Dimensional Accuracy of Alginate Impressions Using Different Methods of Disinfection With Varying Concentrations

This study investigated the effect of 1% and 5.25% of sodium hypochlorite (NaOCl) as spray and immersion solutions on the dimensional accuracy of an irreversible hydrocolloid impression material. Impressions of master models were taken using irreversible hydrocolloid impression material, which was then treated with NaOCl 1% or 5.25% solution, either by spaying or immersion, for 5 minutes, or not treated to act as control. The impressions were then poured with stone, and the dimensional accuracy was determined from the mean of six measurements taken between fixed points using a digital caliper. No significant dimensional changes of gypsum casts obtained from irreversible hydrocolloid impression material sprayed with NaOCl solution were observed, whereas significant change in dimensional accuracy occurred when the casts were immersed in NaOCl solution. Based on dimensional stability alone it would be more appropriate to disinfect irreversible hydrocolloid impression material by spraying it with NaOCl solution rather than immersing it.