Biological Effects On Peripheral Blood,liver And Kidney Before And After Removal Of Dental Alloys

Objective To evaluate the relationship between the metal concentration and biological effects of blood,liver and kidney before and after the removal of dental alloys,in order to provide the lab-based data for promoting the biocompatibility of dental alloys and treatment plan for patients suffering from porcelain-fused-to-metal(PFM)fixed dental prostheses(FDPs)failure.Methods According to ISO 10993,the nickel-chromium(Ni-Cr),cobalt-chromium(Co-Cr),commercially pure titanium(CP-Ti),palladium-based(Pd-based)and gold-platinum(Au-Pt)alloys were put in the cheek pouches of Syrian hamsters for 12 w.In order to determine the time of peak or plateau of total metal concentration,trace metals of peripheral blood in Syrian hamster with these five dental alloys were analyzed by inductively coupled plasma mass spectroscopy(ICP-MS)in 1w,2w,4w,8w and 12 w.On the basis of randomized block method,hamsters in each group were divided into 2 groups(Removal group and Non-Removal group),half of the five dental alloys were removed in the peak time or the initial time of plateau.And then,the trace metals in peripheral blood were also detected by ICP-MS in R1w(1w after removal of the dental alloys),R2 w,R4w,R8 w,R12w.In addition,the observation period will be terminated by the time of the total metal concentration in R group back to the basal line which would be regarded as end time.Afterwards,before and after the removal of dental alloys in peak and end time,the trace metals in blood and organs(liver and kidney)were evaluated by ICP-MS,and then the biological effects of them were evaluated by Acridine orange/ethidium bromide(AO/EB)staining,flow cytometry(FCM)and H&E staining,liver and renal function tests,immunohistochemical(IHC)for autophagy-related protein,TUNEL assay,respectively.Results1.The metal ions released from five dental alloys were found to be accumulated in peripheral blood.More specific,the total metal concentration in blood of Ni-Cr and Co-Cr alloys peaked in 2w and then declined afterwards,and the elevated ions was eliminated faster by removal of these two dental alloys in R4 w.The similar trend was shared in CP-Ti group,in which the peak and end time were 1w and R8 w,respectively.As for Pd-based and Au-Pt groups,the total metal concentration in blood peaked in 12 w and then declined afterwards,and the elimination of increased ions was accelerated by removal of these two alloys,but for Pd-based group,the total metal concentration wasn’t back to basal line until R12 w.What’s more,in spite of CP-Ti and Au-Pt alloys,accumulation of metal ions in liver and kidney was found in three dental alloys and the elevated ions was eliminated by removal of dental alloys.2.Five dental alloys didn’t induce alteration of histopathology and function of liver and kidney.3.Ni-Cr and Pd-based alloys triggered the increment of early apoptotic rate of PBMCs,autophagy level in serum,apoptotic rate and autophagy level in liver and kidney.What’s more,the biological effects were teminated by removal of these two dental alloys,but for Pd-based group,the apoptotic rate and autophagy level of kidney reduced but wasn’t back to normal until R12 w.4.Co-Cr alloy induced the elevation of early apoptotic rate of PBMCs,autophagy level in serum,apoptotic rate and autophagy level in liver and kidney.What’s more,the biological effects were terminated whether by removal of these two dental alloys or not,but the early apoptotic rate of PBMCs wasn’t back to normal until R4 w.5.Except for the the transient elevation of autophagy level in serum,CP-Ti and Au-Pt didn’t trigger the biological changes in liver and kidney,showing favorablebiocompatibility.What’s more,elevation of autophagy level in serum was eliminated whether by removal of these two dental alloys or not.6.There is a positive correlation between the early apoptotic rate of PBMCs and the level of Ni,Cr,Cu,Zn in blood and a negative correlation between the level of p62 protein in serum and the level of Ni,Cr,Zn,Pd,Ag in blood.In addition,the data in kidney and liver also shows a positive correlation between apoptotic rate and the level of Ni,Cr and a negative correlation between the level of p62 and the level of Ni,Cr.Conclusion1.Five dental alloys induced a temporarily accumulation of metals in blood,liver and kidney but had no effect on histopathology as well as liver and renal function.2.CP-Ti and Au-Pt alloys shows favorable compatibility.3.Ni-Cr,Co-Cr and Pd-based alloys induced a transient increment of apoptosis in PBMCs,autophagy in serum,apoptosis and autophagy in liver and kidney.4.Most metals and biological effects reduced or terminated by removal of dental alloys.