Dimensional stability of impression elastic materials: an in vitro study

Abstract

OBJECTIVE: The aim of this in-vitro study is to be able to provide useful information to implementadequate preservation of the impression before and during sending to the appropriate dental prostheticlaboratories, allowing good management of the materials used and the time spent in the chair.MATERIALS AND METHODS: The study evaluated a total of 210 specimens, of which 168 alginatespecimens and 42 silicone specimens, taking a total of 18,228 measurements. The dimensional stabilitywas assessed by measuring linear dimensions and the weight at certain time points.RESULTS: The effects within the sample group due to the time factor, the combination of timeand alginate, the combination of time and environment are significantly important, both for LinearDimension and for Weight. The effects of the factors between groups, “type of alginate” and “type ofenvironment” are also significant. For silicones, the storage temperature and the type of mixing werenot considered as factors that can influence their behavior. On the other hand, the combination of timeand silicone is significant in the linear dimension, in fact the various types of silicone vary over time indifferent ways. Instead, the interaction between time and the type of conservation environment does notgenerate significant differences.CONCLUSION: This first hypothesis has been refused, the data obtained show that the variousbrands of alginates on the market demonstrate different characteristics of stability as a function oftime. The second hypothesis was confirmed by the data obtained, in fact the impressions made withsilicones can be stored at room temperature in airtight containers even up to 30 days without excessivedimensional variations.