Special Cases of Note
Special cases that are instructional and illustrativeof typical zoo dentistry cases
Siberian tiger mandibular canine endodontic procedureOctober 16, 2014Milwaukee 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.
Bonobo MakanzaFebruary, 2015Milwaukee County Zoo.
Rachel - Mongolian (Bactrian) CamelMilwaukee County Zoo.
Bird and Reptile Beaks
Bird beaks and bills, and reptile beaks are not teeth, however, often dentistry techniques have been attempted to repair them. Beaks and bills are made of keratin, not enamel and dentin. There grow in numerous configurations throughout the life of the animal, with a wide range of vascularity.
I attempted to repair various configurations with a range of success. Early on, I like many others was “learning on the job”.
Some basic facts to know are that you cannot bond composite resin restorations to keratin. The nature of the surface and its’ continuous growth will not accept bonding adhesion. Placing retentive pins does not solve that challenge. Slower growing beaks or bills may seem to accept prosthetic additions, but they will eventually fail with even seemingly solid fixation.
If vascular support remains, a damaged beak or bill can grow, so sometimes prosthetic support will allow repair or even regrowth. In these cases, again due to the constant growth, this almost always requires close monitoring and additional repair measures. One should always use the simplest, least intrusive measures, to allow the patient optimum function, with minimum interference to function.
These days there are numerous references to be found on the internet on beak and bill repairs.
- "Treatment and Stabilization of Beak Symphyseal Separation Using Interfragmentary Wiring and Provisional Bis Acryl Composite" Journal of Veterinary Dentistry 2014,Vol. 31, ppg. 255-262. Charles Lothamer DVM, Christopher J. Snyder DVM, Christoph Mans Dr. Vet Med DACZM ECZM, Jason Soukup DVM
Haley, Polar BearBrookfield ZooAbscessed mandibular canine extraction, following failed endodontic treatment
Haley arrived at Brookfield Zoo with a draining abscess of right mandibular canine, at the root apex. At previous zoo she had coronal root canal treatment. She was less than two years old. The canal was very large, the canine immature. The apex had not matured, closed when the endodontic fill was completed. The fill material, consisting primarily of paste extruded through the open open apex. If it had been supposed to be an apexification treatment, it had failed completely, leaving her with an external fistula through the ventral border of the mandible. White paste crumbles were coming through the fistula. Dr. Meehan said the the previous zoo had not provided any dental treatment records. She was on antibiotics. We considered the treatment options. We agreed that removal of the canine would allow the bone to fill in. We agreed that bone would be stronger than trying to keep the canine, reinforcing it with a post. She was being kept apart from her future mate. We agreed to keep her apart until we did a follow up in three months. We did this to protect her from any trauma to the weakened mandible. At three months a radiograph revealed that complete bone repair had been achieved and she was then allowed to be with her mate.