Chemist prepares final solution of samples for analysis in the ICP/MS instrument.

We’ve all heard the news stories about lead found in toys imported from China. WBNS, a Columbus, Ohio, television station, recently investigated the presence of lead in dental crowns, bridges and dentures produced in Asia. The station’s 10 Investigates team began looking into this story after a patient, based on the results of testing by NSL Analytical, sued her dentist over the  presence of lead in her dental crown.

The station found that most dentists rely on outside labs to make their crowns, and that these labs increasingly outsource their work to India, Mexico and China. To check on the safety of crowns imported from China, 10 Investigates obtained eight crowns from four labs in China that advertise in industry magazines. Using a hand-held nondestructive device that screens for lead, the reporters identified one crown as being positive for lead.

Digging Deeper

The aqueous solution is introduced into the plasma flame of the ICP/MS instrument to determine lead levels.

The station sent the crown to NSL for a more in-depth analysis. NSL separated the porcelain from the metal and dissolved the crown in acid to create a solution that chemists use to test for lead.

Tests were run using an inductively coupled plasma/mass spectrometer (ICP/MS) instrument. ICP/MS is a highly sensitive type of mass spectroscopy that can determine element concentrations below one part per trillion. Combining mass spectroscopy and ICP analysis in a single instrument enables the detection of low-level concentrations of lead from parts per billion to 0.1%. After the test on the crown was complete, the instrument gave a reading of 210 parts per million (ppm) of lead, which NSL reported to the TV station.

In response to the story, the Ohio Dental Board adopted a recommendation asking dentists to require their labs to disclose where their dental devices are made. On the national level, the U.S. Food and Drug Administration (FDA) is reviewing the station’s report and developing a strategy to address these findings on all imported dental devices.  

For additional information, visit www.wbns10tv.com or www.nslanalytical.com.