SHORT-TERM CHANGES IN LYMPHOCYTES AFTER PLACEMENT OF SILVER AMALGAM RESTORATIONS IN HEALTHY-SUBJECTS

Objectives. The purpose of this study was to evaluate the changes in l ymphocyte subpopulations that have led to immune system alterations af ter amalgam restorations were placed. Methods. A controlled, quasi-exp erimental pretest-posttest design was used to investigate the immune e ffects of sliver amalgam restorations in a sample of 60 individuals (3 0 experimental and 30 control subjects) aged 18 to 21 y. Two blood sam ples were obtained 15 d apart from each participant. In each experimen tal subject, two amalgam restorations were placed in posterior teeth i mmediately after the first blood sample was collected. The changes in lymphocyte subpopulations in the two groups were compared by multivari ate analysis. Results. There was a greater change in T8 lymphocytes in experimental than in control subjects; increases in B, DR, NK, and CD 45R lymphocytes were smaller in experimental than in control subjects; the changes in T3 and T4 lymphocytes did not differ significantly betw een the two groups. Significance. Despite the statistical significance of some differences between the two groups, the differences are not c onsidered to be clinically relevant for the 2 wk time period after pla cement.