Bit & Bridle

Equine Tooth Abscesses

Other Names

  • Tooth root abscess
  • Apical infection
  • Periapical abscess
  • Dental abscess

What are Equine Tooth Abscesses?

A tooth abscess in horses is a localised bacterial infection that develops at the root tip (apex) of a tooth — hence the term apical or periapical abscess. The infection causes pus to accumulate within or around the tooth root, and can spread to the surrounding bone, periodontal ligament, and adjacent structures. In the case of the upper cheek teeth, the roots sit in very close proximity to the maxillary sinuses, so infections frequently spread into the sinuses — a complication that significantly increases the complexity of treatment.

Tooth root abscesses are one of the most common dental problems seen in horses and are a significant cause of facial swelling, nasal discharge, difficulty eating, and weight loss. They can affect any tooth but are most frequently seen in the cheek teeth (premolars and molars), particularly the caudal upper cheek teeth whose roots are embedded within the sinus cavities.

Horses have hypsodont teeth — meaning the teeth have very long crowns that erupt slowly throughout the horse’s life. This complex dental anatomy makes horses particularly susceptible to certain types of dental disease, and regular dental care is essential throughout their lives.

Causes

Several factors can cause or contribute to the development of a tooth root abscess:

  • Dental fractures: Fractures of the tooth crown or root — caused by trauma, biting on hard objects, or pressure from adjacent teeth — allow bacteria to enter the pulp cavity and migrate to the root tip.
  • Infundibular disease: Decay within the infundibulum (central funnel-shaped structure within cheek teeth) can progress to the pulp and eventually cause apical infection.
  • Periodontal disease: Deep periodontal pockets that form between teeth provide a pathway for bacteria to reach and infect the tooth root.
  • Overcrowded or displaced teeth: Developmental abnormalities, unerupted teeth, or overcrowding can result in pressure necrosis or abnormal wear patterns that predispose teeth to infection.
  • Blood-borne infection: Bacteria circulating in the bloodstream during systemic infection (bacteraemia) can seed the tooth root, causing an abscess as a secondary condition.
  • Age-related changes: In older horses, the pulp chambers narrow and become more vulnerable to infection as teeth wear down and the protective enamel layers reduce.

Symptoms and Signs

  • Facial swelling: A firm or fluctuant swelling on the side of the face or lower jaw, often directly over the affected tooth. The swelling may be warm and painful to the touch.
  • Nasal discharge: Unilateral (one-sided) nasal discharge — particularly if foul-smelling — strongly suggests secondary sinusitis from an infected upper cheek tooth. The discharge may contain food material or pus.
  • Difficulty eating (quidding): Dropping partially chewed food from the mouth is a classic sign of oral pain. Affected horses may be reluctant to eat hard feed or show a preference for soft feeds.
  • Weight loss: As a consequence of reduced feed intake due to pain.
  • Fistulous tract: A discharging tract on the lower jaw is sometimes seen in horses with abscessed lower cheek teeth. This appears as a small hole in the skin that weeps pus or fluid.
  • Head shyness or resistance to bridling: Pain associated with dental disease can manifest as behavioural issues under saddle, particularly when pressure is applied near the affected area.

Diagnosis

  • Oral examination under sedation: A thorough examination with a dental mirror, probe, and speculum (mouth gag) is essential. This allows visualisation of the teeth, identification of fractures, abnormal wear, periodontal pocketing, and exposed pulp.
  • Radiography: Dental radiographs are invaluable for identifying periapical lucency (bone destruction around the root tip), root fractures, and the extent of infection. Standing radiographs or computed tomography (CT) provide the most diagnostic images.
  • CT scanning: Increasingly available at equine referral centres, CT provides detailed three-dimensional imaging of dental structures, sinuses, and adjacent bone — often superior to conventional radiographs for complex cases.
  • Endoscopy: Nasal endoscopy allows direct visualisation of the sinuses and can identify mucosal changes, pus accumulation, or abnormal tooth root protrusion into the sinus cavity.
  • Percussion testing: Tapping affected teeth with a metal instrument may elicit a pain response or produce a dull sound indicating internal pathology.

