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The ATLAS of Dentistry of
the Pet Rabbit has been published in 2010 by Dr. Didier Boussarie et Dr. Franck Rival at the Vetnac editions. This 17 x 24 cm paperback book has 143
pages that are highly illustrated (more than 400 photos and some 40
diagrams). It is a practical guide for veterinarians that deal with pet
rabbit dentistry in their daily work.
The book provides precise
information on the oro-dental characteristics of
pet rabbits as well as anatomically and physiologically peculiarities.
Above all, it provides complete and up-to-date information on the main
diseases affecting their mouth and teeth, and the possibilities and
techniques of treatment.
The 24 pages of chapter 1
deal with anatomical and physiological knowledge: zoological position -
elements of oral anatomy - nutrition, oral dynamics and lifestyle. The 20
pages of Chapter 2 describe the proper examination of a rabbit:
consultation material - methods of restraint - general examination - dental
examination - complementary examinations. Chapter 3, 48 pages, deals
with oral and dental diseases: dental malocclusion (incisors, molars and
premolars) – oro-dental abscesses - diseases
secondary to oral diseases (diseases and disorders caused by an oral
problem) - other oral conditions. Finally, Chapter 4, with 32 pages,
describes treatment options that are often of surgical nature: required
surgical equipment - surgical treatment (analgesia and anesthesia,
malocclusion of incisors and cheek teeth, abscesses and other pathologies)
- associated medical treatment. At the end of the book there are two tables
with the main used analgesic and anesthetic products and to the main
antibiotic drugs that can be used in oral diseases. Finally a glossary of 3
pages defines of the main specialized technical terms used in the book.
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Black
tan Netherland dwarf rabbit
Dwarf lop rabbit
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The dental formula of rabbits is I2 / 1 - C0 / 0 -
PM 3/2 - M 3/3. The different methods used to designate teeth are
summarized in figure 1. At birth the newborn rabbit already possesses its
definitive incisors. Premolars will be replaced around the age of 3-4
weeks. Thus, the final dentition is acquired around 3 to 5 weeks at the
latest.
Teeth of rabbits continue to grow during their whole
life, incisors as well as molars and premolars. For example, the growth
rate of upper incisors is 2 mm per week and that of lower incisors is 2.4
mm per week. The growth of cheek teeth (premolars and molars) is less:
about 2 mm per month. To support this continuous growth, teeth have a
hollow "root" that starts from the deep tooth bud. Abundant
amounts of dental pulp are found in the cavity, which reaches almost to the
outer end of the tooth. The length of the "buccal" part of each
tooth (visible in the mouth) is much smaller than its gingival part (inside
in the gingiva). This feature is clearly visible on the X-ray of Figure 2
Although any type or breed of rabbit can be used
as a pet, in the vast majority of cases pet rabbits are dwarf rabbits descending from the "Polish" breed . These small
sized rabbits (around 1.0 kg for color dwarves and 1.4-1.7 kg for lop rabbits) are
characterized by a shortening of the face and a fairly high consanguinity.
The latter is the consequence of the eager to obtain fur with as much varieties
as possible, starting from a small pool of animals.
These two characteristics predispose
pet rabbits to develop problems of teeth alignment (malocclusion) of congenital
origin, often aggravated by an unsuitable diet. The growth of the teeth continues,
independent of the oral issues, resulting in an abnormal growth of teeth and
oral abscesses if the rabbit cannot wear its teeth off properly. This
explains why dental problems are a common cause of veterinary consultation
for pet rabbits.
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Figure
2 : X-ray of a rabbit skull
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Figure
1 : Dental formula of the rabbit
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Asymmetric
incisor malocclusion. Note the striations in feather shape in the lower incisors,
due to a metabolic bone disease.
Positioning
of the lachrymal duct
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In the chapter on the relationship
between diet and oral problems, the authors emphasize the benefits of
permanently feeding hay to pet rabbits. They render a "pellet-based"
diet responsible for a large part of the disorders, as it seems that all commercially
available pelleted foods has the same composition
and get similar attention by those who make them. A quick tour in pet
stores clearly shows that many foods marketed in France for pet rabbits
(but not all) are, for example, deficient in fibers; the proposed "treats"
for pet rabbits often contain cereals and less than 7% crude fiber, which
may aggravate the lack of fiber.
In addition, and contrary to food
provided to meat rabbits, in the vast majority of pet rabbit food there is
no addition of vitamin D, which is required for calcium metabolism. A very
recent study by Ricci et al. concluded that the Italian pet rabbit
foods are almost all too concentrated in protein and energy but
deficient in phosphorus and many also in calcium (Ricci R., Sartori A., Plagiano C and Dalle Zotte A., 2010. Study
of the nutrient adequacy of feeds for pet rabbits in the Italian market,
World Rabbit Science, 18, 131-137). It seems that the situation is quite
similar in France according to Dr. Boussairie and
Dr. Rival. Under these conditions, it is normal to find, e.g., a
disturbance of the mineral metabolism, which will necessarily have
repercussions on the growth of the teeth and the health of the bones that
support them. Providing a supplement of green or dry fibrous fodder to pet
rabbits is, therefore, a good recommendation, at least as long as the available
pelleted food is not properly balanced. Good hay will provide fiber,
calcium, and vitamin D.
