Lingual

Lingual refers to the inner surface of any tooth in the lower arch — the side that faces the tongue. In the upper arch the equivalent surface is sometimes called palatal because it faces the palate. Lingual surfaces of the lower front teeth tend to accumulate calculus quickly because saliva from the submandibular glands enters the mouth nearby and mineralises plaque. The term also describes lingual braces, an orthodontic system in which brackets are bonded behind the teeth so the appliance is invisible from the front. Knowing lingual direction is essential for charting and treatment planning.