Dental Caries in Horses

Dental caries involving the peripheral cementum is common in large animals. Rarely, the disease progresses and involves enamel and dentine. These carious lesions are usually related to diets that lead to a decrease in the oral pH—eg, silage or forage with a high proportion of soluble carbohydrate, such as oaten hay. A water supply with a low pH can cause the decay of peripheral cementum. Cementum decays at a pH of 6.7; for enamel decay, the pH must be 5.5 or less. Changing the diet or the water source can correct the problem in most cases (1).

Infundibular caries, horse

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Courtesy of Dr. Jack Easley.

Another form of dental caries that occurs in horses involves the two deep infundibula of the upper cheek teeth. Infundibular cement hypoplasia predisposes the infundibula to become filled with feed material that can ferment and produce an acidic environment. As these affected teeth continue to erupt, the weakened decayed crown can fracture midsagittally through the mesial and distal infundibula, leading to oral discomfort and periapical disease. Crown restorative techniques have been used to delay the progress of infundibular caries; after the tooth has fractured, however, oral extraction is the treatment of choice.