I feed mine a few of the Chicken and Turkey Pounce Tartar Control snacks.
They love them!  I run out so frequently, that I end up having to run to
Petco to get them.
 
I looked at the ingredients in the Natures Recipe Tartar Control bits but
I didn't like the ingredients as much as the Pounce ones.  Pounce also
just came out with some that have soft centers but the first ingredient
was liver and mine don't like that.
 
As far as teeth cleaning, I also use some toothpaste from theferretstore
that is really for felines.  It comes with a small toothbrush and also a
finger brush.  It is very difficult to get them to sit still for this so
my hubby helps me hold them.  I haven't noticed a build up of curly
plaque, which I have been told by some is what can be most troublesome.
I have yet to find a scaler that is not too large to use on their teeth.
I shudder at having to have them anesthetized for it also, but they are
really squirmy so I understand the need for a vet to do this.  I had my
first ferret's teeth cleaned by a vet twice (once at three yrs and again
at five).  His teeth were more prone to plaque than the three I have now.
I think that if your ferrets teeth are bad or are getting bad, having the
vet do it is the best way.  I just wish they did not have to be put under
for the procedure, but hey, I request nitrus when I go to the dentist!
LOL
 
I am sure that there is a place to buy those Nature's Recipe treats
online, I just haven't checked.  I'll see if I stumble across a site that
sells them.
 
Dopey's teeth are looking a little yellow and he thinks he is such a stud
muffin, should I try those Crest Whitening Strips?  Just kidding!
[Posted in FML issue 3625]