When veterinarians need to remove diseased cheek teeth, they usually use a standard oral extraction because it is the least invasive technique. However, depending on the condition of the tooth, the vet may use other methods such as transoral screw extraction (removing the tooth with instruments passed through the horse’s cheek) and retraction (hammering/loosening the tooth from the root surface to can be pushed or pulled from the socket).
Ejection of cheek teeth in horses
Due to the unique anatomy of a horse’s head, extractions can sometimes be challenging and potentially cause intra- and/or post-operative complications. “In our study, we wanted to report the outcomes and complication rates of horses that had attempted cheek tooth extraction via oral methods, but where this failed, then required dental retraction,” said Safia Barakzai, BVSc, MSc. Dipl. ECVS, DESTS, FRCVS, of Equine Surgical Referral Ltd., Brighton, UK
“When you push a tooth into the mouth, you create a fistula (surgical passage) between either the sinus and the oral cavity (for the back three to four maxillary teeth) or the skin and the oral cavity (for the front three to four teeth of the upper jaw and the teeth of the lower jaw), he said. “This fistula must then be healed closed, or you may pass a continuous passage of food material, saliva, etc., into the sinuses or through an incision in the skin, which may cause infection.”
Unlike traditional pusher punches, which are 8-10 mm wide, the researchers used custom-made narrow-diameter pusher pins (3 mm or 5 mm) in the 20 cases in their study. Veterinarians can use these narrow pins because the tooth has previously been loosened from the failed oral extraction attempt. Barakzai and her co-author found that a thinner pass created with a narrow diameter repulsion pin healed/closed significantly faster than a larger passage made with a traditional, wider repulsion punch.
“Previously published complication rates for equine dental retraction using traditional wide retraction punches are high (up to 80%), but retraction methods have changed significantly over the past 20 years,” Barakzai said, reducing intra- and postoperative complication rates. .
“The 25% combined intraoperative and postoperative rate in our study is equivalent to the complication rates reported after oral screw extraction,” he explained, which is another commonly used technique where the veterinarian inserts tools and drills through a narrow metal trocar placed through the horse’s cheek. The practitioner then inserts a screw into the diseased tooth and pushes it out into the mouth using a hammer.
Barakzai explained that transoral screw extraction is a useful technique, but the veterinarian needs expensive equipment and significant expertise for an effective result, and not all teeth can be extracted using this method. “Dental repulsion, in contrast, requires much cheaper equipment and 100% of teeth can be removed using this method. We did most of our repulsions on standing sedated horses with nerve blocks in place.’
“Sometimes (the intraoral screw extraction) is unsuccessful and the tooth still needs to be pushed out,” he said.
Good quality radiographs and 3D knowledge of head/dental anatomy are imperative for success, Barakzai said. “We would also recommend using a small sinus flap instead of a hole for the cheek teeth that are in the back of the maxilla to avoid damage to the suborbital canal,” he said, a passageway that contains a vital nerve. “(This damage) could happen if the surgeon doesn’t have a good visual of where the pin is in the sinus.”
Take-Home Message
While the researchers acknowledge that the study had some limitations due to its retrospective design and the small number of cases included, they said they believe that in the right hands, pushing back teeth using narrow-diameter pins can be a useful method for completing complex extractions during traditional oral extraction has failed.
The study, “Ejection of equine cheek teeth using small-diameter repulsion pins: 20 cases,” appeared in Equine Veterinary Journal in June 2024.
