Q. My long yearling Dutch Warmblood mare knocked her tooth out so severely that it had to be removed by my vet. We’re not sure how she did it but I thought that, since it’s a baby tooth, it would be fine (like the kindergartner who knocks out a front tooth and just needs to wait for the adult tooth to grow in). However, I’m coming to understand that it might be different for horses. What is the long-term prognosis for a young horse losing a tooth prematurely?

—Laura, Seattle, Washington

A. The traumatic, premature loss of a deciduous incisor (or “baby tooth” as you’ve referred to it) can be problematic in any species and, in fact, may be urgent in horses. Missing teeth in horses generally lead to malocclusions (misaligned bite) or pathologic (disease-causing), dental problems.  The ability of the horse to effectively use their mouth for eating may be negatively affected by the loss of any one or more teeth. Fracture of the bone that contains the incisors in either the upper or lower jaw is the most common fracture of the horse’s skull, and I see it mostly in “mouthy” colts and less often in fillies.

In the case of your filly, the deciduous central incisor tooth in the lower jaw probably dislocated from the surrounding alveolar bone, or tooth socket, when your filly put her teeth on a hard object and pulled back, or she may have gotten kicked during play. The bony tooth socket most likely broke outward, toward the lip. In a long yearling, the root of the baby tooth is strong because it’s not due to shed until the permanent central incisor erupts at 2 1/2 years.  Prior to eruption of the permanent tooth the root of the baby tooth will become very thin.  In either case, a force strong enough to break the bone may also break the tooth root.  Your veterinarian chose to extract the tooth so the root may have also been fractured.  What remains to be seen is whether the developing permanent tooth bud, which is near the baby tooth, was also damaged. Hopefully it was not, and the tooth will develop and erupt normally. At the very least, I would expect the permanent tooth to erupt a bit prematurely with respect to the adjacent permanent incisor due to the lack of the baby tooth above it.

Crowding may occur should the baby teeth on either side of the missing tooth drift toward the midline. This crowding frequently causes the permanent tooth to make its way towards the surface in a displaced position, usually towards the tongue.  In this case, your veterinarian can perform careful odontoplasty to remove any dental tissue impeding the permanent incisor’s eruption. The occluding tooth in the upper jaw will also require attention, as it will erupt unimpeded downward into the void of the missing baby tooth.

Your veterinarian may want to take periodic radiographs to assess the developing permanent tooth prior to its scheduled eruption. If the tooth bud was damaged, the developing permanent tooth will either never develop or develop in a misshapen way which can cause eruption or periodontal problems. It may even form a cyst within the bone that may expand and damage adjacent teeth. The radiographs above demonstrate the problematic, incomplete, misshapen development of a tooth in a case of a fractured incisive bone. The following pictures are of a two and a half year old mustang with a kick injury to his upper and lower incisors.

Serial radiography will help your veterinarian decide how to best use interventional dental procedures to help your filly attain the most normal, functioning dentition possible.  In any case, the mouth will find a way to function but your veterinarian can help your horse to achieve an optimally functioning mouth.