The shape, size and method of growth of equine teeth cause specific problems. If a horse is born with an upper jaw that is slightly longer or shorter than the opposing lower jaw, the teeth will not line up correctly. Because the upper tooth depends on a matching lower tooth to help wear its surface normally, and vice versa, jaw misalignment spells dental problems. Horses with well-matched jaws will wear teeth more slowly and evenly, often increasing their life span. An unopposed tooth will continue to grow, resulting in a hook or a point.
Hooks occur on the front of the upper teeth and the back of the lower row of teeth.
These points can become sharp and cause chewing difficulty, irritating the gum and possibly leading to an abscess. Points and edges can interfere with the bit and make horses pull away, toss their heads, or display behavior that is often incorrectly attributed to training problems. Due to trauma, such as a kick or a fall, horses can even lose a tooth occasionally. This gives the opposing tooth nothing to wear against, and it will continue to grow out from the jaw. In severe cases, this unopposed tooth will even keep growing into the empty space left by the lost tooth.