Accordingly, the extended-pour alginates have been developed with the ability to maintain the dimensions of the impressions stable through the extended storage time intervals. In some instances, the process of immediate/early pouring could relatively be impossible especially if the impression is planned to be transferred to a dental laboratory. Knowing the former fact mandates the immediate or even early pouring of the irreversible hydrocolloid impressions in gypsum. These inherited phenomena are obviously dependent on impression’s ambient storage condition and time. However, the dimensional instability in response to the syneresis and imbibition phenomena is considered the main drawback of the conventional version of the alginates. The cost effective and easily manipulated irreversible hydrocolloids are one of the most frequently used impression materials in everyday dental practice. Regardless the modern digital approaches, regular dental impressions are still the most reliable method to obtain gypsum casts with an acceptable degree of precision. Accordingly, selection of both impression and cast materials seems critical for optimum biological, functional, and esthetical treatment outcomes. Obtaining successful dental prostheses requires accurate reproduction of soft and hard oral tissues. Spray-disinfection using 5.25% sodium hypochlorite affects the surface details of casts obtained from conventional and extended-pour alginates adversely. Extended-pour alginates offer casts with superior surface details following their immersion disinfection and 120 h of storage. ConclusionĪll alginates materials offer comparable cast dimensions under different testing circumstances. Immersion-disinfected extended-pour alginates produced casts with better detail accuracy following 120 h of storage ( P < 0.05). Generally, casts obtained from spray-disinfected impressions showed lower detail accuracy ( P < 0.05). ResultsĪll gypsum casts exhibited a degree of expansion however, the recorded expansion values did not differ between test categories ( P > 0.05). 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. The dimensional stability and the surface detail reproduction were indirectly evaluated under low angle illumination on the resulted gypsum casts. These impressions were subjected to none, spray and immersion disinfection before their storage in 100% humidity for 0, 72 and 120 h. Two hundred and forty three hydrocolloid impressions were made from one conventional (Tropicalgin) and two extended-pour (Hydrogum 5 and Chromaprint premium) alginates. 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. No data confirmed the ability of these materials to maintain their dimensions and the reproduced oral details following their chemical disinfection. Manufacturers of the extended-pour alginates claimed their dimensional stability through prolonged storage.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |