Dentistry
Introduction and Anatomy
Equine dentistry is an extremely important and often neglected area in veterinary medicine. Good dental care is essential so that horses are able to utilize the feed we give them effectively, dental problems are probably the number one cause of weight loss seen in horses, and to make them as comfortable as possible when ridden.
A horse should always be examined if there are signs of discomfort or disease, however, every horse should have his/her teeth examined at least once a year so that problems can be diagnosed early and good routine dentistry performed to help prevent serious dental problems arising. This makes the dental treatment more cost effective as the treatment for severe dental problems can prove very costly in deed.
Anatomy of Teeth
Horses have two sets of teeth during their lifetime. They have a set of baby (decidious teeth) which start appearing from birth. These are then gradually replaced by a set of permanent teeth. The time at which the permanent teeth begin to appear is shown in the table below. These eruption times are very useful in ageing horses.
| DECIDIOUS | PERMANENT | |
| INCISORS | ||
| first | birth- first week | 1 ½ -2½ years |
| second | 4-6 weeks | 2½- 3½ years |
| Third | 6-9 months | 3 ½-4½ years |
| CANINES | Absent | 4-5 years if ever |
| PREMOLARS | ||
| first (wolf) | Absent | 5-6 months if ever |
| second | Birth-2 weeks | 2 ½ years |
| third | Birth-2 weeks | 3 years |
| fourth | Birth-2 weeks | 4 years |
| MOLARS | ||
| first | Absent | 1 year |
| second | Absent | 2 years |
| third | Absent | 3½ years |
An adult horse’s mouth will contain up to 44 teeth. The mouth is divided into quarters, quadrants, to examine the teeth. Each quadrant will contain 3 incisors, 1 canine (not always), 1 wolf tooth (may or may not be present), 3 premolars and 3 molars. On pasture a horse will graze for up to 18 hours a day chewing food with lateral, side to side, movement of the lower jaw and will wear the teeth evenly. Dental problems, such as hooks or enamel points, can prevent the efficient sideways movement of the jaw which allows the molars to grind food properly and hence cause the signs of dental problems such as difficulty eating and weight loss.
By domesticating horses and changing their diet from grass to hay and concentrates we prevent this even wear of the teeth producing sharp enamel points on the outside of the upper molar arcades and the inside of the lower molar arcades. It is, therefore, not suprising that, in general, horses kept outside on grass all year have more even tooth wear than horses kept in a stable. The sharp enamel points develop because horses have hypsodont teeth, which means that they are not covered by enamel all over the crown, leaving rings of enamel on the tooth surface surrounded by dentin and cement. As enamel is much harder than the dentin and cement it is worn down much slower allowing the sharp points to occur.