Surprise, surprise. A University of Georgia study has found that inorganic mercury - the kind found in your dental fillings folks - really whacks your cells. This was the first study to directly compare the effects of organic mercury (see tuna and other fish) and inorganic mercury (dental fillings.). University of Georgia research has found that inorganic mercury, which was previously thought to be a less harmful form of the toxic metal, is very damaging to key cell processes. The study found - to the researcher's surprise - that inorganic mercury was more toxic than organic mercury. The researchers found that inorganic mercury caused reactive sulfur compounds called thiols that bind strongly with mercury compounds to plummet. The inorganic mercury also was an ace at removing iron from the system.