ABSTRACT
<p><b>OBJECTIVE</b>To explore whether the dental restoration of nickel-chromium (Ni-Cr) based alloys will lead to extra excretions of urinary Ni and Cr.</p><p><b>METHODS</b>Urinary Ni and Cr were repeatedly measured in 33 patients before and 2 months after the dental restoration of Ni-Cr alloys. The associations between alloy restoration and urinary Ni or Cr were analyzed by paired t test and general linear model of repeated measures.</p><p><b>RESULTS</b>A slightly higher urinary Ni was found in patients after 2 month of the alloy restoration, but the difference was not statistically significant (before: 46.4 microg x mol(-1) crea; after: 67.6 microg x mol(-1) crea; P=0.063). This difference was only in female subjects (before: 44.8 microg x mol(-1) crea; after: 73.7 microg x mol(-1) crea; P=0.068). A significant higher urinary Cr was found in patients after 2 month of the alloy restoration (before: 57.0 microg x mol(-1) crea; after: 99.4 microg x mol(-1) crea; P=0.024). This significant difference was only in female subjects (before: 59.8 microg x mol(-1) crea; after: 124.4 microg x mol(-1) crea; P=0.023). General linear models of repeated measurements showed that urinary excretions of Ni and Cr were associated with the number of restoration and the area of metal basis uncovered with porcelain.</p><p><b>CONCLUSION</b>Dental restoration of Ni-Cr alloy might lead to the enhanced excretions of urinary Ni and Cr.</p>
