Grajower R, Lewinstein I, Zeltser C
J Oral Rehabil. 1985 May;12(3):235-45. doi: 10.1111/j.1365-2842.1985.tb00640.x.
Non-precious metal crowns were prepared for natural teeth which were ground to a taper angle of 5 degrees. The movement of the crowns on teeth during repeated try-on seating was measured with a micrometer. Increasing the applied load from 2 to 10 kg resulted in an average crown movement of 63 micron. For most samples this movement continued when try-on was repeated. Casting irregularities were found to create furrows on some regions of the axial tooth surface during try-on seating. The diameter of the ADA specification consistency disk for zinc phosphate cement was found to depend strongly on the P:L ratio and the ambient temperature. The castings were cemented with zinc phosphate cement of controlled consistency. Cementation with a load of 10 kg gave rise to an average crown elevation of 54 micron and a range of measurements between -8 and 113 micron. The effective minimum cement thickness corresponding to this average was calculated to be 4.7 micron. Small negative values of elevation were attributed to deepening of tooth furrows during cementation. An analysis is given of data from the literature, relevant to the cement flow and irregularities in cement thickness.
为天然牙制备非贵金属冠，将天然牙磨成5度的锥角。在反复试戴就位过程中，用千分尺测量冠在牙齿上的移动情况。将施加的负荷从2千克增加到10千克，导致冠的平均移动量为63微米。对于大多数样本，重复试戴时这种移动仍会持续。发现在试戴就位过程中，铸造缺陷会在牙齿轴向表面的某些区域产生沟槽。发现磷酸锌水门汀的ADA规格一致性盘的直径强烈依赖于P:L比和环境温度。用控制稠度的磷酸锌水门汀粘结铸件。在10千克负荷下粘结导致冠的平均抬高量为54微米，测量范围在-8至113微米之间。计算得出对应于该平均值的有效最小水门汀厚度为4.7微米。抬高量的小负值归因于粘结过程中牙齿沟槽的加深。对来自文献的与水门汀流动和水门汀厚度不规则性相关的数据进行了分析。