Treatment

  • Tooth extraction: Extraction of the affected tooth is the most common and definitive treatment for horses with apical infections. In the majority of cases this is performed using oral repulsion techniques under general anaesthesia or, increasingly, minimally invasive oral extraction techniques in standing sedated horses.
  • Socket management: Following extraction, the empty socket is packed with an antiseptic plug (such as dental impression material or Alvogyl) to prevent food impaction and provide a scaffold for healing. The plug is removed and the socket checked at 2-week intervals until granulation tissue has filled the cavity.
  • Sinus flushing: If secondary sinusitis has developed, the sinuses are flushed via a trephination hole drilled through the facial bone. Daily lavage with saline or dilute antiseptic solution is continued until the infection resolves — typically 2–6 weeks.
  • Antibiotics: Systemic antibiotics (commonly trimethoprim-sulphonamide or penicillin) are prescribed post-extraction and continued for several weeks, particularly when sinus involvement is present.
  • Anti-inflammatories: NSAIDs provide pain relief and reduce post-operative swelling.
  • Conservative management: In early or mild cases, particularly in young horses, some veterinary dentists may attempt conservative treatment to preserve the tooth, including endodontic procedures or topical antiseptic application. However, these approaches have variable success rates in horses.

Prevention

  • Schedule annual dental examinations with a qualified equine dental veterinarian or equine dental technician. Young horses (under 5 years) and seniors (over 15 years) should be seen every 6 months due to the rapid changes occurring in their dentition.
  • Dental floating (rasping) corrects sharp enamel points and irregular wear patterns that contribute to periodontal disease and fractures.
  • Monitor horses closely for early signs of dental pain — changes in eating behaviour, quidding, weight loss, or nasal discharge should prompt a dental check without delay.
  • Avoid feeding horses from elevated feeders or hay nets positioned high on walls, as unnatural head position can affect dental wear patterns over time.
  • Ensure adequate forage in the diet — horses are designed to graze with their heads down, and good roughage provides the correct lateral chewing motion that promotes even tooth wear.

Prognosis

Most horses recover well following tooth extraction and appropriate aftercare. The extraction site typically heals fully within 2–4 months. Horses adapt remarkably well to missing teeth and can usually return to normal work and feed intake within weeks of surgery. When sinus involvement is present, recovery may take longer — 3–6 months in some cases — and repeat flushing procedures may be required. The prognosis worsens if the infection has caused extensive bone destruction or spread to multiple sinuses, but even complex cases often respond well to referral-level care.

When to Call the Vet

Do not delay seeking veterinary attention if your horse shows any of the following: one-sided, foul-smelling nasal discharge; a lump or swelling on the jaw or cheek; quidding (dropping food); significant weight loss alongside poor appetite; or a small discharging hole on the lower jaw. Dental infections do not resolve without treatment and will worsen over time. For related reading, see our guide on equine dental health and Equine Sinusitis. The British Equine Veterinary Association (BEVA) can help you locate a qualified equine dental veterinarian.

Frequently Asked Questions

How do I know if my horse has a tooth abscess versus a sinus problem?

The two conditions are closely linked — a tooth abscess in the upper cheek teeth very commonly causes secondary sinusitis. A key diagnostic indicator is that sinus disease caused by dental infection produces a foul-smelling, often one-sided nasal discharge, sometimes containing food material. True primary sinusitis tends to produce a less offensive discharge. A thorough oral examination combined with radiographs or CT scanning is necessary to confirm the diagnosis and identify whether the sinus infection is primary or secondary to a dental problem.

Is a tooth extraction a major procedure for horses?

It depends on the technique used and the location of the tooth. Oral extraction of cheek teeth in standing sedated horses has become increasingly common at referral centres and is generally well tolerated. More complex cases may require general anaesthesia. The procedure is considered routine in equine dentistry, and most horses recover without complications. Your veterinarian will discuss the most appropriate technique based on the individual case.

Can horses eat normally after a tooth is removed?

Most horses return to near-normal eating within a few weeks following extraction. Soft feeds and soaked hay or haylage are usually recommended during the recovery period to prevent food from packing into the socket. Over time, the horse adapts to the gap and opposing teeth may drift slightly, which is why ongoing dental monitoring is important after extraction.

My horse has had a discharging lump on its jaw for months — is it a tooth abscess?

A chronic discharging tract on the lower jaw is a classic presentation of a tooth root abscess affecting the lower cheek teeth. These tracts can appear to heal and then re-open repeatedly. Without treatment — typically extraction of the affected tooth — they will not resolve permanently. Your veterinarian should examine the horse and take radiographs to identify which tooth is responsible.