Composite resin fillings, glass ionomer, zirconia, gold, and porcelain crowns are all biocompatible alternative dental materials to mercury amalgam fillings. In the past, some of the arguments for the continued use of amalgam was that composite fillings did not last as long as amalgams. Research has shown that amalgam fillings placed on molars have a much higher failure rate than composite fillings. Another reason for the controversy of the composite as a viable alternative to amalgam was that some of them contain BPA