Effect of disinfection on gypsum casts retrieved from addition and condensation silicone impressions disinfected by immersion and spray methods

Introduction: The standard procedure of rinsing impressions under running tap water immediately after removal from the mouth eliminates cross contamination along with most saliva and blood. However not all micro-organisms are removed, they can be a source of infection. Surface disinfection to inactivate infectious agents would reduce the potential for disease transmission to dental personnel from contaminated impressions. Aim and Objectives: The objective was to evaluate the effect of disinfection on gypsum casts retrieved from disinfected addition and condensation silicone impressions by spray and immersion methods using various disinfectants. Materials and Methods: Twenty four impressions of each type of silicone material were made from a master model. In each group, 18 of the impressions were disinfected, while the other 6 impressions were considered as a control. The impressions were then rinsed for approximately 10 s under cold tap water and disinfected by an immersion or spray method for 10 min. All impressions were poured in Type IV die stone using a double-pour technique. Results: The dimensional stability of the impressions was evaluated using a travelling microscope and the surface roughness (Ra) was assessed using a perthometer (M1 - Mahs). The means of dimensions and surface roughness were calculated and statistically analyzed using ANOVA. Conclusion: The disinfection procedure didn't show significant changes on dimensional stability and surface roughness of gypsum casts retrieved from disinfected addition and condensation silicone impressions by immersion and spray methods.