THE HEALTHY COLLIE: DENTITION
A Non-erupted Maxillary Canine Tooth in a Dog

by Dr. David E. Hansen, DVM, FAVD
Camloch Collies

Please refer to the previous article for terminology definitions

Patient History / Presenting Complaint
A 14-month-old, 74 pound male Labrador retriever was presented for assessment and treatment of an apparently absent right maxillary canine tooth, right maxillary first premolar tooth, and right maxillary second premolar tooth. (Figure 1) The owner reported that these teeth had never been present. The owner also commented that when visiting the breeder initially, the puppy was very active and rambunctious. A few days later after deciding to purchase the puppy, the puppy was extremely quiet. The breeder had stated that the bitch had bitten down on the puppy's muzzle to "teach it a lesson". The puppy's muzzle was sore, but there was no bleeding. The puppy displayed normal activity after acclimating to his new surroundings. The owner remembered the deciduous maxillary canine tooth falling out on the right side about one month after the left deciduous maxillary canine tooth, but no adult tooth erupted. The dog tended to "snort and sneeze". This was becoming more frequent.

Figure: 1 Missing Teeth

Preliminary Examination
On physical examination the only abnormalities were limited to the patient's muzzle and oral cavity. His muzzle was deviated slightly towards the right. The previously mentioned teeth were not evident. The right maxillary second incisor, and right maxillary third incisor teeth had slight enamel hypoplasia (loss of the enamel in places from damage during development of the tooth bud). The right maxillary third premolar tooth was rotated with the mesial face towards the palate and the distal face towards the buccal pouch, but fully erupted. The dog tended to snort periodically. The patient seemed to resist efforts to examine the right side of his mouth more than the left.

Dental Radiograph
A survey intraoral radiograph of the anterior maxilla showed an almost normal size right maxillary canine tooth, located deep and at the midline of the palate. The right maxillary first premolar tooth, and right maxillary second premolar tooth were not present. (Figure 2)

Figure: 2 Embedded Canine Tooth (arrow)

Surgical Procedure
Prior to starting the surgical procedure, a local nerve block was placed to provide regional anesthesia to the right maxilla. An incision was made from 2mm distal to the upper right third incisor thru the area where the missing teeth normally are, extending palatally to the mesial aspect of the upper right third premolar. A gingival flap was raised off of the palate. The bone over the upper right embedded canine tooth was removed with a dental bur. (Figure 3)

Figure: 3

Once through the bone the glistening white of the enamel was easily distinguished. (Figure 4) The opening was enlarged until the tip of the tooth could be grasped with a forcep.

Figure: 4

There was slight soft tissue resistance as the tooth was extracted with gentle force. The cavity was curetted (scrapped) to remove any lining. After extraction it was noted that there was a small amount of fresh blood coming from the right nostril. The wound was sutured in a simple interrupted pattern. (Figure 5)

Figure: 5

A final radiograph was taken to confirm that the two right upper missing premolars had not been superimposed and hidden by the canine tooth. They were not present. (Figure 6)

Figure: 6

Aftercare
The patient made a normal recovery with a minimal amount of sneezing. He was discharged on an antibiotic to prevent infection and an analgesic for pain. The dog's regular kibble was to be soaked in water to soften it for a period of 5 days and the owner was to withhold chew toys, rawhides etc until the recheck. Exercise was to be restricted for 1 week due to the risk of nasal hemorrhage. A recheck was scheduled in 7 days.

Follow-up
At the 7-day recheck, the patient was doing extremely well. The owner reported that the dog had not missed a meal and the "snorting and sneezing" had stopped since the surgery. There had been no bleeding from the nostrils. The mucosa was healing nicely, although a few sutures were missing. (Figure 7)

Figure: 7

Discussion
This patient was not showing any obvious signs of pain. The increasing frequency of the snorting and sneezing, along with being more mouth shy on the right, were indications that a problem was developing. A crushing trauma to the maxilla at a time when the tooth buds are developing can account for the findings of this case. Intraoral radiographs in young animals are indicated when there are teeth that are apparently absent It should not be assumed that the teeth are absent until proven so. Early treatment of impacted or non-erupted teeth may prevent the formation of a cyst. The formation of a cyst will result in much more tissue destruction and pain for the patient.