Urinary platinum levels associated with dental gold alloys

Platinum concentrations were determined in 50 urine and 20 saliva samples obtained from 50 subjects who had gold dental restorations. In addition, 42 urine and 35 saliva samples were collected from subjects who did not have gold dental restorations. Subjects with gold alloys had significantly (p <.001) higher urinary platinum excretion (mean =11.9 +/- 8.5 ng/gm creatinine, range 1.9-45.8 ng/gm creatinine) than controls (mean = 6.2 +/- 3.2 ng/gm, range = 1.9-14.4 ng/gm creatinine). Mean saliva concentrations were significantly higher in subjects with dental gold alloys (526 pg/gm vs. 8.5 pg/gm; p <.001). A laboratory test with 5 commercially available dental gold/platinum alloys showed that 0.1% sodium chloride mobilized platinum within 1 hr (i.e., 1-18 pg/ml) of its introduction. In conclusion, dental gold/platinum alloys appear to be the main source for urinary platinum excretion from the occupationally unexposed population.