金沉积、高金合金和镍铬合金三种不同基底烤瓷冠边缘适合性的比较研究

Comparison of marginal fit of gold electroforming-ceramic crown,high gold alloy-ceramic crown and nickel chromium alloy-ceramic crown

目的研究比较金沉积、高金合金和镍铬合金三种不同基底烤瓷冠边缘适合性。方法采用离体活髓磨牙36个,环氧树脂包埋后随机分为三组,牙体预备后分别制作金沉积、高金合金和镍铬合金基底烤瓷冠各12个,羧酸锌水门汀粘固完全。低速锯金钢砂盘沿牙体纵轴颊舌向和近远中向切开,用解剖显微镜和图像采集仪采集图像,MISA医学图像分析软件测量三种不同基底烤瓷冠边缘适合性。结果金沉积烤瓷冠边缘间隙为42±5μm,高金合金烤瓷冠和的边缘间隙分别为57±4μm和80±10μm。采用秩和检验,金沉积烤瓷冠与高金合金烤瓷冠边缘适合性在统计学上差异有明显性(P<0.01),金沉积烤瓷冠和高金合金烤瓷冠边缘适合性均与镍铬合金烤瓷冠有显著的统计学差异(P<0.01)。结论金沉积烤瓷冠和高金合金烤瓷冠具有良好的边缘适合性,金沉积烤瓷冠的边缘适合性最好,而镍铬烤瓷冠边缘适合性较差。

Objective To evaluate the marginal fitness of metal- ceramic crowns with 3 different metal copings made of gold - electroforming, high gold alloy and nickel chromium alloy. Methods Thirty six integrally- removed molar teeth which roots were embedded in epoxy resin were divided into three groups randomly after tooth preparation, Group 1 ： gold- electroforming ceramic crowns, Group 2 ： high gold alloy ceramic crowns, Group 3： nickel chromium alloy（ Ni - Cr） ceramic crowns. Crowns were cemented by zinc polycarboxylate cement and re - embedded in epoxy resin. All the samples were sectioned in buccolingual and mesiodistal directions through the teeth axis. The thickness of cement at marginal sites of the ceramic crowns was measured by anatomical microscope and the collected digital images were analyzed by MISA medical image analyzing software. Kruskal - Wallis test was used for statistical comparison. Results The overall marginal discrepancies for the restorations in this study were 42±5μm for gold - electroforming ceramic crowns, 57 ± 4μm forhigh gold alloy ceramic crowns and 80 ± 10μm for Ni- Cr ceramic crowns. The results showed that there were statistical differences between group 1 and group 2 （ P 〈0.01）, between group 1 and group 3 （ P （0.01）, and between group 2 and group 3 （ P 〈 0.01 ）. Conclusion Marginal fitness of gold - electroforming ceramic crowns and high gold alloy ceramic crowns was fine. Among 3 types, the Marginal fitness of gold- eleetroforming ceramic crown was the best, but that of Ni- Cr ceramic crowns was poor.