Rehberg H J
Int Dent J. 1977 Jun 2;27(2):146-53.
The flow behaviour of impression materials during impression taking was first investigated, and reference made to the pressure which occurs in the compound. Individual trays of plastic and shellac-bases which could be softened by heating, and a cold-curing tray material were then also examined: (1) for their distortion by slight loads upon the tray walls; (2) for their ability to retain their shape when stored, and (3) their distortion when temporarily warmed to body temperature. It was found that no tray materials, although graded according to type and thickness, can be considered rigid under experimental conditions, since distortions which were in some cases considerable could be measured. In laboratory experiments, the behaviour of the tray was then measured while taking impressions of models and the precision of the impression was examined at the same time. This confirmed the suspicion that the precision of an impression is to a considerable extent related to the tray material used. The smallest alterations were found when using cold-curing plastic material of a sufficient thickness (greater than 2 mm).
首先研究了印模材料在取模过程中的流动行为，并提及了材料中产生的压力。随后还对加热后可软化的塑料和虫胶基个别托盘以及冷固化托盘材料进行了研究：(1) 托盘壁受到轻微负载时的变形情况；(2) 储存时保持形状的能力；(3) 临时升温至体温时的变形情况。结果发现，尽管根据类型和厚度对托盘材料进行了分级，但在实验条件下没有一种托盘材料可被视为刚性材料，因为在某些情况下可以测量到相当大的变形。在实验室实验中，在对模型取模时测量托盘的行为，并同时检查印模的精度。这证实了一种怀疑，即印模的精度在很大程度上与所使用的托盘材料有关。使用足够厚度（大于2毫米）的冷固化塑料材料时，发现变化最小。
