Methods: The study group consisted of twenty patients previously referred to the Dental Biomaterials Adverse Reaction Unit in Bergen, Norway, for health complaints attributed to amalgam fillings. The patients indicated intensity of general health complaints on numeric rating scales (0-10), before removal of amalgam fillings and at follow-ups at one, three and five years after removal. A symptom index was calculated by adding the scores for the complaints (12 items). Correlational analysis was used to test the statistical significance of a number of potential determinants for changes one, three and five years after amalgam removal. Age, number of amalgam surfaces, concentration of mercury in serum, symptom index before removal, and the clinical and the PSY-5 scales from the Minnesota Multiphasic Personality Inventory-2 (MMPI-2) were tested.
Results: Statistical significant correlations were found between symptom index score before removal and change scores at one, three and five year follow-up. The Pearson correlation coefficients were 0.464, 0.733 and 0.530, respectively (p=0.039, n=20; p<0.001, n=19; and p=0.020, n=19). No other variables were significantly associated with the change score.
Conclusion: The observed decrease in intensity of general health complaints after removal of amalgam fillings in patients with health complaints attributed to dental amalgam was correlated with symptom index before removal. There was no evidence of any significant impact from age, number of amalgam surfaces, concentration of mercury in serum, or the tested variables from the personality test.