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Equine / Horse Dental Problems

The horses teeth can be divided into two main categories;

The incisors at the front which nip and tear the grass. The pre-molars and molars which then grind the food down into a digestable size before swallowing.

To learn more about specific problems that could affect your horses' teeth please click on the jump links to the left or scroll down the list to browse.


Pre-molar and molar problems

Sharp enamel points

Sharp edges known as enamel points will naturally develop over time as the horses teeth erupt. These sharp enamel points will often cause soreness, lacerations and ulcers to the sides of the cheeks and to the tongue. Often horses with sores from these sharp points will find it painful to chew and they will give up and spit out a half chewed ball of hay. This is called quidding and is unfortunately a common occurrence. With routine dental treatments the points will not become sharp and the horse will not suffer these problems.


Deciduous (Milk Teeth) Problems

Between two and a half years and four and a half years the transition from deciduous (milk teeth) to permanent teeth occurs and concerns twenty-four deciduous teeth (12 incisors and 12 pre-molars). Often young horses have problems shedding the deciduous teeth which can a painful experience causing quidding, and difficulty masticating, and can lead to bad habits such as head tossing etc due to the pain.

Often deciduous teeth, otherwise known as caps, break in half because they have trouble being pushed clear by the erupting permanent pre-molar. This may cause them to become retained and infected leading to a foul smelling odour. When caps are retained, dental cysts of the mandible (lower jaw) and the maxilla (upper jaw) can often be observed. These bumps are sometimes referred to teething bumps and will gradually disappear over time. Between the ages of 2 1/2yrs and 5yrs it is most important to have the horse examined every six months by a BAEDT qualified member.


Wolf teeth Problems

Wolf teeth are vestigial teeth and come in many different shapes and sizes. Usually they are short crowned with a root two to three times the length of the crown.

These small conical teeth can often interfere with the bit and as a result they are often removed. This is due to the position of the tooth, which is normally just in front of the molar arcades on the maxilla (upper jaw) and occasionally on the mandible (lower jaw).

Wolf teeth in young horses (under 3) are usually easier to extract completely than wolf teeth in older horses. As the horse gets older the roots of the tooth can become firmly attached to the bone making them much more difficult to extract cleanly.

Blind wolf teeth (unerupted wolf teeth) are usually problematic and are nearly always extracted.


Ramps

Ramped cheek teeth are similar to hooks but have a more gradual slope to the tooth and can also be on the front or back, upper or lower molars. Ramps on the first lower cheek teeth can cause pinching of the soft tissue on the lower bars with contact on the reins. Ramps will also inhibit the natural anterior posterior movement of the mandible, this is particularly important in the ridden horse.

Ramps can create problems to the cheek teeth arcades alignment and put pressure on the Temporal mandibular joint (the hinge joint).


Hooks

horse large hook teeth

Hooks develop due to the misalignment of the molar arcades. This is commonly the result of an over-bite or under-bite (parrot mouth or sow mouth) of the incisor arcades. Unfortunately for horses if a tooth has no opposition it will not be wearing down as it should be.

The part of tooth which is not in any contact will erupt and get more and more pronounced. This is how hooks will get bigger over time. Hooks will restrict the anterior/posterior and lateral movement of the mandible, and large hooks will cause extreme discomfort often leading to quidding, weight loss, choke and even colic.


Excessive Transverse Ridges

The horse is designed to have transverse ridges running across the surface of the teeth, these are very important for the horse to chew and break down forage into a digestable size. Excessive Transverse Ridges are much more pronounced than this and are a series of washboard like ridges that occur across the grinding surface of the molar arcades. Excessive transverse ridges can restrict the movement of the Temporal mandibular joint, forcing the horse to open its mouth to get anterior/posterior and lateral movement of the mandible. This may sound unimportant but the correct function and movement of the mandible and Temporal mandibular joint is vital for the horse. Whilst most would agree that normal ridging is important in the grinding function of the teeth, if these ridges become too exaggerated they will need to be reduced to a normal level, which may well need to be reduced on two or three separate occasions.


Steps

A step occurs when the clinical crown of one cheek tooth is longer than those in the rest of the arcade. This usually occurs when a horse is either missing a cheek tooth, or is opposed to a damaged or impacted cheek tooth. The "step" in the molar arcade will restrict the lateral excursion, and anterior/ posterior movement of the mandible.

The step has to reduced on a six monthly basis through burring and floating so that it does not affect the horse.


Shear Mouth

A shear mouth will occur when the horse is only using one side of its mouth to grind its food. As a result one side is being worn at a faster rate than the other. The table angles of the cheek teeth will be very steep on one side. It will often cause an incisor slant as well. This is fortunately quite a rare dental condition, and work to the incisors as well as the cheek teeth is required to improve the malocclusion.


Wave Mouth

This term describes uneven wear of the molar arcades creating a differing clinical crown heights throughout molar arcades. This problem usually comes from a lack of dental attention as a young horse, impacted molars, which are slow or irregular in eruption or retained caps.

Wave mouths can be difficult to correct fully especially in older horses. However most can be improved especially in younger horses with regular 6 monthly maintenance.


