Torus Mandibularis is an exostosis, a benign localized bony protuberance that develops at the lingual aspect of the mandible. Tori on the palate are referred to as torus palatinus and are discussed separately. Tori (palatinus and mandibularis) are likely caused by a combination of genetic and environmental factors. They tend to occur more often in the Asian and Inuit population with a slight female predilection. They are most commonly noticed during the early adult years. Patients are often unaware of the presence of tori since they usually have been present for a long time and grow very slowly.

Some cases exhibit a "growth spurt" and patients become aware of a fairly rapidly-enlarging mass.

Genetic and environmental factors (such as chronic irritation) likely play a role in the development of these lesions. Some tori may also regress or become smaller over time. Tori are usually painless unless the areas are traumatized.