Zoo and Wild Animal Dentistry. Группа авторов

in horses have been performed and described for many centuries. Initially, this was performed by striking accessible teeth, such as wolf teeth, directly. “With the horse's head tied up high, and his mouth opened wide, take a carpenter's gouge, place the edge at the foot of the wolf tooth, turn the hollow side downwards, holding your hand steady so that the tool may not swerve or slip, then strike the head of the tool a good stroke wherein you may loosen the tooth and bend it inwards, then wrench the tooth out with the hollow side of the tool. Then fill up the empty hole with salt finely brayed.” Trephining was developed as a means of opening the frontal and maxillary sinuses for treatment of nasal diseases caused by glanders or sometimes by dental disease by Lafosse in 1749.

      Until the nineteenth century, dental procedures in animals largely were performed by the owner of the animal, or by horse leechers, farriers and other often illiterate practitioners. “Learning” was handed down from generation to generation, mistakes, superstition, and all. Though the invention of printing in the fifteenth century permitted major advances in the distribution of material, it did not necessarily improve the quality of the information. With few exceptions, there is a distinct lack of critical, observant minds evident in the “veterinary” books of the sixteenth, seventeenth and first half of the eighteenth centuries.

      By the end of the nineteenth century, though the horse was losing its critical utility in the human world, equine dentistry was sufficiently advanced that “Equine Dental Colleges” were established; these were not associated with veterinary schools.

      Two factors that did bring considerable subsequent progress to equine dentistry were development of mechanical gags and of powered dental rasps for “floating teeth.” These features together resulted in significantly improved ability to manage occlusal abnormalities.

      We now accept without question that anesthesia is essential for veterinary dental procedures; however, safe, effective anesthetics are a relatively recent addition to the veterinary armamentarium. Major advances were use of: IV opium in dogs in 1665; nitrous oxide gas in cats in 1779; ether in animals in 1847; barbiturates in 1902; flexible endotracheal tube in1914; and pentobarbital and pentothal in 1931–1934.

      Small animal dentistry got off to a slow start compared with horses. The very early descriptions of dental or oral surgical procedures in dogs sound barbaric (particularly given the absence of practical anesthetic techniques). The indications were sometimes based on superstition rather than medical reality, such as excision of the lyssa (the fibromuscular tube that supports the rostral end of the tongue) to prevent rabies in the dog, described by Pliny (50 CE). On this topic, six hundred years later, Samuel Johnson (author of the first English dictionary) says of the “worm” of the dog's tongue, “it is a substance, nobody knows what, extracted nobody knows why”! There were occasional reports of “advanced” procedures, such as placement of dentures in dogs, in the late nineteenth century, however, significant growth in recognition of and means of treating oral and dental conditions in companion animals did not occur until the latter part of the twentieth century.

The need for attention to oral health in dogs and cats was, in part, precipitated by the major change in pet diets from about 1930 onwards; when domesticated dogs and cats are required to hunt for their own food, or cadaver material was their only food provided, the diet provided significant chewing activity that largely kept severe periodontal disease at bay during the life‐time of the animal. When a defined nutritional profile convenience diet is fed, there is reduced chewing activity and greater build‐up of dental plaque and calculus, such that periodontal disease became the most common clinical abnormality observed in dogs and cats by the end of the twentieth century. When owners provide hard materials such as cleaned processed bone, antlers or cattle hooves, or hard nylon toys, in an attempt to provide chewing activity, the risk of fracture of teeth increases. In addition, dogs and cats were living longer, because major viral diseases such as distemper and parvovirus infection in dogs and panleucopenia in cats were prevented by vaccination, thus enhancing the likelihood of development of chronically progressive diseases such as periodontal disease. The result of these changes is that by mid‐twentieth century, the increasing prevalence and severity of oral and dental diseases in dogs and cats was recognized, primarily among small animal practitioners rather than by those in academia. The impact of use of convenience foods on the oral and dental health of non‐domesticated animals in zoological collections is considerable, because the mouths cannot be examined frequently, and brushing or wiping the surfaces of the teeth as an oral hygiene measure is not possible. This is true not just of carnivores, but also of herbivores, where, for example, chopped hay may provide far less chewing activity than full pasture grazing. Rather than grinding meat and mixing in additional ingredients as required, as was normal previously, most zoos now feed diets that match the form of the natural diet for that species, and provide the essential micronutrients by, e.g. stuffing them into large raw meat pieces for carnivores; this combination provides the tearing and chewing activity necessary to prevent rapid accumulation of dental plaque and calculus.

      Another source of new veterinary dental knowledge from the mid‐part of the twentieth century onward has been use of beagle dogs as a favored animal model for research in dental school laboratories, which has significantly increased the canine periodontal knowledge base.

      One of the important sources of training for the initial core group of “dentally aware” small animal practitioners was human dental practitioners who were invited to consult on canine and feline dental patients. A few human dentists became critical players in veterinary dental continuing education programs, and some (such as Drs. Peter Emily, Peter Kertesz, Mark Tholen, Carl Tinkelman, John Scheels and Boyd Welsch) were important early contributors as volunteer dental consultants to zoos and other non‐domesticated animal collections. As companion animal and particularly zoo and wildlife dentistry developed, the limitations of human dental instruments became evident, particularly in endodontics because of the grossly insufficient length of human endodontic instruments when treating a canine tooth in a large dog or a tiger, in which the root is typically several times as long as the longest human tooth root.

      As veterinary dentistry became a standard part of veterinary medicine in the latter quarter of the twentieth century, individual veterinarians began to devote all of their professional effort to dentistry, and began meeting to discuss topics of mutual interest. This led to the formation of the American Veterinary Dental Society in 1976, and to recognition of dentistry as an area of veterinary specialization starting in 1987. The leaders of this group of board‐certified veterinary dentists included several who, like their dental colleagues mentioned above, volunteered their time as consultants to zoos; early examples were: Drs. Chuck Williams (National Zoo, Washington DC), Ben Colmery (Detroit Zoo), Bob Wiggs (Dallas Zoo), Don Ross (Houston).

      A critical step in the development of zoo and wildlife dentistry has been the willingness of these, and later individuals, to share their experience; there have been two Zoo and Wildlife Dentistry conferences, with abstracts of one of these meetings published in the Journal of Veterinary Dentistry.

      As the content of this book will demonstrate, there are very unique challenges associated with zoo and wildlife dentistry; sharing information about successes and failures is critical to minimize the risk of repetition of failure during the learning curve of individual veterinary dentists. This book is designed to provide a strong collective foundation in that regard.

      In 2017, the American Veterinary Dental College recognized the increasing interest in zoo and wildlife dentistry by establishing an AVDC Zoo and Wildlife Dentistry Certificate program. A Delphi process and examination resulted in recognition of 15 founding AVDC‐ZWD Certificate holders. They are: Drs. Kris Bannon, Jan Bellows, David Clarke, Stephen Coles, Edward Eisner, Roberto Fecchio, Nadine Fiani, Barron Hall, Steven Holmstrom, Loic Legendre, Michael Lowder, Clarence Sitzman, Gerhard Steenkamp, Frank Verstraete and Douglas Winter. This process included developing a list of publications on zoo and wildlife dentistry and related topics, which the ZWD Certificate Organizing Committee plans to make available. Though AVDC‐ZWD certificate holder status is limited to veterinarians, a list of human dentists who have contributed significantly to the development of zoo and wildlife dentistry is under consideration for recognition for honorary status in the ZWD Certificate program.

      This chapter is based on a review of