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Huge Dental Infection in Young Rescue Horse - Diagnosis & Extraction

Updated: Dec 17, 2025


Facial swelling in young horses is always a red flag. While trauma is sometimes the cause, dental disease must be carefully ruled out, especially when swelling develops rapidly and is localized to the maxilla.

In this case, we evaluated a young filly (approximately 1–1.5 years old) that had been rescued just two months prior. She presented with acute, fairly severe swelling on the right side of her upper jaw. On the opposite side, the face appeared normal. This asymmetry immediately raised concern for a dental origin.


Why Facial Swelling Often Means Dental Disease

Swelling over the maxilla is most commonly associated with disease of the upper cheek teeth. While kicks, bites, or wounds can cause similar changes, dental pathology is far more common and far more likely to worsen if left untreated.

Radiographs taken of this filly revealed a clear area of lucency and surrounding bone loss around one of the maxillary cheek teeth. These findings are classic for a periapical abscess, an infection that develops around the root (apex) of the tooth.

Once an infection reaches this stage, antibiotics may temporarily reduce inflammation, but they will not resolve the underlying problem. The infected tooth remains the source, and definitive treatment is required.


Matching the Diagnosis: Clinical Exam, Oral Exam, and Radiographs

One of the most important lessons from this case is the need to correlate all available information before extracting a tooth.

  • Clinical signs: A firm swelling on the right maxilla

  • Oral examination: A draining tract adjacent to the affected tooth

  • Radiographs: Bone loss and infection centered on the same tooth

When these three elements line up, there is no question about which tooth is responsible or what needs to be done. Extracting teeth based on radiographs alone, or on swelling alone, can lead to serious mistakes, including removing the wrong tooth.

In this case, all findings pointed to the same tooth, the 107.


Standing Extraction: No General Anesthesia Required

The tooth was extracted standing, using a maxillary nerve block for local anesthesia. There is a common misconception that advanced equine dental procedures require general anesthesia, a surgical suite, and a large team.

In reality, with appropriate training and experience, the vast majority of equine dental extractions, including infected maxillary teeth and sinus-related cases, can be performed standing. This approach significantly reduces:

  • Risk to the horse

  • Cost to the owner

  • Recovery time

Over thousands of cases, only a very small number truly require general anesthesia due to unrelated medical concerns.

The Underlying Cause: A Patent Infundibulum

Examination of the extracted tooth revealed the root cause of this filly’s problem: a patent infundibulum.

Normally, the infundibula in upper cheek teeth are fully sealed with enamel, preventing bacteria from traveling deeper into the tooth. In this case, the infundibulum never fully closed, allowing oral bacteria to move directly toward the apex of the tooth. This resulted in apical infection, facial swelling, and drainage back into the mouth.

In select cases, early intervention may allow for cleaning and sealing of an open infundibulum. However, due to the extent of decay and infection in this tooth, extraction was the only appropriate treatment.

Special Considerations in Young Horses

Extracting teeth in young horses requires additional care. At this age, the teeth are not fully mineralized and contain a significant amount of pulp and developing tissue. After extraction, it is critical to thoroughly debride the socket.

Even with meticulous cleaning, some residual cells may remain. These cells can mineralize over time and may appear on radiographs years later. While this is typically an incidental and non-problematic finding, it is important to document and communicate this to owners, especially for future pre-purchase exams.

Outcome

The extraction itself took approximately 20–25 minutes once the nerve block had taken effect. The procedure went smoothly, and the filly should experience rapid improvement in comfort as the infection resolves.

This case serves as an excellent example of:

  • The importance of thorough diagnostics

  • Why antibiotics alone are not a solution for apical infections

  • How standing dentistry can safely address advanced disease

  • A less commonly discussed cause of periapical abscesses in young horses

Watch the full case video to see the diagnostics, radiographs, nerve block, extraction, and pathology explained step by step.

If you are a veterinarian or student looking to build confidence in advanced equine dentistry, cases like this highlight why proper training and a methodical approach matter.





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