The blue arrows indicate dental stars, composed of secondary dentin. The “***” and the “vvv” indicate dental cups, each of which is an infundibulum.
Equine lower incisor teeth develop wear-related features that can be used to estimate age. The shape, position, and central “white spot” of the dental star changes with age as the tooth wears. The shape, size, and time of disappearance of the dental cups can be used but it is more variable.
Click here to see a labeled image of a horse’s incisors at ages six and 12 years.
There is a change in the occlusal shape of the incisors with age and wear (from elliptical to trapezoid, round, and then triangular). The angle between the upper and lower incisors becomes more acute (rather than being positioned in a straight line) with age.
Galvayne’s groove is a dark line that appears at the gingival margin on the buccal surface of the third upper incisor (103 and 203) starting at ~10 years of age. It is often used to very roughly estimate age.
Equine odontoclastic tooth resorption and hypercementosis (EOTRH) is a painful condition of the incisors characterized by dental resorption and excessive cementum production.
Horses rarely get cavities, and even more rarely in the incisors.
Refs: The Guide for Determining the Age of the Horse, Amer. Assoc. Eq Practitioners and the American College of Veterinary Surgeons, large animal health topics.
Images courtesy of Uwe Gille and Nora Grenager, VMD, DACVIM.
