Analysis of trace metals in dental and industrial cements

Abstract

Portland cement is used in the construction industry as a binder in concrete. It is manufactured from chalk, limestone and clay which are clinkered at very high temperatures, and then the resultant clinker is ground with gypsum to form Portland cement. The raw materials and the manufacturing process can result in the inclusion of heavy metals in Portland cement. These metals do not usually have any effect on the material properties however they are still considered as contaminants. In recent years Portland cement has been used as a biomaterial. Portland cement with a 4:1 addition of bismuth oxide is marketed as mineral trioxide aggregate (MTA). This material is used mainly as a dental material. The introduction of a material based on Portland cement has raised the concern of the heavy metal inclusion since MTA is in contact with hard and soft tissues. The aim of this research was to evaluate the total arsenic, chromium and lead content of two Portland cements and two mineral trioxide aggregates. In addition the release of these metals in deionised water, and simulated body fluid was also assessed. All cement types showed the same trend for both the total metal content and released species, with chromium being the highest metal present followed by arsenic and lead. The grey Portland cement demonstrated the highest total amount of arsenic chromium and lead. The white Portland and both MTAs had lower values for all the metals. Both MTAs had more acid soluble arsenic and lead than the amount specified by ISO 9917-1 (2007) indicating that the MTA was manufactured in a similar way as the commercial Portland cement.