Campagni W V, Wright W, Martinoff J T
J Prosthet Dent. 1986 Mar;55(3):324-8. doi: 10.1016/0022-3913(86)90112-5.
Fifty crowns were constructed with an indirect technique for a standardized Ivorine tooth preparation to determine whether casting relief would improve the seating of complete cast crowns with zinc phosphate cement. The variables were two grooves in the preparations and die spacer casting relief of approximately 20 to 40 micron. The tooth preparations of two groups had no grooves, but castings were made with internal relief for only one group. Three groups had buccal and lingual grooves in the preparation. One group had no relief, a second group had complete relief, and a third group had relief but not in the grooves. The discrepancies noted before and after cementation of the castings were measured. The average discrepancy for each group and the significance between groups was determined. Results of this study demonstrated the following. Die relief significantly improved the seating of complete cast-gold crowns with or without grooves. Omitting die spacer from grooves did not reduce the benefits of relieving the remainder of the die. Partial internal relief was better than no relief. The grooves did not disrupt seating when die spacer application was complete or specifically omitted from the grooves alone.
采用间接技术制作了50个全冠，用于标准化的象牙色牙齿预备，以确定铸造缓冲是否能改善磷酸锌水门汀全冠的就位情况。变量包括预备体上的两条沟以及约20至40微米的代型间隙铸造缓冲。两组牙齿预备体没有沟，但仅一组铸造体制作了内部缓冲。三组在预备体上有颊舌沟。一组没有缓冲，第二组有完全缓冲，第三组有缓冲但沟内没有。测量铸造体粘固前后的差异。确定每组的平均差异及组间的显著性。本研究结果表明如下。无论有无沟，代型缓冲均显著改善了全冠铸造金冠的就位情况。沟内不使用代型间隙不会降低代型其他部位缓冲的益处。部分内部缓冲优于无缓冲。当完全应用代型间隙或仅在沟内特意不应用代型间隙时，沟不会干扰就位。
