Impression Disinfection and Its Effect on Dimensional Accuracy and Surface Detail in the Times of COVID-19: An In Vitro Study

Introduction The disinfection of impressions is crucial to eliminate the viral and other microbial loads to prevent the cross contamination of diseases. The aim of this study was to compare the effect of different virucidal disinfecting methods on the dimensional accuracy and surface detail reproduction (SDR) of impression materials. Methods A total of 160 samples were fabricated with different impression materials using zinc oxide eugenol (Group 1), alginate (Group 2), polyether (Group 3), and addition silicone (Group 4) impression materials, each containing 40 samples (n=40). These groups were further divided into Subgroups A, B, C, and D (n=10) based on the disinfecting method used. Disinfection was carried out using 0.2% peracetic acid (A), a natural polymer of glucosamine (B), ultraviolet (UV) radiation (C), and ozonated water (D). The disinfected impressions were poured in type IV gypsum, and the obtained casts were checked for dimensional accuracy and surface detail reproduction (SDR). For dimensional accuracy, a one-way analysis of variance (ANOVA) test and, for surface detail reproduction, the chi-square test were used to compare the different subgroups of each impression material separately. Results Zinc oxide eugenol samples showed the lowest mean dimensional change when disinfected with 0.2% peracetic acid (1A=154.1 mu m), and alginate showed the lowest mean dimensional change when disinfected using ozonated water (2D=134.9 mu m). On the other hand, the lowest mean dimensional change observed in polyether and addition silicone samples was those which were disinfected using UV radiation (3C=100.9 mu m and 4C=113.5 mu m). Surface detail was reproduced adequately in most of the samples. Conclusion A 0.2% peracetic acid could be used to disinfect zinc oxide eugenol impressions, ozonated water for alginate impressions, and UV radiation for polyether and addition silicone impressions.