Copper in human subgingival calculus

The Cu concentration as well as the Ca, Mg, Fe, Pb, Zn, and F concentrations were determined in subgingival calculus and the relation of Cu to Zn, Ca, Mg and Fe described. Samples of human subgingival calculus of 60 pieces from 60 subjects were ashed in an acid solution and the cation concentrations were determined with atomic absorption spectrophotometry. The F content was analyzed with an ion-selective electrode. The data was analyzed using the multiple linear regression analysis. The mean +/-SD of the Cu concentration in the subgingival calculus was 48.4+/-59.0 micrograms/g. Four elements, Zn, Ca, Fe and Mg, explained 41.1% of the Cu content. Zn explained 25.5% and the correlation was positive, whereas Ca (10.4%) had a negative correlation with the Cu content. The results showed such a high Cu content that it could affect the mineralization of calculus.