Removing equine cheek teeth is occasionally required in general equine practice. Common indications for extraction include periodontal disease, fracture of a tooth, fracture of the mandible through the alveolus or tooth, periapical tooth root abscess with or without associated sinusitis or cutaneous fistulation, and, less commonly, neoplasia.
In geriatric horses, loosening of the teeth associated with the loss of the reserve crown is common. Affected teeth may be painful, and such horses may lose weight due to their inability to chew properly.
A thorough oral examination is the first step in identifying infected or loose teeth. Many horses with pathology of the cheek teeth show no signs of disease. Thus, complete exams, usually under sedation and using a full-mouth speculum and adequate light source, are important.
Weight loss sometimes accompanies dental disease, especially in geriatric horses, but veterinarians should keep in mind that most horses that lose weight have other problems. Assuming that a thin horse needs dental care can mean missing other, more common causes of weight loss.
Dental radiographs are commonly used to help determine the extent of the associated pathology. A variety of projections may be used to clarify which tooth or teeth are involved. The American Veterinary Dental College offers a helpful chart, “Dental Radiographic Techniques for Horses,” here.
Advanced imaging modalities such as magnetic resonance imaging or computed tomography may be helpful in sorting out the intricate relationship between the cheek teeth and adjacent paranasal sinuses.
Once an abnormal cheek tooth has been identified, a variety of techniques are described to remove it.
Standing oral extraction is usually the first choice in removing diseased cheek teeth. When possible, oral extraction typically has lower morbidity, a shorter healing period and fewer complications compared with other techniques. Oral extraction is usually performed in the standing, sedated horse.
Extremely loose teeth may be removed relatively easily, depending on the amount of reserve crown loss. However, in more complicated cases, regional anesthetic nerve blocks should be performed to decrease pain and safeguard the veterinarian.
Oral extraction of cheek teeth with long reserve crowns, dilacerated roots, apical cementomas or fractured clinical crowns requires a significant investment in instrumentation. Newly developed instruments for sectioning cheek teeth, along with minimally invasive transbuccal extraction techniques, have significantly reduced the time required for oral extaction of cheek teeth compared to trying to lever teeth out with long molar extractors. They also have obviated the need for most invasive surgical extractions, with the attendant costs and risks of general anesthesia.
DR. ROBERT BARATT
If a cheek tooth cannot be extracted orally, repulsion is another option. When a maxillary cheek tooth is repulsed, the sinus above the tooth must be entered by trephination or sinusotomy. The diseased tooth is pushed into the mouth using a mallet and dental punch.
The downside of tooth repulsion is that it requires general anesthesia, with its attendant risks, and it carries a reasonably high complication rate because of broken root tips or alveolar fragmentation. Repulsion of a maxillary cheek tooth leaves a communication between the oral cavity and the sinus, an oroantral fistula.
Typically, and to prevent feed material from packing into the alveolus and being pushed into the sinus, the coronal portion of the alveolus is plugged with hard body dental impression material for two to four weeks while the apical portion of the alveolus fills with granulation tissue. Healing of the defect usually takes several weeks.
An alternative to repulsion of mandibular cheek teeth is osteotomy of the lateral alveolar bone plate. An incision is made over the lateral aspect of the mandible, centered on the affected tooth. Overlying bone is removed, typically with a carbide bur on an air-driven high-speed handpiece so the tooth may be sectioned and the fragments elevated from the alveolus.
While effective, the procedure is not risk-free. Short-term complications include wound dehiscence and infection, but these are usually transient and of little long-term clinical relevance. More serious complications include facial nerve paralysis—both temporary and permanent—fistula development and fracture of the mandible.
Loosen, Drill and Pull
More recently, a minimally invasive transbuccal screw extraction (MITSE) technique has been described for the extraction of cheek teeth with little or no clinical crown. This technique requires a special trochar and cannula that go through the check to allow direct access to the affected tooth with straight instrumentation.
After the tooth has been loosened with elevators and luxators, a drill bit is introduced through the buccal cannula and a hole is drilled into the affected tooth. The hole is then tapped and a threaded pin screwed into the tooth. This pin has a large metal stop on the extra-oral end, and a slotted mallet is used to apply the extraction force needed to pull the tooth from the socket.
Even under the best of circumstances, the long, narrow configuration of the horse’s oral cavity makes adequately visualizing oral structures challenging, and access to the cheek teeth can be difficult.
Oral extraction of loose cheek teeth in the geriatric horse suffering from periodontal disease is usually uncomplicated. However, oral and surgical extraction of fractured or apically infected cheek teeth in the younger horse requires significant investment in equipment and training.
The primary veterinarian should consider consultation with or referral to a board-certified veterinary dentist for more complex extractions. Clients appreciate the care and concern that a primary care veterinarian shows for a horse when the animal is referred to a specialist, when necessary.
In addition, increased potential for liability exists if a procedure is beyond the capabilities of the primary care veterinarian and a referral is not offered.