A Comparative Evaluation of the Influence of Three Different Vehicles on the Antimicrobial Efficacy of Triple Antibiotic Paste against Enterococcus faecalis: An In vitro Study

Comparison of Antibacterial Efficacy of Triple Antibiotic-Loaded Hydrogel Versus Modified Triple Antibiotic-Loaded Hydrogel as Intracanal Medicament Against Enterococcus faecalis: An In vitro Study

OBJECTIVE

Triple antibiotic paste (TAP) is known to have an essential role in the success of endodontic treatment by eliminating pathogens from the root canal system. Unfortunately, it causes discolouration and cytotoxicity at high concentrations. The objective of this research was to assess and compare the antimicrobial effectiveness of various concentrations (1 mg, 5 mg, 10 mg) of TAP, TAP hydrogel (TAPH), M-TAP, and M-TAP hydrogel (MTAPH) against Enterococcus faecalis.

METHODS

The agar well diffusion method was used to assess the antibiotic sensitivity of the following intracanal medicaments: TAP (ciprofloxacin, metronidazole, and minocycline) mixed in a ratio of 1: 1: 1; TAPH, M-TAP (ciprofloxacin, metronidazole, and amoxicillin), M-TAPH and plain hydrogel. Each tested medicament was individually evaluated for its antimicrobial activity against Enterococcus faecalis. Structural and topographical characterisation were analysed using a Scanning Electron Microscope (SEM) and interpreted using ImageJ software. A microdilution broth test was performed to examine the minimum inhibitory concentration and minimum bactericidal concentration (MBC) of M-TAP and TAP.

RESULTS

Except for the plain hydrogel, M-TAP and hydrogel and TAP and hydrogel showed significantly varied inhibitory zones at different concentrations. M-TAPH showed the highest mean zone of inhibition of 21.6, 33.33 and 38.0 mm at a concentration of 1, 5, and 10 mg/mL when compared to TAPH, which showed a mean zone of inhibition of 3.3 mm,12.3 mm, 21.3 mm at the respective concentrations. The MIC study shows that more than 75% of Enterococcus faecalis growth was inhibited by M-TAP at a concentration of 5 μg/mL, whereas TAP showed inhibition at a concentration of 35 μg/mL. MBC results indicate that almost 99.9% of the bacterial population was killed at a concentration of 100 μg/mL (10-1) for TAP and 10 μg/mL (10-2) for M-TAP.

CONCLUSION

The antibacterial efficacy of M-TAP was significantly higher than TAP. Application of M-TAP at lower doses is advised to overcome the disadvantages seen with TAP.

Comparison of Antimicrobial Effects of 445 and 970 nm Diode Laser Irradiation with Photodynamic Therapy and Triple Antibiotic Paste on Enterococcus faecalis in the Root Canal: an In Vitro Study

Background and aim: Colonization of residual organisms in the root canal are major causes of root canal treatment failure. Therefore, the effective removal of organisms during root canal cleaning stages is of great importance. In this study, we aimed to investigate and compare the antimicrobial effects of several methods including high power laser irradiation, photodynamic therapy and triple antibiotic paste (TAP) on Enterococcus faecalis in the root canal. Materials and methods: For the present laboratory study, 80 anterior single canal teeth were randomly divided into seven experimental groups (970 nm diode laser irradiation, 445 nm diode laser irradiation, 660 nm photodynamic therapy with doxycycline as a photosensitizer, TAP, 970 nm diode laser combined with TAP, 445 nm diode laser combined with TAP and sodium hypochlorite groups), each containing 10 teeth, and two positive and negative control groups, each containing five teeth. Afterwards, an E. faecalis suspension was prepared and injected into the root canals of all groups (except the negative control group), and after using the desired lasers or drugs and incubating for the necessary time, the grown colonies were counted and significance level of less than 0.05 was considered. Results:Among seven experimental groups, in those that included triple antibiotic paste (TAP, 970 nm diode laser with TAP, and 445 nm diode laser with TAP groups), no bacteria grew, while the 970 nm and 445 nm diode laser groups had the highest bacterial growth. Statistically, all studied groups were effective, and the results showed a statistically significant difference between groups (P value < 0.05). Conclusion: The findings of the present study show that all of the above-mentioned methods were effective enough for bacterial reduction. Triple antibiotic paste was proved to achieve complete bacterial elimination. Photodynamic therapy with doxycycline as a photosensitizer was shown to provide significant results of bacterial reduction and diode laser irradiation at both wavelengths (970 nm and 445 nm) were also reported to have antibacterial effect, although slightly lower than the previous methods.

Comparative evaluation of antimicrobial efficacy of triple antibiotic paste and amoxicillin clavulanate paste as an intracanal medicament against Enterococcus faecalis: An in vitro study

Background

Triple antibiotic paste (TAP) is the commonly used intracanal medicament against Enterococcus faecalis. Amoxicillin clavulanate paste (ACP) is recommended as a "fall-back" antibiotic when traditional dental antibiotics fail. Literature comparing the antimicrobial efficacy of TAP and ACP in eradicating E. faecalis from the root canal system is sparse; hence, this in vitro study was conducted to evaluate and compare the antimicrobial efficacy of TAP and ACP as an intracanal medicament for endodontic treatment of single-rooted permanent teeth against E. faecalis.

