The overall goal is to restore occlusion, normal anatomy and function.
Restoring and maintaining occlusion is the most important aspect of fixation of symphyseal separation and parasymphyseal fractures.
The mandibular bone at the level of the symphysis is almost completely occupied by dental roots. Therefore, invasive fixation is not recommended. Interdental wiring between the canine teeth provide adequate reduction and stabilization.
Interdental wiring around the canine teeth cannot be done in the absence of one or both canine teeth.
Pharyngeal intubation is not needed for this procedure.
The fractured area is clipped to assess for penetrating injuries. If a penetrating wound is found, an exploratory surgery and debridement of the area is indicated to remove any foreign bodies (i.e. hair).
A comprehensive intraoral examination must be performed to assess for any injury affecting occlusion, teeth trauma and periodontal tissues.
Dental radiographs and a CT are obtained to provide details about the dentoalveolar structures in relationship to the fracture or separation.
Periodontal treatment (teeth scaling and polishing) is performed in preparation for composite bonding to the teeth.
Reduction of the separation or fracture is done digitally, bringing the teeth into normal occlusion, which realigns the bones.
This method is done completely intraorally.
The patient is placed in sternal recumbency.
Wire positioning and tightening
Orthopedic wire is looped around one canine tooth. The wire is continuously twisted until reaching the opposite mandibular canine tooth.
The wire edges are passed around the contralateral canine tooth and twisted until appropriate reduction and stabilization is achieved.
The wire should be cut leaving three twists.
Composite ring application
A composite ring is used around the canine teeth to prevent slippage and breakage of the orthopedic wire.
6. Application of the composite
Irrigate the teeth to be included in the composite. Acid-etch the teeth for 20-30 seconds. Thoroughly irrigate again and dry.
Note: it is paramount that the teeth remain dry throughout the application of the composite.
A composite temporization material is placed on the teeth and contoured to avoid sharp edges or projections. Care is needed to avoid contact with the gingiva.
Once the composite solidifies, smooth the composite with a Goldie bur on a surgical handpiece or a diamond bur on a high-speed handpiece.
7. Debridement and suturing
Wounds should be debrided followed by copious irrigation with sterile saline 0.9%. Soft tissue lacerations are sutured using 4.0 or 5.0 poliglecaprone 25 or other monofilament absorbable suture in a simple-interrupted fashion.
Note: in the oral cavity, due to abundant blood supply, aggressive debridement is rarely needed.
8. Case example
Preoperative radiograph of a symphyseal separation in a dog.
Intraoperative picture of interdental wiring positioning.
Intraoperative picture of composite application.
Intraoperative verification of occlusion restoration.
Postoperative imaging of interdental wiring repair of a symphyseal separation in a dog.
The splint should be cleaned at least once daily using 0.12% chlorhexidine gluconate solution. Another option is to use a water-flossing device.
The patient should wear an Elizabethan collar until removal of the construct.
The wire is kept in place for 4-6 weeks and removed under general anesthesia. The wire is cut at the oral cavity (between the canine teeth) and the wire is gently pulled out. If composite was placed, composite removing forceps are used.
The teeth involved in the fixation should receive periodontal cleaning as moderate to severe gingivitis is seen associated with the fixation wire.