Jaw Fracture Repair
Dr. Murat ÇALIŞKAN
Jaw fractures are common following motor vehicle accidents and dog fights.
Jaw fractures are usually secondary to trauma although pathological fractures are seen
periodically in geriatric animals with severe
periodontal disease which has compromised the jaws
Mandibles do not have a medullary cavity
Common sites for jaw fractures:
A: coronoid process;
B: junction of ramus and mandibular body;
C: condylar process;
D: body of the mandible.
E: fractures may involve fracture of the tooth roots as well;
F: fractures may expose the apical delta often severing the pulp communication with the periodontal ligament. These teeth require root canal therapy if they are to be maintained in the mouth.
G: fractures may expose part of a root but if the apex is not exposed then these teeth can be maintained in the mouth.
Follow-up radiography is advisable to monitor teeth affected in this way.
Jaw fractures are usually described as stable
(favourable) or unstable (unfavourable) depending upon the orientation of the fracture.
A stable fracture is one that has a caudo-dorsal to rostro-ventral orientation.
An unstable fracture has a caudo-ventral to rostro- dorsal orientation
The mandibles are subject to opposing forces.
The masseter and temporal muscles close the mouth while the digastric and geniohyoid muscles and gravity open the mouth.
The dorsal margin of the mandible is the tension side while the ventral mandibular margin is under compression.
A fracture with a rostro-dorsal to
caudoventral orientation is an unfavourable fracture as the forces acting on the jaw
distract the fragments.
A rostro-ventral to caudo-dorsal fracture is a favourable orientation as it leads to
compression of the fragments at stabilisation.
Fracture repair techniques
Tape or fabric muzzle
Inter-fragmentary wiring Inter-dental wiring
Inter-dental acrylic
A tape muzzle in place.
These must be removed after the animal has eaten and once the face has been
cleaned, a clean, dry muzzle must be fitted.
The animal should not be left unattended between muzzle changes.
Fabric muzzles are very useful in mandibular
stabilisation. This muzzle has been worn for four weeks.
The owner diligently replaced the muzzle with a
clean one after each meal, thus preventing muzzle associated dermatitis.
A: Although this three-hole arrangement is correctly placed according to tooth
roots, it does not provide as much stability as the arrangement in B.
B: This arrangement of the three-hole wire placement makes use of the
biomechanical forces on the jaw to improve stability. The dorsal wire is parallel to the tension side and the ventral wire is perpendicular to the fracture line.
Inter-fragmentary wiring.
C: The two-hole wire placement for favourable fracture stabilisation. The wire is perpendicular to the fracture line and anchored rostrally close to the tension side.
D: The four-hole wire placement
configuration. Both wires are arranged perpendicular to the fracture line.
Care should be taken not to place a wire through a tooth root or the mandibular canal.
The inter-dental loop wiring technique
Orthopaedic wire is passed distally around the last molar and courses
rostrally on the buccal aspect of the teeth.
The lingual wire is passed between molars 1 and 2 and over the buccal wire and back between these teeth.
This pattern is continued as far as stabilisation is required. This may cross
the mandibular symphysis if required.
The two loose ends of the wire are twisted together and then each loop protruding buccally around the
buccal wire is twisted in turn until desired stability is attained.
The loops can then be bent ventrally so that they do not irritate or
traumatise the cheek mucosa.
A single loop of wire can be placed mesially around the rostral tooth and distally around the caudal tooth on
either side of a fracture line and the loose ends tightened appropriately.
Interdental acrylic
Interdental acrylic can be used to form a ‘rigid’ fixation device.
The bulk of acrylic should be placed lingually for mandibular stabilisation and buccally for
maxillary stabilisation in order to prevent interference with occlusion.
This dog was kicked in the mouth by a horse. The mandibular right canine
was luxated (partially dislodged from its alveolus) and the tongue had
been ripped from the sublingual tissues by the force.
The tissues were thoroughly cleaned and sutured back in place. An
uneventful recovery followed.
Small Animal Dentistry
A manual of techniques Cedric Tutt
www.vet-dentist.com
