The antimicrobial effect of biopure MTAD on eight strains of Enterococcus faecalis: an in vitro investigation

The purpose of this investigation was to determine the antimicrobial effect of MTAD as a final irrigant on eight strains of Enterococcus faecalis (E. faecalis) and to measure the minimum inhibitory concentration (MIC) and the minimum lethal concentration (MLC) of MTAD. The roots of 240 extracted human teeth were instrumented using 1.3% NaOCl and 17% EDTA. The roots were divided into eight groups and contaminated with one of eight strains of E. faecalis. After irrigating with 1.3% NaOCl, the root canal and the external surfaces were exposed to MTAD for 5 minutes. Roots or dentin shavings were cultured to determine the growth of E. faecalis. The results showed that this treatment regimen was effective in completely eliminating growth in seven of eight strains of E. faecalis. The MIC/MLC tests showed that MTAD inhibited most strains of E. faecalis growth when diluted 1:8192 times and killed most strains of E. faecalis when diluted 1:512 times.     

The antimicrobial effect of MTAD, sodium hypochlorite, doxycycline, and citric acid on Enterococcus faecalis

This study compared the antimicrobial effect of MTAD, two of its components, doxycycline and citric acid, and sodium hypochlorite (NaOCl) in two in vitro models on Enterococcus faecalis. In the bovine tooth model, the lumens of 30 bovine dentin discs were infected with E. faecalis for 2 weeks before treating with either one of the experimental irrigants or saline. Bacteria in the shavings were collected with two sizes of burs and enumerated after overnight culturing. Zones of inhibition were recorded in the agar diffusion model for each irrigant. In the tooth model, NaOCl and doxycycline were more effective than control in killing E. faecalis at the shallow bur depth, but at the deeper bur depth only NaOCl was superior. In the agar diffusion model, NaOCl produced less inhibition than MTAD or doxycycline.     

Inhibitory activity of root canal irrigants against Candida albicans, Enterococcus faecalis and Staphylococcus aureus

The present study evaluated the antimicrobial activity of three root canal irrigants against Enterococcus faecalis, Candida albicans, and Staphylococcus aureus. These microorganisms were incubated in the presence of citric acid (6 and 10%), EDTA (17%), and NaOCl (0.5, 1.0, 2.5, and 5.25%). Agar diffusion tests were performed and redox indicator resazurin was used to evaluate the inhibitory effect of the irrigants on the metabolic activity of these microorganisms. The mean diameters of the inhibition zones for the C. albicans cultures were 11.6 mm (17% EDTA), 5.5 mm (0.5% NaOCl), 12.9 mm (1% NaOCl), 22.1 mm (2.5% NaOCl), and 28.5 mm (5.25% NaOCl). The mean diameters of the inhibition zones for E. faecalis were 2.8 mm (1% NaOCl), 5.4 mm (2.5% NaOCl), and 8.3 mm (5.25% NaOCl). For S. aureus, the mean values were 8.0 mm (17% EDTA), 3.0 mm (1% NaOCl), 8.8 mm (2.5% NaOCl), and 10.0 mm (5.25% NaOCl). Most of the irrigant solutions presented effective antimicrobial activity against C. albicans. A high inhibitory effect on the metabolic activity of E. faecalis was detected when the microorganisms were incubated with 17% EDTA. The same result was reached when S. aureus was incubated in the presence of > 2.5% NaOCl. Altogether, these results indicate that 2.5% and 5.25% NaOCl are microbicides against S. aureus while 0.5% and 1% NaOCl are only microbiostatic against the tested bacteria. The 6% and 10% citric acid as well as 17% EDTA did not affect the viability of any of the assayed microorganisms.     

