Horses have a unique dental structure. Their teeth are divided into two major sections: the incisors, which are the teeth seen in the front of the horse’s mouth, and the cheek teeth, made up of the premolars and molars. The molars and premolars are lined up tightly against each other, creating the appearance of one chewing surface. This alignment of teeth is called the dental arcade. The incisors are separated from the cheek teeth by a large space. Canine teeth can be found in the space between the incisors and premolars. The incisor teeth are responsible for the grasping and tearing of food, while the cheek teeth are used for grinding of feed.

The horse chews in a circular motion with the lower jaw sliding along the upper teeth. This circular motion maintains the occlusive surfaces of the teeth. This motion is reduced as the horse eats smaller feed particles. Horses eating grains and pelleted feeds may chew in almost an up-and-down fashion.

The horse has evolved with the hypsodont tooth seen in the modern horse. Hypsodont teeth are tall and continue to erupt from the gum after forming. These teeth form in the jaw of the horse until the horse is approximately seven years old. Cementum, a hard material that forms part of the tooth, and bone are deposited, which pushes the tooth out of the skull and through the gumline. The part of the tooth that can be seen in the horse’s mouth is called the clinical crown, while the portion in the jaw is called the body or reserve crown. Equine teeth have an interweaving fold of hard enamel and dentin. The enamel is important for grinding feedstuff. The chewing surfaces of the teeth must have enamel-to-enamel contact. If the teeth are offset by abnormal wear, tooth loss or abnormal growth, the enamel-to-enamel contact will be disrupted and the enamel will come in contact with the much softer dentin. This results in the dentin wearing away rapidly and deformation of the softer tooth.

This continuous eruption and wearing of teeth in the horse results in an increase in dental problems and diseases of the oral cavity as the horse ages. While horses rarely have problems with tooth decay or gum disease, their continuously erupting teeth present unique problems. If a tooth is lost or worn abnormally, the opposing tooth will continue to erupt from the gumline. This will result in the tooth impacting the empty socket left by a missing tooth or the dominant tooth continuing to wear into the opposing arcade, magnifying the abnormality. Either of these conditions will result in mouth pain and abnormal chewing patterns. This abnormal chewing can result in weight loss, tooth infection or impaction colic