Objective The aim of the study was to detect the expression of Ki67 and P53 proteins in the gingival issue before and after wearing three kinds of dental casting alloy crowns. Methods The three kinds of dental asting alloys（58% golden alloy, NiCr alloy, NiCr alloy excluding Be） were used to make full crowns for 3 dogs in ach group. Another 3 dogs were taken as control. The immunohistochemistry Envision method was used to measure he expression of Ki67 and P53 proteins in the gingival tissue before wearing the crowns, 2 weeks, 1 month, 2 onths, 3 months after wearing the crowns. Results The expression of Ki67 and P53 proteins in gingival tissue increased month after wearing NiCr alloy and NiCr alloy excluding Be, then decreased gradually. And the expression f Ki67 and P53 proteins in 58% golden alloy group was similar to that in control. No pathological change was observed n all samples. Conclusion Two kinds of NiCr alloy crowns both can increase the expression of Ki67 and 53 proteins in gingival tissue, but 58% golden alloy crowns can not. So compared with NiCr alloy crowns, 58% olden alloy crowns have better biological properties. And none of three kinds of dental alloy crowns may induce ong-term abnormal proliferation in gingival tissue.
