A horse’s horse teeth tell you almost everything about its life: how old it is, how well it has been managed, what it has been fed and even the bits it has been ridden in. Horse dentition is one of the most distinctive features of equine anatomy, because a mature horse carries between 36 and 44 teeth that keep erupting from the jaw throughout much of its life. This guide covers tooth structure, the equine dental formula, the development timeline from foal to aged horse, how to age a horse by its teeth, the common problems your vet will look for and how to keep horse teeth healthy through routine care.
Table of Contents
How Many Teeth Does a Horse Have?
A mature horse has 36 to 44 teeth in total. The variation comes down to sex and the presence of optional “extra” teeth:
- Mares: 36 to 40 teeth, as canines are usually absent or vestigial
- Stallions and geldings: 40 to 42 teeth, with four prominent canine teeth (“tushes”)
- Wolf teeth: small first premolars present in around 30% of horses, often removed before bitting
Horse teeth are hypsodont, meaning the crown is long and continues to erupt from the jawbone throughout life to compensate for wear from grass, hay and grain, at roughly 2 to 4 mm per year. Most of the tooth sits hidden below the gum as the “reserve crown” and is gradually pushed up as the chewing surface wears down. The dental anatomy is also heterodont (several tooth shapes for different jobs) and diphyodont (one set of milk teeth followed by one set of permanent teeth). Foals start with 24 deciduous teeth, all of which are replaced by age 5.
The Equine Dental Formula
Vets and equine dental technicians describe the mouth using a dental formula, which counts the teeth in one half of the upper and lower jaw and then doubles the total. The formula for a permanent equine mouth is written as incisors 3/3, canines 1/1 (or 0/0 in most mares), premolars 3 or 4 / 3 or 4, molars 3/3. The table below sets out how those numbers add up.
| Tooth type | Per side, upper / lower | Total (both sides) | Main job |
|---|---|---|---|
| Incisors | 3 / 3 | 12 | Grasping and tearing grass |
| Canines (tushes) | 1 / 1 (males) | 0 to 4 | Vestigial fighting teeth |
| Wolf teeth | 0 to 1 / 0 to 1 | 0 to 4 | None (often removed) |
| Premolars | 3 to 4 / 3 to 4 | 12 to 16 | Grinding fibre |
| Molars | 3 / 3 | 12 | Grinding fibre |
The premolars and molars together are known as the cheek teeth or arcades, and they account for 24 of the working teeth in a typical mouth. Understanding the formula makes it far easier to follow what your vet means when they talk about a “106” or a “311” using the modified Triadan numbering system at a dental appointment.
Types of Horse Teeth and Their Jobs
Each tooth type sits in a specific part of the mouth and does a specific job. Knowing the basic anatomy makes signs of dental trouble much easier to spot, and it links directly to how a horse processes feed through its digestive system.
Incisors
The 12 incisors at the front of the mouth, six upper and six lower, are used to grasp and tear grass. They are the teeth a vet or equine dental technician inspects first when ageing a horse, because the wear pattern, angle and shape change in predictable stages.
Canines (Tushes)
Four canine teeth sit between the incisors and the cheek teeth in male horses. They erupt at around 4 to 5 years of age, are not used for chewing and are thought to be remnants of fighting teeth from wild equine ancestors. They sometimes accumulate tartar and may need scaling. Our dedicated guide to equine canine teeth covers the male-specific tushes in more detail.
Premolars and Molars (Cheek Teeth)
The 24 cheek teeth, three or four premolars and three molars in each quadrant, do the real work of grinding fibrous feed into a swallowable bolus. They are tightly packed in arcades that work as a single grinding surface, with the upper arcade slightly wider than the lower. This anatomy is the reason horses develop sharp enamel points on the outside of the upper arcade and the inside of the lower arcade, the points the vet “floats” off at the annual dental.
Wolf Teeth
Wolf teeth are small, peg-like teeth that erupt just in front of the first cheek tooth in roughly one-third of horses. They have no chewing function and frequently sit exactly where the bit rests in the mouth, causing discomfort. Most are removed at the routine dental in the year before the horse is started under saddle. For the full picture see our guide to wolf teeth in horses.
Deciduous vs Permanent Teeth
Because horses are diphyodont, every young horse grows two generations of teeth. Foals are born with, or quickly grow, 24 deciduous (“milk” or “baby”) teeth: 12 incisors and 12 cheek teeth. These temporary teeth are smaller, whiter and more sharply shelled than the permanent teeth that replace them.
As the permanent teeth erupt underneath, they push the milk teeth out. The shed remnants are called “caps”, and a partly shed cap can sit at an angle and cause sharp edges or discomfort, which is one reason youngstock need more frequent dental checks than adults. By around five years of age the last milk tooth has gone and the horse has a complete set of permanent teeth in wear. Knowing whether you are looking at deciduous or permanent incisors is the single most reliable way to tell a horse under five from an older animal.
