Dental Diseases of Llamas and Alpacas

DENTAL DISEASE IN LLAMAS AND ALPACAS
Andy Niehaus, DVM, MS, Diplomate ACVS
Farm Animal Surgery, The Ohio State University, Columbus, Ohio
Dental disease is a common condition affecting llamas and alpacas. Abscessation of the
teeth and the surrounding bone is the most common problem but other dental issues such as
malocclusion, tooth fractures, uneven teeth, tooth overgrowth, worn teeth, and retained
deciduous teeth also occur.
Radiographic Imaging
Radiographic imaging is the mainstay diagnostic modality to localize and diagnose dental
disease in camelids. Due to the “busy” nature of the mouth and skull, excellent radiographic
technique is necessary to obtain diagnostic images. Commuted tomography, intraoral images,
and fistulograms are other techniques that may be employed to accurately diagnose and localize
dental lesions.
Sedation is very helpful to obtain good quality radiographs. Motion needs to be abolished
and the animal needs to hold his or her mouth open to avoid superimposition of the mandibular
and maxillary arcades. Although other protocols exist, IV xylazine at 0.2 mg/kg for llamas and
0.3 mg/kg for alpacas is typically sufficient.
Lateral, dorsoventral (DV), and 45- degree right and left oblique projections should be
made. The DV projections should be made without a mouth gag; all other projections should be
made with a mouth gag to separate the maxillary from the mandibular arcades.
The oblique projections are the most valuable to localize disease to specific teeth since
they highlight specific arcades without summation of the opposite hemi-mandibular arcade.
Each oblique view highlights one mandibular arcade and the opposite maxillary arcade. Properly
marking the radiographs is of utmost importance. This is best achieved by placing both right and
left markers on the plate to indicate which hemi-mandible and maxilla are being highlighted. 1
A thin, well marginated, radiolucent periodontal ligament surrounds each tooth root and
should be visible on radiographs. The alveolar bone adjacent to that area should appear smooth
and uniform. The most common radiographic abnormalities include abscessation around the
tooth roots evident as a radiolucent pocket surrounding a tooth root, osteomyelitis affecting the
alveolar bone evident as lysis and sclerosis of the adjacent alveolar bone, and sequestra.
Tooth root abscessation
Dental abscessation is the most common dental condition afflicting camelids. Although
every tooth is a candidate for developing an abscess, mandibular teeth are 15 times more likely
than maxillary teeth to be affected and cheek teeth are 14 times more likely to be affected than
incisors or canines. 2 South American camelids are diagnosed with tooth root abscesses
significantly more often than ruminants. Tooth root abscesses are most common in camelids
around 5 years of age. 3,4
Although the pathogenesis of tooth abscesses has not been established. Theories include
mastication of rough and stemy forages leading to oral abrasions allowing ascension of
commensal organisms, premature breakage of the deciduous cap when the permanent teeth are
erupting, fractured teeth, trimming of fighting teeth exposing the pulp cavity, decay of the
infundibulum, and hematogenous spread of bacterial pathogens. Most organisms cultured from
tooth abscesses are representatives of the normal oral flora. 5
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Camelids with tooth abscesses usually present with a hard, bony swelling over the
affected tooth. Reactive bone and osteomyelitis contribute to the swelling. The degree of
swelling is generally indicative of the chronicity of the disease. A draining tract may also be
present in late stages of disease. Most animals eat normally and are not painful when
masticating although pain on mastication and subsequent anorexia and weight loss are possible
clinical signs. External palpation of the swelling is frequently painful.
The history and clinical signs are usually sufficient to make a diagnosis but differentials
include packing of cud within the mouth, mandibular osteomyelitis without tooth involvement,
soft tissue abscess, salivary mucocele, and neoplasia. A good physical examination including a
sedated oral exam should be performed. Definitive diagnosis is based on radiographic
examination. If draining tracts are present, contrast fistulography may be a useful adjunctive
technique. 6
Generalized primary osteomyelitis (lumpy jaw) is another differential. It is difficult to
clinically distinguish from tooth root abscesses. Since cases of tooth abscesses usually have
some degree of osteomyelitis, radiographic appearance is also similar except the lytic areas are
not centered around a specific tooth; rather a more generalized osteomyelitis is apparent.
Mandibular sequestra are another differential. Non vital tooth roots can be thought of as
sequestra in themselves and therefore present similarly to tooth root infections. Sequestra can be
due to a previous mandibular or tooth root infection, mandibular fracture, or can be idiopathic.
As with the other differentials, radiographic imaging is necessary to accurately diagnose and
localize.
Successful treatment of tooth root abscesses can be achieved with either long term
medical therapy, surgical therapy, or a combination. 3 Most tooth roots abscesses in chronic
states of disease do not respond well to medical therapy alone and require surgery to remove the
nidus for infection (tooth and tooth root). Surgical options include tooth extraction, tooth
splitting, tooth root resection, root canal, and bone debridement. 7 These techniques are
performed under general anesthesia.
The author prefers a ventrolateral approach to the mandible for tooth extraction. A 5 cm
incision centered over the affected tooth is created incising through the skin, subcutaneous
tissues, and periosteum. The periosteum is reflected dorsally exposing the mandibular bone.
After a pneumatic burr is used to remove the lateral alveolar plate of the mandible, the tooth can
be removed by freeing the periodontal ligament. The tooth is pried from its alveolar socket. The
alveolus should be debrided and thoroughly flushed with a dilute antiseptic solution. If a large
defect is created, it can be packed with dental wax, PMMA, or dental impression material to
prevent feed material from becoming impacted. Establishing ventral drainage is an objective of
the procedure.
