Dr. John Scheels - Exotic Animal Dentistry
 
Dr. John Scheels - Exotic Animal Dentistry Dr. John Scheels - Exotic Animal Dentistry
×
 
Home
The Zoo Team
Recent Cases

Page 2 - Herbivores

Cases

Please note that as a dental consultant I will only address the dental and oral pathosis components of these cases, leaving the anesthesia and other medical treatments to the veterinarians. I will use example cases with common pathoses encountered and those which I have sufficient photo series to illustrate them.

Dall Sheep Endodontic Case

When a mandibular swelling was observed on this Dall sheep ewe by an observant keeper, an anesthesia was scheduled. Under general anesthesia, radiographs revealed periapical lesions and typical bony swelling due to pulpal degeneration, infection and inflammation of the alveolar bone. The intraoral pulp exposure was due to a cusp fracture. After shaving and cleansing the region, the lesion area was entered with a lateroventral approach. After reflecting the overlying skin, the cancellous bone was curetted and cut away with surgical dental burs, always using copious amounts of coolant water. When the tooth apices were exposed a retrograde endodontic procedure was performed. It was restored with amalgam. More recently of course we have utilized EBA and MTA. The cusp fracture was restored. The surgical site was closed after contouring rough bone edges. Oral antibiotics are not an option with ruminants so catching up or squeeze caging it was required to administer injections of antibiotics for several days. Follow up examinations including radiographs revealed healing and bone fill of the mandibular ventral border.

Dr. John Scheels - Exotic Animal Dentistry

Dall sheep: Bony lesion on jaw due to abscessed molar
(Click image to enlarge)
Dr. John Scheels - Exotic Animal Dentistry

Dall sheep: Radiograph of periapical lesion and bony swelling reaction to abscessed molar
(Click image to enlarge)
Dr. John Scheels - Exotic Animal Dentistry

Dall sheep: Surgical approach to root apices
(Click image to enlarge)
Dr. John Scheels - Exotic Animal Dentistry

Dall sheep: Apisectomy, retrograde fills, immediately post op
(Click image to enlarge)
Dr. John Scheels - Exotic Animal Dentistry

Dall sheep: Bone healed, 9 month follow up
(Click image to enlarge)

Equine Endodontic Case

When mandibular swelling was noted associated with likely a kick wound, radiographs revealed that two tooth root tips were fractured. There was no intraoral trauma or pathosis. A retrograde endodontic procedure was performed. Follow up examination and radiographs revealed good healing. And even more importantly we confirmed that the tooth continued to erupt at the same rate of the adjacent teeth. This was very satisfying to observe, because when this case was performed in the early 1990s we were not aware of anyone else doing so and recording the continued eruption. I presented this case among others at the 1994 AVDS meeting, at the exotic animal section. Again, we were using amalgam then, but utilize EBA or MTA now.

Dr. John Scheels - Exotic Animal Dentistry

Equine: Area prepped for surgical approach
(Click image to enlarge)
Dr. John Scheels - Exotic Animal Dentistry

Equine: Radiograph reveals roots fractured by kick to mandible
(Click image to enlarge)
Dr. John Scheels - Exotic Animal Dentistry

Equine: Root apisectomy, retrograde endo fills sealed with amalgam
(Click image to enlarge)
Dr. John Scheels - Exotic Animal Dentistry

Surgical closure.
(Click image to enlarge)
Dr. John Scheels - Exotic Animal Dentistry

Equine: Endo fills, bone healed
(Click image to enlarge)
Dr. John Scheels - Exotic Animal Dentistry

Equine: Surgical area healed, 6 month follow up
(Click image to enlarge)

Llama and Equine Case Lessons

Among the initial large herbivore cases that I encountered, several were llamas with an abscessed mandibular premolar or molar. They presented with swellings of the bone surrounding the affected tooth abscess. My first instincts were to extract these teeth and debride the lesions, using dental or oral surgery rotary instruments to remove the bony swellings. It is quite challenging to remove these teeth through the oral cavity. Superior instruments available today permit these extractions, and are handled regularly by equine veterinarians. I highly recommend utilizing the expertise of experienced equine veterinarians if possible with cases such as the very large Bactrian camels at Milwaukee County Zoo. Captive exotic animal cases will not be able to followed up on as thoroughly as domestic equine cases though. Therefore, the zoo veterinarian will make the final decisions on treatment options.

