Effects of disinfection procedures on surface quality of compound impressions and the resultant gypsum casts.

Abstract

Objective: To evaluate the effects of disinfection procedures on the detail reproduction of type I impression compound and the surface quality of the gypsum casts poured against the disinfected impressions. Materials and methods: To make the specimens for detail reproduction test, thirty-five compound impressions of a brass test block (ADA Specification no. 3) were made. These impressions were divided into 7 groups. Five impressions were randomly chosen for each of the disinfectant-method combinations and control groups. For the six experimental groups, impressions were disinfected using either spraying with or immersion in 2.4% glutaraldehyde (Cidex), or 1: 213 iodophor (IodoFive) or 0.525% sodium hypochlorite (Hi-chlor). Five non-disinfected impressions served as controls. Each impression was visually evaluated for detail reproduction before and after disinfection and then poured with Type III dental stone. The resultant stone casts were evaluated for detail reproduction. To assess the surface roughness of the stone specimens, another thirty-five compound impressions of a glass slide were made and five impressions were randomly chosen to subject to each disinfection protocol as described in the detail reproduction test. All impressions were poured with dental stone. The surface roughness of the casts was recorded using a profilometer. The average surface roughness was compared using Tukey HSD test at 95% confidence interval. Results: The surfaces of compound impressions did not deteriorate after disinfection with Cidex or IodoFive but deterioration was noted after spraying with or immersion in Hi-chlor. The stone casts obtained from Cidex and IodoFive groups showed smooth surfaces and continuous fine lines while degradation of the casts occurred when compound impressions were subjected to Hi-chlor. The average surface roughness of the casts obtained from Hi-chlor spray and immersion were significantly different from each other and from the remaining groups (p<0.05). Conclusion: Cidex and IodoFive using as spray or immersion disinfection did not deteriorate the surfaces of compound impressions and the stone casts. Loss of surface detail and surface porosity could be observed after disinfection with Hi-chlor.