Comparative evaluation of the efficacy of three commercially available disinfectants on irreversible hydrocolloid materials by spray method – an in vitro study

Objective: Present study was carried out to evaluate and compare the efficacy of three most commonly used disinfectants on irreversible hydrocolloid material. Materials and Methods: A total of 60 alginate disks with 13mm diameter and 2mm height were prepared with irreversible hydrocolloid material. These specimens were divided into four groups (n=15), i.e, Group A Distilled Water, Group B Sodium Hypochlorite, Group C Glutaraldehyde and Group D Iodophor. All alginate specimens were contaminated with Staphylococcus aureus strain for 1 min. After contamination Group B, C and D specimens were disinfected by spray method, whereas, group A specimens were only washed with distilled water. All the specimens were placed into the test tubes containing nutrient broth media for 30 sec. 25um of nutrient broth solution was plated on soyabean casein digest agar plates for determination of minimum inhibitory concentration. The number of colonies were identified and colony forming units (CFU) were counted. Between and within group differences in antibacterial activity was analyzed using one way ANOVA test of significance and Post Hoc Test. Result: 53.33% of the samples disinfected with Sodium Hypochlorite and 33.33% of the samples disinfected with Gluteraldehyde showed complete disinfection. All the samples disinfected with Iodophor showed bacterial growth but colonies were countable, whereas, all the samples washed with distilled water showed uncountable bacterial growth. Conclusion: Sodium Hypochlorite is the most effective disinfectant followed by Glutaraldehyde and Iodophor.