Dental Corner: Canine orthodontics: Providing healthy occlusions


Dental Corner: Canine orthodontics: Providing healthy occlusions

Jul 01, 2006

The idea of orthodontic correction for dogs frequently elicits snickers and causes uninformed eyes to roll. People often assume that orthodontic procedures are purely cosmetic and are reserved for show dogs. But nothing could be further from the truth. In fact, the American Kennel Club does not permit dogs that have had their heritable oral anatomy altered to be shown in its conformation classes.

In people, orthodontic correction is used to treat abnormal occlusions and to improve aesthetics. In dogs, the goal of orthodontic treatment is to provide a healthy and functional occlusion—something to which every dog is entitled.


Figure 1A. A normal occlusion, or scissor bite. The maxillary incisors overlap the mandibular incisors, and the mandibular canine teeth are positioned midway between the maxillary third incisor and canine teeth on the same side when the mouth is closed. 1B. The mandibular premolar cusps point to the midpoint of the interproximal space of the maxillary premolar of their counterparts (i.e. the central cusp of the mandibular second premolar is pointing up at the interdental space between the maxillary first and second premolars).
The normal occlusion in dogs is the scissor bite (Figures 1A & 1B). This occlusion is found in wild Canis species and in many domestic breeds, such as German shepherds. Any deviation from the scissor bite is called a malocclusion. However, in some domestic breeds (e.g. English bulldogs), people have selectively bred for an occlusion other than a scissor bite. In fact, as of January 2005, 50% (79 breeds) of all 159 American Kennel Club breeds were allowed occlusions other than a scissor bite.1 Thus, many of our canine patients have normal-for-the-breed-standard occlusions that by health standards would be considered malocclusions. But while 50% of purebred dogs have malocclusions, not all of them require orthodontic therapy.

There are three skull types in dogs: dolichocephalic (long, narrow head; e.g. collies), mesocephalic (medium-proportioned head; e.g. German shepherds), and brachycephalic (short, wide head; e.g. pugs). Each of these types is predisposed to certain orthodontic problems. With so much variation in what is considered normal occlusion for a breed standard, it is important to focus on what is healthy for an individual patient.


One classification of malocclusion is based on the length of the maxilla in relation to the length of the mandible. A class I malocclusion is one in which one or more teeth are incorrectly aligned but the mandible-to-maxilla relationship is normal. A class II malocclusion—also termed an overbite, overshot, or, more accurately, overjet—occurs if the mandible is relatively shorter than the maxilla. A class III malocclusion—also termed an underbite, undershot, or, more accurately, underjet—occurs if the maxilla is shorter than the mandible.