![]() |
Hero helps me revise a paper by keeping my notes warm. |
Animal Referral Hospital and
Sydney Pet Dentistry veterinarian Christine Hawke gave a superb talk last night
on the topic of extractions in cats – when to do them, when not to do them.
Depending on which study
you read, around 50 per cent of cats (28-67%) suffer from tooth resorption
during their lifespan. It is painful.
Dr Hawke discussed
different ways of classifying tooth resorption in cats, one of which classifies
lesions by type.
Type 1 is inflammatory in
nature, often beginning in the root and working its way up to the crown, but on
radiographs the root looks like a root. There is a distinct tooth, distinct
bone and a periodontal ligament holding the two apart. Crown or not, these
babies need to be extracted.
Type 2 occurs when the
periodontal ligament is lost and replacement resorption of the root occurs.
(Odontoclasts are basically osteoclasts – normally, unlikely bone, the teeth do
NOT undergo constant remodelling thanks to a tooth-bone-barrier. But when that
barrier is breached, the root surface is exposed due to damage of cementum or
the periodontal membrane, the odontoclasts access it. The remodelling process
can then continue as part of normal skeletal bone turnover).
On radiographs, these are
those “ghost teeth”. You can sometimes see there was a tooth there, but there
is NO periodontal ligament. The teeth are being progressively replaced by bone.
Attempting extraction, even where a crown is present, can be very frustrating.
But the only way to tell
is dental radiographs.
Dr Hawke’s theory that the
difference between Type 1 and 2 is essentially one of the degree of
inflammation.(Type 3 is a combo of type 1 and 2 in the same tooth).
Diagnosis of tooth
resorption in cats requires examination under general anaesthetic with a dental
explorer, and intraoral radiographs. (Remember that cats often have additional
roots – or as Dr Hawke says, “cats like to throw dental curveballs”).
Many clients ask if these
lesions can be somehow filled? The short answer is no. Extraction is the gold
standard. Leaving the inflammatory lesions in situ isn’t good.
So what do you do with
type 2 lesions? If you are sure its Type 2, coronial amputation is appropriate.
First you need to rule out the presence of a periodontal ligament (a thin black
line hugging the tooth on radiographs), periodontitis and gingivitis,
endodontic disease and retroviral infection.
When done properly this
has a very high success rate.
An envelope flap is made
and the crown is removed slightly below the crest using a round bur. This
ensures that a clot formed over which granulation tissue can form.
So what were the take-home
messages?
- Tooth resorption in cats is common and painful
- The aetiology is not completely understood
- Radiographs are essential for diagnosis and treatment planning: “Doing dentistry without x-rays is like doing orthopaedics without x-rays”.
- Treatment options are limited to extraction of affected teeth and coronal amputation of selected teeth.