Urinary levels of nickel and chromium associated with dental restoration by nickel-chromium based alloys.

This paper aims to investigate if the dental restoration of nickel-chromium based alloy (Ni-Cr) leads to the enhanced excretions of Ni and Cr in urine. Seven hundred and ninety-five patients in a dental hospital had single or multiple Ni-Cr alloy restoration recently and 198 controls were recruited to collect information on dental restoration by questionnaire and clinical examination. Urinary concentrations of Ni and Cr from each subject were measure by graphite furnace atomic absorption spectrometry. Compared to the control group, the urinary level of Ni was significantly higher in the patient group of <1 month of the restoration duration, among which higher Ni excretions were found in those with either a higher number of teeth replaced by dental alloys or a higher index of metal crown not covered with the porcelain. Urinary levels of Cr were significantly higher in the three patient groups of <1, 1 to <3 and 3 to <6 months, especially in those with a higher metal crown exposure index. Linear curve estimations showed better relationships between urinary Ni and Cr in patients within 6-month groups. Our data suggested significant increased excretions of urinary Ni and Cr after dental restoration. Potential short- and long-term effects of Ni-Cr alloy restoration need to be investigated.

[A cross-sectional survey on immunological function after dental restoration of nickel-chromium alloy].

OBJECTIVE: To investigate the immunological function parameters in patients undergoing dental restoration of nickel-chromium (Ni-Cr). METHODS: Seven hundred and ninety-five Ni-Cr alloy consumers as exposure group, together with 198 controls, were surveyed by the questionnaire and the biological examination of immunological function. RESULTS: After splitting all subjects into three groups of equal sample size by urinary Ni or urinary Cr, serum interleukin-1beta(IL-1ß) was found to be significantly higher in the group of urinary Ni > 115.73 µg/mol creatinine comparing to the group of urinary Ni < 37.28 µg/mol creatinine (P < 0.05). No changes of immunological parameters in surm [tumor necrosis factor-alpha (TNF-α), IL-1ß, and IL-6] were found in other groups of urinary Ni or Cr. Both one way analysis of variance (ANOVA) and linear regression analysis did not find any association between serum changes of immunological parameters and the parameters of alloy restoration (period, number and the level of metal crown uncovered with porcelain). CONCLUSIONS: This study did not show positive associations between dental restoration of Ni-Cr alloy and serum levels of TNF-α, IL-1ß and IL-6.