Laufer B Z, Baharav H, Ganor Y, Cardash H S
Maurice and Gabriela Goldschleger School of Dental Medicine, Tel Aviv University, Israel.
J Prosthet Dent. 1996 Nov;76(5):466-71. doi: 10.1016/s0022-3913(96)90002-5.
An impression of the margins of a prepared tooth and adjacent gingival sulcus must be of sufficient thickness to withstand distortion and tearing when the impression is removed from the mouth. The purpose of this study was to compare the dimensional accuracy of Elite, Examix, and Express polyvinyl siloxanes; Permadyne polyether; and Permlastic polysulfide elastomeric impression materials. These materials were used to make impressions of a metal model that simulated prepared abutments with gingival sulci of various widths. A traveling microscope was used to measure the abutments and impression widths, and the number of defects in each impression was recorded. Between 70% and 100% of the abutment impressions with sulcular widths of 0.05 mm exhibited defects, which prevented accurate measurements in this group. Express material demonstrated a high number of defects in the 0.10 and 0.16 mm sulcular width groups. No great difference in average maximum distortion values or coefficients of variation (CV) were detected among the materials used to make impressions of abutments with sulcular width groups of 0.2 to 0.4 mm. For the sulci of 0.16 mm and less, Examix and Permiastic materials exhibited distortion and a CV comparable to the impressions of the wider sulcular groups, whereas Elite and Permadyne showed greater distortions and CVs. The differences were not statistically significant (analysis of variance) because of the larger CV among the groups. The larger coefficient of variation in the 0.1 and 0.16 mm sulcular width groups demonstrated inconsistencies in obtaining good impressions of abutments with such narrow sulcular widths.
预备牙边缘及相邻牙龈沟的印模必须具有足够的厚度，以便在从口腔中取出印模时能承受变形和撕裂。本研究的目的是比较Elite、Examix和Express加成型硅橡胶印模材料；Permadyne聚醚印模材料；以及Permlastic聚硫橡胶弹性体印模材料的尺寸精度。这些材料用于制作一个金属模型的印模，该模型模拟了具有不同宽度牙龈沟的预备基牙。使用移动显微镜测量基牙和印模的宽度，并记录每个印模中的缺陷数量。在龈沟宽度为0.05mm的基牙印模中，70%至100%出现了缺陷，这使得该组无法进行准确测量。Express材料在龈沟宽度为0.10mm和0.16mm的组中出现了大量缺陷。在用于制作龈沟宽度为0.2至0.4mm基牙印模的材料中，未检测到平均最大变形值或变异系数（CV）有很大差异。对于龈沟宽度为0.16mm及以下的情况，Examix和Permlastic材料的变形和CV与较宽龈沟组的印模相当，而Elite和Permadyne材料的变形和CV更大。由于各组之间的CV较大，差异无统计学意义（方差分析）。在龈沟宽度为0.1mm和0.16mm的组中，较大的变异系数表明，对于如此窄龈沟宽度的基牙，难以获得一致的良好印模。
