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Vol. 68, No. 9
ISSN: 1488-2159
October 2002


The Weight of Wastes Generated by Removal of Dental Amalgam Restorations and the Concentration of Mercury in Dental Wastewater


• Albert O. Adegbembo, BDS, DDPH, MSc •
• Philip A. Watson,, DDS, MScD •
• Stanley J. Lugowski, PhD, MSc •

A b s t r a c t

Objective: To determine the amount of amalgam entering the waste stream during removal of dental amalgam restorations.

Methods: Dental amalgam restorations were removed from anatomic replica teeth and natural teeth by means of a tungsten carbide bur, a high-speed handpiece and a conventional suction system. The weight of amalgam particles trapped in the primary and secondary solids separators was determined. Amalgam particles were filtered from wastewater with 15-µm filter paper and weighed. The concentration of total mercury in the effluent collected (by instantaneous flow-through) during the removal of amalgams, with and without an ISO-certified separator, was measured by means of cold-vapour atomic absorption spectrophotometry.

Results: About 60% by weight of the amalgam removed was found in the effluent, about a third was retained in the primary solids separator and less than 10% was retained in the secondary solids separator. The ISO-compliant separator reduced the concentration of mercury in the instantaneous flow-through discharge by 99.4%, from 31.2973 mg/L to 0.1800 mg/L.

Conclusions: About 60% of the waste generated during the removal of amalgams escaped the primary and secondary solids collectors and was released into the wastewater. An ISO-certified amalgam particle separator was effective in removing the amalgam from the wastewater.


MeSH Key Words: dental amalgam/analysis; dental waste/analysis; spectrophotometry, atomic absorption
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