The study looked at how mercury from dental fillings is excreted in feces. They found that most of the mercury from fillings is in an oxidized form and likely bound to certain compounds in the body. When individuals with fillings excrete mercury, 80% of the mercury from fillings and sulfhydryl groups is excreted, but only 40% of mercury vapor is excreted. In individuals with moderate fillings, only a small amount of mercury from fillings was found in their feces, with most of it being in the form of oxidized mercury.