Grinding Teeth (Bruxism) in Horses

Key Takeaways

Bruxism is the medical term for teeth grinding. It is both audible (as a grinding, rumbling noise) and visible (as a strange motion in the jaw). 

• In horses, bruxism is typically related to pain

• Commonly, horses that are experiencing colic, dental pain, or painful or irritating equipment during training grind their teeth

• Foals tend to grind their teeth if they have gastric ulcers

• Bruxism can also be related to anxiety

• Horses who are grinding their teeth require prompt veterinary attention to determine and treat the cause of the pain or resolve the cause of anxiety

• Diagnostic tools include physical and oral examination, endoscopy, and investigation of handler/horse behavior by a behavioral expert

• Treatment depends on the underlying cause including pain relief or changes to training or handling methods

A Closer Look: What is Bruxism in Horses?

Bruxism, also known as teeth grinding, is an uncommon sign of physical or psychological discomfort in horses. Horses that grind their teeth require prompt veterinary attention to determine the underlying cause. Horses showing severe symptoms such as colic require emergency medical attention.

Possible Causes

Bruxism is related to pain, whether physical or psychological. 

Sources of physical pain include:

• Colic (stomach pain)

• Ulcers, especially in foals

• Dental pain or other oral problems

• Pain related to training equipment, such as uncomfortable bits, straps that are too tight or irritating, tight fitting nose-bands, etc.

Sources of psychological pain include:

• Stress related to performance

• Stress related to changes to routine

• Stress related to travel

• Poor social standing within the herd hierarchy

• Poor relations with a handler or rider

Risk Factors

Bruxism is described as having a sudden or progressive onset, and being occasional, repetitive, continuous, or compulsive.

Sudden onset bruxism is typically related to sudden pain, including colic or traumatic injury.

Progressive onset bruxism is typically related to progressive pain including dental pain or worsening arthritis.

Occasional and repetitive bruxism are typically related to pain that comes and goes, such as equipment-related pain, stress anxiety, or to the presence of people or other horses with whom it has difficult relationships.

Continuous bruxism is typically related to ongoing pain, such as with gastric ulcers, or associated with neurological disorders.

Compulsive bruxism occurs when the horse is soothed by the act of grinding its teeth, so that even when the painful stimulus is removed, the grinding continues as an obsessive habit.

Testing and Diagnosis

Diagnostic tools to identify the underlying cause of bruxism include:

• Physical examination

• Oral examination

• Lameness examination

• Endoscopy

• Bloodwork

• Diagnostic imaging such as x-rays or ultrasound

Horses with sudden onset bruxism are often experiencing colic. In these cases, diagnostic tools include:

• Nasogastric intubation

• Rectal examination

• Bloodwork

• Abdominal ultrasound

Note: nasogastric intubation should only be performed by a veterinarian. There is no safe way to intubate a horse at home.

In cases where no physical ailment is detected, investigation into the social and behavioral life of the horse is required. This is best carried out by a behavioral expert.

Treatment depends on the underlying cause, and may include:

• Pain medication

• Antibiotics, in the case of infections

• Anti-inflammatories, in the case of inflammatory conditions

• Changes to diet or routine

• Changes to handling and training

• Changes to the social environment

Similar symptoms

Bruxism is fairly distinctive, however a horse that finds a bit uncomfortable often moves its jaw in a similar manner. Playing with the bit or champing the bit is common in young horses who have minimal experience with bitting.

Associated Symptoms

Sudden onset bruxism is often accompanied by other signs of colic, including:

• Rolling 

• Getting up and down

• Biting or kicking at the flanks

• Groaning

• Curling the lips back (Flehmen response)

• Sweating

• Labored breathing

Other symptoms of dental pain include:

• Quidding or dropping feed

• Difficulty chewing

• Eating slowly

• Avoiding the bit

Bruxism is sometimes a symptom of a neurological disorder. In this case, associated symptoms include a lack of coordination, holding the head in an odd asymmetrical position, or head pressing.