Veterinary Orthodontics

 

Case report: Lance maxillary canines in a Shetland sheep dog

     This Sheltie presented at the age of 9 months with labioversion of the mandibular canines (laterally tipped) secondary to mesioversion of the maxillary canines (lance canines). The owner had noticed that the mandibular canine teeth were frequently catching the upper lips.

The treatment options given in this case were:

• extraction of teeth in traumatic occlusion (mandibular canine teeth)
• crown amputation of the mandibular canine teeth, with vital pulp capping and composite restoration
• orthodontic movement of the canine teeth into correct occlusion

The owners elected the orthodontic treatment and had already made arrangements to neuter this dog.

The orthodontic appliance fabricated on the anesthetized patient was an elastic chain from the maxillary canine teeth to anchorage on the maxillary 4th premolar-1st molar unit. These anchorage teeth were connected with a wire-reinforced acrylic which also included enough build up of acrylic on the occlusal aspect of the 1st molars to act as a bite block. In this fashion, a slightly open bite would allow for distal tipping of the maxillary canines past the mandibular canines:

 

This type of appliance exerts small forces on the maxillary canine teeth, but requires frequent shortening of the elastic chain due to fatigue of the elastic material. Fortunately this was a very compliant patient, and the owners were able to replace the chain if it was dislodged and shorten it at 3-4 day intervals.

After 2 months the maxillary canines had been tipped distally enough to create a space for the mandibular canine teeth, and the orthodontic appliance was removed. The mandibular canines were still slightly tipped laterally, but shifted into normal occlusion over the next few months.