In the context of veterinary dentistry, occlusion refers to the way the teeth of the upper jaw and lower jaw come together. In the canine patient, normal occlusion is seen when the lower canine teeth fit evenly between the upper canine and third incisor teeth, the lower incisor teeth occlude just behind the upper incisor teeth, the lower premolar teeth occlude in front of and interdigitate with the upper premolar teeth, and the crowns of the upper fourth premolars occlude to the outside of the lower first molar teeth. The various classes of malocclusion occur when there is deviation from this ideal occlusion either from a discrepancy in the length of the upper and lower jaws, malposition of a tooth or teeth, or a combination of both. Displacement of one or both of the canine teeth in the lower jaw resulting in traumatic contact with the palate is the most common malocclusion in dogs for which orthodontic movement is indicted. Other treatment options for this type of malocclusion include extraction and crown amputation with vital pulp therapy. If left untreated, potential problems include defects in the palate, oronasal fistulae (communication between the mouth and nasal cavity), tooth wear, incomplete tooth eruption, temporomandibular joint dysfunction, periodontal disease and behavioral issues.
In the case presented here, a 6-month old Wheaton Terrier dog was successfully treated for a painful mispositioned lower left canine tooth using an acrylic incline plane appliance. This appliance is placed temporarily on the teeth of the upper jaw and a ramp is formed to allow tipping pressure to be placed on the lower canine tooth. This pressure promotes tooth movement in order to achieve a normal or non-traumatic position of the tooth.
Awake examination of the patient showing a normal relationship between the upper and lower jaws with malpositioning of the lower left canine tooth causing trauma to the palate.
Creation of the acrylic appliance on the teeth of the upper jaw with a ramp to allow tipping pressure to be placed on the lower canine tooth.
Re-examination one week after placement of the appliance shows a desirable, non-traumatic position of the lower left canine tooth and a retainer period of 5 weeks is recommended.
Image shows non-traumatic positioning of the lower left canine tooth on the day of appliance removal.
Recheck 8 weeks after removal of the of orthodontic appliance showing the patient remaining in normal occlusion.
Recheck 6 months after appliance removal. The lower left canine tooth remains tipped to its normal position.
Case submitted by: Kevin Haggerty, MVB, DAVDC