Chemical analysis and microstructure examination of extended-pour alginate impression versus conventional one (characterization of dental extended-pour alginate)

Alginate impressions are not dimensionally stable. The recommended storage time for a conventional alginate is maximum 30 min. However, extended-pour alginate exhibits dimensional stability up to 100 h. For better understanding of the nature of extended-pour alginate, chemical analysis was performed by X-ray florescence spectrometer, compared to conventional alginate. Fourier transform infrared spectroscopy was used to determine the functional groups of both alginates. The organic content weights and microstructures were assessed. The higher Ca:Na ratio, lower organic content, and higher powder: water ratio might contribute in increasing the dimensional stability of the extended-pour alginate. Neither the functional groups nor the microstructure differed between both types.