Stamping and Embossing

My old dentist retired, and so I went to a new dentist for my cleaning/check-up. He found two cavities (which didn't surprise me, my old dentist knew they were there but thought they were too small to worry about yet) but also that five teeth with composite resin fillings-ie, all the teeth I have fillings on, I think-were suffering from decay around the filling. He feels they need to be refilled, and he prefers using amalgam fillings because they last longer, etc. My question-are those safe? I've seen arguments on both sides, but can't get a definitive answer. I'd like to know before I get the first tooth worked on, perhaps even before I decided to keep this person as my dentist.