Evaluation of Outgassing, Tear Strength, and Detail Reproduction in Alginate Substitute Materials

Abstract

Alginate substitute materials are inexpensive polyvinyl siloxane (PVS) impression materials that exhibit better detail reproduction and tear strength than alginate. Alginate substitute materials do show slightly more outgassing and resulting cast porosity than traditional alginates, particularly when they are poured soon after mixing. To reduce cast surface porosity, a minimum pouring delay of 60 minutes is suggested. SUMMARYObjective: To compare three alginate substitute materials to an alginate impression material for cast surface porosity (outgassing), tear strength, and detail reproduction.Materials and Methods: Detail reproduction tests were performed following American National Standards Institute/American Dental Association (ANSI/ADA) Specification No. 19. To measure tear strength, 12 samples of each material were made using a split mold, placed in a water bath until testing, and loaded in tension until failure at a rate of 500 mm/min using a universal testing machine. For cast surface porosity testing, five impressions of a Teflon mold with each material were placed in a water bath (37.88C) for the in-mouth setting time and poured with vacuum-mixed Silky Rock die stone at 5, 10, 30, and 60 minutes from the start of mixing. The gypsum samples were analyzed with a digital microscope for surface porosity indicative of hydrogen gas release by comparing the surface obtained at each interval with four casts representing no,

Alginate Substitute as a Promising Impression Material for Dental Implant Restorations: A Comparative In-vitro Study

“…The present study found in both groups, the percentages of deviations and the absolute changes (in µm) from typodont model for PVS impression material were less compared to those of alginate substitute impression material however, the differences were not statistically significant. This finding supported the dimensional stability of alginate substitute impression material that was reported by Baxter et al [28] Although, the PVS still the material of choice for multiunit implant restoration according the recommendation of Schmidt et al (2018), who reported that the impression material had the greatest effect on the impression accuracy and recommended the polyvinyl siloxane impression materials for multiunit restoration supported by non-parallel dental implants. [34] In contrast to previous findings, researchers found that, the PVS was not superior to other irreversible hydrocolloid materials if splinted impression coping technique was used for impression of multiunit implant restoration.…”

“…These impression materials have been reported to offer improved detail reproduction, tear strength, and dimensional stability. [28] In the present study, it was found that there was no statistical significance difference between the open and closed tray impression techniques using the monophase PVS material. This is in agreement with the findings of Osman et al and Wenz et al [29,30] In contrast, Daoudi et al and AlQuran et al found that the open tray impression technique was more accurate and significantly superior to closed tray impression technique.…”

Impression Material Selection and Soft Tissue Management in Contemporary Fixed Prosthodontics

“…Alginate substitutes. These substances have better mechanical properties than conventional alginate [11]. Alginate substitutes are of a lower cost than traditional PVS, but more expensive than alginate.…”

Surface detail reproduction and dimensional stability of contemporary irreversible hydrocolloid alternatives after immediate and delayed pouring

“…Recent studies have reported that these two irreversible hydrocolloid alternatives were more accurate with regard to the surface detail reproduction and they were dimensionally stable over an extended period. [ 26 27 28 29 ] However, the number of laboratory and clinical investigations on these materials is much lower than the number of studies on traditional irreversible hydrocolloids.…”