Gold fillings have electrical properties which some people consider to be a form of toxicity. Palladium is sometimes mixed in with cheap gold filling to make them harder,palladium is somewhat toxic. Ceramic fillings not composite are considered the best though they have aluminum in them, next best is Gold with PLatinum. Composite fillings may not last that long and have assorted chemicals in them.
I went to Nuevo Progresso, mexico, near brownsville . YOu just walk across the border. Go one or two blocks turn right to Dr. Oliveras, a lady dentist,nice small office with modern equipment. Work was done by her lady assistant, Meera. With the economy as it is you can negotiate a lower price maybe 100 per filling or less.
If you go to a US dentist make 100% sure to only get Pure Gold/Platinum and no palladium. IN the US gold inlays are about 500$ or more.