A comparison of the antimicrobial efficacy of NaOCl/Biopure MTAD versus NaOCl/EDTA against Enterococcus faecalis

The purpose of this investigation was to compare the antimicrobial efficacy of irrigating with 1.3% NaOCl/Biopure MTAD versus irrigation with 5.25% NaOCl/15% EDTA in the apical 5 mm of roots infected with Enterococcus faecalis. Bilaterally matched human teeth were sterilized and inoculated with E. faecalis. After chemomechanical root canal preparation, the root-ends were resected and pulverized in liquid nitrogen to expose E. faecalis in dentinal tubules or other recesses away from the main root canal system. The number of colony forming units (CFU) of E. faecalis per mg was determined from the pulverized root-ends. No significant differences were seen (t = 0.70, p = 0.495) between the number of colony forming units of E. faecalis for teeth irrigated with 5.25% NaOCl/15% EDTA (mean 131 +/- 291 CFU/mg) versus those teeth irrigated with 1.3% NaOCl/Biopure MTAD (mean 187 +/- 237 CFU/mg). This study demonstrated that there is no difference in antimicrobial efficacy for irrigation with 5.25% NaOCl/15% EDTA versus irrigation with 1.3% NaOCl/Biopure MTAD in the apical 5 mm of roots infected with E. faecalis.     

Chemomechanical reduction of the bacterial population in the root canal after instrumentation and irrigation with 1%, 2.5%, and 5.25% sodium hypochlorite

Given the importance of bacteria in the development of periradicular lesions, the eradication of the root canal infection is paramount in endodontic treatment. This study evaluated the in vitro intracanal bacterial reduction produced by instrumentation and irrigation with 1%, 2.5%, and 5.25% sodium hypochlorite (NaOCl) or saline solution. Root canals inoculated with Enterococcus faecalis were instrumented and irrigated with the solutions tested. Canals were sampled before and after preparation. After serial dilution, samples were plated onto Mitis salivarius agar, and the colony-forming units grown were counted. Inhibitory effects of the three NaOCl solutions on E. faecalis were also evaluated by means of the agar diffusion test. All test solutions significantly reduced the number of bacterial cells in the root canal (p < 0.05). There was no significant difference between the three NaOCl solutions tested (p > 0.05). Nonetheless, all NaOCl solutions were significantly more effective than saline solution in reducing the number of bacterial cells within the root canal (p < 0.05). The three NaOCl concentrations showed large zones of inhibition against E. faecalis. The results of this study suggest that regular exchange and the use of large amounts of irrigant should maintain the antibacterial effectiveness of the NaOCl solution, compensating for the effects of concentration.     

Effect of MTAD on Enterococcus faecalis-contaminated root canals of extracted human teeth

The purpose of this investigation was to compare the antimicrobial effect of MTAD (a mixture of a tetracycline isomer, an acid, and a detergent) with that of NaOCl with and without EDTA. Eighty-five extracted human teeth were contaminated with Enterococcus faecalis for 4 weeks. After biomechanical instrumentation using 1.3% or 5.25% NaOCl as root canal irrigant, the root canal and the external surface of each tooth were exposed to a 5-min application of MTAD, 1.3% NaOCl, 5.25% NaOCl or a 1-min application of EDTA followed by irrigation with 5 ml of 1.3% NaOCl or 5.25% NaOCl. Teeth or dentin shavings were cultured to determine presence or absence of the test bacteria. Fisher's exact test showed that the combination of 1.3% NaOCl as a root canal irrigant and MTAD as a final rinse was significantly more effective against E. faecalis than the other regimens. The chi2 test showed no difference between the other regimens.     

Comparative evaluation of endodontic irrigants against Enterococcus faecalis biofilms

The aim of this study was to compare the efficacy of root canal irrigants against E. faecalis biofilms using a novel in vitro testing system. Biofilms grown in a flow cell system were submerged in test irrigants for either 1 or 5 minutes. Statistical analysis revealed a significant relationship between test agent and percentage kill of the biofilm bacteria (P < 0.05). No statistically significant relationship between time and percentage kill was found. The percentage kill of the biofilm bacteria was: 6% NaOCl (>99.99%), 1% NaOCl (99.78%), Smear Clear (78.06%), 2% chlorhexidine (60.49%), REDTA (26.99%), and BioPure MTAD (16.08%). Post-hoc analysis showed a significant difference between 1% and 6% NaOCl, and all other agents including Smear Clear, 2% chlorhexidine, REDTA, and BioPure MTAD (P < 0.05). Within the parameters of this study, both 1% NaOCl and 6% NaOCl were more efficient in eliminating E. faecalis biofilm than the other solutions tested.     

