I'd really love a dentist's opinion of this question:

I have noticed that the literature for nicorette says that it can
loosen fillings.  I am wondering specifically:

a) is it the Nicotine (or some other additive in Nicorette) that
loosens the fillings?

or

b) is it just because it's a GUM? (because I can chew gum just fine
without loosing fillings)

or

c) is it because some people chew the HARD nicorette really vigorously?
(Which I won't)

or

d) Something else entirely? ;)

Any answers are much appreciated.