Dimensional accuracy of irreversible hydrocolloid impressions disinfected with ozonated water

Disinfection of dental impressions is an essential step in dental infection control. The aim of this study was to evaluate dimensional accuracy of an irreversible hydrocolloid impression material after disinfection with either immersion in or being sprayed on by ozonated water. In this in vitro study, 50 irreversible hydrocolloid impressions were made from an acrylic maxillary model including 4 Straumann abutment analogues and divided into 5 groups: control group, groups with 5 and 10 minutes of immersion in an ozone solution, and groups with 5 and 10 minutes of ozone solution sprayed on (n = 10). The impressions were then poured in type IV dental stone. Dimensions and distances of stone dies in each group were measured using Coordinate Measuring Machine with an accuracy of 1 micrometer. Percentages of dimensional changes in the diameter and height of the dies and the distances between them were statistically analyzed using ANOVA, one-sample t-test and paired t-test (α = 0.05). One-way ANOVA did not reveal any significant differences in dimensional changes between the test and control groups. Diameters and heights of the dies in all the groups decreased in comparison to the model. One-sample t-test showed that except for the height of the die without undercut in groups of 5- and 10-minute spray (p value = 0.01 and p value = 0.02) and the diameter of the die with undercut in the 10-minute spray group (p value = 0.02) there were no significant differences in any of the dimensions in comparison with the model. Paired t-test did not show any significant differences between dimensions of the dies with and without undercuts between the groups under study. The accuracy of irreversible hydrocolloid impressions is not affected by immersion in ozonated water. Spraying for 5 and 10 minutes will lead to smaller dies.