Related Experiment Video
Updated: May 17, 2026
Improved Enzyme Protection Assay to Study Staphylococcus aureus Internalization and Intracellular Efficacy of Antimicrobial Compounds
Published on: September 8, 2021
A Comparison between the Antimicrobial Effects of Triple Antibiotic Paste and Calcium Hydroxide Against Entrococcus
Alireza Adl1, Nooshin Sadat Shojaee, Mohamad Motamedifar
1Department of Endodontics, Dental School, Shiraz University of Medical Sciences, shiraz, Iran.
Introduction:
The purpose of this study was to determine the in vitro antimicrobial ability against Entrococcus (E.) faecalis of triple antibiotic paste and its components compared with calcium hydroxide mixtures.
Materials And Methods:
An agar well diffusion assay and MIC method were used to determine the efficacy of the experimental medicaments in removing E. faecalis. Medicaments were divided into 9 groups; triple antibiotic powder with saline or chlorhexidine, metronidazole, ciprofloxacin, minocycline antibiotics were also separately tested (with normal saline), and Ca(OH)2 (plus normal saline or 2% chlorhexidine). These medicaments were evaluated at four concentrations of 25, 50, 100 and 200 μgram per mL in an agar well diffusion test. The diameters of the growth inhibition zones for each group were recorded and compared. The minimum inhibitory concentrations (MIC) of tested medicaments that are required to kill E. faecalis were also determined. The differences between groups were analyzed by Kruskal-Wallis and Mann-Whitney U tests.
Results:
The largest inhibition zones were observed for the triple antibiotic mixture/saline, triple antibiotic mixture/2% chlorhexidine and minocycline/saline, and the smallest for Ca(OH)(2)/saline, Ca(OH)(2)/2% chlorhexidine. Concentration increases produced greater antibacterial effects in all groups. The MIC determination method showed similar results.
Conclusion:
The results suggest that the triple antibiotic paste with either 2% chlorhexidine or normal saline would be the preferred medicament against E. faecalis and, among its three components, minocycline has the greatest antibacterial effect.
Insights
Triple antibiotic paste with saline or chlorhexidine demonstrated superior antimicrobial activity against Enterococcus faecalis compared to calcium hydroxide. Minocycline showed the most potent antibacterial effect among the triple antibiotic components.
Area of Science:
- Endodontics
- Microbiology
- Infectious Diseases
Background:
- Enterococcus faecalis is a common pathogen in persistent root canal infections.
- Calcium hydroxide (Ca(OH)2) is a widely used intracanal medicament.
- Triple antibiotic paste (TAP) is an alternative intracanal medicament with broad-spectrum antimicrobial properties.
Purpose of the Study:
- To compare the in vitro antimicrobial efficacy of TAP and its components against E. faecalis.
- To evaluate the efficacy of Ca(OH)2 mixtures against E. faecalis.
Main Methods:
- Agar well diffusion assay and minimum inhibitory concentration (MIC) method were employed.
- Medicaments tested included TAP (with saline or chlorhexidine), individual antibiotics (metronidazole, ciprofloxacin, minocycline), and Ca(OH)2 (with saline or chlorhexidine).
- Antibacterial activity was assessed at various concentrations (25-200 μg/mL).
Main Results:
- TAP with saline or 2% chlorhexidine exhibited the largest inhibition zones against E. faecalis.
- Minocycline alone also demonstrated significant antibacterial effects.
- Ca(OH)2 mixtures showed the smallest inhibition zones.
- Increased concentrations of medicaments enhanced antibacterial effects.
Conclusions:
- TAP, particularly when combined with saline or 2% chlorhexidine, is a highly effective medicament against E. faecalis.
- Minocycline is the most potent antibacterial component within TAP against E. faecalis.
- These findings support the use of TAP as an effective intracanal medicament for treating E. faecalis infections.
Related Concept Videos
01:28Antimicrobial Effectiveness
01:25Clinical Significance of Antibiotic Resistance