Killing of Enterococcus faecalis by MTAD and chlorhexidine digluconate with or without cetrimide in the presence or absence of dentine powder or BSA

The antibacterial efficacy of irrigating solutions and local disinfectants used in endodontics appears poorer in vivo than in vitro. One explanation may be inactivation by compounds present in the root canal. MTAD (a mixture of tetracycline isomer, acid, and detergent) is a new root canal irrigation solution with antibacterial activity. The aim of this study was to investigate the antibacterial activity of MTAD and chlorhexidine towards two strains of Enterococcus faecalis and the inhibitory effects of dentine and bovine serum albumin on the antibacterial activity. Survival of bacteria exposed to the medicaments in the presence or absence of inhibitors was monitored in an in vitro model. Full concentration (100%) MTAD and 0.2% chlorhexidine rapidly killed both strains. Combining chlorhexidine with cetrimide further reduced the time required for killing. The presence of dentine or BSA caused a marked delay in killing by both medicaments. The two E. faecalis strains tested showed minor differences in their susceptibility to the disinfectants.     

Comparison of the antimicrobial efficacy of 1.3% NaOCl/BioPure MTAD to 5.25% NaOCl/15% EDTA for root canal irrigation

The purpose of this study was to compare the antimicrobial efficacy of 1.3% NaOCl/BioPure MTAD to 5.25% NaOCl/15% EDTA for root canal irrigation. Twenty-six bilaterally matched pairs of human teeth were collected. The teeth were incubated with Enterococcus faecalis for 4 weeks. The teeth were divided into two experimental groups and one positive control group. The canals were instrumented and irrigated with either 5.25% NaOCl/15% EDTA or 1.3% NaOCl/BioPure MTAD. Bacterial samples were collected after instrumentation/irrigation and after additional canal enlargement. Statistical analysis of the data using the Wilcoxon Signed Rank test showed significant differences between the experimental groups. The first bacterial samples revealed growth in 0 of 20 samples with 5.25% NaOCl/15% EDTA irrigation and in 8 of 20 samples with 1.3% NaOCl/BioPure MTAD irrigation. Samples taken after additional canal enlargement revealed growth in 0 of 20 samples in 5.25% NaOCl/15% EDTA and in 10 of 20 samples in 1.3% NaOCl/BioPure MTAD group. This investigation showed consistent disinfection of infected root canals with 5.25% NaOCl/15% EDTA. The combination of 1.3% NaOCl/BioPure MTAD left nearly 50% of the canals contaminated with E. faecalis.     

茶多酚、MTAD和次氯酸钠液抑制粪肠球菌及其生物膜的作用比较

目的:检测中药茶多酚、MTAD、52.5 g/L次氯酸钠抑制根管壁粪肠球菌生物膜的能力,并分析中药茶多酚作为根管冲洗液的可行性。方法:采用微孔板滴定法检测茶多酚,MTAD和52.5 g/L次氯酸钠液对粪肠球菌的最小抑菌浓度(MIC)和最小杀菌浓度(MBC),采用琼脂扩散实验检测3种抗菌剂对粪肠球菌的抑菌圈。通过建立粪肠球菌感染根管3周和6周的模型,分别用茶多酚、MTAD和52.5 g/L次氯酸钠液对粪肠球菌感染后的根管进行处理,然后对根管壁生物膜中的细菌生存情况进行定性定量分析,比较这3种根管冲洗液抗粪肠球菌生物膜的能力。结果:MIC、MBC和琼脂扩散实验显示:3组冲洗剂对粪肠球菌均有抑制作用。在粪肠球菌感染根管3周的生物膜中,MTAD和次氯酸钠液可以完全抑制粪肠球菌生物膜,茶多酚处理后虽仍有粪肠球菌生长,但明显低于生理盐水处理组的细菌生存数,差异有统计学意义(P<0.05)。在粪肠球菌感染根管6周的生物膜中,次氯酸钠液可以完全抑制细菌生长,茶多酚和MTAD作用后仍有活菌生长,但与对照组相比,细菌生存数均显示了8个log值的下降,差异有统计学意义(P<0.05)。结论:52.5 g/L次氯酸钠液具有很强的抑制根管内粪肠球菌生物膜作用,而茶多酚和MTAD也具有一定的抑制粪肠球菌生物膜的能力。     

