Taking On A Bear Of A Toothache At The Zoo

Zoo dentistry is one of the least talked about specialties within veterinary oral care. Companion animal, equine and zoo dentistry are growing and changing as human oral care techniques are applied to multiple species to attain a higher quality of life and remove pain. 

Zoo dentistry is most often accomplished behind the scenes. The zoo veterinarian, zoo veterinary dentist and their health care teams breach the “wild kingdom” to identify and remove oral pain. Because of this necessary approach, not as much is known about this specialty.

The individuals who rarely get the deserved credit for the early detection of zoo animal oral pain are the keepers, handlers and zoo technicians. They study each animal in their care daily and are astute in noticing habit changes that could signify  oral discomfort.

Food shifting, not eating certain hard foods, excessive salivation after eating or decreased appetite are first seen by these caretakers.

Spectacled Bear

I am privileged to be the zoo dentist at The Beardsley Zoological Gardens in Bridgeport, Conn.

The South American spectacled bear is found in the Andes Mountains of Venezuela, Colombia, Ecuador, Bolivia and Peru. Gerald Durrell brought a spectacled bear, Pedro, to the Jersey Zoo in 1963. A female from the Chicago Zoo was successfully mated with Pedro, and the first two litters were born in 1972 and 1974.

These bears are arboreal, using their sharp front claws to climb. They build leafy platforms in the trees where they feed and sleep.

They are mainly plant eaters, eating fruit, bromeliads and palms. They will eat some rodents and insects, but they are a minor part of their diet.

Ecologists have shown that the fruit these bears eat plays a significant role in rain forest ecology.

The seeds are excreted in the bear droppings as they travel. This produces a new generation of fruit trees in multiple rain forest habitats.

They are one of the smaller bear species, with males weighing 200 to 350 pounds and females 125 to 175 pounds. Their body length is from 5 to 6 feet, and they are the only bears found in South America. They do not hibernate and are active all year because of their warm native climate.

About 2,500 of these bears remain in the wild and are endangered because of habitat loss. In South America, even though it is illegal, they are hunted for their fur and meat.

Chica at the Zoo

Chica was presented with a history of hypersalivating after eating and food shifting of some of the hard foods in her diet. Without digital oral radiology, it would have been impossible to reach an expedient diagnosis and perform the proper treatment on Chica. With portable dental X-rays, we quickly reached a diagnosis and set up treatment.

On oral radiology, a premolar was noted with a crown-root fracture. Two root canals on teeth that had undergone earlier conventional endodontic care had suspicious sites of apical osteolysis, and the root canals were redone. The premolar was extracted with a full thickness mucoperiosteal flap, and the site was bone grafted before closure with absorbable 3-0 PDS II suture.

In companion animals, it is not difficult to recapture a new digital X-ray on a tooth that has undergone endodontics at an earlier time. In zoo species, anesthesia is more complex. The patient must be darted with induction chemical restraint tranquilization and then brought to the zoo operatory, where it is intubated and placed under gas inhalation anesthesia.

Because of movement of species through the network of national zoos, the veterinary dentist might not have the ability to follow up on his own patient if the animal needed to be re-anesthetized.

The zoo endodontic patient must be treated quickly while under anesthesia, and there is no margin for error. Treatment must be precise and perfectly performed. The importance of oral radiology cannot be overemphasized.

Zoo Endodontics

Before embarking on zoo endodontics, the operator must be trained in oral radiology and companion-animal endodontic procedures.

On the East Coast, contact Dr. Ira Luskin, Dipl. AVDC, at the Animal Dental Training Center. He has an excellent training center in Baltimore, Md., with intermediate to advanced courses. 

On a national level, the yearly Veterinary Dental Forum also has excellent courses. Proper education to work in the zoo setting requires oral surgery and endodontic courses with multiple laboratory experiences and it is essential to have a mentor who has performed procedures in the zoo setting. 

The endodontic files for conventional root canal therapy for bears and zoo cats are specialized. For years, those working in the zoos would have their own personal files machined to a 120mm or more length for canal debridement. These H-Files are now commercially available. 

Many bears have draining fistulous tracts that require both conventional and surgical root canals (apicoectomies). After exposing the apical portion of the root and completing a root resection, retrofilling is initiated.

Retrofilling  procedures involve debriding and shaping the apical 3mm to 5mm of the root to create a suitable space for the retrofilling material.

Because the opening of the draining tract is so large in most bears, the exposure is quite dramatic. Using radiosurgery and a loop electrode, the granulation tissue can be removed so that the retrograde material can hermetically seal the apex. 
Super EBA and IRM are the most universally used retrofilling materials.

Chica in Recovery

Within a week after repeating the root canal therapy and removing the premolar with the crown-root fracture, Chica was back to normal. Her diet was kept soft, and antibiotics were instituted in a banana.

It is our responsibility to care for those species that we keep in zoos and wildlife preserves. As we create a comfortable environment for species preservation, there must be a commitment to remove pain and provide quality of life.

Zoo dentistry is truly a team effort. Dr. Howard Hochman, zoo veterinarian at Connecticut’s Beardsley Zoo, and his technicians and handlers provided an excellent operatory and anesthesia experience for Chica during oral surgery.

None of the work could ever have been accomplished, with such precision and expedience, without their valuable help.

Special words of gratitude are offered to Dr. Hochman and his excellent co-workers. 

Also, a special thank you to Peter Emily, DDS, Dipl. AVDC, internationally recognized zoo dentist, for the mentoring that he provided to me in my early years of oral education. He has allowed me to enter the field of zoo dentistry and help those creatures large and small that need oral attention.  <HOME>

Dr. DeForge is an adjunct professor at Northwestern Connecticut College and Mercy College. He has a telemedicine oral X-ray reading service for analog and digital X-rays, VetDent Oral Imaging Services. He may reached at dondeforge@aol.com.

 

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