Dental Development Timeline: Foal to Aged Horse
Equine dental development follows a remarkably predictable timeline, which is why teeth are still the most reliable way to estimate the age of a horse without paperwork. The eruption dates below relate to the permanent teeth unless stated otherwise.
| Age | What erupts or changes |
|---|---|
| Birth to 1 week | Deciduous central incisors and first three deciduous cheek teeth appear |
| 4 to 6 weeks | Deciduous middle incisors erupt |
| 6 to 9 months | Deciduous corner incisors erupt; foal now has all 24 milk teeth |
| 2.5 years | Permanent central incisors replace the milk versions |
| 3.5 years | Permanent middle incisors erupt |
| 4.5 years | Permanent corner incisors erupt |
| 5 years | “Full mouth”: all permanent teeth in wear |
| 6 to 8 years | Cups wear out of the lower incisors (6: centrals, 7: middles, 8: corners) |
| 10 years | Galvayne’s groove appears at the gum line of the upper corner incisor |
| 15 years | Galvayne’s groove extends halfway down the tooth |
| 20 years | Galvayne’s groove reaches the wearing surface |
| 25 to 30 years | Groove worn away from the top; incisor angle becomes increasingly horizontal |
5 to 10 Years: The Wear Marks Develop
Between 5 and 10 years the cup-shaped infundibula (depressions on the chewing surface of the incisors) gradually wear away. As each cup disappears, a small “dental star” appears in front of it: a darker line of exposed secondary dentine that the horse lays down to protect the pulp. By 6 the lower central incisor cups are gone, by 7 the middle ones and by 8 the corners. This is where the phrase “long in the tooth” comes from, as older horses’ incisors look longer because more of the crown has erupted out of the jaw.
10 to 20 Years: Galvayne’s Groove and Profile Changes
From around ten years, Galvayne’s groove becomes the headline ageing feature. It is a dark vertical channel that appears at the gum line of the upper corner incisor at 10, reaches halfway down the tooth by 15, extends the full length by 20, then recedes from the top so that only the lower half remains by 25. It is a useful rough guide rather than an exact clock.
20+ Years: The Aged Mouth
In the geriatric horse the incisors meet at progressively shallower angles, almost horizontal in some 20-year-olds and sharply slanted in 30-year-olds. The chewing surface of the cheek teeth wears flat and may develop “smooth mouth”, reducing the horse’s ability to chew long fibre. Soaked feeds and chopped forage become essential to maintain weight, a key consideration as horses move through their later life stages.
Ageing a Horse by Its Teeth
Ageing a horse by its teeth is part science, part art. The Animal and Plant Health Agency and the United States Department of Agriculture both publish standardised ageing diagrams, but the rule of thumb for owners is:
- Under 5: count permanent incisors as they erupt, in the order central, middle, corner
- 5 to 10: watch the cups disappear from the lower then the upper incisors, and the dental stars appear
- 10 to 15: Galvayne’s groove appears and starts to extend
- 15 to 20: Galvayne’s groove reaches the chewing surface
- 20+: incisor angle becomes increasingly horizontal and the cheek teeth wear flat
There is also the so-called “1-2-3 rule” for the eruption of the permanent incisors: the centrals come in at roughly 2.5 years, the middles at 3.5 and the corners at 4.5, giving the handy 1, 2, 3 spacing of years 3, 4 and 5 when each pair comes into wear. Diet, conformation and bit habits all skew the picture: a crib-biting horse wears its incisors unevenly, and horses on hard feeds wear differently from those at grass. Ageing is reliable to within 1 to 2 years on well-managed horses up to about 8, after which it becomes a broader estimate. For a step-by-step walkthrough see our guide on how to tell a horse’s age by its teeth.
Common Horse Teeth Problems
Even with routine dental care, problems arise. The most common conditions an equine vet or qualified equine dental technician (EDT) treats include:
Sharp Enamel Points
The most common issue. Because the lower jaw is narrower than the upper, the outer edges of the upper cheek teeth and the inner edges of the lower cheek teeth never wear evenly. Sharp points form, cutting the cheeks and tongue. Floating (rasping) the points smooth is the bread-and-butter of equine dentistry.
Hooks, Ramps and Wave Mouth
- Hook: excess crown on the front of the upper second premolar or the back of the lower last molar, common in horses with overshot or undershot bites
- Ramp: a sloping rather than flat chewing surface, often on the lower last molar
- Wave mouth: alternating high and low spots across the cheek-tooth arcade, usually caused by years of neglected dentistry
Diastema
A diastema is a gap between adjacent cheek teeth that traps food. The trapped feed ferments, creating periodontal disease, painful gum infection and bad breath. Diastemata are increasingly recognised as a major cause of weight loss and quidding in older horses and are treated by widening, packing or cleaning at advanced equine dentistry referrals.
