TIGER ENDODONTICS:
CANAL BEING DEBRIDED
Among Siberian tigers, one of the more common dental problems is injury to the maxillary cuspids, or canine teeth as they are called in veternary terms. They are sometimes injured in collisions with the bars of the tiger's cage or in playing with various toys provided for the tiger's recreation. When it becomes obvious, through signs and symptoms which will be described later, that a cat has an infection stemming fron an injured tooth, a decision on treatment must be made. In all instances concerning the canine tooth, root canal treatment is to be preferred over extraction which would leave the tiger disfigured by the loss of the tooth root, and large amounts of the maxilla would have to be sacrificed in order to make it possible to remove the very large root safely. Such a procedure could lead to a traumatized and infected maxillary sinus cavity just as would lack of any treatment. Because of the great size of Siberian tigers, they must maintain a diet including large amounts of protien, and for reasons of alimentery physiology, the diet must include also the fur, hide, and bones of animals. This diet cannot be managed with an infected tooth or an incomplete dentition. Without such a diet, the cat would quickly pass into a negative nitrogen balance through catabolism of the very large skeleto-muscular system.
BEFORE
In the case of Gingras, the diagnosis was made on the basis of specific signs and symptoms. It was noted that for some time the large cat had undergone a personality change and was not eating properly. As time went on he was observed to bat his face with his paw with increasing frequency. Finally, the presence of a broken tooth was noted and the veterinarian informed.
Under the supervision of the veterinarian, a consultation with a general dentist and an endodontist carried out under general anaesthesia confirmed the presence of a broken maxillary right canine. Aproximately 50 millimeters (two inches) of crown was missing and the pulp was exposed. Lateral skull X-ray projections were obtained and the canal was "sounded for depth" with an orthodontic wire. The preliminary measurement was 90 millimeters of remaining root canal length. The veternarian prescribed an anibiotic as a prophylaxis against infection as the area of pulpal exposure was large - nearly 14 square millimeters.
The endodontic procedure performed for the cat was similar to human procedures except that once a working length is determined, no further x-rays are needed since the apical delta which is a feature of feline dental anatomy, provides a definite stop. The use of the rubber dam is indicated for the usual reasons it is employed in human endodontics, but in this case it was not possible to apply one because of the great diameter and conical shape of the root at the level of fracture. In this case access to the root canal provided by the fracture was adequate, but sometimes access to the root canal must be made from the facial aspect to provide straight line approach to the apex. This is necessitated by the very sharp curvature of the tooth at about the gingival level. The size of the root canal poses a dilemma to clearing and shaping and obturation. Files can be made from coping saws (round blades with teeth on 360 degrees of the circumference) with handles fabricated from cold-cure acrylic and used as rasps or barbed broaches. Endosonics can be imployed in combination with sodium hypochlorite. The tip of a Cavitron 2001 unit can be modified by attaching 100 millimeters of orthodontic wire with silver solder. Profuse bleeding from the very vascular apical delta can be controlled by hydrogen peroxide and pipe cleaners soaked in Epinepherine. Pipe cleaners are also used to dry the canal.
CANAL PREPARED FOR FILLING
Packing the canal is also problematic. Sealer (Ross' #811 in this case) is placed at the apex with the flexible needleguard of a no. 14 ga., 5 1/4 in. angiocatheter and multiple tuberculin syringes loaded from the end at the finger flange and affixed to the needleguard which is left in the canal and slowly withdrawn as subsequent syringes of sealer are emptied into the canal. When sealer is noted at the access cavity, the guard is removed from the canal and a single gutta percha point hand rolled from a warmed stick of temporary stopping (Hygenic) and previously tried in the canal for fit is inserted to the apex. No attempt is made at condensation. The access is closed with amalgam and occlusal dental film is exposed. The length of the dental procedure in this case was ninety minutes.
INSERTION OF FILLING
Post-operative presecription of an antibiotic and anaesthetic recovery are managed by the supervising veterinarian. As in humans, a yearly dental examination (under general anaesthesia) includes a check-up, post-operative, endodontic X-ray image.
TOOTH "RESTORED"
We believe that careful preparation including a review of the available veterinary dental literature, consultation with dentists who have performed this treatment at other zoos, adaptation of basic biological principals and endodontic techniques coupled with a little ingenuity, organization, and rehersal, can make this very unique experience proceed smoothly. Indeed, future procedures will be carried out with very little change in the regimen as described in this paper.
Subsequently, a second Siberian tiger, a female named NIKITA, was treated using the above described technique. At last notice, both tigers were doing well and still partici-pating in the captive breeding program to propagate their species.
