Disinfecting efficacy of three chemical disinfectants on contaminated diagnostic instruments: A randomized trial

CONTEXT: Cross infection remains one of the major challenges in the dental profession, especially in field settings. Transmission of hepatitis B, hepatitis C, and human immunodeficiency virus have raised a major concern for patients and dental staff. These risks can be eliminated by effective sterilization and disinfection techniques. AIM: The aim was to compare the disinfecting efficacy of three chemical disinfectants on contaminated diagnostic instruments. SETTINGS AND DESIGN: This was a randomized, cross over trial conducted among three participants selected from a research laboratory, Bhopal, Madhya Pradesh, India. MATERIALS AND METHODS: The study participants were examined 4 times on different days. Each time, the coded mouth mirrors of different make were used, and the disinfection was accomplished using coded disinfectants. The reduction in total viable count was compared between the three groups (2% glutaraldehyde, 6% hydrogen peroxide (H(2)O(2)) and 99.9% ethyl alcohol) with distilled water as negative control and autoclaving as a positive control. Furthermore, the predisinfection count was compared between the instruments of different make. STATISTICAL ANALYSIS USED: Statistical analysis was performed using paired t-test and One-way ANOVA. The statistical significance was fixed at 0.05. RESULTS: Autoclaved instruments resulted in complete elimination of viable micro-organisms. Maximum reduction in microbial load was observed after disinfection with H(2)O(2) followed by glutaraldehyde, ethyl alcohol and distilled water in descending order. Furthermore, maximum microbial contamination was recorded on locally manufactured mirrors, while standard plain mirrors showed least contamination. CONCLUSIONS: Although, a significant reduction in total viable count was observed with all the disinfectants evaluated in the present study, none of the disinfectants was successful in completely eliminating the viable micro-organisms.