In Dr. Murray Fowlers' book on South American Camelids, which I highly recommend as a quality reference, regarding dentition and pathosis, he mentions but does not illustrate the lateral buccomoty approach to access the molar region. My friend and colleague, Dr. Peter Kertesz, recommended I practice the lateral buccotomy approach on cadavers prior to an actual case.

Working with equine veterinarian Dr. Jo Randolph, we utilized cadaver heads to review the anatomy of llama and equine oral cavities prior to using the lateral buccotomy approach. With thorough preparation I have successfully used the lateral buccotomy approach on llamas, horses and other species with similar anatomy.

Dr. John Scheels - Exotic Animal Dentistry

Llama: Cadaver dissection, note probe in Stensons' duct
(Click image to enlarge)
Dr. John Scheels - Exotic Animal Dentistry

Llama: Lateral buccotomy, horizontal incision, approach to extract molar
(Click image to enlarge)
Dr. John Scheels - Exotic Animal Dentistry

Llama: Healing surgical area.
(Click image to enlarge)

If an abscessed posterior tooth is beyond repair, it usually should be extracted. I say "usually" because in some species, considering the patients' entire dentition, removing an abscessed tooth may be worse than keeping it in position. For example, in some species such as rhinos and tapirs extraction may be all but impossible. Even if it was done, and theoretically it could be, the risks of jaw fracture, and limitations of follow up care due to anesthesia considerations are riskier than treating a low grade chronic infection.

A common llama case presentation is an abscessed third premolar or first molar. Swelling on the mandible is usually the first sign noticed by caregivers. By this stage in the pathosis, usually a significant periapical lesion has developed including lysis of the root apices. The usual treatment considered on these easily managed animals is extraction. However, a retrograde endodontic approach should certainly be considered to maintain the tooth. This has been described.

Extraction through the oral cavity in these species is very challenging. Again, currently equine veterinary dentists are using the oral approach in horses and llamas regularly these days with improved equipment and training. I can attest that these are very challenging because of experience. Note that the roots of the llama mandibular molars are very wide and can be convoluted.

The etiology of the abscess is usually due to enamel fractures leading to pulp exposure, or advanced periodontal disease associated with malocclusion. If endo is to be considered, one must consider whether the original etiology can be resolved also.

To access the posterior teeth using the lateral buccotomy, follow proper surgical protocol cleansing the oral cavity and surgical site. The lateral buccotomy incision is made at the level of the occlusal plane in the horizontal plane. Visualize the orifice of Stensons duct from the parotid gland, to avoid severing the duct. Consider inserting a flexible piece of plastic to monitor its position. Dissect carefully to avoid any significant vascular vessels or branches of the facial nerve. Avoid cutting the masseter muscle if possible, but for more posterior teeth it may need to be dissected. The skin, buccinator muscle and oral mucosa will be encountered. Utilizing retractors the tooth can now be accessed. The tooth can be sectioned and an appropriately designed gingival flap made to access and remove buccal bone overlying the roots. A key point is to design the flap so that suturing is done over solid bone to avoid flap dehiscence. Following appropriate alveoplasty and flap closure the cheek can be closed in layers.

Another key element of managing an extraction, especially on a mandibular tooth on a patient whose diet cannot be altered and that will not be readily sedated or anesthetized for follow up care is how to manage the extraction site. The question is whether to close the extraction site, the alveolus and if you cannot, which is usually the case, how to keep food from entering the alveolus. First, it is difficult if not impossible to surgically close a mandibular extraction site in any species with the ideal tensionless flap, without creating additional surgical wound issues. It is much easier on maxillary sites, but with gravity in its favor, maxillary surgical sites do not present the same magnitude of food impaction issue.

In the late 1980s or early 1990s I came upon the idea of using dental waxes to close plug the alveoli. I was aware of the various techniques used at the time, some quite ancient and crude to plug and manage dental surgical sites. I know that many other people, especially in the equine field came upon the wax technique also. We discovered this among us at various veterinary dental meetings. I have used the wax plug technique successfully in mandibular extraction cases in many species, ranging from moose to warthogs.

When hemostasis is achieved the plug is formed from pink sheet dental wax to fit the alveolus very tightly. It should be approximately one half of the length of the extracted tooth root. This allows granulation in the base of the alveolus. When the wax plug is eventually lost primary healing will have occurred, the effect of food impaction and eventual infection is minimized. *See the tooth extraction section of this site for pictures of wax plug use.

