When the back or molar teeth become irregular, sharp, and chipped, they cut the cheeks or the sides of the tongue, and prevent the horse masticating his food properly; this imperfect mastication leads to what is called "quidding," the horse dropping pellets of half-masticated hay from his mouth. There is also usually loss of condition and unthriftiness.

The teeth will require careful examination to ascertain their condition. The mouth requires to be kept open by a gag balling-iron, and a particular-shaped rasp is employed to file down the sharp teeth.