North American pet ferrets with dental calculus = 94.1%.
Feral New Zealand ferrets with dental calculus = 2.3%.
Wild polecats (all combined) with dental calculus = 0.0%.
99.0% of all animals with dental calculus were pet ferrets.
 
Dental plaque--that sticky, bacteria-laden whitish film that forms over
all tooth surfaces--is dangerous because it is so strongly associated
with gingivitis, periodontal disease, reactive and resorbed bone, and
other dental pathologies and diseases.  You cannot measure dental
plaque in a ferret skeleton because it does not survive the process of
skeletalization.  However, that is of little consequence because you CAN
measure the degree of presence of dental calculus, or tartar.  Dental
calculus is mineralized plaque, so if it is present, you can safely
assume plaque was present as well.  Dental calculus is commonly seen on
both the tongue (lingual) and cheek (buccal) side of tooth surfaces, but
is rarely seen on the parts of the teeth that wear against each other.
The problem isn't the stuff on the sides of the teeth--that is just a
cosmetic concern unless it builds up to the point of interfering with
chewing.  The danger is when it is at or just under the gumline, where
it initiates or exacerbates gum disease; dental plaque is just the first
domino in a series that leads to tartar, periodontal disease, dental
abscesses, low-grade systemic infections, and in many cases, organ
disease.  The problem is if it is on the tooth, it is also at or just
under the gumline.
 
Within hours to days of forming, plaque begins to mineralize in the
presence of saliva and oral minerals.  You simply cannot stop it, and
while it MAY be possible to slow it's growth by manipulating pH, removing
sticky, sugary sweets, or limiting other carbohydrates, it WILL continue
to form and to cause problems.  You really need to understand this you
CANNOT stop the formation of plaque, or the mineralization of it into
dental calculus.  It will happen regardless of food, of the chewing
objects, even of the pH.  Ferrets have such a susceptibility to form
dental plaque that it will form in ferrets that have gastric tubes in
place so food never contacts the oral cavity.  Ferrets are so susceptible
to dental plaque that it has been proposed that they become the animal
model of choice to model periodontal disease in humans (for those of you
that do not know, humans are considered to have the worst dental problems
of all the mammals on the planet mostly because of diet).
 
As common as dental calculus is in pet ferrets (94.1% of the studied
ferrets had measurable tartar), it is just as uncommon in the feral New
Zealand ferrets (2.3%), black-footed ferrets, and steppe and European
polecats (0.0%) studied.  In this study, 99.0% of all teeth having
dental calculus came from pet ferrets.  While there are few reports that
quantify the number of pet ferrets or feral New Zealand ferrets with
dental calculus, there are several studies of polecats and black-footed
ferrets that match the results obtained in this study.  The results also
matched other wild species similar to ferrets in size and diet.  Those
results were expected, but what was shocking was when I factored in the
diet of the pet ferrets.  I expected to see large amounts of dental
calculus in ferrets fed kibble.  What I didn't expect was that ferrets
fed a diet that included bone and the occasional mouse STILL had a
significant amount of dental calculus.  Only when the ferret was fed a
significant amount of bone on a daily basis, as well as mouse carcasses
at least 5 times a week, was dental calculus significantly reduced.
 
Let me summarize:
1) ferrets are extremely susceptible to the formation of dental plaque
   and subsequent calculus (a species trait),
2) almost all pet ferrets have significant amounts of dental calculus,
3) wild polecats and feral New Zealand ferrets do not have significant
   amounts of dental calculus,
4) pet ferrets fed a diet containing large amounts of bone and mouse
   carcasses have little dental calculus, and
5) dental calculus will form regardless of diet (excluding those eating
large amounts of bone and mouse carcasses).  Can these facts answer the
question, Why are the teeth of polecats and feral New Zealand ferrets
clean of dental calculus, while pet ferrets have significant amounts of
the material covering their teeth?
[Posted in FML issue 4517]