Dr. Richard Chanin DMD dismantles the Saxe “Nun Study”


Dr. Richard Chanin, DMD

Dr. Richard Chanin DMD ofThe International Academy of Oral Medicine and Toxicology disscusses one of the flaws in the Saxe study: “Dental amalgam and cognitive function in older women: findings from the Nun Study”, which was published in the Journal of the American Dental Association (JADA) and widely promoted to discredit the link between mercury exposure (as from dental amalgam) and Alzheimer’s disease.


“Dental amalgam and cognitive function in older women: findings from the Nun Study”.

J Am Dent Assoc. 1995 Nov;126(11):1495-501.

Background. Mercury, or Hg, is a neurotoxin that has been speculated to play a role in the pathogenesis of Alzheimer’s disease, or AD. Dental amalgam releases low levels of Hg vapor and is a potential source of Hg for a large segment of the adult population.

Methods. The authors studied 68 subjects with AD and 33 control subjects without AD to determine Hg levels in multiple brain regions at autopsy and to ascertain the subjects’ dental amalgam status and history. The subjects were from central Kentucky and Elm Grove, Wis. The authors conducted dental amalgam assessments during the lives of the majority of subjects and in some subjects at the time of autopsy only. The authors also determined three dental amalgam index scores—Event (placement, repair or removal of amalgam), Location and Time In Mouth—in addition to the numbers of and surface area of occlusal amalgam restorations. The authors determined Hg levels in multiple brain regions andperformed full neuropathologic evaluations to confirm the normal status of the brain or the presence of AD.

Results. The authors found no significant association of AD with the number, surface area or history of having dental amalgam restorations. They also found no statistically significant differences in brain Hg level between subjects with AD and control subjects.

Conclusions. Hg in dental amalgam restorations does not appear to be a neurotoxic factor in the pathogenesis of AD. The authors found that brain Hg levels are not associated with dental amalgam, either from existing amalgam restorations or according to subjects’ dental amalgam restoration history.

Clinical Implications. Dental amalgam restorations, regardless of number, occlusal surface area or time, do not relate to brain Hg levels.

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 Nun Study

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