Effect On Periodontal Tissue Of Dogs After Restored With Three Types Of Base Metal Porcelain Crown

Objective: To investigate the effect of three kinds of PFM on periodontal tissue by means of measuring gingival cells Bcl-2, Bax, Ki67 and p53 expression. Compared differential expression to provide a theoretical basis for the clinical selection of repair materials.Methods: Select 5 local hybrid dogs and each of them has had full-mouth scaling and root planning by hand. Taking a model and making custom impression tray. Selected 20 canines as experimental subjects were randomly divided into four groups. A group were restored with cobalt-chromium alloy, a group were restored with pure titanium, a group were restored with silver-palladium and another as the control group without any restored. Collect the gingival tissue before restoration and on the 1st, 2nd and 3rd month after restoration and measured gingival cells Bcl-2, Bax, Ki67 and p53 gene expression by RT-PCR method.Results:(1) The Bcl-2, Bax, Ki67 and p53 gene expression of each experimental group compared with control group were no significant difference before PFM repaired(P>0.05).(2) The Ki67, p53 gene expression of cobalt-chromium alloy group and silver-palladium alloy group compared with control group were increased after 1 month(P<0.05). The Bcl-2, Bax gene expression of cobalt-chromium alloy group and silver-palladium alloy group compared with control group were no significant difference after 1 month(P>0.05). The Bcl-2, Bax, Ki67 and p53 gene expression of pure titanium group were no significant difference after 1 month(P>0.05).(3) The Ki67 gene expression of cobalt-chromium alloy group compared with control group was decreased after 2 month(P < 0.05). The p53 gene expression of cobalt-chromium alloy group compared with control group was increased after 2 month(P<0.05). The Bcl-2 and Bax gene expression of cobalt-chromium alloy group compared with control group were no significant difference after 2 month(P>0.05). The Bcl-2, Bax, Ki67 and p53 gene expression of pure titanium group were no significant difference after 2 month(P>0.05). The Ki67 gene expression of silver-palladium alloy group compared with control group was decreased after 2 month(P<0.05). The Bax and p53 gene expression of silver-palladium alloy group compared with control group were increased after 2 month(P<0.05). The Bcl-2 gene expression of silver-palladium alloy group compared with control group was no significant difference after 2 month(P>0.05).(4) The Bcl-2, Bax and p53 gene expression of cobalt-chromium alloy group and silver-palladium alloy group compared with control group were increased after 3 month(P<0.05). The Ki67 gene expression of cobalt-chromium alloy group and silver-palladium alloy group compared with control group were decreased after 3 month(P<0.05). The Bcl-2, Bax, Ki67 and p53 gene expression of pure titanium group compared with control group were no significant difference after 3 month(P>0.05).Conclusion: Pure titanium had no obvious effect on gingival cell apoptosis and proliferation, cobalt-chromium alloy and silver-palladium alloy are more likely to cause gingival cell apoptosis and proliferation.