Periodontal Disease and Tooth-Root Abscesses
Disease of the gums and supporting tissues, often secondary to diastema or impaction, is the most common cause of eventual tooth extraction in horses over 20. Left untreated it can progress to a painful tooth abscess, which in upper cheek teeth may even break out as a one-sided nasal discharge from an infected sinus.
Equine Odontoclastic Tooth Resorption and Hypercementosis (EOTRH)
A relatively recently recognised condition affecting the incisors of older horses, where teeth are slowly resorbed and replaced with abnormal cementum. It is painful, progressive and often only diagnosed on incisor radiographs. The usual treatment for advanced cases is incisor extraction, which most horses tolerate remarkably well. Read more on our equine tooth resorption (EOTRH) page.
Infundibular Caries
Horses develop their own form of decay in the cup-shaped infundibula of the cheek teeth. Once the enamel is breached, the underlying cementum and dentine erode quickly. Caries are increasingly picked up on detailed dental exams and may need monitoring, filling or extraction depending on severity.
Routine Equine Dental Care
World Horse Welfare and the British Horse Society both recommend a sensible schedule of checks:
- Adult horses (5 to 18 years): a dental check every 6 to 12 months
- Youngstock under 5: every 6 months, as milk teeth shedding and permanent teeth erupting need closer monitoring
- Senior horses (18+): every 6 months, as diastema, EOTRH and tooth loss become much more common
- Performance horses: every 6 months for bit comfort and contact
The UK has a tiered system of dental practitioners. Routine rasping can be carried out by a vet or by a qualified equine dental technician registered with the British Association of Equine Dental Technicians (BAEDT) or the World Wide Association of Equine Dentistry (WWAED). Sedation and extractions can only legally be performed by a vet. Always ask to see qualifications before booking, as the field is unregulated outside vet practices and unqualified “horse dentists” can do real damage.
Dental health and feeding are tightly linked. A horse that cannot grind its forage properly will struggle to hold condition, so it is worth reading our guide to horse feeding and nutrition alongside this article, especially for seniors where soaked or chopped forage may be needed.
Signs Your Horse Needs Its Teeth Checked
Horses are remarkably good at hiding dental pain, so by the time a horse is dropping food or losing weight the problem is usually well advanced. Catch it earlier by watching for:
- Quidding: dropping balls of half-chewed feed
- Slow eating or tilting the head while chewing
- Bit resistance: head tossing, leaning on one rein, refusing contact
- Foul-smelling breath
- Whole grains appearing in droppings
- Weight loss despite adequate feed
- Facial swelling or nasal discharge from one nostril (possible tooth-root infection)
- Behavioural changes: grumpy when bridled, head-shy on one side
If bit discomfort is part of the picture, some owners of older or dentally compromised horses move to a bitless bridle such as an English hackamore while the underlying problem is managed. The MSD Veterinary Manual also publishes detailed dental eruption tables if you want to dig deeper into the science.
Frequently Asked Questions
What type of dentition do horses have?
Horses are heterodont, diphyodont and hypsodont. Heterodont means they have several tooth shapes (incisors, canines and cheek teeth) for different jobs; diphyodont means they grow one set of milk teeth followed by one set of permanent teeth; and hypsodont means the teeth have very long crowns that keep erupting throughout life to replace the surface lost to grinding.
How often should a horse have its teeth checked?
Once a year is the absolute minimum for adult horses. Every 6 months is recommended for youngstock under 5, seniors over 18 and any performance horse where bit comfort matters. The check itself takes 15 to 30 minutes and is rarely traumatic with sympathetic handling.
What is “floating” a horse’s teeth?
Floating is the routine rasping of sharp enamel points off the cheek teeth using a manual or motorised file. It removes the points that cut the cheeks and tongue, smooths the chewing surface and corrects minor uneven wear. It does not normally require sedation in calm horses, though most yards now use mild sedation for the horse’s comfort and the practitioner’s safety.
Can you really tell a horse’s age from its teeth?
Yes, within limits. Up to about 8 years the eruption and wear of the incisors gives an age accurate to within 1 to 2 years. After that the picture becomes a broader estimate based on the disappearance of the cups, the dental stars, Galvayne’s groove and the changing angle of the incisors. Diet and habits such as crib-biting can skew the reading.
Why does my horse drop food when eating?
Quidding (dropping partially chewed food) is the classic sign of dental pain. Possible causes include sharp enamel points, diastema, fractured cheek teeth, EOTRH or tongue injury. Get a vet to examine the mouth, as the cause is almost always treatable, but the longer it is left the harder it is to put right.
Do horses get tooth decay like humans?
Horses develop a different type of decay called infundibular caries in the cup-shaped depressions of the cheek teeth. Once the enamel is breached, the underlying cementum and dentine erode rapidly. Caries are increasingly recognised on detailed dental exams and may need filling or extraction depending on severity.
