The wolf tooth is the no longer functional first premolar tooth in the horse. They are small teeth, usually found just in front of the second premolar (chewing teeth), but quite a few erupt on the cheek side of the premolar or on their own in front of the other cheek teeth in the gap towards where the bit goes. This is termed the interdental space. Occasionally, double wolf teeth are seen.
Wolf teeth come in a variety of shapes and sizes and different positions. Some will be more problematic than others.
The number and position of wolf teeth is quite variable.
The appearance of the exposed crown is not necessarily a reflection of the size or shape of the root. In this respect they are a bit like an iceberg because there may be more tooth than expected under the gum. Consequently some tiny wolf teeth may have large roots and be more difficult than anticipated to remove. If they are not extracted very carefully, it is possible to snap off the top of the tooth and leave the root behind.
Some 40 to 80% of domestic horses have at least one wolf tooth, most commonly in the upper jaw. Those in the lower jaw are more rare and likely to be associated with discomfort with the bit. They can be hard to see and are best detected by feeling a little bump on the gums of the lower jaw.
Wolf teeth usually appear or erupt when the horse is six to 18 months of age, but this also varies.
In some two- or three-year-old horses, wolf teeth may be shed with the premolar caps (baby chewing teeth), partially because their roots may be pushed out by the adult teeth growing through. This may explain why many more (80-90%) young horses than adult horses (15-25%) have wolf teeth, even in groups of horses which have had no dental work done. These must have had wolf teeth that fell out rather than were removed.
Unerupted wolf teeth, referred to as blind wolf teeth, can be detected as firm nodules under the gum in front of the cheek teeth in some horses. These are often painful and may be covered with ulcerated gum membranes and may require removal. This must be done with caution, as without careful examination (possibly including X-rays) it may be difficult to establish the precise position and size of such teeth. A blind extraction without knowing what is going on under the gum can result in complications and should be avoided.
Some wolf teeth in two- and three-year-olds have resorbed roots that may give a false impression that the tooth was broken during extraction.
This information formed part of a veterinary feature in Horse & Hound (28 September, ’06)