Recent Articles


Horses Teeth

posted May 6, 2012, 7:12 PM by Claire Murray

Types of teeth in Mammals

When talking about teeth we can divide them into groups according to the pattern that the enamel is laid down and the type of crown they have Humans have BUNODONT teeth. They are characterized by cone shaped cusps that look like little volcanoes. The whole of the exposed crown of the tooth is covered in enamel in the same way as icing covers a cup cake

Horses have LOPHODONT teeth. The volcano like cusps have become confluent or joined to form lophs. If you look at the surface of a horse tooth you can see bands of enamel with softer dentine and cementum between the bands.








Fig 1. This is an upper molar from a 4 year old

Cattle and cloven hoofed ruminants have SELENODONT teeth. These teeth are similar to horses in that the enamel is formed in bands but the bands form crescents like the shape of the moon.

There are also differences in crown height: People have short crowned teeth that develop and erupt into full maturity relatively quickly and then they grow no more. These teeth are called BRACHYDONT and are designed to for soft food that causes little wear.

Horses have HYPSODONT teeth that are tall crowned. There is a generous surplus of reserve crown below the gum line that erupts at the same rate as it wears until this reserve crown has been used up at which time the tooth expires and falls out. This is a fantastic design nature has provided to deal with the abrasive effects of the tuff, dry food that horses have evolved to live in. It is also a very important point to remember because it is this characteristic that causes all sorts of problems for domestic horses.

Some animals such as rodents have teeth that are ever growing. It doesn’t matter how much they are used as long as they are supplied with nutrients they will continue to grow and erupt. These teeth are called HYPSELODONT


Position and types of horses teeth: Take note of this picture as the molars at the back of the mouth and incisors at the front of the mouth rarely get adjusted sufficiently, if at all by uneducated practitioners or if the horse is unsedated.


Incisors

If you part a horse’s lips, at the very front of its mouth you can see its incisors. A horse has 12 deciduous or baby incisors that are followed by 12 permanent incisors with six housed on the upper jaw and 6 on the lower jaw. These teeth are used for nipping or incising the food. If you view them at eye level, the line they meet at should be straight, giving the appearance of a smile. It is the incisors that are mainly used in ageing a horse using the set patterns of wear on the cups, dental star and enamel spot as indicators, along with Galvayne’s Groove, shape of teeth and hooks on upper corner incisors.














Canines

Behind the incisors are conical shaped teeth that are called canines. They are different from the other teeth in that they don’t hyper-erupt when not in wear and in fact we do not want them to ever come into wear. They are mainly found in males and their function is for tearing. In the wild, stallions will grab each other around the jugular vein, in the neck, using their canines and can cause serious injury. Obviously this is not something we want to happen in our domestic horses so these teeth are usually shortened and rounded to a suitable height.

The canines can also be known as: fighting teeth, tushes, fangs and bridle teeth. Sometimes they are mistaken for wolf teeth which is a serious mistake because unlike wolf teeth, canines have long curved roots that make them very difficult to remove. The only time they need removing is if they become broken or diseased.


Wolf Teeth

Wolf teeth are small vestigial (atrophied or functionless from the process of evolution) teeth that are not required any more. They used to be a grinding tooth millions of years ago, but have gone out of use due to a change in the diet of horses. It is very important that all wolf teeth are removed from ridden horses, even blind or un-erupted ones that are beneath the surface of the gum. This is because they are small and only have one root making them very sensitive. They are positioned right where the bit lies creating a painful situation for the horse that can be likened to you having a splinter and your clothing constantly brushing against it.


Premolars and Molars

At the back of the mouth are the premolars and molars. They are the chewing or grinding teeth and can collectively be known as the cheek teeth. It is important that they can meet together along the length of the arcade and that the full surface can be used for grinding. The wolf teeth are actually the first premolars but behind them there are three functional premolars in each arcade. They are deciduous teeth so they have baby teeth followed by the permanents which erupt at particular ages. Behind the premolars are three molars in each arcade. Molars are accessional teeth meaning that they have no deciduous predecessors. They develop as a permanent tooth from the beginning.

Common Molar Problems

posted May 6, 2012, 6:18 PM by Claire Murray   [ updated May 6, 2012, 7:00 PM ]

Hooks are where half or less of a tooth becomes protuberant forming a point through abnormal wear. They are most commonly found on the upper #6 premolars or lower #11 molars and restrict or totally prevent anterior posterior movement which is required for comfortable efficient mastication and particularly in performance horses that are required to work in an outline.











Ramps involve more than half the tooth being protuberant due to abnormal wear and give the general feel of a ski jump. They are most commonly found on the lower #11 molar, right at the back of the mouth which is an area that is difficult to access due to a lack of room and a problem that is largely left unaddressed by ill trained/unknowledgeable practitioners. Like hooks they prevent backwards and forwards movement of the mandible.


High teeth can form various patterns such as a wave or step along the cheek teeth arcade (row of teeth) but they all create loss of function and imbalance in some way. They are generally present as a result of other factors such as retained caps, missing teeth, hooks, ramps etc. These teeth need to be reduced in height to restore function and allow an uninterrupted passage of food along the dental arcade. Maintenance will keep the high area from again being a problem until the opposing teeth (if they are present) erupt up to the level of the rest of the teeth on the arcade. If there is a missing tooth/teeth that horse will require regular, on going maintenance to the area in question.











Sharp Enamel points or edges.
Due to the fact that in a horse’s mouth the upper arcades of teeth are set wider apart than the lower ones they are prone to developing sharp, unworn points on the outer edge of the surface of the upper teeth and inside edge of the surface of the lower teeth. Left untreated these cause lacerations and abscesses of the cheeks and tongue.


