Depending on the case, composite resin fillings originally designed for human dentistry may be the solution to managing these cavities in equine teeth, said Christopher Pearce, MRCVS, veterinary dental specialist and director of The Equine Dental Clinic. in Wimborne, UK.
If the growth cavity is large enough to threaten dental health and not yet infected, composite resin fillings can solve equine dental problems before they start, Pearce said. Strong and bonded – but can wear down at the same natural rate as horses’ teeth – composite fillings can stop the pain, disease and breakage that tooth decay can cause.
“We know enough to know that when we see cavities of a certain size in a certain tooth, we can say to clients with a fairly high degree of confidence, ‘OK, I know your horse looks good and performs well, and he or she just won the competition at the weekend, but he’s got a big cavity in his 109 cheek tooth and he’s 14 years old,” Pearce said. “Teeth with cavities of this size within the next two or three years may develop sinusitis or a root abscess or may break the tooth. So now we have the same options that a human dentist would give you,” including not only extraction or waiting but filling the cavity.
Lower caries: A developmental cavity
Unlike humans, horses have upper cheek teeth that develop deep folds called infundibula, Pearce explained. In young horses the upper teeth develop their outer walls first and are then filled with a dental material known as cementum. For reasons yet to be determined, some horses lack cementum in their upper cheek teeth—especially the first cheek teeth to emerge—leaving a gap, usually deep within the tooth. This gives the appearance of a solid tooth, even though it is somewhat hollow.
Because horses’ teeth are constantly erupting as their surfaces wear down, these hollow spaces slowly work their way to the surface, Pearce said. Eventually, depending on the size of the cavity, the surface wears away enough to reveal the hole underneath – often when the horse has reached puberty.
These cavities may not cause problems if they are small, he said. But when the underlying cavities are large, they can fill with food, which, when combined with naturally occurring bacteria in the mouth, can begin to ferment and create acid. When that happens, the horse can develop pain, sinus infections and/or mouth infections, she said. In some cases the tooth may break in two.
Saving teeth affected by caries with fillings
While teeth affected by underlying pathogens may eventually need to be removed, Pearce said it is possible to save teeth by filling them before problems arise. He and his fellow researchers adapted techniques previously used by equine dentists and researchers to fill such cavities, he said. This involves removing the impactor, thoroughly cleaning the cavity, and filling the hole with a solid, self-adhesive material that fits the shape.
Although they initially considered using hard materials such as glass ionomer cements and porcelain, scientists realized that flowable and solid resin—the “white” composite fillings used in human dentistry—were better suited to equine dentistry because they are slightly less hard and wearable. . with use, Pearce said.
Between 2006 and 2012 Pearce and colleagues followed the progress of 92 horses (with a mean age of 14 at the time of treatment and a range of 6 to 25 years) with 223 cheek tooth fillings. They didn’t know, however, whether resin filling was a successful long-term solution, he said. So the research team looked back at these previously treated horses to see how they fared over the years.
They found that even 11 years later, 99% of the treated horses—all with at least a five-year history of sealings—had no adverse effects or abnormalities as a result of the sealings. Almost 85% of the fillings were fully intact, with a wear rate similar to that of the surrounding tooth.
Even so, fundus filling requires significant training in equine veterinary and dental medicine as well as the technique itself, Pearce said. Practitioners should also be skilled in identifying ideal candidates based on the severity of underlying caries and the associated risks if left untreated.
Pearce CJ, Brooks N. Long-term follow-up of Infundibula restorations of equine cheek teeth (2006-2017). Front Vet Sci. 2022 Jan 14 8:793631. doi: 10.3389/fvets.2021.793631. PMID: 35127882; PMCID: PMC8809405.
