Electron Microscopy of Etched Dental Crown Surfaces and EDS Studies following Immersion in Hydrochloric Acid

Abstract

A number of distinctive dental porcelain-fused-to-metal (PFM) crown artefacts were received by the authors. It was suspected that these crowns had been immersed in hydrochloric acid for seven days. One of the authors (AF) was asked if this could be demonstrated.

A sample of the same metal used for casting the crown copings was received from the laboratory that manufactured the original crowns and this was examined by the authors (AF and PH) using scanning electron microscopy (SEM) and EDS (Electron Dispersive Spectroscopy).

Subsequently the sample of metal was immersed in the same brand of hydrochloric acid in which the original crowns were alleged to have been immersed, and for the same time period (seven days). It was then re-examined by SEM and EDS to determine what changes had occurred.

SEM examination of the original crowns was then undertaken and similar features to those observed in the sample of metal were observed, and the component elements of the crown metal were verified as being similar to that of the sample. We concluded that the original crowns had been immersed in a corrosive substance, although this test did not identify the specific identity of the corrosive.