Polishing Composite Fillings to Remove Stains: I was working on fillings for my patient and I noticed some of her old composite work, which was completed by a different dentist at her old office, was starting to show it’s age. Composites, the white resin fillings, often look impeccable the day that they are placed. Little by little composites tend to lose their beauty because they discolor around the margins, due to stains collecting at these areas.