Mercury generation potential from dental waste amalgam.
OBJECTIVE
The main objective of this study was to quantify the total amount of amalgam used in dental offices in the state of Illinois and to estimate the fractions of amalgam waste material generated during dental procedures. A second objective was to estimate the fractions of non-contact, contact, and tooth retained amalgam through an in vitro study.


METHODS
The collection system consisted of containers placed in six dental offices and clinics to collect the material from the in-line trap (contact amalgam) and the excess dental amalgam not placed into the oral cavity (non-contact amalgam). In order to have comparable results, the data was adjusted by the number of dental chairs being used and the number of working days.


RESULTS
The range for the non-contact amalgam was from 0 to 102 g, and for the contact amalgam, from 2 to 16 g. The median estimate of non-contact amalgam generated from the 6 dental offices was 421 mg/day/chair, whereas the median estimate of contact amalgam was 64 mg/day/chair. For the in vitro study, 40 one and two surface amalgams (bicuspids and molars), was distributed as follows, 46+/-20% in the tooth, 43+/-19% as non-contact amalgam, and 11+/-4% as contact amalgam.


CONCLUSIONS
Based on survey data from the ADA concerning the number of working days per year, the number of practicing dentists, a 50%, by weight, mercury content in amalgam, and the generation estimates from this project, it was estimated that the practicing dentists in the State of Illinois (6455) have the potential to generate 947 kg of non-contact mercury per year, which is recyclable, and 144 kg of contact mercury which has the potential to be discarded in the environment, or be partially recycled. If this approach is applied to the total population of practicing dentist in the United States (123,641), then 18,159 kg of recyclable, non-contact mercury may be generated per year, whereas 2763 kg of contact mercury may be discarded in the environment, or be partially recycled.
Drummond
James L
JL
Department Restorative Dentistry, University of Illinois at Chicago, Chicago, IL 60612-7212, USA. drummond@uic.edu
Cailas
Michael D
MD
Croke
Kevin
K
D003723:Dental Amalgam / Q000032:analysis*; D003770:Dental Offices; D003793:Dental Restoration, Permanent; D018057:Dental Waste / Q000032:analysis*; D017743:Equipment Reuse; D006256:Hazardous Waste / Q000032:analysis; D006801:Humans; D007087:Illinois; D017744:Medical Waste Disposal; D008628:Mercury / Q000032:analysis*
D018057:Dental Waste; D006256:Hazardous Waste; D017744:Medical Waste Disposal; D003723:Dental Amalgam; D008628:Mercury