A horse’s teeth begin to erupt in the first few days after birth, and they continue to grow throughout most of a horse’s life. Therefore, dental problems can occur at any age. A "baby" tooth might not shed properly, resulting in an impacted permanent tooth. A horse less than three years of age might have problems with the emergence of permanent teeth. An older horse might need attention because of lost or damaged teeth. The most common dental problems faced by a horse, however, are the result of the horse’s normal anatomy–the horse’s maxillae (upper jaw) is wider than the mandible (lower jaw).

As the upper and lower teeth grind food, the surface of the tooth is worn away naturally. Each tooth slowly continues to grow to replace the portions that are ground away by normal wear. Problems occur when the edges of the teeth become sharp from not being worn off. These sharp edges, or uneven wear patterns, usually occur on the outside or cheek side of the upper teeth and inside or tongue side of the lower teeth because the upper jaw is wider than the lower.

"The teeth are like a grist mill–two grinding stones," explained Fred Faragalla, DVM, an equine practitioner in Creedmoor, N.C. "But the upper teeth don’t meet and grind off the outer edges, and the lower teeth don’t meet to grind off the inner edges. So, this sets the horse up to have ‘points’ that stick up and prevent the horse from chewing from side to side and creates a vicious cycle for digestion and mastication as the teeth continue to erupt."

Also, when any permanent tooth is lost or damaged, the opposite tooth continues to grow. Since this tooth doesn’t have an occlusive tooth to wear against, it tends to become elongated. This also can occur when a marked overbite or underbite is present