Following surgery, the author packs the wound with an absorbable packing material to
control hemorrhage. The defect is packed for at least a few days to control the loss of feed
material and saliva. The packing should be changed on a daily basis and the surgical site lavaged
with dilute antiseptic solution. The presence of packing within the defect prevents the defect
from closing prematurely but may inhibit drainage.
Maxillary tooth involvement is rare but if needed extraction can be accomplished in a
similar manner. Closure of the skin incision is permitted because ventral drainage is now
accomplished into the oral cavity. Tooth repulsion should be used with caution to avoid the risk
of fracture.
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Following extraction of the diseased tooth, the patient should be treated medically.
Arcanobacter pyogenes is the most commonly isolated organism cultured from camelid tooth
root abscesses, and penicillin, Ceftiofur and florfenicol are appropriate drugs based on culture
and sensitivity data. 4 Non steroidal anti-inflammatory drugs are also appropriate to decrease
inflammation and pain associated with the osteomyelitis and tooth extraction. Isoniazid is an
antimicrobial agent that has good penetration into walled off types of environments, and is useful
in the treatment of camelid tooth abscesses.
Antimicrobial and anti-inflammatory drugs used to treat tooth root infections
Drug Dose Frequency Route Duration
Procaine
Penicillin G
33,000 Units/kg Once Daily IM 14 days
Ceftiofur 2 mg/kg Once Daily IV * / IM 14 days
Florfenicol 20 mg/kg Every other day IM 3 treatments
Isoniazid 10 mg/kg Once Daily Orally 30 days
Flunixin 1 mg/kg Once – Twice IV / IM As needed
meglumine
Daily
*
Sodium Ceftiofur is the only ceftiofur formulation that can be given intravenously.
The prognosis for cure following tooth extraction is good, and is not affected by the
location or number of teeth affected. There is a higher mortality rate associated with animals
presented in thin or emaciated conditions. 4
Anesthesia for Mandibular Surgery
General anesthesia is recommended for tooth extractions unless the abscess is in a
chronic state which will permit an easy oral extraction. Anti-inflammatories and analgesics post
operatively are recommended. Endotracheal intubation is highly recommended to prevent
aspiration of the saliva, blood, and lavage that accumulates in the oral cavity during the surgical
procedure.
An alveolar (mandibular) nerve block can supplement general anesthesia, and provides
analgesia short term post operatively. Local anesthetic is injected at the mandibular foramen
(medial aspect of the ramus of the mandible). This is located by palpation of the most prominent
portion of the most caudoventral aspect of the mandible immediately rostral to the ventral curve
of the ramus. Full insertion of an 18 gauge 1.5 inch needle towards the zygomatic arch works
well to approximate the level of the foramen in adult camelids. Alternatively injection into the
mental foramen will allow backflow of local anesthetic and anesthetize the alveolar nerve. The
mental foramen is often palpable 2-3 cm caudal to the incisors. The needle is inserted into the
foramen and the injection is performed while placing a finger over the foramen to create a seal.
Retained Deciduous Teeth
Retained deciduous teeth occur when the deciduous incisors fail to fall out when the
permanent teeth erupt. This is usually a cosmetic problem, although the potential exists to cause
difficulty prehending. The retained deciduous teeth are smaller, are usually the more rostral
located teeth, and may be loose while the permanent teeth are larger, located more caudal
(lingual surface), and are usually more stable. 5
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Method of removal is dependent on the how firmly they are attached. They may be
easily extracted with minimal force or may require the use of a dental elevator. If more than
mild force is needed for extraction, heavy sedation or a light plane of anesthesia will be
necessary. Extraction of teeth that are firmly attached carries a risk of damage to the permanent
tooth roots.
Teeth Trimming
There are multiple indications for trimming teeth in camelids. Overgrown mandibular
incisors can resulting in difficulty prehending food or can become a cosmetic blemish. The
fighting teeth (upper and lower canines and the upper 3 rd incisors) are commonly trimmed in
male llamas and alpacas. The incisors and fighting teeth can be trimmed with a cutting wheel
attachment on a hand held rotary tool. An alternative to using a rotary tool to trim the incisors is
to use obstetrical wire to saw the teeth.
Premolars and molars that do not properly oppose the opposite arcade can become
overgrown, which is common in cases of previous cheek tooth extraction. If mastication is
impaired due to overgrowth, the teeth can be floated using small equine dental instruments.
Enamel points on the buccal side of the maxillary check teeth and the lingual side of the
mandibular check teeth are normal because the mandibular arcade does not sit as wide as the
maxillary arcade, and should not be floated.
References:
1. Mattoon JS: Radiographic Technique for Dental Disease of Camelids, in Current
Veterinary Care and Management of Llamas and Alpacas, Columbus, OH, pp 232-238
2. Niehaus AJ, Anderson DE: Retrospective Study of Camelid Tooth Abscesses, inThe
Ohio State University, 2007
3. Cebra ML, Cebra CK, Garry FB: Tooth root abscesses in New World camelids: 23 cases
(1972-1994). J Am Vet Med Assoc 209:819-822, 1996
4. Niehaus AJ, Anderson DE: Tooth root abscesses in llamas and alpacas: 123 cases (1994-
2005). J Am Vet Med Assoc 231:284-289, 2007
5. Fowler ME: Dental Disease, in Medicine and surgery of South American camelids:
llama, alpaca, vicuña, guanaco (ed 2nd). Ames, Iowa State University Press, 1998, pp
112-120
6. Thrall DE: Textbook of veterinary diagnostic radiology, in Textbook of veterinary
diagnostic radiology (ed 3rd). Philadelphia, W. B. Saunders, 1998, pp 107-109
7. Anderson DE: Tooth Root Abscesses, in Camelid Medicine, Surgery, and Reproduction,
Columbus, Ohio, pp 87-88
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