Kumar Sandeep, Yadav Deepti, Yadav Reena, Arora Aman
Department of Prosthodontics, Jan Nayak Ch. Devi Lal Dental College, Sirsa, India.
Indian J Dent Res. 2014 Mar-Apr;25(2):184-7. doi: 10.4103/0970-9290.135916.
This study was aimed to determine the effect of various tray spacer thickness and subsequent repeated pours on the accuracy and dimensional stability of the impression made from monophasic polyvinyl siloxane material.
Custom trays with different spacer thickness (2, 4 and 6 mm) were used for making an impression of a master model simulating 3 unit fixed partial denture with monophasic polyvinyl siloxane material. These impressions were poured with die stone and repoured. Distance between the reference points were measured and subjected to statistical analysis.
Casts obtained from 1 st , 2 nd and 3 rd pour of the impression in 2, 4 and 6 mm spacer thickness tray have similar dimensional accuracy amongst each other and with the master model except in molar diameter and inter-abutment distances of cast obtained from 6 mm spacer thickness tray.
The vertical distance of stone dies were decreased, whereas horizontal distance increased as the thickness of impression material is increased. There were statistically non-significant changes occurring among the repeated pours in 2, 4 and 6 mm spacer thickness.
2 and 4 mm spacer thickness are acceptable for making an impression for three unit fixed partial denture with monophasic polyvinyl siloxane material and it was not affected by two subsequent (1 st and 2 nd) repeated pours.
本研究旨在确定不同托盘间隔厚度以及随后的重复灌注对单相聚硅氧烷材料印模的准确性和尺寸稳定性的影响。
使用具有不同间隔厚度（2、4和6毫米）的定制托盘，用单相聚硅氧烷材料对模拟3单位固定局部义齿的主模型制取印模。这些印模用石膏灌注并再次灌注。测量参考点之间的距离并进行统计分析。
在2、4和6毫米间隔厚度托盘中，印模第一次、第二次和第三次灌注所获得的铸型彼此之间以及与主模型相比，除了6毫米间隔厚度托盘所获得铸型的磨牙直径和基牙间距离外，具有相似的尺寸精度。
随着印模材料厚度增加，石膏模型的垂直距离减小，而水平距离增加。在2、4和6毫米间隔厚度的重复灌注之间发生的变化在统计学上无显著意义。
对于用单相聚硅氧烷材料制取3单位固定局部义齿的印模，2和4毫米的间隔厚度是可接受的，并且不受随后两次（第一次和第二次）重复灌注的影响。
