Periodontal Disease in Horses

Peter Borgdorff
Photos by: 
Peter Borgdorff


The teeth of the horse are held into their sockets by periodontal ligaments. These are microscopic fibrous strands which connect the teeth to the bone and that remodel as teeth develop and erupt. Periodontal ligaments also afford the teeth with a very small amount of movement which cushions forces that are exerted on the teeth when grinding takes place. The gums cover the bone and part of the tooth in order to protect the periodontal ligament and other vital structures of the alveolus (socket). The edge of the gum has a special shape and this allows salivary fluid to fill this margin. All these elements, combined with a rich blood supply, are effective in providing protection against infection.


Periodontal disease (pictured above) is an oral disease affecting the structures around the teeth. A minor form of periodontal disease is called gingivitis which affects the gum margins and this condition is evident when gums start bleeding lightly on touch. Gingivitis is very common in the horse and its discovery should not be seen as remarkable. The continuous eruption of the teeth at a younger age makes it an almost self-correcting phenomenon as long as it is combined with regular and appropriate dental care by a well-trained equine dental practitioner. The gums restore as periodontal tissue regenerates. More severe forms of periodontal disease progress to gums receeding off the teeth and bone loss in that. The ultimate price for persistent and serious periodontal disease is tooth loss which in many circumstances can be prevented with careful dental correction planned to take place over a period of time.


Typically, in a horse with periodontal disease, we find feed impaction in affected areas. A myriad of symptoms can subsequently occur; from bad odour to slow eating and from severe weight loss to life-threatening colic. Cranky or intolerant behaviour by the horse is often reported by owners in more severe cases. In short, there are many symptoms resulting from periodontal disease and horse owners are advised to note down all irregular behaviour that is observed.


The main factor contributing to periodontal disease is the presence of transverse ridges which push feed into the space between two opposing teeth during the mastication of feed. A very small amount of feed lodged may result in gingivitis which is called stage one periodontal disease known as gingivitis. When there is more severe impaction of feed, this can also lead to severe stages of periodontal disease right up to stage four, which causes a tooth to be lost. Other factors that contribute to the occurrence of periodontal disease are: trauma to teeth such as fractures, displaced teeth caused by crowding especially in Arabians and in smaller breeds, and plaque formation due to mineral and other food particle adherence to the teeth.


A moderate degree of periodontal disease is very common, the main causes being feed lodged between incisors and molars, as well as the build-up of plaque on canines in the male horse. Regular professional dental care is essential as a first step to combating periodontal disease.

Associated Conditions

Conditions frequently found when there is the presence of periodontal disease:

  • Lateral and linear tooth drift
  • Tooth loss

Treatment Objectives and Frequency

As explained in our article ‘equine dentition’, the horse’s teeth continue to erupt for much of its life and the structures surrounding the teeth continue to adjust. This means that areas suffering from periodontal disease benefit from renewed gum and tooth structures which replace old cells in damaged structures. What makes feed packing such an important cause of damage to tooth structures and tooth viability is not only the mechanical pressure on structures but also the fact that decomposing feed produces bacteria and acids that destroy vital structures. Decay is one of those effects. If there is the presence of impacted feed, remedial filing by an equine dental practitioner is needed to reduce the length of opposing tooth extension, such as transverse ridges, to reduce the chance of feed fragments being compacted into the affected areas. If treatment is carried out gradually over a number of treatments and without damaging too much of the vital grinding contours of the teeth, it is an excellent method of reducing the incidence and degree of periodontal disease. In any case, far more preferable to treating the symptoms at great expense and with dubious benefit.


Remarkably, owners of horses can make great improvements in the way teeth wear and consequently, the occurrence of transverse ridges; diet adjustments to reduce the amount of short fibre and replace it with longer fibre are very effective in ensuring more even wear across tooth surfaces. Although it is the horse's nature to forage over large areas and ingest many types of long-fibred grasses, we provide them with grazing over very small areas and refined feeds. In summary, the following feeds lack long fibre:

  • Chaff
  • Over-grazed pasture
  • Pellets
  • Pre-mixed feeds
  • Cereal feeds
  • Bran and pollard

Although it is vital to feed an adequate range of nutrients, these nutrients should complement a diet that is as close to their natural diet as possible, with the aim being the provison of a larger quantity of long fibre in the diet. Feeding long fibre has significant benefits:

  • It wears the teeth much more evenly.
  • Horses spend more time chewing and ingesting the same quantity of feed, thus keeping themselves happily occupied.
  • Significantly improved digestive health.
Edited for publication by NEDP.