Recent cases that are instructional and illustrative
of typical zoo dentistry cases
Siberian tiger mandibular canine endodontic procedure
October 16, 2014
Milwaukee County Zoo.
"Tula" is a 2 1/2 year old Siberian tiger, weighing 242 pounds. She fractured her mandibular canine when playing with her littermate, sister, on an elevated structure. An observant zookeeper spotted the canine tip piece, approximately 1 1/2 cm. long, shortly after the incident and confirmed by observing the tigress, that the canine was short, fractured.
Tula did not seem to be in pain or distress and her behavior was normal according zookeepers. However, I am aware of fresh fractures of this type, exposing the pulp and nerve caused some captive carnivores to be in so much pain and distress that they attacked and killed a cage mate. ("Bubba", Brookfield zoo, year?)
Approximately ten days later, on October 16, 2014 the zoo veterinarians, primarily Drs. Jennifer Haussmann and Vickie Clyde, sedated Tula, and transported her to the Milwaukee County Zoo Animal Health Center. Following the vets and techs establishing an intravenous line, attaching a pulse-oximeter and intubation establishing general anesthesia, we were given permission to start the dental procedure.
A brief oral exam revealed no other oral or dental pathology warranting treatment other than the mandibular right canine. The pulp was exposed with pulp tissue at the surface of the opening. The fractured canine segment and observation of the tooth had already established the pulp exposure (Figure 1).
The pulp was vital. The preoperative radiograph (Figure 2) revealed the pulp on this young animal widened a short distance beyond the fracture.
After explaining to the veterinarians, I used the high speed dental hand piece to cut another approximate cm off of the tooth to permit optimal pulp access for the endodontic procedure (Figures 3 and 4).
I extirpated the pulp and nervous tissue with a 100 mm endo file. Working length was established at 72 mm. This correlated with my measurement and estimation from the preoperative radiograph. Using successively larger diameter files, and copious irrigation with NaOCl and RC prep the canal was shaped and dissenfected (Figures 5, 6 and 7).
Hemostasis was established and the pulp was dried with sterile pipe cleaners. They must be actual pipe cleaners comprised of absorbent cotton. Not colorful craft items. Bag and sterilize (Figure 8).
After fitting the master gutta percha cone at the established working length, the canal was then obturated with PCA endo filler paste (a ZOE based paste) by placing the Large Volume Veterinary Endodontic Syringe needle at the apex and backfilling as it is withdrawn. The paste was deposited with a 20 gauge, 2 1/2 inch spinal needle (Figure 9). Additional gutta percha points were then placed and condensed in the canal.
A zinc phosphate cement base was placed over the endo fill. The access opening was briefly prepared and a composite resin restoration placed. I rounded and smoothed off the fractured canine edges when polishing the composite resin (Figure 10).
The entire dental procedure was completed in 53 minutes. Tula recovered from her anesthesia uneventfully. A successful procedure facillitared by excellent general anesthesia by the veterinarians. See the fill radiograph (Figure 11).
This conventional endo approach also called coronal or orthograde is certainly the technique of choice for a fresh, vital pulp, endodontic procedure. Considering the delta apex on mature carnivore teeth, if this tooth was abscessed and or a significant amount of lysis of the apex or a large lytic area in the adjacent alveolar bone was observed, a surgical retrograde approach would have been necessary to treat properly. Also, again considering the delta apex of the tooth, periodic examination including radiography of the tooth root is necessary to monitor the success of the conventional endodontic procedure. The necessity of such follow up should be indicated in the patient's chart so that if she must be sedated for some other reason, the dental exam and radiographs will be done also.
Zookeepers are reminded to be particularly observant of behavior or signs that may indicate pain or abscessation of the tooth.
Milwaukee County Zoo.
Siberian Tiger Mandibular Canine Endodontic Procedure