AAEP Convention 2005: How To Repair Incisors

Mandible (lower jaw) and premaxillary (upper jaw) fractures are common equine head injuries, according to David Moll, DVM, MS, Dipl. ACVS, professor of large animal clinical sciences at Oklahoma State University. There are many described techniques to repair theses types of fractures, including interdental wiring, intermedullary pins, lag screws, external fixation, or a combination. During the 51st Annual American Association of Equine Practitioners Convention, held in Seattle, Wash., Dec. 3-7, 2005, Moll explained how to use interdental wiring to repair these fractures in a standing horse.

According to Moll, most mandibular and premaxillary fractures are commonly avulsion (forcible separation) type fractures that often separate incisors, leaving them attached only by surrounding tissue. These injuries can appear to be devastating, but with appropriate therapy they generally have a good prognosis of returning to normal functionality and appearance.

In pastured horses, fractures can sometimes go unnoticed for a day or even longer, but they are usually quite obvious to the owner when opening the horse's mouth. Moll said signs of incisor fractures include incisor malalignment, difficulty chewing, the horse keeping his mouth open (lower jaw dropped), and difficulty eating. Additionally, an old fracture might smell bad because of infection.

Technique

To repair mandibular fractures involving incisors, Moll uses a process of interdental wiring. "It requires very little training," he said. "Interdental wiring has minimal complications and doesn't require special equipment. You can almost get everything you need at the local hardware store."

Moll uses 18-gauge stainless steel wire, a 14-gauge needle, wire twisters or pliers, wire cutters, a battery-powered drill, small bone curettes, and a hemostat. The procedure is performed under sedation (a combination of detomidine and butorphanol) while the horse remains standing.

He pushes the needle through the horse's gums on both sides of the fracture, and inserts the wire through the needle. A minimum of one wire (preferably two) is wrapped around the base of stable neighboring teeth to secure the fracture, overlapping the wires if possible.

"Tightening the wires is the most important part of the procedure," Moll said. "Fracture stability should be checked with each wire." After surgery, the wires should be checked routinely. According to Moll, this type of fracture usually heals within six to eight weeks, at which time the wires can be removed. "Phenylbutazone should be given for several days after the injury to help control the pain so the horse can eat comfortably," Moll said.

Complications

The most common complication that you run into is wire breakage, Moll said. "The good news is if you have two wires, the other one will be able to hold the tooth in place," he added. "That's why I always try to use a second wire if possible."

Another concern associated with this type of injury is contamination. "You have to worry about contamination of the site," Moll explained. "A lot of these fractures are three to four days old by the time you see them (meaning more chance of infection). The good news is that the mouth has such a great blood supply that helps aid in healing."

About the Author

Chad Mendell

Chad Mendell is the former Managing Editor for TheHorse.com .

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