Materials and Methods

This in vitro, experimental study evaluated 60 root samples obtained from extracted single-rooted human permanent teeth. The canal diameter was enlarged and subsequently infected with E. faecalis for 21 days. Four groups of the contaminated samples were treated with TAP, ACP, calcium hydroxide (positive control), and saline (negative control), respectively. Dentinal shavings were collected at the end of the 1st, 7th, and 10th day and inoculated in agar plates. The number of colony-forming units was determined, and the data were statistically analyzed using the Kolmogorov-Smirnov and Shapiro-Wilks test. P <0.05 was considered statistically significant.

Results

The mean number of E. faecalis colony counts across all 3 test days demonstrated that TAP exhibited the highest inhibition of bacterial growth, followed by ACP which is not statistically significant (P = 1.00).

Conclusion

Considering the limitations of this in vitro study, the findings suggest that ACP could be an effective alternative intracanal medicament to TAP for endodontic therapy.

Propylene Glycol Potentiates the Inhibitory Action of CTZ Paste on Antibiotic-Resistant Enterococcus faecalis Isolated from the Root Canal: An In Vitro Study

This study aimed to evaluate if the change of vehicle for CTZ (Chloramphenicol, Tetracycline, zinc oxide, and Eugenol) paste improves the inhibition of Enterococcus faecalis in vitro. The vehicles evaluated alone and mixed with CTZ were Eugenol, propylene glycol (PG), super-oxidized solution (SOS), grapefruit-seed extract (GSE), and 0.9% saline solution as a negative control. A clinical isolate of E. faecalis was morphologically and biochemically characterized, and its antimicrobial susceptibility was tested using 20 antimicrobial agents. Once characterized, the clinical isolate was cultivated to perform the Kirby-Bauer disc diffusion method with paper discs embedded with the different vehicles mixed or used alone, and incubated at 37 °C for 24 h. Data were analyzed using one-way ANOVA, and the means were compared using Tukey test with a significance level of p < 0.05. For vehicles used alone, GSE presented the greatest inhibition showing a statistically significant difference with the rest of the vehicles. When vehicles were mixed with the CTZ paste, PG showed a greater inhibition with a statistically significant difference from the rest of the vehicles. In conclusion, the vehicle used to mix the CTZ paste plays an important role in the inhibition of E. faecalis in vitro; therefore, we consider that this can be an important factor to achieve success in the use of this technique.

Efficacy of Ciprofloxacin, Metronidazole and Minocycline in Ordered Mesoporous Silica against Enterococcus faecalis for Dental Pulp Revascularization: An In-Vitro Study

Pulp revascularization of teeth with necrotic pulp has become an alternative treatment in cases with immature apex. Microbial control is essential to achieve a successful outcome and continued root development. Enterococcus faecalis (E. faecalis) is the most frequently isolated bacterial species in root canals of endodontically failed teeth. Our main goal was to compare the in-vitro antimicrobial efficacy of different antibiotic formulations delivered by ordered mesoporous silica (OMS) against E. faecalis. To determine antibiotic susceptibility, we tested OMS and triple antibiotic paste (TAP; ciprofloxacin:metronidazole:minocycline) with different reagents in different concentrations, using the Kirby−Bauer disk diffusion method. OMS and metronidazole showed no antibacterial activity against E. faecalis. Mixtures of OMS and antibiotics in proportions of 2:2:14 and 4:1:7 (mg/L of ciprofloxacin:metronidazole:minocycline, respectively) showed the lowest antibacterial activity. The antibacterial activity of the combined solutions of ciprofloxacin and metronidazole was significantly higher (p < 0.005). Combinations in different concentrations of minocycline, ciprofloxacin, and metronidazole in OMS have shown activity against E. faecalis, although the combined use of ciprofloxacin and metronidazole has shown the most effective results. This study demonstrates the efficacy of intracanal antibiotic combination paste activity against E. faecalis, avoiding the use of minocycline, whose undesirable effect of teeth staining is a common problem for patients and professionals in dental clinic.

Antimicrobial effects of different concentrations of simvastatin versus triple antibiotic paste on Enterococcus faecalis biofilms at different stages of development

Background. This study assessed the antimicrobial effects of different concentrations of simvastatin versus triple antibiotic paste (TAP) on Enterococcus faecalis biofilms at different stages of development. Methods. In this in vitro study, 70 human single-rooted mature premolars were decoronated, instrumented, and autoclave-sterilized. Next, an E. faecalis suspension was prepared and inoculated into the canals to obtain 4- and 6-week biofilms. After ensuring biofilm formation, the samples in each group were randomly assigned to 5 subgroups (n=12): 1 mg/mL TAP, 10 mg/ mL TAP, 1 mg/mL simvastatin, 10 mg/mL simvastatin, and positive control (phosphate-buffered saline solution). The medicaments were applied in the canals, and the teeth were incubated for one week. Dentin samples were collected by a rotary file, cultured, and the number of E. faecalis colonies was counted. The Kruskal-Wallis, Mann-Whitney U, and Wilcoxon tests were used for data analysis (α=0.05). Results. There were significant differences in colony counts between the two concentrations of TAP and the control group against both 4- and 6-week biofilms (P<0.05). The antibacterial effect of 10 mg/mL TAP and simvastatin was stronger than that of 1 mg/mL concentration against the 4- and 6-week E. faecalis biofilms (P<0.05). Furthermore, 10 mg/mL TAP and simvastatin were more effective against the 4-week biofilms than the 6-week biofilms (P<0.05). Conclusion. According to the present results and since biofilms may remain viable in the root canal system for weeks to months, applying 10 mg/mL TAP and simvastatin might be more effective.