Lead in Dental Restorations

In recent TV reports lead has been reported on partial bridges and dental crowns. Given the recent concern regarding lead in toys which were manufactured in China, this has lead to significant concern in the dental community, especially at dental laboratories responsible for fabricating these products. The immediate assumption is that the lead is present because the bridge was manufactured in China. However, the origin of the lead appears to be the stains used and could occur in dentures manufactured anywhere in the world. There is a need to assure the dentist and their patients that the restorations being installed are safe and lead free.

X-ray fluorescence (XRF) provides a quick and easy to non-destructively test restorations which have been produced for the presence or absence of lead.  In addition the same equipment can provide an assay of the precious metal content of a restoration, thus confirming that the alloy used has the proper content.  An example of the analysis possible is shown in Figure 1.  In this case, a very small amount of lead (29 ppm) was found.  This lead is probably contained in the stain which is used to color the tooth.

The analysis of dental work can be carried out with either the X-MET3000TXR+ (include picture of handheld X-MET) or the X-STRATA 980.  The X-MET is a light portable analyzer which can analyze the surface of dentures and other dental work, while the X-STRATA 980 is a benchtop instrument with the ability to measure the surface of the work or down into the cavity which holds the crown (as shown in Figure 2) or any other surface which needs to be measured.  Either instrument can detect lead on porcelain down to a few parts per million (ppm).