EFFECT OF PLACING, REMOVING AND POLISHING OF AMALGAM RESTORATIONS ON 24-H URINARY MERCURY CONCENTRATION

Twenty-four-hour urinary mercury concentration were assessed in 43 pat ients before and after removing old amalgam fillings (8 pts), placing (13 pts), and polishing of amalgam (22 pts). Baseline analyses 8 days before the treatments showed on average 18.5 +/- 7.2 mu g mercury mass excreted per 24-h urine samples. The removal of old fillings caused a total excreted mass of 56.3 +/- 32.3 mu g Hg, the placing of amalgam 45.9 +/- 26.2 mu g Hg, and the polishing 56.25 +/- 33.77 mu g Hg, resp ectively, one day after the treatments. When compared with the baselin e values, the urinary mass excreted remained significantly elevated du ring the 8-day follow-up. However, all Hg values measured were below t he WHO recommandations for the threshold limits for urinary mercury.