Kathryn Woolley
Qualified Equine Dental Technician

Mind the gap…  Diastemata explained

A diastema (singular) is a condition whereby there is an abnormal gap between teeth. These abnormal gaps can be found in the incisor teeth but more commonly in the cheek teeth.  A diastema may not cause a problem in some horses.  However in horses with a diastema present the gap can pack with food, which then ferments in the oral environment causing bacteria to thrive leading to infection and inflammation of the surrounding tissues. This infection called periodontal disease can cause destruction of tissue securing the tooth in place and will eventually lead to the loss of the tooth.

Food trapped in between cheek teeth

Diastemata can be caused by a number of factors:

Initially these gaps can be caused from abnormal tooth eruption, if the tooth erupts out of the jaw at an abnormal angle it becomes displaced from the other teeth in that row.  Consequently there will be gaps between the abnormal tooth and its adjacent teeth. 

Accentuated transverse ridges are another cause of diastemata.  When a tooth has a pronounced transverse ridge on the tooth surface it may wear in between the opposing teeth and cause a gap to form.

General weakness in arcades (rows of teeth) - This is when there is a lack of force between the front tooth and the back tooth of the arcade.  This force holds all the teeth together, therefore if there is a weakness in the arcade, gaps will form in between the teeth resulting in the trapping of food in the gaps. As the horse ages gaps naturally form between teeth.  This is due to the teeth getting narrower towards the root.  These gaps weaken the arcades causing food to trap between teeth.

About Me
Why Equine Dentistry
Processes & Procedures
Links and Testimonials
Dental Articles
Contact Me
Missing teeth - when a tooth is removed or falls out, a large gap remains.  Over time the natural force of the arcade will push the teeth together so the gap will close up.  During this process the gap may not close up evenly causing a closed diastema to form.  This is where the teeth close up at the top near the tooth surface, but not at the bottom, therefore trapping food in the gap between the gumline and the tooth.


Symptoms of horses with a diastema that trap food include bad breath, packing of feed in the mouth and pain when eating. Horses may chew on one side of the mouth if there is pain present or hold their head in abnormal positions when chewing. These horses may also be more prone to colic since they are unable to chew their food properly.


Currently new research is being undertaken regarding the best treatment option for this dental problem.  The most effective method of treatment is to enlarge the gap, so that feed will not remain in the gap but will be naturally flushed out with saliva as the horse chews. Occasionally antibiotics both orally and directly onto the infected area around the tooth may be required. If this treatment is not effective, extraction of the tooth may be required but this is the last option as this could cause further diastemata to develop in the same dental arcade.

© 2017 All content copyright. Kathryn Woolley KT Equine Dentistry