revised final - Agency for Toxic Substances and Disease Registry ...

MERCURY 297
2. HEALTH EFFECTS
dimensions had improved considerably, but there was no difference between the succimer and placebo
groups. These findings suggest that some patients with environmental illness may substantially benefit from
placebo.
Stoz et al. (1995) studied 185 mothers with tooth amalgam filling surfaces ranging from 0 to 780 mm 2 and
found no relationship between the blood values of the women and their children and the size of the surfaces
of the amalgam fillings. All mothers gave birth to healthy children. Malt et al. (1997) evaluated the physical
and mental symptomatology of 99 self-referred adult patients complaining of multiple somatic and mental
symptoms attributed to dental amalgam fillings. These patients were compared with patients with known
chronic medical disorders seen in alternative (n=93) and ordinary (n=99) medical family practices and
patients with dental amalgam fillings (n=80) seen in an ordinary dental practice. The assessments included
written self-reports, a 131-item somatic symptom checklist, Eysenck Personality Questionnaire, the General
Health Questionnaire, and Toronto Alexithymia Scale. Somatic symptom complaints were categorized by
exhaustion, and musculoskeletal, cardiovascular, and gastrointestinal effects. The mean number of silver
fillings surfaces were 40.96 in self-referrents as compared to 36.61 in the dental practice patients. No
correlation between number of dental fillings and symptomatology was found. Self-reports suggested that
62% suffered from chronic anxiety. Forty-seven percent suffered from major depression compared with
none in the dental control sample. Symptoms suggesting somatization disorder were found in 29% of the
dental amalgam sample compared with only one subject in the 272 comparison subjects; 37.5% of the dental
amalgam patients reported symptoms of chronic fatigue syndrome compared with none in the dental control
sample and only 2 and 6%, respectively, in the two clinical comparison samples. The dental amalgam group
reported higher mean neuroticism and lower lie scores than the comparison groups. The authors concluded
that self-referred patients with health complaints attributed to dental amalgam are a heterogeneous group of
patients who suffer multiple symptoms and frequently have mental disorders. The authors report a striking
similarity with the multiple chemical sensitivity syndrome.
An ad hoc review group of the DHHS Working Group on Dental Amalgam examined 175 literature articles
concerning mercury amalgam (DHHS, 1997). The articles represented an assortment of literature from peerreviewed
journals and a variety of other print media. None of the 12 expert reviewers evaluating the articles
suggested that any study under review would indicate that individuals with dental amalgam restorations
would experience adverse health effects. Many of the reviewed articles were reported to suffer from
inadequacy of experimental control, lack of dose-response information, poor measurement of exposure, and
a variety of other experimental design inadequacies.