Mandibular and maxiallary fractures are open fractures.
Fig. S4A: Fracture of the incisor region in a 7-year-old Arabian stallion. The rostral fragment could easily be displaced through finger pressure.
Fig. X4A: Intraoral radiographic view of a rostral mandible fracture. Several incisor tooth roots are fractured. Some displacement is visible.
4.1.3 Preoperative management
Carry out a detailed examination of the entire animal, with special emphasis on the injured region, prior to surgery. Pay special attention to metabolic disorders such as dehydration, acid base derangements, and nutritional status. The animal may not have eaten for a considerable time. Plan the surgical procedure carefully, and cleanse the mouth thoroughly before intubation. Do not remove any loose teeth prior to fracture repair because the teeth brace each other and can thereby confer stability. If necessary, the loose teeth can be removed at a later stage or at the time of implant removal. Often, such removal proves unnecessary.
4.1.4 Management options
Selected fractures of a single mandibular ramus may sometimes be treated conservatively. Surgical options will vary with the configuration of the fracture. Following repair, the incisors can be rasped down to prevent contact with the opposing arcade, protecting the repair from strain for several weeks.
4.1.5 Surgical procedures
A distinction is made between intraoral and extraoral fixation techniques. In some instances, combined modalities are used.
4.1.5.1 Intraoral fixation techniques
Cerclage wires
Cerclage wires are the most frequently applied fixation devices for dental fractures in the rostral mandible and maxilla [2]. They are very versatile and may also be used in conjunction with other implants. Furthermore, they are quite economic.
These devices are mainly used to fix fractures in the rostral half of the mandible. Several wiring techniques are described in the literature and their selection depends on the preferences of the surgeon [1, 2].
Pass the wire between the teeth from inside to outside. If this proves difficult or impossible, drill holes of 2 mm diameter between the teeth at strategic locations facilitate passage (Fig. S4B). A large needle may be sufficient in younger foals [2] (Fig. F4D).
Fig. S4B: With the help of a 2 mm drill bit a hole is drilled between the incisor teeth to facilitate placement of the wires.
Fig. F4D: Cerclage wiring of a fracture of J2 and J3. A 14-gauge needle is inserted between the teeth and a 1.25 mm stainless steel wire threaded into the needle cannula as it is withdrawn.
Cerclage wiring is the most frequently employed technique in the repair of rostral fractures.
The following techniques are available: wiring of the teeth in a figure-8 fashion from left to right, or including at least two teeth on either side of the fracture [1]. Application of overlapping wire loops [2] allows individual tightening of the loops (Fig. F4E) and results in greater stability than with the sinsuoid wire loop technique mentioned above. The Obgeweser technique [1] involves extruding wire loops from the inside to the outside between each of the teeth (Fig. F4F, Fig. S4C). The wire loops may be prepared with special bending pliers. Feed one end of the wire through each wire loop in front of the teeth and unite it with the other end (Fig. S4D). Then tighten each loop by twisting it with a pair of pliers (Fig. S4E). This type of fixation is extremely stable and may be left in place for several months (Fig. X4B).
Wire loops may be applied in a variety of ways.
Fig. S4C: Wire loops are exited from the lingual side between the incisor teeth.
Fig. F4E: The fracture is treated with two cerclage wire loops; one around J1 and J2 and the other in figure-8 fashion around J2 and the adjacent healthy canine tooth.
Fig. F4F: An alternative method involves exiting wire loops from the lingual side to the labial side, followed by feeding of one end of the wire through each loop. After uniting and tightening the two wire ends, each wire loop is tightened as well, resulting in the most stable of all wire fixations. The twisted ends are directed toward the gingivae.
Fig. S4D: One end of the wire is fed through each of the loops in front of the incisor teeth.
Fig. S4E: The wire ends are united and tightened securely. Then each of the wire loops is tightened individually, resulting in superior stability of the fixation.
Fig. X4B: The fracture shown in Fig. S4A and Fig. X4A was reduced and repaired with the Obwegeser technique. Note, a wire loop was placed around each tooth and tightened. The fixation remained in place for 6 months. No teeth had to be removed.
When the rostral part of the incisors or the diastema is fractured, some type of fixation placed further caudally is indicated. Include the canine teeth in male horses (Fig. F4G) or one or two of the premolar teeth. In the latter case, feed the wire around P2 after prior drilling of a 2.5 mm hole between P2 and P3 (Fig. F4H) and unite the ends of the wire further rostrally [2]. Tighten the fixation by twisting the long wire loop at the diastema with one end of a Steinmann pin (Fig. X4B).
Drill holes in the bone of the diastema to allow cerclage fixation of fractures without encircling the teeth.
Drilling small holes into the diastema on either side of the fracture allows application of wire in a figure-8 fashion through the holes [2]