Anesthesia | Periodontal Disease | Extractions
Endodontics | Orthodontics | Neoplasia
Trauma | Dysphagia | The Feline Oral Cavity
The hallmark of oral surgery advancements is in the area of reconstructive surgery following trauma. The goal of surgical correction is re-establishment of function with a minimum of discomfort. This is accomplished with the use of orthodontic wire (26 gauge to 32 gauge stainless steel) and dental acrylics (self curing and light cured). Radiographic evaluation of oral trauma is essential for effective treatment planning. While extra oral "scout films" give an overall impression of the extent of hard tissue trauma experienced by the animal, intraoral films are critical for evaluation of tooth root and periodontal injury.
Intraoral radiographic interpretation of oral injury must include the status of:
Perhaps the most important observation to make while examining dental films of recent oral trauma is the animal's periodontal health. A firm understanding of periodontal lesions is necessary to properly distinguish between preexisting oral pathology and acute oral trauma. Too many times treatment planning for fracture repair misses the predisposing periodontal lesions that precipitated the fracture thus ensuring a nonhealing repair.
In addition, monitoring post operative fracture healing paying particular attention to endodontic and periodontic health of teeth at the fracture site is important. If the fracture involves the alveolus of a tooth, radiographic monitoring of the affected tooth is essential. Any evidence of bone resorption or periodontal disease must be addressed. Likewise, apical disease indicating pulpal death must not be ignored. Quite often teeth are endodontically compromised but are needed for fracture stabilization. Without proper endodontic therapy and monitoring of teeth, fracture healing will not occur.
Most maxillary fractures are stabilized with the use of interdental wiring patterns and acrylic. Compression of the maxilla is repaired with expansion of the maxillary bone to its original configuration and application of rigid fixation. Stainless steel wire is "figure eighted" as needed from the molars to the canines and incisors. If needed, wire is placed across the hard palate to the contralateral teeth to provide retention of the dental acrylic. Dental acrylic such as Triad (light curing) or Jet Acrylic (self curing) is used to provide support across the hard palate. Since this material is so strong, very little is needed to stabilize the maxilla. Premaxillary fractures and maxillary symphiseal separations are treated much the same way using figure eighting wire from at least the lateral incisors from one side to the other. If more support is required the pattern includes the canines. Minimal amounts of acrylic are used on the hard palate to provide support to the premaxilla. Home care includes daily cleaning of the appliance with hydrogen peroxide products such as Glyoxide. Clinical healing occurs in six to eight weeks and the appliance is removed at this point. If the appliance is properly constructed and maintained, minimal amounts of irritation will be present. If the owner is unable or unwilling to keep the appliance clean it should be removed sooner rather than later.
In addition, temporarily bonding the jaws partially closed will accomplish the goals of providing fixation and maintaining occlusion. Light cure composites work well. Standard restorative techniques are used in preparing the tooth surfaces to be bonded together. The occlusion is reduced enough to provide stability and yet allow ingestion of a liquid diet. As a rule the canines are used for bonding but occasionally the carnassials are included to provide additional support. Again, clinical healing occurs rapidly and the composite is removed in six to eight weeks. Weight loss is anticipated and the owners are instructed to feed a high calorie diet such as A/D.
The worst case scenario for canines is the use of a muzzle to maintain occlusion and provide support during healing. The prefabricated "blue muzzles" work well to accomplish this goal. If needed, a firm muzzle is placed for the first few days while the animal is hospitalized, keeping the jaws in occlusion 100% of a 24 hour day. Close observation is required in case vomiting occurs. Aspiration pneumonia may occur if the muzzle is not quickly removed. Generally a looser muzzle is used after three to four days to allow for ingestion of gruel and water. The dog is sent home with instructions for its owner to keep the muzzle in place and to remove it only to clean the dog's face and muzzle. Occasionally Elizabethan collars are needed to keep the dog from attempting muzzle removal. Muzzles are used for eight to ten weeks or until the jaws are functioning normally.
IM pins and bone plates are rarely used and usually are contraindicated. These devices compromise the ability to maintain occlusion and may result in damage to tooth roots.
The mandible is repaired in much the same way as the maxilla. In addition to figure eighting, wire and acrylic cerclage and interosseous wires are used to create additional planes of support. Anterior mandibular fractures are stabilized using wire and acrylic. Regardless of the fracture pattern wire is figure eighted from the premolars rostrally to the incisors. An acrylic splint is placed on the lingual surface of the reaming teeth incorporating the preplaced wires. Attention is made to ensure noninterference with the maxillary arcades. Symphiseal separations are reduced using cerclage wires and occasionally acrylic (especially in cats). Midbody fractures are repaired with the addition of cerclage wires (if they are oblique) or interosseos (if they are vertical). When drilling holes for interosseous placement of wire it is mandatory to identify the roots of the remaining teeth radiographically and by palpation. If tooth roots are inadvertently penetrated, endodontic therapy is required to preserve the tooth. Disaster cases are managed by bonding the jaws partially and temporarily closed as in maxillary fractures. Muzzles are used to provide support to the mandible and protect it from excessive occlusal forces. Complications encountered with mandibular and maxillary fractures include alveolar fractures and pulpal exposures. Simple alveolar fractures that do not compromise the apex of the affected tooth respond well to reduction and stabilization. However, if the apical blood supply is destroyed, endodontic treatment is indicated if the tooth is to be salvaged. Occasionally the tooth must be maintained to establish occlusion. If this is the case endodontics can be postponed for several months due to time or money limitations, but at some point must be completed to ensure healing of the fracture. If ignored, the resulting apical granuloma may return to haunt the surgeon by creating a nonunion.
Because each case presentation is different, the surgeon must be familiar with many techniques and let experience dictate which is indicated. If occlusion is not restored the animal will suffer many years of discomfort while the animal's body corrects the problem using the inflammatory process.
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