What to Consider Before Tooth Removal in Horses (AAEP 2012)
In some cases, veterinarians need to remove diseased cheek teeth via screw extraction and repulsion through the cheek. | Courtesy Dr. Edward Earley/Cornell University

When veterinarians need to remove diseased cheek teeth, they typically use standard oral extraction because it is the least invasive technique. However, depending on the tooth’s condition, the veterinarian can utilize other methods, such as transbuccal screw extraction (removing the tooth using instruments passed through the horse’s cheek) and repulsion (hammering out/loosening the tooth from the root surface so it can be pushed or pulled out of the socket).

Cheek Tooth Repulsion in Horses

Due to the unique anatomy of an individual horse’s head, extractions can sometimes be challenging and potentially cause intra- and/or postoperative complications. “In our study, we wanted to report on the outcomes and complication rates of horses that had had cheek tooth extraction attempted via oral methods, but where this had failed, … they then required dental repulsion,” said Safia Barakzai, BVSc, MSc, Dipl. ECVS, DESTS, FRCVS, of Equine Surgical Referral Ltd., in Brighton, U.K.

“When you repulse 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 maxillary cheek teeth and mandibular teeth),” she said. “This fistula then needs to heal closed, or you can get a continual passage of food material, saliva, etc., into the sinuses or skin incision, which can cause infection.”

Studying Repulsion Pins for Horse Cheek Tooth Extraction

Contrary to traditional repulsion punches, which are 8-10 mm wide, the researchers used purpose-made narrow-diameter repulsion pins (3 mm or 5 mm) on the 20 cases in their study. Veterinarians can use these narrow pins because the tooth has been preloosened by the failed oral extraction attempt. Barakzai and her co-author found that a thinner passage 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 repulsion using traditional wide-repulsion punches are high (up to 80%), but repulsion methods have changed significantly over the last 20 years,” Barakzai said, reducing intra- and postoperative complication rates. 

“The 25% combined intra- and postoperative rate in our study is equivalent to the complication rates reported after transbuccal screw extraction,” she explained, which is another commonly used technique where the veterinarian introduces instruments and drills via 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 transbuccal screw extraction is a useful technique, but the veterinarian needs expensive equipment and significant expertise for an effective outcome, and not all teeth can be removed using this method. “Dental repulsion, by contrast, requires much cheaper equipment and 100% of teeth can be removed using this method. We performed most of our repulsions in standing sedated horses with nerve blocks in place.”

“Sometimes (transbuccal screw extraction) is unsuccessful, and the tooth must still be repulsed,” she said.

Tips for Success With Repulsion Pin Extractions

Good-quality radiographs and a three-dimensional knowledge of head/dental anatomy are imperative for success, Barakzai said. “We also would advise using a small sinus flap rather than a trephine (skull) hole for the cheek teeth located in the back portion of the upper jaw to avoid damage to the infra-orbital canal,” she said, a passage which contains a vital nerve. “(This damage) could occur if the surgeon does not have good visualization of where the pin is positioned in the sinus.”

Take-Home Message

While the researchers acknowledge the study had some limitations due to the retrospective design and small case numbers included, they said they believe that in the right hands, tooth repulsion using narrow-diameter pins can be a useful method for completing complex extractions when traditional oral extraction has failed.

The study, “Equine cheek tooth repulsion using small diameter repulsion pins: 20 cases,” appeared in Equine Veterinary Journal in June 2024.