次氯酸钠对粪肠球菌杀菌效果的体外研究

目的体外评价次氯酸钠(NaOCl)对粪肠球菌的杀菌效果及浓度依赖关系。方法采用纸片扩散法药敏实验观察NaOCl对粪肠球菌的抑菌环大小(mm),直接接触法观察NaOCl对粪肠球菌的灭活时间。结果5.25%NaOCl的抑菌环直径最大,4.00%与2.50%、1.00%与0.50%差异无显著性。5.25%NaOCl在30s内可杀死全部粪肠球菌,2.50%NaOCl杀死粪肠球菌需要15min,随浓度的下降,杀死细菌所需要的时间延长。结论高浓度NaOCl的效果优于低浓度NaOCl,2.50%NaOCl基本可满足临床要求。     

In vitro antibacterial effect of different irrigating solutions on Enterococcus faecalis

Was evaluated the minimum inhibitory concentration (MIC) and the antibacterial effect (AE) of 2.5% NaOCl, 0.2% chlorhexidine gluconate (CHX) and 17% EDTA on Enterococcus faecalis. The antibacterial capacity was assessed by difusion in agar. The AE was evaluated on contaminated root dentin, employing apical and middle portions of human roots, sterilized and contaminated with Enterococcus faecalis, immersed in the irrigation solutions and incubated at 37 degrees C. Viable cells were counted at 0, 4, 8 and 24 hours. MIC: NaOCl and CHX: 0.2%, EDTA below 5%. Diffusion in agar: NaOCl 2.5% = 21 mm. CHX 0.2% = 14 mm. EDTA 17% = 20 mm. Effect on root dentin: NaOCl 2.5%: Enterococcus faecalis was totally inhibited for 24 hours in the apical area, and for 8 hours in the middle area. CHX 0.2% elicited a reduction of more than 5 log CFU and EDTA 17% induced a reduction of more than 3 log CFU at all the time points examined in the apical and middle areas.     

Reduction in antimicrobial substantivity of MTAD after initial sodium hypochlorite irrigation

Potential intrinsic tetracycline staining of intraradicular dentin has been observed when BioPure MTAD was employed as the final irrigant after initial rinsing with NaOCl. This study examined the effect of NaOCl-MTAD interaction on the antimicrobial substantivity of MTAD in dentin. Dentin cores previously irrigated with either MTAD, or in conjunction with 1.3% NaOCl as an initial irrigant were placed on blood agar plates inoculated with Escherichia faecalis at 10(5) cfu/ml. Dentin cores irrigated with 1.3% NaOCl only, and autoclaved dentin disks were used as the respective positive and negative controls. After anaerobic incubation, the mean diameter of bacterial inhibition zones formed around the MTAD group was significantly larger than the NaOCl/MTAD group, which, in turn, was not significantly different from the NaOCl positive control. Oxidation of MTAD by NaOCl resulted in the partial loss of antimicrobial substantivity in a manner similar to the peroxidation of tetracycline by reactive oxygen species.     

An in vitro comparison of the antimicrobial effects of various endodontic medicaments on Enterococcus faecalis

The purpose of this in vitro study was to investigate the antimicrobial action of Dermacyn (Oculus Innovative Sciences, Petaluma, CA), BioPure MTAD (Dentsply Tulsa Dental, Johnson City, TN), 2% chlorhexidine (CHX; Ultradent, West Jordan, UT), and 5.25% sodium hypochlorite (NaOCl) against Enterococcus faecalis (American Type Culture Collection 4082). Eighteen Petri dishes of BHI agar were inoculated with E faecalis. Each Petri dish had five saturated paper disks placed. Four of the disks were saturated with a different test solution, and the last paper disk served as the control and was saturated with sterile distilled water. The plates were randomly distributed into two groups. Group one (n=9) was incubated aerobically and group 2 (n=9) was incubated anaerobically for 48 hours at 37 degrees C. The largest diameter of the zones of microbial inhibition was measured in millimeters and recorded. Statistical analysis was performed with repeated-measures analysis of variance. BioPure MTAD showed significantly (p<0.05) more zones of microbial inhibition than 5.25% NaOCl, 2% CHX, and Dermacyn. Sodium hypochlorite and CHX showed significantly (p<0.05) more zones of microbial inhibition than Dermacyn. The zone of inhibition between NaOCl and CHX was not significant (p>0.05). The control group showed no microbial inhibition.     

