass, and indicate where the decay is present. Occlusal indicates the top, or biting surface of a molar. Incisal is the same surface for an anterior tooth. Mesial and distal indicates the sides of the teeth in both the anterior and posterior. Lingual is the back of any tooth surface, while buccal represents the face of the posterior teeth. For an anterior tooth this is the facial surface. Another important fact to note is that once you cross the midline of your mouth , which is between the front teeth, mesial and distal reverse. So a MBD on tooth number 2 would be a three surface filling starting on one side and going across the face of the tooth to the back side. An IL on tooth number 8 would be the biting surface and back of the tooth. Knowing these surface indicators will make it less stressful when you hear them called out.