Objective: Elemental release is important because it plays a significant role in material biocompatibility. The aim of this study was to investigate the release of metal ions from four fixed prosthodontic materials.
Methods: Specimens were prepared using the conventional lost wax technique for gold and nickel-chromium (Ni-Cr) alloys, and by cutting blocks and bar for CAD-CAM ceramic and stainless-steel (St-St) alloy, respectively. All specimens were polished (600grit SiC paper), and ultrasonically cleaned with ethanol for 5min. After they were immersed in 0.9% sodium chloride (NaCl) and 1% lactic acid, and were kept at 37 degrees C for 7 days, the elemental release (mug/cm(2)) from each material was analyzed by using inductively coupled plasma mass spectroscopy. The rate (n=5) was statistically analyzed by ANOVA/Tukey test (p<0.05). Two immersion blank solutions were used as a negative control group.
Results: Higher elemental release (mean+/-S.D.) of all elements from all materials was evident into the lactic acid solution except for Ag. In the gold alloy, there was significant difference (p<0.05) between Zn and other released elements in the NaCl solution, and it also revealed significant difference between Pd or Ag and Cu which detection value was more than Zn (but no statistical difference) into lactic acid solution. The Ni was significantly more released from Ni-Cr alloy than the other elements into both NaCl and lactic acid solutions. The same was observed for Fe released from St-St alloy. There was more significant release of K than Al from CAD-CAM ceramic in only NaCl solution.
Significance: Transient exposure of tested materials to an acidic environment is likely to significantly increase the elemental release from them. The significant higher release of Ni from Ni-Cr alloy, and Zn, Cu from gold alloy was evident.