Last month's article described an attempt at definitive unilateral mandibular fracture repair using titanium mesh in a Shih
Tzu. On the third postoperative day, the patient removed the Elizabethan collar and created a similar fracture in the opposite
mandible. Consequently, we were faced with bilateral mandibular fractures and only four remaining teeth (canines). This case
was further complicated by severely compromised mandibular bone quality and quantity secondary to severe periodontal disease.
Repair techniques overview
Noninvasive mandibular fracture repair ideally uses the existing teeth as anchors for wire or acrylic splints. Screws used
to secure plates often traumatize teeth as well as the inferior alveolar artery and nerve within the mandibular canal. Screws
also lack sufficient purchase when used in mandibles in which bone is compromised from periodontal disease.
A possible alternative in this case was stabilization with composite bonding of the mandibular and maxillary canine teeth—a
simple and quick procedure that has been used to successfully repair mandibular fractures in dogs and cats. Cats are particularly
well-suited anatomically because of their long canine teeth that allow direct splint application (Photo 1).
Photo 1: The canine bonding for fracture repair in a cat. The close approximation of the canines simplifies the technique
in this species. (Photos courtesy of Dr. Beckman)
Adjustments for this challenging patient
Several factors in this patient made use of the composite bonding technique challenging. Lateral deviation of the mandibular
canines, comparatively shorter canine teeth compared with mesocephalic dogs and an increased space between the maxillary and
mandibular arcades required some adjustments to our traditional approach.
To compensate for these challenges, we created a flexible mold using suction tubing to span the gap between the arcades, serving
as a reservoir for the composite (Photo 2). We measured and cut the mold to allow enough room between arcades so the patient
could comfortably lap up gruel with its tongue.
Photo 2: The fabricated suction tubing used to accommodate the challenges with this canine patient.
After anesthetizing the patient, we carefully prepared the teeth to ensure optimal bonding of the composite. The teeth were
thoroughly scaled and then polished with flour pumice to remove all plaque, which would retard the composite's ability to
adhere to the tooth. Fluoride-containing pastes will interfere with material setup, necessitating the use of pumice.
We then etched the canine teeth with 37 percent phosphoric acid for 30 seconds. The etchant was thoroughly rinsed and dried
with an oil-free air source. A thin layer of primer/bonding agent was placed on the canine teeth and then light-cured (Photo
3). Instructions for working with bonding agents vary considerably from manufacturer to manufacturer, so always read and follow
the directions exactly to ensure optimal bonding.
Photo 3: Light-curing a bonding agent on another patient.
We then placed flowable composite into the mold. The fractures were reduced by recreating proper occlusion (Photo 4), and
the composite was light-cured to harden it. We used an accelerated light-cured composite that cures in five seconds. After
placement, we attempted to open the mouth with moderate force to ensure the composite's stability.
Photo 4: The suction tube splint after fabrication.
Postoperative care and further troubles
The owner was instructed to maintain the Elizabethan collar at all times, except when the dog was continually observed during
eating. Multimodal analgesia was initiated with orders to be continued indefinitely pending recheck.
Regrettably, the patient returned two days later with the composite fractured and dislodged from two of the canine teeth.
Remember, this patient is extremely active, despite the fractures. We speculated that the technique failed in this patient
because of the anatomical challenges described above. A much more aggressive approach with a more secure device and orders
for strict cage rest would be required if we were ever to achieve stability long enough for these fractures to heal.
Once again, teeth would provide an excellent anchor to stabilize both jaws with wire and acrylic; however, this patient was
edentulous except for the canines. Unfortunately, we cannot manufacture teeth to provide an anchor for a more aggressive and
more stable splint. Or can we?