Dental Conditions
When a horse has healthy teeth, they are clean, even with one another, and line up well. Proper dental health is crucial to the comfort and overall health of a horse. However, not all horses own the perfect mouth. Dental problems can be caused by misaligned jaws, uneven wear patterns, and gum infection. They can be painful and cause a plethora of behavorial and ingestion challenges. Dental malocclusions can lead to head tossing, unwillingness to accept the bit, unwillingness to eat, biting, and head shyness. A responsible horse owner will moniter her horse's teeth, ensuring they are healthy and clean. In the event of a dental issue, a qualified veterinarian should be consulted to correct the issue.
Horses chew in a circular motion, so the incisors and cheek teeth do not meet the opposing incisors or cheek teeth when the horse's jaw is closed. Horses are herbivores and eat grasses, which are quite abrasive; therefore, the enamel of a horse's tooth is very strong, though has soft areas. The circular chewing motion ideally allows the horse's teeth to be worn in an even pattern, though dental issues can inhibit this. Horse teeth grow at a rate of 2-3 mm a year, in order to prevent the horse from completely wearing their teeth away. Dental Formula Canine teeth are sexually dimorphic. Hypsodont teeth grow continuously, found in herbivores. The smoother tooth surface, in comparison to ruminants, is known as lophodont. A horse might have a dental issue if they exhibit the following symptoms:
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A diagram of the horse jaw, with teeth labeled (1).
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Dental Deformaties
1. Wolf Teeth
Wolf teeth are extra teeth in front of the pre-molars and are found in approximately 70% of horses. It is a common misconception that male horses are more likely to develop wolf teeth. The teeth are usually found on the upper jaw, but can be located on the lower jaw. Wolf teeth have been found in branches of the equine's evolution; they used to be the same size as the other molars, and participated in the grinding of the brush that composed these ancient horse's diets. As horse's diets shifted to being grass based during evolution, the molars became larger and negated the need for the wolf teeth. Thus, wolf teeth are a vestigial structure. Wolf teeth should be removed if the horse is being ridden or worked in a bit, as they can cause pain and discomfort from the bit hitting against them (2). |
2. Caudal Hooks
Caudal Hooks are caused by abnormal growth and wear from not having an opposing surface to be worn against and only occur on the back molars of a horse's mouth. Horses with underbites, where the lower incisors sit in front of the upper incisors, or overbites, where the upper incisors sit in front of the lower incisors, are especially prone to developing caudal hooks. Overbites and underbites are often hereditary; however, the lower jaw can move forward due to another malocclusion, a disalignment of the jaw. If left unattended, the hook can grow down into the lower jaw, causing further pain and infection. Proper dental maintaince and monitoring can prevent the development of caudal hooks.
Caudal Hooks are caused by abnormal growth and wear from not having an opposing surface to be worn against and only occur on the back molars of a horse's mouth. Horses with underbites, where the lower incisors sit in front of the upper incisors, or overbites, where the upper incisors sit in front of the lower incisors, are especially prone to developing caudal hooks. Overbites and underbites are often hereditary; however, the lower jaw can move forward due to another malocclusion, a disalignment of the jaw. If left unattended, the hook can grow down into the lower jaw, causing further pain and infection. Proper dental maintaince and monitoring can prevent the development of caudal hooks.
3. Rostral Hooks
Rostral Hooks occur only on the front molars in the mouth. They are also due to uneven wear on teeth that is caused by overbites or underbites, and should be regularly monitored to prevent pain and infection.
Rostral Hooks occur only on the front molars in the mouth. They are also due to uneven wear on teeth that is caused by overbites or underbites, and should be regularly monitored to prevent pain and infection.
4. Ramps
Similar to hooks, a ramp is uneven wearing of the teeth, but on the lower jaw. Ramps can be affect both the first lower premolar and the last lower molar. They are likely to occur if the upper front premolar deciduous cap, or baby tooth, never falls out, preventing normal growth of a permanent premolar. It can also be caused by a tooth that is not reduced with corresponding grinding from the opposing tooth. It prevents horses from chewing freely side to side, due to the pain from the sharp point of the ramp, resulting in excessive molar wear. This repetitive improper use of the jaw for chewing can force lower jaw forward over time, causing an under bite. Ramps may pose greater discomfort issues to horses that are worked with a bit as well. An equine dentist can help reduce ramps in horses teeth.
