The incisor teeth are sometimes broken by external violence, and the same accident may result to the molar teeth from being brought forcibly together while a piece of stone, or a nail, or some other hard substance is interposed between them.

Fracture of the incisor teeth commonly results from the animal falling forcibly on the mouth. The breakage here is usually in a transverse direction, while in the molars it extends from the crown towards the fang. Much less importance attaches to the one than to the other. Fracture of the latter causes severe toothache, and seriously interferes with mastication, while at the same time it permits the food to enter the alveolus, or socket, which gives lodgment to the fangs, and lays the foundation for further mischief.

In all cases where a tooth is fractured vertically, so as to interfere with the fang, it should be removed, or failing this, in case of an incisor, it should be broken off short so that the gum may overgrow the stump. (See "Minor Operations".)

Fractured teeth may be recognized by the blackish-yellow discoloration which they undergo, and the offensive odour they give out, as well as by the accumulation of food in the line of the crack.