The Effect Of Plasma Treatment On The Candida Albicans On The Surface Of Vinyl Polysiloxane Dental Impression

Test Ⅰ The effect of argon plasma treatment on the candida albicans on the surface of vinyl polysiloxane dental impressionObjective: To evaluate the effect of argon plasma on the candida albicans on the surface of vinyl polysiloxane dental impression.Methods:36 cylinder specimens of vinyl polysiloxane dental impression material were made, inoculated with candida albicans suspension, and randomly divided into 2 groups. All species were subjected to the following treatments:(1) treated with argon plasma for 300 seconds (2) no treatment (control). The efficacy of the disinfection procedure was evaluated by determining the number of colony forming units (CFU) recovered from species.Results: The amount of recovery Candida albicans after argon plasma treatment (136.667±82.676) CFU was reduced significantly compared with the control group (289444.444±90220.137) CFU.99.953 percent of Candida albicans on the surface of vinyl polysiloxane dental impression were killed with argon plasma treatment (p<0.05)Conclusions: The amount of Candida albicans on the surface of vinyl polysiloxane could be reduced significantly by argon plasma treatment. The killing rate with argon plasma dosen’t reach the disinfection standard (99.99%).Test Ⅱ The effect of hydrogen peroxide plasma on candida albicans on the surface of impression with different durationObjective: To evaluate the effect of hydrogen peroxide plasma on candida albicans on the surface of impression within different treating time.Methods: 72 cylinder specimens of vinyl polysiloxane dental impression material were made, inoculated with candida albicans suspension, and randomly divided into 4 groups. Group1:treated with hydrogen peroxide plasma for 100 seconds. Group2: treated with hydrogen peroxide plasma for 200 seconds. Group3:treated with hydrogen peroxide plasma for 300 seconds. Group4:no treatment (control). The efficacy of the disinfection procedures was evaluated by determining the number of colony forming units (CFU) recovered from species.Result: 99.898 percent of candida albicans on the surface of vinyl polysiloxane dental impression were killed after 100 second plasma treatment,99.937 percent of candida albicans were killed with hydrogen peroxide plasma treatment after 200 second plasma treatment, and 99.995 percent of candida albicans were killed with hydrogen peroxide plasma after 300 second plasma treatment.Conclusion:The experimental data indicated that 99.995 percent of Candida on the surface of vinyl polysiloxane dental impression were inactivated with hydrogen peroxide plasma treatment after 300 second. The killing rate with hydrogen peroxide plasma reaches the disinfection standard (99.99%).Test Ⅲ Dimensional accuracy of vinyl polysiloxane dental impression after hydrogen peroxide plasma treatmentObjective: To determinate the dimensional accuracy of plasma treated vinyl polysiloxane dental impression.Methods:A metal model casted by Ni-Cr allegation was used as a master model of the dimensional accuracy test.20 silicone impressions of master model were made and radomly divided into 2 groups. (1) treated with 50% hydrogen peroxide plasma for 300seconds (2) no treatment (control). All impressions were poured with type Ⅳ gypsum and working casts were formed. The distances between reference points on casts were measured using a Digital vernier caliper.Result:There was no significant difference in size between the experiment group and control group(P>0.05).Conclusion:The dimensional accuracy of vinyl polysiloxane dental impressions was not affected by plasma treatment.