Effect of Disinfecting Solutions On The Dimensional Stability of Alginates

Objectives: Alginate impression materials have been used in dentistry to fabricate prosthesis and for treatment planning. It is essential to disinfect the impression materials before they are dispatched to the laboratory for further work. One of the important considerations in terms of disinfection of alginate impression materials is the possible change in dimensional stability when the alginates are subjected to disinfection procedures. The aim of this study was the accurate measurement of dimensional changes, made on samples of defined dimensions. Methods: The samples were prepared in rectangular strips (60x10mm²) with two different thicknesses of 1.5 and 3mm. These measurements were carried out on two alginate [Hyrdogum(Zhermack) and Blue Print Ceramix (Jeltrate®,Dentsply)] impression materials in dry condition and immersed it in disinfectant solutions [Perform I.D and hypochlorite(schulke-mayer)] and distilled water. These measurements were determined at five minute intervals for a period of one hour. Results: 3mm BluePrint Cremix showed greater shrinkage than 3mm Hydrogum. While, 1.5mm Hydrogum appeared to have uniformly greater shrinkage as compared to 1.5mm BluePrint Cremix. There was significant difference between 1.5 and 3mm thicknesses of both Hydrogum and BluePrint Cremix (p≤0.05). The 1.5mm samples showed much higher shrinkage than 3mm samples. Conclusion: Immersion of the alginates in the same disinfectant showed variable linear shrinkage indicating that slight changes in composition could lead to variable results. In addition to that, there were significant difference in the linear shrinkage between the two thicknesses of the same alginate material; this indicates the possibility of distortion in actual impressions where the geometry is complex.