Horses have two sets of teeth during their lifetime. The first set, the deciduous or baby teeth, are replaced by permanent teeth by the time the horse is five years old.

The permanent teeth are made up of:

Dentine - The sensitive living tissue inside the tooth which has nerves and receives nutrients from the blood vessels to feed the tooth

Enamel - The hardest substance in the body, this layer is of varying thickness

Cementum - the outer layer which holds the tooth together

All three substances are exposed on the grinding surface of the tooth, although the dentine is not sensitive here. The varying hardness of these substances causes the grinding surfaces of the tooth to wear irregularly, which improves the efficiency of the chewing process.

Each tooth is up to 3-4in long with most of the length embedded in the jaw below the gum line. The clinical crown is the part of the tooth that is visible above the gum line. As this wears down through the constant grinding of food the tooth grows up from below the gum ensuring the visible tooth remains at a constant size.

As long as each tooth has another tooth to grind itself against, it will wear at an even rate. Problems occur when there is a gap between teeth. If one tooth has no opposing grinding surface to wear against, it will continue to grow, eventually damaging the gum on the opposite jaw.

Six-monthly visits from your equine vet or equine dental technician will ensure problems like this are kept under control, preventing high levels of discomfort for your horse

GETTING TO GRIPS WITH WOLF TEETH

Facts about wolf teeth

Karen Coumbe MRCVS

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.

Karen Coumbe MRCVS

It is quite common to have a horse’s wolf teeth removed, but is this really necessary,

When you learn that a horse has wolf teeth, there is a tendency to think he must have sprouted werewolf-like fangs. It is easy to confuse them with the larger canine teeth or tushes. These sit in the middle of each side of the horse's jaw, between the incisors or biting teeth that fit in front of the bit, and the chewing or molar teeth at the back of the mouth behind the bit. Wolf teeth, however, are usually tiny and not easy to see at all.

Horse owners are often surprised when the vet shows them the vestigial remnants that are the wolf teeth. The standard responses vary from "Where?" as they peer over, looking for something dramatic to "Oh, is that all it is?" or even the logical: "How can that cause a problem to an animal the size of a horse?" to which it can be hard to provide a satisfactory answer.

Such comments are valid because we are not talking about elephant tusks here. The majority of horse wolf teeth are only a few sizes larger than the child's tooth left under the pillow for a tooth fairy to find.

When you realise how small and apparently innocuous wolf teeth are, added to the fact that when in their proper anatomical position, they should not interfere with the bit, it is hard to see how they cause a problem. It seems logical that they may irritate if there is something unusual, such as a loose wolf tooth that may wobble uncomfortably, a tooth that has erupted in the wrong place or a particularly sharp tooth. Otherwise, they may be best left alone, on the basis that if it isn't broken, don't fix it.

Do wolf teeth need to be extracted?

The role of wolf teeth in causing oral discomfort has been widely debated and is controversial. Tradition and client pressure are the most common reasons for their removal. Also, cynically, whoever extracts them will earn a fee. So historically wolf teeth removal has been customary practice, as it can be preferable to do something to the horse rather than modify other factors, such as riding style.

I believe most wolf teeth cause no problem to the horse, but do concern their human connections. This is because:

The presence of a wolf tooth can affect the rasping of molars to form a bit seat, This is when the edge of the second check tooth is rounded to accommodate the bit and is said to be beneficial to the performance horse

Displaced or sharp wolf teeth can cause pain on the cheeks when pressure is put on by the bit and bridle

Some wolf teeth do become loose, diseased or associated with persistent ulceration, which may cause pain

There are cases where wolf teeth problems have been blamed for all sorts of horrors, such as headshaking.

Without a proper scientific trial controlling other factors such as tack, rider and many other variables, it is impossible to know if wolf teeth hinder a horse.

If done properly, effective wolf tooth extraction is unlikely to be harmful. The fact that the horse has some time off while the gum wound is healing may also allow other issues to subside. Following extraction, the horse should not be ridden for up to two weeks, or sometimes even longer, while the gum heals and any bruising goes down.

Q: A friend recently told me that when the equine dentist rasps her horse's teeth, he createsbit seats. What are bit seats and what is their purpose?

John Edmunds replies: Creating bit seats involves rounding and smoothing the front surfaces of a horse's first cheek teeth to create a more comfortable condition for the horse when he has a bit in his mouth, enhancing his performance and improving his attitude to work.

Upper bit seats let the bit ride higher in a horse's mouth, freeing the tongue and allowing it to maintain a more forward position.

Lower bit seats avoid puncturing, pinching and bruising of the lower area of the cheek.

The combination of upper and lower bit seats prevent loose flesh over the lower bars of the mouth from becoming trapped and pinched between a horse's cheekteeth.

As the rider takes up a contact on the horse's mouth, some bits (especially D-ring types) tend to narrow quickly. This creates excessive pressure on the cheeks pushing them against the teeth. Bit seats eliminate this discomfort.

It takes a lot of experience to create good bit seats, and they are easier to maintain than to form. When installing bit seats the dentist should consider:

what type of bit the horse is ridden in

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