While this study has often been used to suggest mercury from amalgam fillings is not related to Alzheimer's disease or cognitive dysfunction, other researchers have found major flaws with this study including the fact that researchers failed to document whether the nuns without current dental amalgam fillings had them earlier in their lives (i.e. before needing dentures) [Dr. Richard J. Chanin, DMD discuss deficiencies of the Saxe Nun study, Mercury Exposure, http://www.youtube.com/watch?v=4YEaspBj1rk ].
"Abstract: The authors determined the number and surface area of occlusal dental amalgams in a group of 129 Roman Catholic sisters who were 75 to 102 years of age. Findings from this study of women with relatively homogeneous adult lifestyles and environments suggest that existing amalgams are not associated with lower performance on eight different tests of cognitive function."
Saxe SR, Snowdon DA, Wekstein MW, Henry RG, Grant FT, Donegan SJ, Wekstein DR. Dental amalgam and cognitive function in older women: findings from the Nun Study. Journal of the American Dental Association. 1995; 126(11):1495-1501.