Linear dimensional stability of irreversible hydrocolloids with and without disinfection at different storage times

Irreversible hydrocolloids have been used in dental practice for decades and their pouring time has been suggested to be as short as possible; however the latest generation of alginates exhibit better properties, which could influence the fidelity of the casts. Objective: To evaluate the linear dimensional stability of stone casts obtained using two irreversible hydrocolloid brands (Cavex ColorChange and Jeltrate) after disinfection. Material and methods: Samples were divided into 16 groups (n = 10) according to brand, storage time and disinfection. Impressions were taken of a metallic master model made of stainless steel with two abutments. Cast models were obtained using type IV gypsum, after disinfection with sodium hypochlorite at 1% or without any disinfection followed by storage for four different times (immediate pouring, and after 24, 72 or 120 hours storage after obtaining the impressions) and the models were measured with a digital caliper. Data were submitted to ANOVA 3-way followed by Tukey’s test (α < 0.05). Results: A statistically significant difference was detected with Jeltrate Plus after 72 and 120 hours in storage (with and without disinfection), as well as Cavex without disinfection. Differences were found for Cavex with disinfection/24 hours storage, when compared to immediate pouring (P < 0.05). The alginates presented similar behavior regarding disinfection for the same time (P > 0.05). Conclusion: Storage longer than 24 hours affects the fidelity of casts. Disinfection does not promote significant alteration at any of the experimental times with either material.