Amalgam Removal Efficiency of Separators And Filtration Devices

Objectives: This study was to determine the amalgam removal efficiency of 12 amalgam separators and 2 filtration devices because of heightened awareness of amalgam in dental wastewater. Methods: Amalgam removal efficiency was measured according to International Standard ISO 11143 for “empty” and “full” conditions for each amalgam separator. A slurry of 10 g of amalgam particles conforming to the particle size distribution in ISO 11143 was dispersed in 1L of water containing 1 g of sodium pyrophosphate. The slurry was introduced into the amalgam separator along with additional filtered water to reach manufacturer's specified flow rate. The effluent from the amalgam separator was collected and filtered through pre-weighed filters (12 µm, 3 µm, 1.2 µm). The filters, with the retained amalgam particles, were dried to constant weight. Amalgam removal efficiency of the separator was calculated from the mass of amalgam retained on the filters. Results: The amalgam removal efficiencies (mean (SD)% N=3) of the separators were: A 1300: 99.27 (0.11), Amalgam Boss: 99.17 (0.14), Amalgam Collector CE-18: 99.40 (0.79), ECO II: 97.05 (0.22), Hg 5: 98.53 (0.35), Hg 5 FR: 98.03 (0.40), Hg 5 HV: 98.88 (0.38), MRU 10c: 99.97 (0.01), MSS 1000: 99.54 (0.03), Merc II: 98.06 (0.14), Rasch 890-1000: 98.94 (0.37), Rasch 890-6000: 98.31 (0.44), and filtration devices were: Serfilco 0.5: 98.09 (0.16), and Serfilco 100: 97.58 (0.43). ANOVA and Tukey tests showed differences (p<0.01) among the amalgam removal efficiencies. Additional results show no statistical differences between the “empty” and the “full” separator (p<0.01, t-test) for each amalgam separator. Conclusions: The twelve amalgam separators and the two filtration devices exceeded the ISO 11143 requirement of 95% amalgam removal efficiency. It would be sufficient for the International Standard to test amalgam separators only in the “empty” condition. This work supported by the ADA.