Expression of Ki67 and P53 proteins in gingival tissue after wearing casting alloy crowns / 华西口腔医学杂志

<p><b>OBJECTIVE</b>The aim of the study was to detect the expression of Ki67 and P53 proteins in the gingival tissue before and after wearing three kinds of dental casting alloy crowns.</p><p><b>METHODS</b>The three kinds of dental casting alloys (58% golden alloy, NiCr alloy, NiCr alloy excluding Be) were used to make full crowns for 3 dogs in each group. Another 3 dogs were taken as control. The immunohistochemistry Envision method was used to measure the expression of Ki67 and P53 proteins in the gingival tissue before wearing the crowns, 2 weeks, 1 month, 2 months, 3 months after wearing the crowns.</p><p><b>RESULTS</b>The expression of Ki67 and P53 proteins in gingival tissue increased 1 month after wearing NiCr alloy and NiCr alloy excluding Be, then decreased gradually. And the expression of Ki67 and P53 proteins in 58% golden alloy group was similar to that in control. No pathological change was observed in all samples.</p><p><b>CONCLUSION</b>Two kinds of NiCr alloy crowns both can increase the expression of Ki67 and P53 proteins in gingival tissue, but 58% golden alloy crowns can not. So compared with NiCr alloy crowns, 58% golden alloy crowns have better biological properties. And none of three kinds of dental alloy crowns may induce long-term abnormal proliferation in gingival tissue.</p>

Study of DNA damage of buccal mucosal cells after wearing casting alloy crowns / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To test the corrosion behavior of three kinds of dental casting alloys and to investigate the effect of the released metal ions on the DNA damage of dog buccal mucosal cells.</p><p><b>METHODS</b>Three kinds of frequently used dental casting alloys were used to make full crowns for dogs. The concentration of the released metal ions was measured after the restoration of 2 weeks, 1 month, 2 months and 3 months. The DNA damage of buccal mucosal cells was studied by the method of SCGE.</p><p><b>RESULTS</b>The metal ions released from NiCr and NiCrBe were detected in buccal mucosal cells while the amount of the ions released from noble alloy (gold 58%) was too small to be detected. The DNA damage of mucosal cells increased after restoration of NiCr and NiCrBe crowns.</p><p><b>CONCLUSION</b>The noble alloy (gold 58%) is most corrosion resistant of the three alloys and has good biocompatibility. The NiCr and NiCrBe are prone to corrode and have cytotoxicity to cells.</p>