Oral trauma (Proceedings)

Oral trauma can occur from many sources of force to the facial area. Some common signs displayed by small animals that have suffered oral trauma are:

     • Pawing at face

     • hemoptysis - bloody saliva

     • trismus - unable to move mouth

     • dysphagia - unable to eat

     • halitosis

Trauma sources can be sharp or blunt. Tissue damage can be derived from heat or cold, chemicals or electricity. Bone, tooth and/or soft tissue may be involved. Tooth fractures may be uncomplicated (no pulp exposure) or complicated (pulp exposed). Bone will fracture at predictable places in the cat or dogs oral cavity. The blood supply to the soft tissue and the high levels of IgA antibody in the saliva and crevicular fluid potentiate tissue survival and rapid healing. The mandible is a hinged structure with predictable muscle stresses on body fractures. Fractures extending in a caudodorsal direction are considered favorable fractures while those extending in a craniodorsal direction are termed unfavorable fractures due to the caudoventral forces of the muscular attachment to the mandible and gravity.

Fracture treatment involves these specific goals:

     • Allow for closure of the mouth

     • Treat soft tissue injury

     • Reestablish functional occlusion

     • Return patient back to normal ASAP

     • Fracture healing

Where teeth are located, generally the best form of fixation of an oral fracture is with wire and cool curing acrylics. The closure of the gingiva, due to the low level of elasticity, often acts as a very good first line of immobilization of jaw fractures. Wire can help to hold the fragments in alignment while acrylic is placed and cured over the wire and teeth. Where stability is difficult to achieve or fractures tend to telescope on themselves, interfragmentary wiring is beneficial in conjunction with intraoral acrylic splinting.

Feline mandibular symphyseal fractures/separations may be treated with a simple figure of eight orthodontic wire (23-25ga.) around the mid-coronal area of the mandiblular canine tooth to offer initial stabilization. Complete immobilization of the fracture can be accomplished by covering the orthodontic wire with cold cure acrylic (Build-It by Pentron) after acid etching the canine teeth with 37-40% phosphoric acid and applying a primer/adhesive.

A mid-body mandibular fracture may be treated with wire and acrylic. A layer of acrylic (Build-It by Pentron) is applied to dry, acid-etched and primer/adhesive coated teeth. The skin on the ventral cortex of the mandible several teeth caudal and cranial to the fracture is surgically clipped and prepped. A 2-3 mm. stab incision is made throught the skin prep of the ventral mandible to the ventral mandibular body cortex. A 24 gauge orthopedic circlage wire is inserted into an 18 gauge hypodermic needle and passed from the gingival crest next to acrylic splint, holding tight to the lingual side of the bone, exiting through the ventral skin stab incision. The needle is removed from the wire and passed again from the buccal gingival crest holding tight to the bone of the buccal side of the mandibular body exiting through the ventral skin stab incision. The ventral portion of the wire is passed dorsally into the needle and threaded into the oral cavity. The hypodermic needle is removed and the wire is twisted tight over the splnt forming a full circlage of the body of the mandible. Additional acrylic is laid down to cover the wire and as needed to add strength to the splint. Care should be taken to apply the acrylic to the lingual side of the teeth where the teeth occlude closely with the maxillary cheek teeth. The splint may be continued around the canine teeth to form a "J" shaped splint. The divergence of the mandibular canine teeth locks the appliance in place securely along with the twists of the full circlage wires cranial and caudal to the body fracture. Any sharp edges of acrylic or contact of acrylic to the gingival should be removed with a fluted diamond bur on a high-speed handpiece. Care should be taken to guard the bur from inadvertent contact with soft tissue. Homecare relies on daily irrigation under and around the appliance with copious amounts of water followed by an application of 0.12% chlorhexidine. Radiography of the fracture and if appropriate, removal of the splint may be done in 8 weeks. The splint is reduced with an acrylic bur on a low speed handpiece and/or a fluted diamond bur on a high speed handpiece. The circlage wires may be transected with the diamond bur and removed from the body of the mandible. The teeth are cleaned and polished. Minimal gingivitis is to be expected but should resolve following removal of the appliance in 4-7days.

References

Wiggs RB and Lobprise HB, Veterinary Dentistry Principles and Practice, Lippincott-Raven 1997; 263

Legendre L, Use of Maxillary and Mandibular Splints for Restoration of Normal Occlusion, etc. JVD, 15 , 1998, 179-181

Niemiec BA, Intraoral Acrylic Splint Application, JVD 20, 2003, 123-126