Alzheimer's disease, dental amalgam and mercury.
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 and performed 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.


CONCLUSIONS
Dental amalgam restorations, regardless of number, occlusal surface area or time, do not relate to brain Hg levels.
Geriatric Oral Health Program, College of Dentistry, University of Kentucky, Lexington, USA.
S R
SR
Saxe
M W
MW
Wekstein
R J
RJ
Kryscio
R G
RG
Henry
C R
CR
Cornett
D A
DA
Snowdon
F T
FT
Grant
F A
FA
Schmitt
S J
SJ
Donegan
D R
DR
Wekstein
W D
WD
Ehmann
W R
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Markesbery
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000139:chemically induced* / Q000473:pathology; D000704:Analysis of Variance; D001923:Brain Chemistry; D016022:Case-Control Studies; D003723:Dental Amalgam / Q000032:analysis / Q000737:chemistry / Q000633:toxicity*; D003792:Dental Records; D003793:Dental Restoration, Permanent / Q000009:adverse effects / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D008297:Male; D008628:Mercury / Q000032:analysis* / Q000633:toxicity; D012044:Regression Analysis; D018709:Statistics, Nonparametric
D003723:Dental Amalgam; D008628:Mercury