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Every Tooth Tells a Story: Random Equine Dental Pathology Part 2
- Nick Moore DVM
- Aug 4
- 6 min read
If you've read Every Tooth Tells a Story: Random Equine Dental Pathology Part 1, you already know the premise: an extracted tooth is more than something that came out of a horse's mouth. It is evidence.
Once the tooth is in your hand, you can often work backward. The roots, pulp, fracture lines, areas of resorption, periodontal changes, and abnormal development can all provide clues about what happened while that tooth was still inside the horse.
In Part 1, we looked at several examples of this, including EOTRH, patent infundibula, endodontic disease, pulp exposure, and severe infundibular fractures.
But that was only the beginning. For Part 2, we reached into the same collection of extracted teeth and pulled out another group of cases without knowing what we would find. And once again, the teeth had plenty to tell us.
A Supernumerary Tooth Can Create Its Own Problems
The first specimen was actually two teeth that had been sitting right next to each other. One was a normal tooth, and the other was a supernumerary tooth—an additional tooth beyond the normal dental complement. Supernumerary teeth can occur in a variety of locations. They are often found behind the 11s, but they can also occur on the palatal side or in other unusual positions. In this case, the additional tooth was associated with severe periodontal disease. There was a draining tract, along with significant remodeling and reaction around the supernumerary tooth.
The important lesson isn't simply that horses can have extra teeth. It's that an abnormal tooth in an abnormal location can change the environment around it. Crowding and abnormal spaces can create conditions where periodontal disease develops and becomes difficult to manage. The extracted teeth allow us to see that relationship much more clearly.
A Tooth Can Look Relatively Normal While the Apex Tells a Different Story
The next tooth demonstrated a very different type of problem.
The occlusal portion of the tooth looked relatively normal, considering the severity of the disease occurring around the root. When we looked at the apical portion, there was significant enlargement, remodeling, and evidence of chronic infection. This is an important diagnostic concept in equine dentistry: The part of the tooth you can see isn't necessarily the part of the tooth that's causing the problem.
In young horses, particularly, teeth can develop significant periapical disease without dramatic changes being immediately obvious from the oral aspect. The mechanisms behind these infections can be complicated. Blood-borne bacteria may be involved, and developing or erupting teeth may create conditions that allow infection to become established. These cases can be particularly challenging because the clinical appearance of the tooth may not match the severity of the disease around its roots.
History, oral examination, and radiographs all become important pieces of the puzzle. In some acute cases, CT can provide additional information, particularly when changes have not yet become obvious on conventional radiographs.
When Normal Anatomy Goes Out the Window
Then we pulled out an especially unusual upper 6. Normally, an upper cheek tooth has three relatively clean-looking roots. This one did not.
There was excessive cementum formation, abnormal root development, and a draining tract. The overall appearance was highly abnormal and consistent with a dysplastic tooth—a tooth that developed abnormally. It was also a technically interesting tooth because its abnormal shape made extraction more difficult.
This is one of the reasons a strong understanding of normal anatomy is so important. When you know what the normal tooth should look like, abnormalities become much easier to recognize. And when the anatomy is abnormal, the treatment plan may need to change with it.
The Abscess That Drains Where You Can't See It
Another tooth came from a very young horse and showed extensive evidence of a severe periapical abscess. The roots had not developed normally, and there was substantial pathology around the apical region.
But there is an important point here that applies to many dental cases: An abscess doesn't necessarily mean an obvious swelling. Purulent material has to go somewhere. If the infection drains into the oral cavity, the horse may simply swallow it. From the owner's perspective, there may be little to see. There may be no facial swelling. No obvious external draining tract. No dramatic change in behavior. Yet significant infection may be occurring at the root of a tooth. This is one reason horses can have more advanced dental disease than their outward appearance would suggest.
When infection eventually breaks into a sinus or through the jaw, it becomes much more obvious. But that visible problem may simply be the point at which a disease process that has been developing for some time finally becomes externally apparent.
When Infundibular Disease Ends in Fracture
We also found another example of severe infundibular caries.
In this case, the infundibular defect had progressed to the point that the tooth fractured through the affected area. This is a useful companion to the infundibular pathology discussed in Part 1.
The important question isn't simply, "Is this tooth fractured?" It's: Why did it fracture?
In a tooth with advanced infundibular caries, the disease has weakened the structure of the tooth. If the problem is recognized earlier, restoration may sometimes provide an opportunity to preserve the tooth and reduce the risk of progression to fracture.
Once the fracture has occurred, however, the situation changes considerably. The extracted tooth shows exactly how the defect progressed and where the tooth fractured.
Chronic Infection Can Reshape the Root
Another upper 6 showed significant resorption of one of its roots. There were draining tracts and evidence of chronic infection, including areas where feed had been packing.
Over time, chronic infection doesn't simply sit in one place. It can change the surrounding tissues and the tooth itself. In this case, the affected root had undergone substantial resorption, leaving only part of the original root structure. Again, the extracted tooth gives us a physical record of that progression.
Not All Fractures Are the Same
One of the teeth in this group was an upper 11 with a fracture through the pulp structures and extending toward the palatal root. This was not an infundibular fracture.That's an important distinction.
The infundibula are separate structures from the pulp horns and pulp chambers, and fractures can involve different portions of the tooth. Looking at an extracted tooth allows us to follow the fracture line and understand exactly which structures were involved.
For the clinician, that distinction matters because the underlying disease process and treatment considerations can be very different depending on what has fractured and why.
When Infection Creates a Path Through the Root
Another extracted tooth showed a small opening through the root itself. This was evidence of the destructive effects of chronic infection. The infection had eroded through the root, creating a pathway through which purulent material could drain into the oral cavity.
There were also changes to the pulp and significant blunting of the root. It's another example of why chronic dental disease can be difficult to understand if we only look at one part of the tooth. The final pathology may look dramatically different from the original problem that started the process.
A Collection of Teeth Is Really a Collection of Case Histories
Part 1 showed us several different ways equine dental disease can manifest after extraction. Part 2 adds another layer to that picture.
We see:
Supernumerary teeth and associated periodontal disease
Periapical infection that may not be obvious from the occlusal surface
Developmentally abnormal teeth
Severe infection in young horses
Chronic infection and root resorption
Fractures involving different structures of the tooth
Advanced infundibular disease
Infection that can drain into the oral cavity rather than producing obvious external signs
Taken individually, these may seem like a collection of unusual cases. Taken together, they demonstrate something much more important. Equine dentistry is diagnostic medicine. The clinician isn't simply looking for sharp enamel points or deciding where to reduce a tooth. The clinician is trying to understand what is happening inside the mouth.
That means putting together the history, clinical signs, oral examination, tooth anatomy, radiographs, and, when appropriate, advanced imaging. The extracted tooth can then become the final piece of the puzzle.
Start With Part 1, Then Look at Part 2
If you haven't read the first installment, it's worth starting there.
Part 1 introduces the concept and walks through several different examples of pathology, including EOTRH, patent infundibula, endodontic disease, pulp exposure, and severe infundibular fractures. Part 2 builds on that foundation by looking at additional examples where the pathology is sometimes much less obvious from the oral aspect.
Together, the two articles make a good reminder of one of the most important principles in equine dentistry: Every tooth tells a story. The challenge is learning how to read it.
Want to Learn More?
If you're a veterinary professional interested in expanding your knowledge in equine dentistry, we offer training courses on equilibration, diagnosis, endoscopic assessment, and more. You can always contact us at mooredvmeducation@gmail.com or call the office at 512-508-8141.
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