DENTISTRY
• Unless you’ve had advanced training, avoid plating
jaw fractures for fear of compromising tooth roots.
Also avoid placing intramedullary pins into the man-
dibular canal. The mandibular canal carries the neu-
rovascular structures—it’s not an intramedullary canal.
• Removing teeth (or parts of teeth) in the fracture line
is usually a good idea (Figures 3A-3C and 4A and 4B).
Figures 1B. A cat's mandibles deviated toward the left,
secondary to a right-sided mandibular fracture.
(All photos courtesy of Dr. Jan Bellows)
•
Figure 3A. A radiograph of an immature right mandibular first
molar in the fracture line.
Determining whether the fracture is favourable
or unfavourable is important in deciding which
method of fixation is best. Attached jaw muscles
either compress (favourable) or distract (unfavour-
able) the fractured segments.
Favourable mandible fractures run dorsocaudal to
ventrocranial. These fractures compress because
of the upward pulling of the masseter and tempo-
ralis muscles, and downward and caudal pulling of
the digastricus. Stabilization of the tension surface
may be all that is required for bony healing.
Unfavourable fractures run dorsocranial to ven-
trocaudal and distract the fracture fragments. The
alveolar crestal bone is considered the tension
surface, while the ventral cortex is considered the
compression surface (Figure 2).
Figure 3B. The immature first molar.
Figure 2. An illustration of favourable and unfavourable jaw frac-
tures.
Figure 3C. The healed fracture site before removal of wires and
splint.
Issue 04 | AUGUST 2017 | 33