A simple and effective method for addition silicone impression disinfection

Abstract

Purpose: Although dental impression disinfection is determinant to reduce the cross-infection risk, some studies have shown that, in real practice, the disinfection procedures vary considerably. Thus, the aim of this study was to evaluate the antimicrobial effectiveness and the impact on the dimensional stability of addition silicone' impressions of water wash and the most clinically used disinfection solutions: 3% hydrogen peroxide, commercial disinfectant MD520 (Durr) and 1% and 5.25% sodium hypochlorite.

Materials and methods: For this investigation, dental impressions were taken on 16 volunteer dental students. The antimicrobial effectiveness of each procedure was evaluated by pour plate method. The dimensional stability was evaluated using a standardized stainless-steel model, according to ANSI/ADA nº19 specification.

Results: The study results showed that water wash does not alter the dimensional stability of addition silicone impressions but doesn't reduce the microbial load of the material (P>.05). On the other hand, addition silicone disinfection by immersion with 3% hydrogen peroxide, MD520 (Durr), or sodium hypochlorite at 1% and 5.25% does not alter the dimensional stability significantly but reduces > 99.9% of the microbial load of the impressions (P<.001).

Conclusion: Addition silicone impressions should always be disinfected after water wash in order to reduce effectively the cross-infection risk. All disinfectants tested showed high antimicrobial efficiency without significant changes in three-dimensional shape of impressions. Hydrogen peroxide and sodium hypochlorite are of particular importance because are easily accessible in dental setting. The less explored hydrogen peroxide could be a valuable alternative for silicone impressions disinfection.

Keywords: Disinfection; Hydrogen peroxide; Silicone elastomers; Sodium hypochlorite.

Fig. 1. Scheme of the standard model surface and geographic reference to side A, which consists on 3 parallel lines with 25000 µm long, and side B, represented by 2 parallel lines with 5000 µm long.

Fig. 2. Microbial adhesion on silicone impressions, after the different treatments. Bars represent mean and the error bars represent standard error of the mean. ^*P < .001 vs control and ^#P < .001 vs water wash 30 s. Both P values were calculated using Kruskal-Wallis test, and the significance values were adjusted by the Bonferroni correction for multiple comparisons.

Fig. 3. Dimensional changes measured on sides A and B, after the different treatments. Bars represent mean and the error bars represent standard error of the mean.