Evaluation of cytotoxicity of MTAD using the MTT-tetrazolium method

Previous studies have shown that MTAD (a mixture of a tetracycline isomer, an acid, and a detergent) is an effective antibacterial irrigant as a final rinse to remove the smear layer from the instrumented surface of root canals. In this investigation we examined the cytotoxicity of MTAD compared with that of commonly used irrigants and medications. L929 fibroblasts were grown on cell culture plates and were placed in contact with various concentrations of test irrigants and medications. The cytotoxicity of these materials was evaluated 24 h after incubation using MTT assay. Means and standard deviations of absorbance were calculated for each group and statistically analyzed to determine presence or absence of significant difference between the means. The 50% inhibitory dose values were calculated, ranked, and statistically analyzed using the sign interval for median. Based on our results it seems that MTAD is less cytotoxic than eugenol, 3% H2O2, Ca(OH)2 paste, 5.25% NaOCl, Peridex, and EDTA and more cytotoxic than 2.63%, 1.31%, and 0.66% NaOCl.     

Additive effect of a diode laser on the antibacterial activity of 2.5% NaOCl, 2% CHX and MTAD against Enterococcus faecalis contaminating root canals: an in vitro study

This in vitro study was performed to evaluate the effect of a diode laser and common disinfectants used in combination on mono-infected dental canals. One hundred and six single-rooted human premolars were prepared and contaminated with Enterococcus faecalis. After two weeks of incubation, samples were divided into two experimental groups (n = 48) and two control groups (n = 5). In the first group, the teeth were rinsed for 5 min with either sterile saline, 2.5% NaOCl, or MTAD, or for 1 min with 2% chlorhexidine gluconate (CHX). In the other group, samples were additionally irradiated with a 810-nm diode laser at 2 W output for 5 × 5 s. Intracanal bacterial sampling was done, and the samples were plated to determine the CFU count. In the first group, 2.5% NaOCl was as effective as 2% CHX and significantly more effective than MTAD (P < 0.008). In the second group, either MTAD, 2% CHX or 2.5% NaOCl in combination with laser treatment had a similar effect. Absence of growth was seen only for MTAD plus laser treatment. Complete elimination of E. faecalis was seen only for the combination of MTAD with diode laser irradiation. Combination therapy with MTAD irrigation and diode laser irradiation, within the parameters used in this study, can be recommended as an effective treatment option for complete elimination of E. faecalis from the root canal system.     

次氯酸钠溶液抗菌体积分数的测定

目的评价次氯酸钠溶液对牙龈卟啉单胞菌、中间普雷沃菌、具核梭杆菌和粪肠球菌牙髓病原菌的体外抗菌性能。方法采用琼脂稀释法测定次氯酸钠溶液对牙龈卟啉单胞菌、中间普雷沃菌、具核梭杆菌和粪肠球菌的抗菌活性,其抗菌活性以最低抑菌体积分数(MIVF)和最低杀菌体积分数(MBVF)表示。结果次氯酸钠溶液对牙龈卟啉单胞菌、中间普雷沃菌、具核梭杆菌和粪肠球菌的MIVF分别为0.035%、0.07%、0.018%和0.28%,MBVF分别为0.035%、0.07%、0.035%和0.28%,其总的抗菌效果排序分别为具核梭杆菌、牙龈卟啉单胞菌、中间普雷沃菌和粪肠球菌。结论次氯酸钠对口腔常见厌氧菌有抑制和杀灭作用,具有理想的抗菌性能。0.5%MBVF的次氯酸钠溶液的抑菌性能可满足临床需求。     

Antimicrobial Effect of Conventional Root Canal Medicaments vs Propolis against Enterococcus faecalis, Staphylococcus aureus and Candida albicans

