My advice to anyone....NEVER allow these rip-off people to replace fillings which are giving you no problems.
A similar-sounding dentist ruined several of my teeth a few years ago after having carried out such unnecessary work.
Having fillings replaced just weakens the tooth and shortens its life. I'm not a dentist, but I do have a brain and a good understanding of human biology.
Don't pay the extra money, put in writing to her why you're not paying, and complain to your local health authority.
That's what I'd do anyway.
