Hafezeqoran Ali, Rahbar Mahdi, Koodaryan Roodabeh, Molaei Tina
Department of Prosthodontics, School of Dentistry, Tabriz University of Medical Sciences, Tabriz, Iran.
Dental and Periodontal Research Center, Faculty of Dentistry, Tabriz University of Medical Sciences, Tabriz, Iran.
Int J Dent. 2021 Sep 27;2021:9977478. doi: 10.1155/2021/9977478. eCollection 2021.
The dimensional accuracy of casts is essential in the quality of fixed prosthesis treatment, whereby the impression method is a very crucial factor affecting it. The aim of this in vitro study is to compare the dimensional accuracy of casts resulting from two types of silicone impression materials in different impression techniques and frequent times of cast preparation.
A metal model was made from two prepared abutments, and 10 casts were prepared from each material technique ( = 40). The impressions were made by condensation and addition silicone (one-stage and two-stage impressions). The casts were made from same impressions 1 h, 24 h, and 14 days. The diameter, height, and the distance between two dies were recorded. Data were analyzed by repeated measure ANOVA ( value <0.05).
The dimensional accuracy of all four materials techniques of impression (diameter, height, and the distance between dies) was the same in different times of impression. Dimensional accuracy of the die diameter and distance between dies in one-stage (Speedex) condensation silicon and one-stage (Panasil) addition silicone did not differ significantly, and their one-stage method developed more accurate casts compared to the two-stage method of the same impression material. The height of the casts prepared from the one-stage method through Speedex and Panasil did not differ significantly from the two-stage method of the same impression material.
One-stage condensation silicone and one-stage addition silicone material techniques offered the maximum dimensional accuracy in the obtained casts. The time of impression did not have any significant effect in the accuracy of any of the four impression material techniques.
模型的尺寸精度对于固定修复治疗的质量至关重要，而印模方法是影响其的一个非常关键的因素。本体外研究的目的是比较两种类型的硅橡胶印模材料在不同印模技术和不同模型制备次数下所得到模型的尺寸精度。
由两个预备好的基牙制作金属模型，每种材料技术制备10个模型（共40个）。使用缩合型和加成型硅橡胶制作印模（一步法和两步法印模）。在1小时、24小时和14天后，由相同的印模制作模型。记录模型的直径、高度以及两个铸模之间的距离。采用重复测量方差分析进行数据分析（P值<0.05）。
在不同的印模时间下，所有四种印模材料技术（直径、高度和铸模之间的距离）的尺寸精度相同。一步法（Speedex）缩合型硅橡胶和一步法（Panasil）加成型硅橡胶的铸模直径和铸模之间距离的尺寸精度无显著差异，并且与相同印模材料的两步法相比，它们的一步法制作出的模型更精确。通过Speedex和Panasil一步法制备的模型高度与相同印模材料的两步法制备的模型高度无显著差异。
一步法缩合型硅橡胶和一步法加成型硅橡胶材料技术在所获得的模型中提供了最大的尺寸精度。印模时间对四种印模材料技术中的任何一种的精度均无显著影响。
