Perhaps it should be harder to actually remove one of the Teeth. A lot harder. ^.^
(These are unique minor artifacts, so if you actually manage to collect all of them... and use all of them at once... well, congratulations on finding so many, and good luck dealing with showing up to 32 signs and being forced to abide by 32 influences or suffer -32 to everything...)
If the rules allow it, then somewhere some guileful player will convince his GM to let him do it, and then said GM will blame Pact Magic for his own mistakes. (See about 90% of the Psionics myths as case studies.)
Given that "I'm gonna use a whole ton of teeth at the same time!" is what Dahlver-Nar himself did, and look how he turned out (to save everyone the trouble of looking up his legend - he got yanked into the Void by some "unknown event" and became a Vestige/Spirit himself), I think any GM faced with that situation has precedent already in place... >=)