Aim: To evaluate and compare antimicrobial effect of various root canal medicaments against Enterococcus faecalis, Staphylococcus aureus and Candida albicans. Materials and methods: Six root canal medicaments: 2% sodium hypochlorite (NaOCl), 2% chlorhexidine (CHX) Calcium hydroxide (Ca(OH)2), EDTA, MTAD and propolis and three microorganisms: Staphylococcus aureus, Enterococcus faecalis and Candida albicans were used. These strains were inoculated in brain heart infusion (BHI) and incubated at 37 degrees C for 24 hours. For the agar diffusion test (ADT), petri plates with 20 ml of BHI agar were inoculated with 0.1 ml of the microbial suspensions, using sterile swabs that were spread on the medium, obtaining growth injunction. Paper disks were immersed in the experimental solutions for 1 minute. Subsequently, four papers disks containing one of the substances were placed on the BHI agar surface in each agar plate. The plates were incubated at 37°C for 48 hours. The diameter of microbial inhibition was measured around the papers disks containing the substances. One way ANOVA followed by Tukey's post-hoc test were used. p-value >0.05 was considered statistically significant. Results: Propolis and other irrigants were found to be effective on C. albicans, S. aureus and E. faecalis. CHX and MTAD were found to be most effective amongst all the materials tested followed by propolis. Conclusion: Propolis showed antimicrobial activity against E. faecalis, S. aureus, C. albicans. It appears that propolis is an effective intracanal irrigant in eradicating E. faecalis and C. albicans. Clinical significance: Propolis is an effective intracanal irrigant in eradicating E. faecalis and C. albicans. It could be used as an alternative intracanal medicament. Keywords: Root canal medicaments, Enterococcus faecalis, Staphylococcus aureus, Candida albicans, Propolis. How to cite this article: Mattigatti S, Jain D, Ratnakar P, Moturi S, Varma S, Rairam S. Antimicrobial Effect of Conventional Root Canal Medicaments vs Propolis Against Enterococcus faecalis, Staphylococcus aureus and Candida albicans. J Contemp Dent Pract 2012;13(3):305-309. Source of support: Nil Conflict of interest: None declared.     

Antibacterial substantivity of a new antibiotic‐based endodontic irrigation solution

The aim of this study was to evaluate the residual antibacterial activity of Tetraclean, MTAD and 5.25% sodium hypochlorite (NaOCl) in bovine root dentin in vitro. One hundred and ten dentin tubes prepared from bovine incisor teeth were infected in vitro for 14 days with Enterococcus faecalis. Thereafter, the specimens were divided into five groups as follows: Tetraclean; MTAD; 5.25% NaOCl; infected dentin tubes (positive control); and sterile dentin tubes (negative control). Dentin chips were collected using round burs into tryptic soy broth and after culturing, the number of colony‐forming units (CFU) was counted. The number of CFU in all experimental groups was minimum after treatment, and the results obtained were significantly different from each other at any time period (P < 0.05). The Tetraclean group showed the most effective antibacterial action at all five experimental periods (P < 0.05). MTAD group showed the least antibacterial activity after treatment. However, at days 7, 14, 21 and 28 MTAD showed more effective antibacterial action than NaOCl. In each group, the number of CFU increased significantly by time‐lapse (P < 0.05). In conclusion, the residual antibacterial activity of Tetraclean was significantly greater than MTAD and 5.25% NaOCl.     

In vitro evaluation of effect of various endodontic solutions on selected physical properties of white mineral trioxide aggregate

During endodontic therapy various irrigating solutions at different concentrations and duration are used. These chemical solutions may affect the setting reaction of mineral trioxide aggregate (MTA). The aim of this study was to evaluate the effect of sodium hypochlorite (NaOCl) (5.25%), chlorhexidine gluconate (CHX) (2%), ethylenediaminetetraacetic acid (EDTA) solution (17%) and BioPure MTAD on surface micro-hardness and flexural strength of white MTA. Twenty-five disk-shaped and 25 bar-shaped specimens were divided into five groups and were stored under distilled water, NaOCl (5.25%), chlorhexidine CHX (2%), EDTA solution (17%) and BioPure MTAD for 7 days. The micro-hardness of disk specimens was measured while the flexural strength was tested on bar specimens. EDTA and BioPure MTAD significantly reduced the hardness and flexural strength as compared with other groups. Under distilled water strength remained high; therefore, a final flush with distilled water before placement of MTA is advocated, especially if decalcifying agents are used during the clinical procedure.