Good question! I was wondering the same thing since I also have only one filling in my mouth (but am not too happy that it's there).

I have serious doubts about finding a dentist in my country who has any clue about safely removing amalgam fillings. Which begs the question, which is worse: keeping the filling in your mouth since it's only just one, or having it improperly removed and cope with the innevitable inhalation of mercury vapors? What's essentially more poisonous longterm? Which is the lesser of two evils?