[Research on the effect of amalgam restorations on human nervous system].
OBJECTIVE
To understand the influence of amalgam restorations on human nervous system.


METHODS
WHO NCTB and neurobehavioral questionnaire were used to make an epidemiologic investigation of people with amalgam restorations,and compared them with the control groups.


RESULTS
The scores of people whose teeth were filled with amalgam within 20 years were much higher than those beyond 20 years in digit span test and digit symbol test. In the latter group there were more people who thought they occurred 'memory descending' than the former. It indicated that there was some intra-relation between long-term amalgam contacting and memory descending. But in 19-29 and 30-39 age groups, the test group scored higher than the control group significantly in digit span test, and in digit symbol test the test group also had a score much higher than the control group in 30-39 age groups. This indicated that amalgam had no effect on memory. In pursuit aiming test II the error number of the test group was higher than that of the control group, and people who had amalgam restorations over 20 years occurring 'motion unflexible' were more than those within 20 years. But in the same time, in 30-39,40-49 age groups the test groups scored higher than the control groups in right number and sum number index,so we were not sure that amalgam do any harm to motor nerve.


CONCLUSIONS
It can not be determined that amalgam restorations have any effect on human nervous system currently.
Department of Endodontics, School of Stomatology, Shanghai Second Medical University, Shanghai 200011, China.
S B
SB
Sun
J P
JP
Liang