I've been meaning to do this one for awhile too, finally got a few minutes.
Canines on small and large mammals are subject to cracking due to various reasons, method of cleaning, environment, heat and cold, dryness and moisture. These particular canines came off of a wolf that I've had for over 4 years. It sat at my cabin in a bin for over 4 years getting cleaned naturally

before I found the time to go get it (and a few others). Needless to say I'm lucky to still have these teeth, cracked or not! They were subject to ALL the above elements

So, first pic is before I begin. You can see the cracking in each tooth. Most often they will crack on the lines that are already present on most teeth.

Next I took each tooth and cracked it completely (EEK! say some of you) but there's a method to my madness. Before I'd tried to just glue the teeth together in the cracks only to have the pressure from it cracking previously make them come apart again. So, take em apart!

Fit each tooth back together to make sure it fits properly and the crack is going to seal well. I'll address a problem tooth in the next step. Super glue approximately the top 1/3 of the tooth, squish em together and hold for about 30 seconds. Yup, inevitably you end up with super glue on the fingers.

Sometimes you end up with a tooth that doesn't want to go back together properly and you have to make some adjustments. Often just taking a small piece of the root of the tooth off will solve the problem and the tooth will go back together quite nicely.

You end up with the root having a hole in it, but who cares? It's going to be down in the skull where no one can see it. The important part of the tooth has been fixed!

You will still see cracks in the bottom parts of the tooth when you're done, again it doesn't matter as that part won't be seen!

My skull was out in a snowbank and I just went and dug it out (I know, more elements on an already abused skull). As soon as it thaws and dries, I'll post some pics with the teeth in it.