Do Different Proportions of Antibiotics in the CTZ Paste Interfere with the Antimicrobial Action? In Vitro Study

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.