不同制作方法对双重冠经循环摘戴后固位力影响的研究

Effect of Various Materials on Retention of Telescopic Crowns after Repeated Insertion/separation Cycles

目的 研究不同制作方法对双重冠经循环摘戴后固位力的影响。方法 制作一个标准预备体,以此为基础用 4种方法(镍铬-镍铬组、金钯-金钯组、镍铬-金沉积组及金钯-金沉积组)制作内冠外形一致的双重冠,并测量经循环摘戴(循环过程中用人工唾液湿润)最大至8000次后双重冠固位力的变化情况。结果 金钯内冠的固位力较镍铬内冠大,固位力随循环摘戴次数的增加而降低,金沉积外冠的降低速度小于铸造外冠。金钯-金钯组、金钯-金沉积组的固位力较大,镍铬-金沉积组次之,镍铬-镍铬组最低。结论 双重冠固位力随循环摘戴次数的增加而降低。金钯内冠的固位力大于镍铬内冠的固位力,金沉积外冠固位力比铸造外冠更大。

Objective To study the effect of various materials on retention of telescopic crown assemblies after repeated insertion/separation cycles. Methods For four groups of telescopic crown assemblies, with 5 pairseach, the inner crowns and outer crowns were made of Ni - Cr & Ni - Cr,Au - Pd & Au - Pd.NiCr & Au and Au - Pd & Au, respectively. The shapes and sizes of the inner crowns were the same. Then each telescopic crown was subjected to up to 8000 insertion/separation cycles. Artificial saliva was used during the process of the test. The retentive force of telescopic crowns was investigated after repeated insertion/separation tests. Results The retentive force of Au - Pd inner crown group was larger than that of Ni - Cr group. The retentive force of all groups diminished gradually. The retentive force of electroformed outer crown groups diminished more slowly than that of cast crown groups, and became larger than that of cast crown groups after certain insertion/separation cycles. The retentive force of electroformed outer crown groups kept a relatively high level after more insertion/separation cycles . Conclusion The retentive force of telescopic crowns diminished gradually as the insertion/separation cycles increased. The retentive force of Au - Pd inner crown groups was larger than that of Ni - Cr groups. The retentive force of electroformed outer crown groups kept a higher level after more insertion/separation cycles than that of cast outer crown groups.