Deposition Of Nickel-chromium From Oral Nickel-chromium Alloy In The Mouse Liver, Kidney And Effects Of DNA Damage

Dental metal-ceramic alloys including Ni-Cr alloy affected by the saliva in the patient's mouth will release some mental ions. Recent researches have show that metal ions ,which are released constantly from Ni-Cr dental casting alloys by corrosion, can penetrate gum tissues, saliva, mucosa, blood and organs. It has been documented in vitro evidence that the metal ions with cytotoxicity and genotoxicity can alter the immune response, induced gingivitis and allergic reactions. The dispute of its safety is limited in oral cavity and neighbor tissues, however, the relevance between Ni-Cr alloy and systemic disease, such as liver and nephridium toxicosis, are poorly understood. In this study, the deposition of nickel-chromium from oral nickel-chromium alloy in the mouse liver, kidney and effects of DNA damage were investigated in vivo, which will offer some theoretic evidences for further exploring .[Research purposes]The aims of this study was to analyze the number of elements in blood ,kidney and liver of mice after injecting the mixture of nickel-chromium by ICP-MS。To investigate the DNA damage of mouse liver and kidney induced by the mixture of nickel-chromium with SCGE. To evaluate its long-term clinical safety of Ni-Cr porcelain crown.[Research Methods]1 Nickel, Chromium test: 42 healthy mice, Kunming closed group, male and female, weight 20±1g.The mice were randomly divided into 3 groups according to body weight and gender. Prepared the high concentration of mixed solution with 0.4μg/ml of nickel ions and 0.05μg/ml chromium ions. Then the solution was diluted four times as the low concentration solution. Mice were administered tail vein injections 0.5ml/d with different concentration levels of the mixture of nickel-chromium. Then test the number of nickel-chromium in the 7th day and 30th day by ICP-MS.2 SCGE:In the 30th day, DNA damage of mouse liver and kidney were detected by the method of single cell gel electrophoresis(SCGE).All the data were analyzed by SPSS 17.0 software.[Research Results]1 Blood: At the end of 7 and 30 days, there was no statistically significant difference in the content of nickel-chromium in the blood between the low concentration group and the control group(P>0.05).The content of nickel- chromium in the blood of high concentration group was significantly higher than in the low concentration group and control groups(P<0.05).2 Liver: The content of nickel-chromium in liver was positively correlated with in blood. At the end of 7 and 30 days, there was no statistically significant difference in the content of nickel-chromium in the liver between the low concentration group and the control group(P>0.05).The content of nickel- chromium in the liver of high concentration group was significantly higher than in the low concentration group and control groups(P<0.05).3Kidney: The content of nickel-chromium in kidney was positively correlated with in blood. At the end of 7 and 30 days, there was no statistically significant difference in the content of nickel-chromium in the kidney between the low concentration group and the control group(P>0.05). The content of nickel- chromium in the kidney of high concentration group was significantly higher than in the low concentration group and control groups(P<0.05),whereas the content of nickel in the kidney of high concentration group was no significant difference between others(P>0.05).4 In the low concentration group and control group, there was no significant difference in the content of nickel-chromium in the blood, liver and kidney between the 7th day group and 30th day group(P>0.05). In the high concentration group, the content of nickel-chromium in the blood, liver and kidney in the 30th day group was significantly higher than in the 7th day group(P<0.05),but the content of nickel in the liver of the 30th day group was no significant difference from the 7th day group (P>0.05).5 SCGE showed: There was no significant difference in the effects of DNA damage between the low concentration group and the control group(P>0.05). The main performance of the damage were 0level(>85%)andⅠlevel(<15%)). There was also no significant difference in the effects of DNA damage between the high concentration group of liver and others (P>0.05).The number of DNA damage in the high concentration group of kidney was a litter higher than others(P<0.05). The main performance of the damage were I level(75%)andⅡlevel(15%))[Conclusion]1 The content of nickel-chromium in liver and kidney was positively correlated with in blood.2If trace amounts of nickel-chromium constantly enter into blood circulation, it will be no adverse reaction for systemic.3If a higher concentration of nickel-chromium constantly enter into blood circulation, it may be depositions of nickel-chromium in the liver and kidney with the extension of time. It is suggested that it's not a best choice for Ni-Cr dental casting alloys when you lost too many teeth and you are young.