Dentofacial Trauma in Small Animals
Teeth and jaws play a prominent role in the interaction of animals with their environment. This predisposes them to traumatic injury, most commonly fights with other animals, automobile impacts, getting caught on fences, or falling onto hard surfaces. Mandibles can also suffer spontaneous pathologic fractures due to severe periodontitis around the mandibular first molars or to neoplasia.
A fractured tooth with a red or black spot in the center of an irregular crown surface indicates pulp exposure. A missing tooth after trauma might be avulsed or may be fractured with retained root fragments, which can be determined radiographically. Fractured mandibles cause acute malocclusion and inability to eat. The midline of the mandible is usually displaced toward the side of the fracture. The mouth may be held open, particularly in bilateral mandibular fractures.
Fractured teeth are treated as described above (see Endodontic Disease in Small Animals). Avulsed teeth can be replaced if treated promptly (within hours). The owner should immediately place the tooth in a tooth transport medium or milk, without touching the root. The alveolus and root surface should be gently flushed with lactated Ringer's solution to remove dirt, and then the tooth placed into the alveolus and stabilized for 1 mo with interdental wiring. Rigid stabilization with acrylic or composite is less ideal for the periodontal ligament repair because it encourages ankylosis, but it may be a good idea to protect against abuse of the recently replaced tooth. Root canal therapy is done when the fixator is removed.
Soft-tissue trauma is repaired using primary closure with absorbable sutures. Oral soft tissues are vascular and heal quickly. Oral flushes with dilute chlorhexidine solution every 2 days helps decrease oral bacteria during healing.
Maxillary fractures can be stabilized with wire and sutures. Mandibular fractures can be more challenging; when possible, they can be repaired with interdental wiring and an intraoral splint made of bis-acryl composite resin. Other options include tape muzzling, cerclage wiring, interarch splinting, intraosseus wiring, external skeletal fixation, or miniplates. Preserving normal occlusion is important. With rigid stabilization, the pet can usually readily eat soft food until the appliance is removed in 6–8 wk.
Caudal mandibular body fractures in the area of or caudal to diseased molars requiring extraction are much more problematic because of the lack of teeth on both sides of the fracture and the thinner bone caudal to the body of the mandible. Plates can be used, but the prognosis is guarded. Interarch splinting (ie, between the upper dental arch to the lower dental arch) can be successful, but there is a risk of aspiration while the splint is in place if the animal vomits. A feeding tube is used until the splint is removed.