Nissan J, Gross M, Shifman A, Assif D
Department of Prosthodontics, The Maurice and Gabriela Goldschleger School of Dental Medicine, Tel Aviv University, Tel Aviv, Israel.
J Oral Rehabil. 2002 Apr;29(4):357-61. doi: 10.1046/j.1365-2842.2002.00820.x.
Variations in the bulk of wash in a putty-wash impression technique can result in dimensional changes proportional to the thickness of the wash material during setting. The purpose of the study was to determine the amount of wash necessary to achieve accurate stone models while using a two-step putty-wash impression technique with polyvinyl siloxane (PVS) impression material. A total of 45 impressions were made of a stainless steel master model, 15 impressions for each wash thickness (1, 2 and 3 mm). The model contained three full-crown abutment preparations, which were used as the positive control. Accuracy was assessed by measuring six dimensions (occlusogingival and interabutments) on stone dies poured from impressions of the master model. One-way analysis of variance (ANOVA) showed statistically significant differences amongst the three wash bulk groups, for all occlusogingival and interabutment measurements (P < 0.001). The overall discrepancies of the groups using wash thickness of 1 and 2 mm were smaller than the group with 3 mm wash thickness. Therefore, wash bulks of 1 and 2 mm were most accurate for fabricating stone dies, using PVS impression materials. This can be achieved by using the temporary crown to create the desired wash space in the preliminary putty impression. Wash thickness > 2 mm was inadequate to obtain accurate stone dies.
在油灰-冲洗印模技术中，冲洗材料用量的变化可能会导致在凝固过程中尺寸变化与冲洗材料的厚度成比例。本研究的目的是在使用两步法油灰-冲洗印模技术及聚硅氧烷（PVS）印模材料时，确定获得精确石膏模型所需的冲洗材料用量。对一个不锈钢主模型共制作了45个印模，每种冲洗材料厚度（1、2和3毫米）制作15个印模。该模型包含三个全冠基牙预备体，用作阳性对照。通过测量从主模型印模灌注的石膏模型上的六个维度（咬合龈向和基牙间）来评估准确性。单因素方差分析（ANOVA）显示，在所有咬合龈向和基牙间测量中，三个冲洗材料用量组之间存在统计学显著差异（P < 0.001）。使用1毫米和2毫米冲洗材料厚度的组的总体差异小于使用3毫米冲洗材料厚度的组。因此，对于使用PVS印模材料制作石膏模型，1毫米和2毫米的冲洗材料用量最为准确。这可以通过使用临时冠在初步油灰印模中创建所需的冲洗空间来实现。冲洗材料厚度> 2毫米不足以获得精确的石膏模型。
