The effect of nickel as product of recasting nickel chromium on gingival fibroblasts apoptosis

Nicr restoration recasting causes an increase of ni solubility in artificial saliva. nickel [ii] can freely enter the cell and behaves as a free radical causing oxidative stress and inducing apoptosis. the purpose of this study was to determine the highest [ni] in the artificial saliva and its effect on apoptosis of gingival fibroblasts. three types of nicr restoration are prepared (casting ; one-time recasting and two-times recasting). each restoration consisted of 8 speciments,and was subsequently immersed in artificial saliva for 7 days. the highest [ni] in each restoration was exposed to the gingival fibroblasts culture with a density of 105,and incubated for 1,3,and 7 days. analysis of [ni] was performed by aas,whereas apoptosis was determined by the used tunel assay method. the highest [ni] on restoration casting was 0.780 μg/l; while one-time recasting was 3.002 μg/l,and two-times recasting was 6,320 μg/l. there was an interaction between increased ni solubility and exposure duration to apoptosis of gingival fibroblasts (p< 0.0001). the greatest mean ± sd of apoptosis was on the exposure of 6,320 μg/l with an incubation period of seven days ( 62.13 ± 2.85 ). it can be concluded that the higher [ni] is exposed to gingival fibroblasts in cell culture,the higher the incidence of apoptosis. nickel [ii] suspectedly enters into the cell via dmt - 1,which subsequently triggers apoptosis characterized by ros generation and reduction of bcl-2 expression.