Cure For a Toothache

Abby is a Tennessee Walking Horse mare who was recently purchased by a Virginia family as a 5-year-old and shipped there from Tennessee to train and show. A dental examination six months after purchase found that her right and left lower first cheek teeth, 306 and 406 on the Triadan numbering system (a system used consistently to number teeth across different animal species), were cut off at the gum line sometime the previous year.

This practice has become recognized in some equine sports as molar cutters and power tools have become more common. Use of these tools without appropriate training has led to more aggressive removal of normal tooth surface. Some trainers have encouraged the practice, thinking the bit is interfering with the lower teeth. The common practice of slightly rounding the front edge of the lower cheek teeth with hand floats has progressed to leveling off the entire tooth at the gum line.
Abby had complications from the pro-cedure, most likely due to the age at which it was done and the technique used. In a young adult horse, the five to six normal pulp horns of the premolar ex-tend from just below the crown down the length of the tooth root. When the teeth were cut, it left all of the pulp horns exposed. Pulp is the living tissue within the pulp chambers and root canal. It is comprised of blood and lymph vessels, nerves, collagen, and connective tissue.

The new owners had Abby examined by respected veterinarian and equine dentistry specialist, Bayard A. Rucker, DVM, of Lebanon, Va. Rucker’s examination noted swellings on the lower jaw similar to eruption bumps (the normal condition of bone development around a newly erupting permanent tooth). In a 5-year-old mare, these were not eruption bumps, but swelling due to osteomyelitis or bone infection from abscessed tooth roots. Radiographs showed the classic signs of tooth root infection. The lamina dura (bony area around the tooth socket to which the periodontal ligament anchors the tooth to the jaw bone) was eroded and invisible on radiographs. The normal radiographic space around the tooth typically occupied by the periodontal ligament was widened, indicating loss of the ligament attachment and destruction of the bone. Rucker also noted on visual assessment that the pulp horns of the two affected teeth were open and draining, indicating infection down the length of the root.

Rucker said, “The cutting off of the premolars appears to be an extreme type of ‘putting in a bit seat,’ and there is no valid reason for doing this procedure. Whoever did this was grossly uninformed on the reasons for doing this, and on the complications that could follow.”

The prognosis for these dead teeth is poor—they will not continue to erupt over the course of the horse’s life, as would healthy teeth. Two treatment options were considered. In this case, the teeth were extracted intra-orally (from within the mouth). If enough of the tooth surface can be grasped with forceps, after a releasing incision of the gum tissue, intra-oral extraction can be performed. If the tooth cannot be removed from inside the mouth, a trephine procedure can be performed where the tooth is removed from the lower jaw surface after drilling away the supporting bone. Postoperative care consists of daily lavage (rinsing) of the extraction sites and an extensive antibiotic regimen to treat the bone infection.

A more technically challenging procedure is to cap the pulp horns on the tooth surface and perform a root canal from the lower jaw surface. The difficulty level is high due to the intricacy of the canal lining and the necessity for complete removal of the pulp material and tight packing of the root canal. Lengthy antibiotic treatment is necessary to prepare for endodontic procedures on infected teeth.
Long-term aftercare requires a dental exam every six months and floating (filing) the opposing upper premolars. Normally, wear against the lower teeth keeps them level with the other teeth of the upper jaw. Without the opposing grinding action of the lower premolars, these teeth will grow longer than their neighbors, creating tooth and jaw interference. Because of financial considerations, the owners elected to remove the affected teeth. The procedure was performed under general anesthesia. Rucker was able to remove the right lower cheek tooth by the intraoral method. The left lower cheek tooth required the trephine procedure. The teeth were removed without complication.

Abby’s prognosis is good. Her comfort and performance will improve and the bumps on her jaw should resolve, leaving a pleasing cosmetic appearance. Rucker’s advice to readers: Engage the services of trained and experienced veterinary dentists to perform endodontic and periodontal procedures. The health of the horse and the financial investment will both be optimized.

About the Author

Kimberly Peterson, DVM

Kimberly Peterson, DVM, is an AAEP member and assistant professor in the Department of Veterinary Technology at Morehead State University in Morehead, Ky. Her husband, Eric, is an equine practitioner, and their family lives in Lexington.

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