Excessive Transverse Ridging (ETR).
Due to the soft nature of the feed we give our horses and the grazing that is available to them, the hard bands of enamel on the tooth surface to do not wear as quickly as the softer dentin and cementum substances which make up the remainder of the tooth. This leaves ridges of unworn tooth where there are concentrations of enamel bands giving the arcade of teeth a washboard like effect. The ridges occur at the anterior and posterior margins of each tooth. Left untreated the ridges become more accentuated until the mouth resembles mountains and valleys rather than a row of teeth.



Periodontal disease is where an accumulation of bacteria causes breakdown of the soft tissues resulting in separation of the gums and periodontal ligaments from the tooth. At first small pockets occur, but eventually if nothing is done, the tooth will be lost. In the early stages good dentistry usually totally reverses the problem. Periodontal disease can be found any where in the mouth and is usually secondary to other problems that cause an interruption to the food flow through the mouth or the circular chewing action. In a fully functioning mouth the large quantities of saliva that are produced and the chewing action provides a cleaning effect for the gums and teeth. They stay healthy and this problem does not occur.

All the above problems are not a natural occurrence but they have become common in our domesticated horses due to the environment they live in. They are problematic for the horse and have the potential to shorten the horse’s life as well as cause pain, dysfunction and poor performance. Many of the worst problems have been found in horses that were showing no outward signs. In fact waiting until there are physical signs may be a very unwise decision as by then the problems are likely to be very advanced. It stands to reason that in nature a horse does not show a physical weakness until the body can no longer cope as this after all, would make it a prime target for prey animals.


Other Problems

Long canines, can get caught on the bit as it is removed from the mouth, causing some horses to become afraid of having their bridle removed. They can also get long enough to pinch the tongue or even lacerate it. Occasionally a horse may have canines which come into occlusion (contact) which is undesirable.


Bite damage. This is on the bars of the mouth but is often seen in the corners of the lips.

Whole mouth dentistry saves you money

posted May 6, 2012, 6:13 PM by Claire Murray

Horses receiving regular care.
  • Need less feed as they are better able to utilize what you give them
  • Have lower vet bills as their general health is improved
  • Have lower chiropractic bills as the dentistry is about TMJ comfort and TMJ’s are related to the Altas. The atlas affects the sacrum as the atlas is connected to the withers via the nucal ligament and the wither is connected to the sacrum via the longissimus dorsi muscle. When the sacrum shows inflammation it is also common to have nerve pressure on the sciatic nerve which causes pain and a decrease in circulation to the hind legs. Yep can all be secondary to dental problems!
Can you afford not to use this type of dentistry?

How much do you spend on a day competing? Probably the money from entry fees and petrol for one weekend a year would pay for your horse’s comfort. If the above reasons aren’t enough to convince you perhaps your improved competitive results would be.

Horses’ teeth affect their whole body not just the way they can chew.

posted May 6, 2012, 6:09 PM by Claire Murray

Areas affected by a horse’s dentition:

General health:
  • The amount of nutrients absorbed from food eaten is related to how well the food is chewed. So it stands to reason that a mouth that is not functioning to its full potential is not going to allow the horse to make the best use of the feed it eats. Colic or diahorrea can result from dental problems.
  • Loose or infected teeth can set up a low grade infection throughout the whole body.
Temperament:
  • A horse that is in pain due to imbalances within its mouth often shows temperament problems. Many clients report back that after full mouth dentistry their horses have become much happier, quieter, are no longer head shy. The list goes on and on.
Muscles:
  • Horses with dental problems can not move to their full potential and will often show sore muscles and/or muscle wastage especially over the ‘top line’.
Vertebral alignment:
  • Unbalanced teeth set up compensations throughout the body. If your horse needs to see a chiropractor more than a couple of times it probably has dental problems.
Performance:
  • Many ridden problems are teeth related. For example being above the bit, on the forehand, tilting the head, chewing the bit, opening the mouth, better on one rein than the other, difficult to stop, reluctant to take up the contact etc.
It must be remembered that not all horses show outward signs of their suffering. For example unbeknown to the owner and rider an overseas horse that was short listed for the Olympics was found to have lower #11 ramps (last molars at the back of the mouth on the bottom jaw) that were so protuberant that they were wearing into the soft tissue and bone of the upper jaw. Unfortunately this is not an uncommon occurrence but it demonstrates how some horses will just grin and bear their discomfort. I Feel it is our responsibility to ensure they are not suffering in this manner.

If your horse has only had dentistry with out sedation and using hand floats it will have dental problems!

Pamphlet - Why do Horses Need Dentistry

posted Apr 30, 2012, 4:56 PM by Claire Murray

Horses have evolved to live in a dry semi-arid environment where they are free to roam an average of 30-40km/day in search of grazing and water. Their incisors are designed to nip off the grass. Then tongue and cheeks manipulate this food into the grinding cheek teeth where it is chewed and manipulated into a rope like bolus and saliva is added in great quantities in the first steps of digestion.

Humans have domesticated horses and now provide them with conditions that are very different from their natural environment. Our breeding programs rarely take dentition into consideration and natural selection no longer takes place. This leads to conditions requiring all NZ horses to have a dental check up at least once a year and some more frequently.

The attached pamphlet is well worth a read to learn more about Equine Dentistry and how people like me can make a difference to your horses' well-being.

Dental Instruments

posted Oct 14, 2009, 11:16 PM by Claire Murray   [ updated Apr 30, 2012, 4:54 PM ]

Here is an article that I wrote to give an insight into the tools of the trade.

Common Dental Problems

posted Oct 14, 2009, 11:11 PM by Claire Murray   [ updated Apr 30, 2012, 4:47 PM ]

Quite often I am asked about the kinds of things I can help with. This article gives you an insight into some of the common problems I come across in the course of my work.

1-7 of 7