Diseased and infected teeth (Caries)

Teeth can become diseased or infected due to trauma, abnormal wear over a long period of time or old age.

Chronic infection of the teeth can lead to general health problems, and can also cause infections of the sinus where the tooth root sits.

Caries can sometimes be difficult to see properly but with the use of a good quality headlight and dental mirror this becomes easier.

Caries can be filled to help reduce the risk of the tooth fracturing in the future. Peripheral caries affect the sides of the teeth. These cannot be filled and appear to be more common where horses are fed haylage for most of the time.


Displaced and rotated cheek teeth

Cheek teeth can become dispaced or rotated.

This is normally due to overcrowding of the cheek teeth arcades, and where the teeth are short of space. Periodontal pocketing around these displaced or rotated teeth is common, and they may also cause ulceration to the tongue or cheeks. This can be an extremely painfull condition.

Severely displaced cheek teeth may require extracting, although routine removal of sharp edges will stop ulcers and soft tissue damage.


Diastema

A diastema is a gap between two teeth. These areas are very prone to grass and food impaction. This material then breaks down over time and will cause periodontal pocketing and gum recession. These diastemas can be extremely painful and will often lead to quidding and foul smelling breath.

At present picking out these diastemas and flushing out the area with high pressure air and water, or in some cases actually widening the gap seems to be the best treatment plan. However it can be an extremely painfull and persistant condition for the horse which will require ongoing monitoring and treatment.


Supernumary Teeth

Supernumary or ‘extra’ teeth are rare, but can cause problems especially if they are unoposed. It is vital that the overgrowths are reduced at least twice or three times a year.


Incisor Problems

The incisor teeth are found at the front of the horses mouth and are used for nipping the grass. It is normal for the horse to have a set of twelve decidous incisors, which are replaced by twelve permanent incisors.

One of the main dental problems occurs in the domestic horse due to its lack of continuous grazing. In a study at the royal veterinary school, Edinburgh, it was found that the horse eats for an average of 16 hrs per day while out at grass. This time is obviously greatly reduced when horses are fed rations of hay in the stable. The study also found that horses fed on hay take far fewer bites with their incisor teeth. This leads us to the main problem. The incisors are being erupted at a constant rate, but in many stabled horses the incisors are not being worn down at the correct rate because much of the time the horse is not eating. Below are some incisor malocclusions.


Ventral Curvature (smile)

When the incisors are curved upwards at both sides when viewed head on, hence the term a 'smile'. In this instance the lower corner incisors are too long, as are the upper central incisors. The problem with a smile, is that the incisors cam off each other and force the cheek teeth apart too early. It restricts the lateral excursion, and 'grind' of the cheek teeth. The table angles of the cheek teeth are often too steep as a result. The problem is corrected through the use of power work again, or in a mild case with the use of a hand float, while the table angles in the cheek teeth can also be corrected by hand.


Slant (diagonal bite)

When looking at the incisors from the front of the horse, the incisors should look almost horizontal. In some cases they are not and are clearly on a slant. This is called a 'slant mouth', or 'incisor wedge'. The horse with a slant has upper incisors which are too long meeting lower incisors which are too short on one side of the mouth. On the other side the problem is reversed. The result being a severe 'slant.' This type of situation is corrected using power work while the horse is sedated by the vet. It is also not uncommon for there to be quite severe cheek teeth problems, when the horse has a slanted incisors. These problems have to be addressed at the same time.


Dorsal Curvature (frown)

When the incisors curve downwards, causing the appearance of a frown. It is the opposite of a smile but causes similar problems with the cheek teeth. It is again corrected by realigning the incisor arcades, usually with the use of power tools.


Missing Tooth

horse missing tooth

When a horse is missing a permanent incisor, or has a badly damaged incisor, a problem will develop over time. The problem is that as the incisors are erupting normally, they are usually worn by the opposing teeth. If one is missing, the healthy opposing incisor will grow into the gap. This causes a blockage, and will 'lock' the incisors. As the healthy tooth continues to erupt, so the situation becomes worse. Horses with this problem will probably be quidding, and will 'chomp' its food with a vertical, up and down chewing motion. The remedy is to reduce the overlong incisor using either a diamond disc cutter, or carbide burr. The tooth will always need regular dental attention.


Overbite

horse over bite

Commonly referred to as a "parrot mouth." This is not an uncommon problem, and is where the upper incisors protrude too far forward in relation to the lower incisors. It is also common to find large 1/6, 2/6 upper rostral hooks, and large 3/11, 4/11 lower caudal hooks on the molar arcades. In most cases a procedure known as an "incisor reduction" and corrective floating, is performed to restore anterior-posterior movement of the jaw, and to reduce pressure that this exerts on the Temporal mandibular joint.


Underbite

Or commonly referred to as a "sow mouth" this is a fairly rare abnormality, and is where the lower incisors protrude too far forward in relation to the upper incisors. It is also common to find large 3/6, 4/6 lower anterior hooks and large 1/11, 2/11 upper caudal hooks on the molar arcades. Again the most common procedure to correct this abnormality is an "incisor reduction" and corrective floating, which has the same affect on the tempro-mandibular joint as the above overbite.