Oral diseases that bring a pet rabbit
owner to consult a veterinarian are mostly cases of malocclusion (= long
teeth) or abscesses of the face. Indeed, because of the continuous growth of
the teeth and, therefore, of their continuous renewal, caries (tooth decay)
are rare in rabbits. In these cases it is necessary to add certain ocular
affections as the bacteria will migrate from the base of infected teeth to
the eye via the lachrymal duct. The latter connects the lachrymal sac of
the eye and the nasal cavity but passes very closely to the base of the
roots of the upper incisors and the upper premolars.
Oral problems of a rabbit may be apparent as in
the case of a malocclusion of the incisors, with teeth coming out of the
mouth. In other cases, it is useful, if not necessary, to use radiography
to correctly diagnose the problem, especially for malocclusions of the cheek
teeth.
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Cases of
malocclusion in pet rabbits
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Latero-lateral
view of a malocclusion of the cheek teeth accompanied by osteitis. Please,
note the absence of joining of the premolar upper and lower teeth
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Dental
catastrophe with a rupture of the cortical mandibular bone. The roots of
the first and second premolar teeth have grown in circle through bone
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Secondary
malocclusion of the incisors after a malocclusion of the cheek teeth and a mandibular
hyperelongation. The upper PM2 (DJS1) shows
complete dystrophic lesions, the lower premolars are strongly tilted
forwards
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Molar
malocclusion with development of a mandibular cavitary
abscess. Malocclusion is here in an early stage
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To help practitioners refine their
diagnosis, a number of cases are commented by the authors, using photos of
a clinical case and the radiography of the same subject.
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History: a
precious help given by the owner of the rabbit in order to make a proper
diagnosis by the veterinarian
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To be able to make a correct
diagnosis and offer the owner a treatment adapted to his/her
pet rabbit, the practitioner will need to know as much as possible about
this animal and its history. It is therefore desirable
that the owner can indicate the following:
· Age of
the rabbit (this helps determine more easily between congenital and
acquired diseases);
· Way of
life (in a cage, free-range, outside, possibility to be exposed to
natural/sun light);
· Diet (a
sticker indicating the content of the pelleted food is helpful);
· Behavior
(anorexia, excessive salivation, lethargy, frequent grooming of the fur).
The ingestion of cardboard or fabric may be indicative of dental problems;
· Medical anamnesis
(pathologic history of the rabbit, and, when possible, details of its
ancestors if known);
· History
of dental problems and already given treatments ;
· Reason
that leads an owner to bring its rabbit for a consultation.
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The oral examination on an anesthetized
rabbit can be done easily after positioning the mouth opener over the cheek
retractor
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Untreated
malocclusion problems cause feeding difficulties for the animal. The
consequence is a loss of weight followed by lethargy that quickly alerts
the attentive owner.
Oral or dento-alveolar abscesses are common in pet rabbits and
are always associated with infection of the root of one or more teeth. They
are most often consecutive to a penetration followed by an elongation of
the dental roots in the cortical bone tissues. These oral abscesses are usually
painless. They are not accompanied by anorexia since they barely affect food
uptake and chewing, and do not generate hyperthermia except in the case of
enteropathy associated to stasis of the cecum. They are typically
asymptomatic remain unnoticed - unless accidentally
discovered, until the appearance of a tumefaction that worries the owner
and motivates the consultation of a veterinarian.
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Endoscopic
view of the oral cavity of a rabbit
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For
veterinary practitioners, the conditions of the general examination and
especially of the oral exam are listed, commented and illustrated. In the
majority of cases, and especially for the observation of molar and premolar
problems, general anesthesia of the rabbit is recommended for an effective
observation. It is essential if the practitioner intends to make an
endoscopy examination. On the other hand it is advisable to perform the
general examination on a wake animal as its reactions provide useful
information.
If an x-ray is necessary, it
can be done on a wake rabbit if it is calm and cooperative and if the
practitioner has a great experience. Sedation or flash-anesthesia are,
however, preferable and can improve the quality of observation after a good
positioning of the animal.
We will not present here the
different treatment techniques. On the whole, it should be remembered that
accidental incisor malocclusions can often be treated without removing the
teeth, yet, in a large number of cases extraction of one or more teeth is
necessary. Abscesses are often a consequence of underlying dental
pathologies. The abscess should be excised and dissected in its entirety,
keeping in mind that only the complete management of dental problems will
be able to avoid recurrences. The complete treatment of all the problems
generally requires several surgical treatments.
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The Atlas of dentistry in pet rabbits (ISBN
978-2-917389-01-0)
Can be ordered directly from Dr. Didier Boussarie
3, rue du Clos 02000 Monanpteuil
Price: 60.- Euros + 5.- shipping within France)
(check to Dr.
Boussarie Didier)
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by Dr. Didier
Boussarie
