The evaluation of wear of gypsum type III in cast from alginate impressions after disinfecting by spray or immersion technique

Abstract

Disinfection of alginate impressions by immersion or spraying method with disinfecting agents is considered for effective infection control. The purpose of this study was evaluation of wear of type III stone casts made from alginate impressions after being disinfected by spray or immersion methods.Meterials and Methods: Four common disinfecting agents (5.25% Sodium hypochlorite, 2% Glutaraldehyde , Micro 10 and Deconex) were selected and the samples were divided into four groups of 40 subjects with two subgroups of 20 subjects and a group of 20 subjects were selected as control group (totally 180 casts). Each groups were disinfected with one of disinfecting agents and each subgroup disinfected with spraying or immersion method. The control group was not disinfected . After disinfecting impressions, they were poured standardly with stone plaster. The casts were separated from trays after 45 minutes and maintained in a dry environment for 24 hours and were weight with Digital a balance before wear test and then provider wear machine were used and samples were weight again. Wear rate were calculated with comparision of sample weight before and after of wearing. Data were analyzed by using descriptive statistical tests , ANOVA & DUN CAN with SPSS/15 statistical soft ware . Results: There were statisticaly significant differences between different groups in the mean of Surface wearing. Spraying or immersioning by Micro 10 and spraying by 5.25% sodium hypochlorite had the least wear and spraying and immersion by Deconex caused the greatest wear. Conclusions: In the limitation of our study, it is advised to disinfecting the alginate impression by Micro 10 with sprary or immersion methods and by is 5.25% sodium hypochlorite with spraying .