The primary objective of veterinary orthodontics is to provide a comfortable bite for companion animals. Cosmetics are often
improved, however orthodontic care is never provided for deceptive purposes. Our ethical priority is to provide genetic counseling
to avoid future problems associated with malocclusions. Traumatic malocclusions are painful for pets and painfully expensive
Veterinary orthodontic services may be interceptive (directed at prevention) or involved in the application of forces to move
teeth to establish a functional and more comfortable bite.
What characterizes a normal occlusion (bite)?
Seven characteristics are useful for the evaluation of the bite in companion animals:
Photo 1: Scissors bite.
Head dimension or shape dictates whether the occlusion is functionally acceptable: mesaticephalic (medium length and width e.g. German Shepherd),
brachiocephalic (short, wide head e.g. Boxer) or dolichocephalic (long, narrow head e.g. Whippet or Saluki).
A "scissors bite" refers to the incisor occlusal relationship (Photo 1).
Photo 2: Canine interlock.
The canine interlock suggests a proper fit of the upper and lower dental arcades (Photo 2).
The premolar interdigitation refers to the "pinking shear" appearance from a side view (Photo 3).
Photo 3: Premolar interdigitation.
The carnassial teeth alignment allows for a functional bite.
A consistent "freeway space" is a result of the relationship between the upper and lower arcades.
Head symmetry helps determine relationships between dental arcades.
There is variability between breeds in evaluating a "normal" or acceptable occlusion. This is the reason for consideration
of the head dimension or shape. An acceptable bite for a Boxer is not acceptable for a German Shepherd.
A "scissors bite" refers to the proper occlusal relationship between the upper and lower incisors. All six upper incisors
should be just rostral to and overlap the six lower incisors. The cusp tips of the lower incisors should rest on the cingulum
of the upper incisors. The cingulum is a shelf-like surface of the distal (caudal) aspect of the incisor teeth.
If you don't find a "scissors bite", you are very likely looking at a malocclusion.
This malocclusion may be a traumatic occlusion where there is tooth-on-tooth or tooth-on-soft-tissue contact (Photo 4). These
conditions can be tremendously painful even in patients who demonstrate no discomfort. It has been postulated that companion
animals avoid demonstrating pain to avoid being culled from the pack. When you identify a traumatic malocclusion, the patient
deserves prompt dental care.
Photo 4: Traumatic malocclusion; note persistent deciduous canine.
Canine interlock is important for normal development. The interlock physically directs and maintains the appropriate upper-to-lower
jaw length relationships in the growing animal. Lack of this interlock suggests a discrepancy in jaw lengths and a malocclusion.
In the normal occlusion, the lower canines will fit in the space between the upper canine and the corner (lateral or third)
incisor and there will be no physical contact between these teeth as shown in Photo 3.