Abstract Objective:

To evaluate the antimicrobial action of the CTZ paste in three different proportions by diffusion in agar with the microorganisms: Enterococcus faecalis,Escherichia coli, and Candida albicans.

Material and Methods:

Three different proportions of antibiotics were tested: GROUP A - CTZ paste in the ratio of 33.33% chloramphenicol + 33.33% tetracycline + 33.33% zinc oxide, mixed with 2 drops of eugenol (1:1:1 ratio); GROUP B - CTZ paste in the proportion of 25% chloramphenicol + 25% tetracycline + 50% zinc oxide, mixed with 2 drops of eugenol (1: 1: 2 ratio); GROUP C - CTZ paste with 13% chloramphenicol + 13% tetracycline + 74% Zinc Oxide, mixed with 2 drops of eugenol (1:1:6 ratio); PC GROUP - Positive Control (0.12% Chlorhexidine); and NC GROUP - Negative Control (0.9% Saline solution). Data were analyzed through descriptive statistics (means and standard deviation). The one-way ANOVA and Tukey's test were used, with a significance level of 5% Results: No statistical differences for Enterococcus faecalis between groups A, B, and C (p = 0.1986) were found. There were statistical differences for Escherichia coli between groups B and C (p = 0.029), and for Candida albicans between groups A and C (p = 0.006). Groups A, B, and C had significant differences with both Positive and Negative Controls for all the microorganisms Conclusion: The three different ratios of CTZ paste showed antimicrobial efficacy against Enterococcus faecalis,Escherichia coli, and Candida albicans microorganisms.