STUDIES ON SYNERESIS AND IMBIBITION IN REVERSIBLE HYDROCOLLOID

¹ Department of Dental Materials, Indiana University School of Dentistry, Indianapolis, Ind.

1. A method for quantitatively determining the changes in water content of reversible hydrocolloid materials in various storage media has been described.

2. Changes were induced by storage in any medium with the magnitudes being dependent on the nature of the environment and the storage time. Only slight changes in moisture were observed when materials were stored in 100 per cent humidity. Generally the materials were not as stable in 2 per cent potassium sulphate as in humidity; however, the stability varied with the different brands of hydrocolloid employed. Specimens stored in distilled water exhibited definite increases in moisture content, while the water content of hydrocolloid allowed to remain in air was markedly reduced.

3. As would be expected the greatest portion of these changes occurred at the surface of the specimens with the deeper layers being affected to a lesser extent and only after prolonged storage.