A dental fracture classification system has been adopted by the American Veterinary Dental College.12 The key diagnostic questions to ask are 1) What is the anatomical extent of the fracture? 2) Is the pulp exposed? 3) Is
there radiographic evidence of pathology?
Enamel infraction An incomplete fracture (crack) of the enamel without loss of tooth substance
Enamel fracture A fracture with loss of crown substance confined to the enamel
Uncomplicated crown fracture A fracture of the crown that does not expose the pulp (Figures 2A & 2B)
- Complicated crown fracture A fracture of the crown that exposes the pulp (Figure 3)
Uncomplicated crown-root fracture A fracture of the crown and root that does not expose the pulp
Complicated crown-root fracture A fracture of the crown and root that exposes the pulp
Root fracture A fracture involving the tooth root. (Because of the complexity of treament options for this fracture, we will not discuss
this topic in this article.)
Uncomplicated fractures result in dentin exposure. With open dentin tubules exposed to the environment, A-delta nerve fibers
in the pulp are stimulated. This stimulation, which is due to an increase in the flow rate of the free fluid in the dentinal
tubule, is called the hydrodynamic mechanism of dentin sensitivity.9 Although the pulp is not directly exposed, oral bacteria are small enough to travel through an exposed dentinal tubule and
invade the pulp.13 In uncomplicated dental fractures, the tooth may or may not become diseased
3. A complicated crown fracture of the right maxillary canine tooth in a cat. In domestic cats, the pulp chamber extends almost
to the coronal tip. Always be suspicious of a complicated crown fracture with any amount of crown loss in a cat's canine teeth.
When the pulp is directly exposed to the oral environment (complicated fractures), pain and pulp necrosis are always the consequences.
In the acute stage, these injuries are intensely painful because of activation of A-delta nociceptors. As the pulp dies, the
A-delta nociceptors necrose, but the type C nociceptors are still intact, transmitting dull, aching pain. Additionally, as
infection travels apically (toward the root tip), periapical disease can occur. The possible results include periapical osteitis,
periapical granuloma, true abscess with or without draining sinus tracts, tooth resorption, and secondary periodontal disease.
Before therapy is selected, obtain dental radiographs to assess the alveolar bone, root, periodontal ligament space, pulp
chamber space, and root canal space for radiographic evidence of endodontic disease and its extent. Even if extraction has
been selected, radiographic assessment is necessary to plan the extraction in light of possible root ankylosis, fractured
roots, supernumerary roots, and the health of the surrounding tissue.
Treatment options for fractured teeth include vital pulp therapy, root canal treatment, bonded composite restoration, crown
restoration, and extraction.