Analysis of the dimensional stability of extended-storage irreversible hydrocolloids
The dimensional stability of alginates is poor when comparing to others materials and they should be poured immediately. The manufactures have launched new alginates, called extend-storage alginates, that purpose to be poured up to 5 days. The aim of this study was to evaluate the dimensional stability of two alginates dimensional stable (Cavex ColorChange and Hydrogum 5) and to do a comparative analysis with a conventional alginate (Jeltrate Plus). Materials and methods. It was used a standard model of acrylic resin representing an upper dental arch. Eight impressions were made for each alginate and three different storage times were used: 30 minutes, 48 hours and 96 hours. The distance between two parallels and fixed points in the molds were measured to analyze the dimensional change. The data was analyzed using SPSS 20.0 for windows. The level of significance was set at α=0,05. Results. For Cavex ColorChange and Hydrogum 5 alginates there was no statistically significant difference between the different storage times (p>0.05). Jeltrate Plus alginate suffered significant dimensional changes in different storage times. Although this study showed the delay to pour the mold for Hydrogum 5 and Cavex ColorChange, one can not neglect the care they require including adequate proportion of dust and water and keep the mold under good conditions of moisture. Conclusão. The results suggest that alginates Cavex ColorChange and Hydrogum 5 can be poured on up 96 hours and Jeltrate Plus should be poured immediately.