Similar to hooks, a ramp is uneven wearing of the teeth, but on the lower jaw. Ramps can be affect both the first lower premolar and the last lower molar. They are likely to occur if the upper front premolar deciduous cap, or baby tooth, never falls out, preventing normal growth of a permanent premolar. It can also be caused by a tooth that is not reduced with corresponding grinding from the opposing tooth. It prevents horses from chewing freely side to side, due to the pain from the sharp point of the ramp, resulting in excessive molar wear. This repetitive improper use of the jaw for chewing can force lower jaw forward over time, causing an under bite. Ramps may pose greater discomfort issues to horses that are worked with a bit as well. An equine dentist can help reduce ramps in horses teeth.
5. Waves
Waves are a wave-like wear pattern on the premolars and molars in the mouth. This extreme, uneven wearing is due to a culmination and neglection of other dental issues, like delayed emergence of permanent teeth, ramps, missing teeth, or hooks. Proper dental care prevents waves.
Waves are a wave-like wear pattern on the premolars and molars in the mouth. This extreme, uneven wearing is due to a culmination and neglection of other dental issues, like delayed emergence of permanent teeth, ramps, missing teeth, or hooks. Proper dental care prevents waves.
6. Stepped Molars
Stepped molars are when the teeth grind in a manner that causes an unusual height difference in the molars, preventing them from moving their jaw forward or backwards. This exhasperates the condition, creating further wear in this uneven shape. It is usally caused by a mature cheek tooth growing into a space that a permanent tooth has not yet grown into because of delayed growth.
Stepped molars are when the teeth grind in a manner that causes an unusual height difference in the molars, preventing them from moving their jaw forward or backwards. This exhasperates the condition, creating further wear in this uneven shape. It is usally caused by a mature cheek tooth growing into a space that a permanent tooth has not yet grown into because of delayed growth.
7. Accentuated Transverse Ridges
Accentuated Transverse Ridges are caused when a misaligned jaw causes the hard enamel of the upper or lower teeth to wear into the soft enamel of the opposite teeth. This created a divets and ridges on the molars of the teeth being improperly grinded. The ridges can also be caused if the horse is not chewing in a standard circle motion. Without treatment, this condition can cause the teeth to seperate, allowing food to get stuck in the space and cause gum disease.
Accentuated Transverse Ridges are caused when a misaligned jaw causes the hard enamel of the upper or lower teeth to wear into the soft enamel of the opposite teeth. This created a divets and ridges on the molars of the teeth being improperly grinded. The ridges can also be caused if the horse is not chewing in a standard circle motion. Without treatment, this condition can cause the teeth to seperate, allowing food to get stuck in the space and cause gum disease.
Estimating Age from Teeth
Being able to estimate a horse's teeth is a handy skill for horse owners and equestrians to have. From identifying a horse's approximate age by it's teeth, horse buyers can tell if they are being sold the horse that is being advertised. Horses donated or rescued can also benefit from being aged by their teeth; it lets the people who end up with them know what potential health problems to expect or what kind of past a horse has had. Horses' teeth tell much about their history.
There are several indicators of a horse's age in his teeth:
Rule of 8 for Deciduous Teeth:
By 8 days of age, central incisors have erupted
By 8 weeks of age, the intermediate incisors have erupted
By 8 months of age, the corner incisors have erupted
Galvayne's Groove: An indent in the corner incisors. At age 10, appears near the gum. At age 15, extends half way down the tooth. At age 20, extends the entire length of the tooth. At age 25, appears only on the bottom half of the tooth. By age 30, the groove is completely gone.
7 and 11 year hook: A hook on the corner incisors can form as the mouth changes shape from losing deciduous teeth or from the jaw sliding forward due to chewing patterns. If this hook appears, it will appear first at age 7, disappear at age 9, and reappear by age 11. By the time the horse is in his late teens, it will have disappeared again and will not reappear.
Angle of Incidence: Refers to the angle the teeth protrude from the gums and meet the opposing teet. Young horses' teeth are more vertically aligned, while older horses' teeth have a greater slope from the mouth.
Cups: A small divet in the middle of the incisors indicated by dark coloring, usually obolong in shape.
Dental Stars: a yellowish colored spot that appears in front of the cups, close to the front of the incisor.
Marks: A shallow cup that has become circular and is growing towards the back of the tooth, as a result of age, is called a mark. They look similar to cups, but change shape with the tooth and are lighter in color.
Enamel ring: the white ring around the cups and the mark. By age 9, dental stars are merging with the enamel rings.
Under 9 years of age, a horse's teeth are rectangular in shape
From 9 to their midteens, a horse's teeth are more round in shape
In their late teens and older, a horse's teeth are more triangular in shape
There are several indicators of a horse's age in his teeth:
Rule of 8 for Deciduous Teeth:
By 8 days of age, central incisors have erupted
By 8 weeks of age, the intermediate incisors have erupted
By 8 months of age, the corner incisors have erupted
Galvayne's Groove: An indent in the corner incisors. At age 10, appears near the gum. At age 15, extends half way down the tooth. At age 20, extends the entire length of the tooth. At age 25, appears only on the bottom half of the tooth. By age 30, the groove is completely gone.
7 and 11 year hook: A hook on the corner incisors can form as the mouth changes shape from losing deciduous teeth or from the jaw sliding forward due to chewing patterns. If this hook appears, it will appear first at age 7, disappear at age 9, and reappear by age 11. By the time the horse is in his late teens, it will have disappeared again and will not reappear.
Angle of Incidence: Refers to the angle the teeth protrude from the gums and meet the opposing teet. Young horses' teeth are more vertically aligned, while older horses' teeth have a greater slope from the mouth.
Cups: A small divet in the middle of the incisors indicated by dark coloring, usually obolong in shape.
Dental Stars: a yellowish colored spot that appears in front of the cups, close to the front of the incisor.
Marks: A shallow cup that has become circular and is growing towards the back of the tooth, as a result of age, is called a mark. They look similar to cups, but change shape with the tooth and are lighter in color.
Enamel ring: the white ring around the cups and the mark. By age 9, dental stars are merging with the enamel rings.
Under 9 years of age, a horse's teeth are rectangular in shape
From 9 to their midteens, a horse's teeth are more round in shape
In their late teens and older, a horse's teeth are more triangular in shape
Value |
Corner Incisors |
Intermediate Incisors |
Central Incisors |
Cup Disappearance |
8 years old |
7 years old |
6 years old |
Dental Stars Appearance |
10 years old |
9 years old |
8 years old |
Marks Appearance |
11 years old |
11 years old |
11 years old |
Age of Eruption
Bibliography
1. http://www.rvc.ac.uk/review/dentistry/basics/triadan/other.html
2. http://evds.net.au/article_wolf_teeth.php
3. http://www.mitchellplainfarm.com/dental-care-and-development.html
4. http://www.trotusa.com/TROT_-_The_Retirement_of_Thoroughbreds/About_Horse_Teeth_-_TrotUSA.html
5. https://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&ved=0ahUKEwjMsZjAw_fQAhUJ4yYKHYWtAasQjRwIBw&url=https%3A%2F%2Fwww.studyblue.com%2Fnotes%2Fnote%2Fn%2Flarge-animal-teeth%2Fdeck%2F2409237&psig=AFQjCNHBNpKn5PwxBl0FBB2wmK4YwxbPKw&ust=1481936927133894
6. https://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwjB5pCxxvfQAhVW22MKHUj8BkMQjRwIBw&url=http%3A%2F%2Fwww.texasequinedentist.com%2Fequine-dental-care%2Fcommon-equine-dental-problems.html&psig=AFQjCNF2sFvNGL9OXs9inQJuJ6tK5f1Dmg&ust=1481937424901764
7. http://fisherequinedentistry.com/equine-dentistry/equine-teeth-problems/
8. http://www.mwveterinaryservices.com/dental-abnormalities.html
2. http://evds.net.au/article_wolf_teeth.php
3. http://www.mitchellplainfarm.com/dental-care-and-development.html
4. http://www.trotusa.com/TROT_-_The_Retirement_of_Thoroughbreds/About_Horse_Teeth_-_TrotUSA.html
5. https://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&ved=0ahUKEwjMsZjAw_fQAhUJ4yYKHYWtAasQjRwIBw&url=https%3A%2F%2Fwww.studyblue.com%2Fnotes%2Fnote%2Fn%2Flarge-animal-teeth%2Fdeck%2F2409237&psig=AFQjCNHBNpKn5PwxBl0FBB2wmK4YwxbPKw&ust=1481936927133894
6. https://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwjB5pCxxvfQAhVW22MKHUj8BkMQjRwIBw&url=http%3A%2F%2Fwww.texasequinedentist.com%2Fequine-dental-care%2Fcommon-equine-dental-problems.html&psig=AFQjCNF2sFvNGL9OXs9inQJuJ6tK5f1Dmg&ust=1481937424901764
7. http://fisherequinedentistry.com/equine-dentistry/equine-teeth-problems/
8. http://www.mwveterinaryservices.com/dental-abnormalities.html
Class completed November 2016-January 2017 | Class met everyday weekly for 1 and 1/2 hours