Dimensional change of impression materials for dental prothesis using different measuring methods

Abstract

The aim of this study was to verify the effectiveness of alternative techniques for measuring the linear dimensional change of molds obtained by different impression materials. A stainless-steel die containing three lines was used to get the impressions. The impression materials were handled according to the manufacturers' instructions. After gelation/polymerization time, the molds (n=12) were stored for 30 minutes and the lines were subsequently measured using: a microscope (Olympus Measuring Microscope STM; Olympus Optical Co) with a 30x magnification (MM, control group), a digital caliper (Mitutoyo Digimatic; Kawasaki) (DC) and digitization using a digital camera (Canon EOS Rebel 3Ti; Canon) (DI). For each mold, a mean of the length of the lines was obtained. For each impression material, the difference in the length between the metallic matrix and the mold was considered as linear dimensional change (%). The data were submitted to the non-parametric Kolmogorov-Smirnov test, followed by one-way Analysis of Variance (ANOVA) for each material, and the means were compared by the Tukey test (α=0.05). The DI group promoted values of dimensional accuracy without significant differences with the control group (MM), except for the putty-body condensation silicone. The DC group showed significant differences for MM and DI groups for all impression materials tested. The DI group showed to be a reliable methodology (Standard error of the mean <10%) to measure the linear dimensional change of all impression materials. The DI group presented molds with linear dimensional change values without significant differences with MM group, except for the putty-body addition silicone. The digitization is a reliable methodology to evaluate the linear dimensional changes of molds made with impression materials, except for the putty-body elastomeric impression materials.

Effect of inter-dental abutment distance on the impression accuracy of digital and conventional methods

“…ital and conventional impression accuracy, its impact on digital and conventional impressions has been studied comparatively in many studies [42,43]. Based on the results of our study, the inter-dental abutment distance difference between the two impression methods was significant.…”

The Effect of Cassava Starch and Modified Cassava Starch on Dimension Stability of Alginate Impression

“…19, which is that the linear dimensional change of irreversible hydrocolloid impression material must not exceed 1.0%. 24,25 The smallest percentage of dimensional change is found in alginate with the addition of 40% modified cassava starch. It indicates that alginate with the addition of modified cassava starch results in a more stable mold than alginate with the addition of 40% cassava starch and pure alginate.…”

Comparative analysis of dimensional changes in autoclavable polyvinyl siloxane (PVS) impressions under various Sterilization/Disinfection Protocols: A randomized controlled trial

“…The main advantage of this method is its precision in measuring the linear distance between two points in a specimen. Furthermore, measurements conducted following ISO standards are considered scientifically acceptable ( Oliveira et al, 2021 ). The stereomicroscope was used with a mechanical stage to measure the inter- and intra-abutment distances of the dental impressions.…”