Spekes Gazelle Case

Dr. John Scheels - Exotic Animal Dentistry

Spekes gazelle presenting with swelling on left mandible. Bony enlargement is reaction to dental infection. History of dental pathosis in primary dentition at previous institution.
(Click image to enlarge)
Dr. John Scheels - Exotic Animal Dentistry

Draining lesion on ventral border of mandible over enlarged bony region.
(Click image to enlarge)
Dr. John Scheels - Exotic Animal Dentistry

Shaving of hair reveals bony enlargement and two draining tracts.
(Click image to enlarge)
Dr. John Scheels - Exotic Animal Dentistry

Lesions over enlarged bony area.
(Click image to enlarge)
Dr. John Scheels - Exotic Animal Dentistry

Intraoral exam revealed malformed, vertically fractured third mandibular premolar.
(Click image to enlarge)
Dr. John Scheels - Exotic Animal Dentistry

Extracted fractured tooth fragments, granulomatous tissue and impacted food particles.
(Click image to enlarge)
Dr. John Scheels - Exotic Animal Dentistry

Initial surgical approach in drainage tract area revealing layers of honeycomb like secondary bone growth resulting from the chronic infection in mandible.
(Click image to enlarge)
Dr. John Scheels - Exotic Animal Dentistry

Following thorough removal of secondary bone layers, debridement and irrigation, beads impregnated with antibiotics are placed into surgical site which is closed with drain sutured in place.
Note: When possible a culture is taken of the wound area prior to the procedure date to determine which antibiotics should be chosen for the surgical site treatment.
This case healed well with no additional bony enlargement.
(Click image to enlarge)

This page:
Cases

Page 1: Discussion

THE WEDGE®

Radiolucent Mouth Prop for Dogs and Cats

NOTICE: Veterinarians have used spring-loaded mouth "gags" in cats and dogs for many years. However, the spring-loaded devices are no longer recommended. A study published in THE VETERINARY JOURNAL (2014) showed that the spring-loaded "gags" generating constant force contributes to bulging of the soft tissues between the mandible and the tympanic bulla in cats. This force leads to the compression of the maxillary arteries as they course through the osseous structures. In cats the maxillary arteries are the main source of blood supply to the retinae and brain.

Reduction of the blood flow can result in temporary or permanent blindness and neurologic abnormalities. Spring-loaded "gags" constant force can also cause jaw muscle strain and injury to the temporomandibular joints.

It is recommended to use "static" mouth props such as the WEDGE. Be sure to not open the jaw to its maximum to avoid muscle strain and temporomandibular jaw injury.

Dr. John Scheels - Exotic Animal Dentistry 
(click image to enlarge)
 

The WEDGE® is a one-piece, radiolucent mouth prop. The patented, anatomic design holds the carnivore mouth open during anesthesia by securely engaging the premolars and molars.

Dr. John Scheels - Exotic Animal Dentistry
PATENTED
 

The WEDGE®:

Dr. John Scheels - Exotic Animal Dentistry 
(click image to enlarge)
 

Developed and patented by Dr. John L. Scheels, dental consultant to the Milwaukee County Zoo, Adjunct Assistant Professor, University of Wisconsin-Madison School of Veterinary Medicine.

"The (Scheels) Veterinary mouth prop's biggest asset is its simplicity - open the mouth and stick it in!...it does not interfere with radiographic detail, can be ultrasounded, and autoclaved...can be used for dental and oral surgery procedures...is positioned within the mouth, unlike the spring loaded (extra-oral) devices which can be in the way of the operator and interfere with positioning the patient..."

~ Paul E. Howard, D.V.M.,

Vermont Veterinary Surgical Center, Burlington, Vermont.

Order The WEDGE® from any of these veterinary equipment suppliers:


L.V.V.E.S

Large Volume Veterinary Endodontic Syringe™

Click here for more details
Dr. John Scheels - Exotic Animal Dentistry 
(click image to enlarge)
Dr. John Scheels - Exotic Animal Dentistry 
(click image to enlarge)

An endodontic syringe developed by Dr. John Scheels specifically for veterinary use in all species for complete and consistent obturation of root canals over 30mm long or with large pulp chambers. It permits the positive deposition of endodontic sealer and filler pastes at the apex of these long teeth. NO SPECIAL NEEDLES are required as it may be used with any standard size hub. Plastic, metal, threaded or non-threaded needle hubs will seal well on the tapered syringe nipple.

Purchase from Shipp's