Physical properties and compatibility with dental stones of current alginate impression materials

Abstract

This study examined physical properties and compatibility with dental stones of two types of alginate impression materials. Five powder-type alginate impression materials (Alginoplast EM, Aroma Fine, Algiace Z, Coe Alginate, Jeltrate Plus) and a paste-type alginate impression material (Tokuso AP-1) were used. The dynamic viscosity immediately after mixing was measured by means of a controlled-stress rheometer. The gelation times were determined according to Japanese Industrial Standards (JIS) T6505, and recovery from deformation, strain in compression and compressive strength were determined according to the International Organization for Standardization (ISO) specification 1563. Detail reproduction and surface roughness of type III dental stones (New Plastone, New Sunstone) and a type IV dental stone (Die Stone) were evaluated using a ruled test block as specified in the ISO specification 1563 and a profilometer, respectively. The alginate impression materials evaluated in this study were all in compliance with the ISO specification 1563 and JIS T6505. The alginate impression materials had similar mechanical properties after gelation, whilst a wide range of dynamic viscosity immediately after being mixed, gelation times and compatibility with dental stones were found among the materials. The paste-type material had a higher dynamic viscosity and a shorter gelation time than the powder-type materials. The best surface quality was obtained with the paste-type material/type III dental stone cast combinations. The materials should be selected in consideration of initial flow, setting characteristics and compatibility with dental stones. The results suggested that a paste-type material would better meet the requirements of an alginate impression material.

Effect of High-Molecular-Weight Sodium Alginate on the Viscosity and Characteristics of Alginate Impression Materials

“…None of the materials could reproduce the 20 μm-line, which was in accordance with the finding in previous studies that no alginate impression materials that are powder-type can reproduce a 20 μ m-line. 18 The surface roughness of all the experimental materials determined in this study were approximately equal to those reported in past studies, [19][20][21] and not significantly different from the surface roughness of ALF. The results of these two tests indicate that the addition of HWSA has little effect on the compatibility of the materials with dental stones.…”

Digitization of dental alginate impression: Three-dimensional evaluation of point cloud

“…Historically, impressions were taken using non-elastic materials for both soft and hard tissues 1) . Alginate was originally introduced to replace non-elastic materials, particularly for impressions of hard tissues 2) . In general, rubber impressions are used for the production of a stone model (type IV) for fixed dental prostheses.…”

Analysis of filler particle levels and sizes in dental alginates

“…A study comparing dental alginates' inorganic fraction and their mechanical and physical properties was not found in the literature. Differences among materials are not directly related to filler content 6,14 , but it seems to be very important to be considered 2,3,9 . The inorganic particles observed by SEM pictures are cell walls of algae from the division Chrysophyta, class Bacillariophycea.…”

“…Similar to composite resins, the filler fraction may also have an effect on alginate properties. Giordano 2 , Anusavice 3 and Murata et al 9 did not make a correlation between inorganic particles and alginate properties but the authors state that filler size and content are closely related to accuracy and compressive strength results.…”

“…Irrespective of composition, certain physical properties of impression materials are required to warrant clinical success. Elastic recovery, strain in compression, compressive strength, thixotrophy, compatibility with dental stones, surface roughness, tear energy, dimensional stability and hydrophilicity are some of these important properties 5,8,9 . Nonetheless, alginate has some disadvantages as it poorly reproduces surface details, it is not dimensionally stable when stored, and it is usually best poured immediately [1][2][3] .…”