There is a study showing higher levels of mercury in certain areas of the brain for those who have Amalgam fillings compared to those who have no fillings, or fewer filling surfaces (one filling might have four surfaces).
Mercury & Other Toxic Metals in Humans: Proceedings from the First International confernece on Biocampatiblity of Materials, Edited by Hal Huggins 1989.
There are two studies indicating higher concentrations of mercury in the brain in Alzheimer's patients autopsied compared to non-Alzheimer's patients.
The best way to stop mercury poisoning in the body is to remove the source of mercury that is contaminating the body. The body eliminated some mercury through the liver bile to feces route, urine, breath, and sweat.