The accuracy of gypsum casts obtained from the disinfected extended-pour alginate impressions through prolonged storage times

Abstract

Background Manufacturers of the extended-pour alginates claimed their dimensional stability through prolonged storage. No data confirmed the ability of these materials to maintain their dimensions and the reproduced oral details following their chemical disinfection. Therefore, this study evaluated the dimensional stability and surface detail reproduction of gypsum casts obtained from disinfected extended-pour alginate impressions through different storage time intervals. Methods Two hundred and forty three hydrocolloid impressions were made from one conventional (Tropicalgin) and two extended-pour (Hydrogum 5 and Chromaprint premium) alginates. These impressions were subjected to none, spray and immersion disinfection before their storage in 100% humidity for 0, 72 and 120 h. The dimensional stability and the surface detail reproduction were indirectly evaluated under low angle illumination on the resulted gypsum casts. At α = 0.05, the parametric dimensional stability data were analyzed using One-Way ANOVA and Tukey’s comparisons, while the nonparametric detail reproduction data were analyzed using KrusKal Wallis and Mann–Whitney's tests. Results All gypsum casts exhibited a degree of expansion; however, the recorded expansion values did not differ between test categories (P > 0.05). Generally, casts obtained from spray-disinfected impressions showed lower detail accuracy (P < 0.05). Immersion-disinfected extended-pour alginates produced casts with better detail accuracy following 120 h of storage (P < 0.05). Conclusion All alginates materials offer comparable cast dimensions under different testing circumstances. Extended-pour alginates offer casts with superior surface details following their immersion disinfection and 120 h of storage. Spray-disinfection using 5.25% sodium hypochlorite affects the surface details of casts obtained from conventional and extended-pour alginates adversely.

A Promising Potential of Brown Algae Sargassum polycystum as Irreversible Hydrocolloid Impression Material

“…As a rule of thumb, the concentration value will be greatly influenced by the molecular weight of the alginate. The higher the molecular weight, the higher the viscosity [2,14]. Previously published studies reported that the viscosity of dental impression material can be increased if the extraction of potassium alginate is carried out using freshly harvested seaweed [16,23,24].…”

“…Impression procedure is one of the most crucial steps in producing successful dental appliances, indirect restorations, and prostheses particularly in the orthodontic and prosthodontic field [1][2][3]. The impression material is especially beneficial for molding serrated jaws or partial edentulous jaws to obtain a dental cast for master study [1,4].…”

“…Ideal criteria for impression material should meet these requirements: adaptive to the oral tissues, viscous enough to be loaded in the tray, set into rubbery or rigid solid in a reasonable amount of time, dimensionally stable, and biocompatible [2,8]. Recently, irreversible hydrocolloid (alginate) is the most popularly used impression material in dental field owing to its excellent clinical and physical properties including ease of handling in processing, highly acceptable recording of details, minimum equipment necessary, and flexibility of setting time [6,9].…”

“…Moreover, alginate is considered inexpensive and well tolerated by patients, with favorable aroma and taste [1,8]. Despite the advantages of this material, the hydrophilic nature of alginate causes its dimensional stability to diminish over time due to water absorption (imbibition) and water release (syneresis) phenomena [1,2,9]. In order to prevent deformation, some studies recommended pouring the mold immediately or within a few minutes of being removed from the mouth [1,2,5,10,11].…”

“…Despite the advantages of this material, the hydrophilic nature of alginate causes its dimensional stability to diminish over time due to water absorption (imbibition) and water release (syneresis) phenomena [1,2,9]. In order to prevent deformation, some studies recommended pouring the mold immediately or within a few minutes of being removed from the mouth [1,2,5,10,11]. In an attempt to argue the criteria for an ideal impression material, some researchers were keen to formulate a new irreversible hydrocolloid impression material [12,13].…”