Endodontic Pathogens Research Articles

Quantitative Analysis of Candidate Endodontic Pathogens and Their Association with Cause and Symptoms of Apical Periodontitis in a Sudanese Population.

Objective:To investigate the prevalence of key endodontic pathogens and their association with the clinical features and the cause of apical periodontitis.Methods:The study population included patients referred to Khartoum Dental teaching Hospital, Sudan for endodontic treatment. Samples were collected from single-rooted teeth carious or traumatised teeth with clinical and radiographic evidence of apical periodontitis. The endodontic pathogens Porphyromonas endodontalis, Fusobacterium nucleatum and Treponema denticola were quantified by real time polymerase chain reaction (qPCR). The prevalence of each species was identified at both a low detection threshold (>50 bacteria) and a high detection threshold (>1000 bacteria).Results:75 patients (mean age 30.1 yrs SD 10.1) were included in the analysis. The most prevalent bacterium at both the low and high threshold was F. nucleatum followed by T. denticola at the low threshold and P. endodontalis at the high threshold. There was no association with symptoms at the low detection threshold, but at high threshold P. endodontalis was associated with swelling, adjusted odds ratio (OR), 9.32 95%CI 1.11- 78.66, P=0.04. All species were more prevalent in apical periodontitis due to caries only at the low detection threshold, OR=5.01 (P=0.006) for T. denticola; 4.84 (P=0.01) for F. nucleatum; and 3.62 (P=0.03) for P. endodontalis.Conclusion:There was a high prevalence of the F. nucleatum, T. denticola and P. endodontalis in apical periodontitis associated with caries. None of these bacterial were associated with pain but the presence of P. endodontalis at high levels was associated with swelling.

Essential Oil from Psidium cattleianum Sabine (Myrtaceae) Fresh Leaves: Chemical Characterization and in vitro Antibacterial Activity Against Endodontic Pathogens

Endodontic infections result from oral pathogenic bacteria which reach and infect dental pulp, as well as surrounding tissues, through cracks, unrepaired caries and failed caries restorations. This study aims to determine the chemical composition of essential oil from Psidium cattleianum leaves (PC-EO) and to assess its antibacterial activity against endodontic bacteria. Antibacterial activity of PC-EO was evaluated in terms of its minimum inhibitory concentration (MIC) values by the broth microdilution method on 96-well microplates. Bacteria Porphyromonas gingivalis (MIC = 20 µg/mL), Prevotella nigrescens (MIC = 62.5 µg/mL), Fusobacterium nucleatum (MIC = 12.5 µg/mL), Actinomyces naeslundii (MIC = 50 µg/mL), Bacteroides fragilis (MIC = 12.5 µg/mL), Aggregatibacter actinomycetemcomitans (MIC = 6.25 µg/mL) and Peptostreptococcus anaerobius (MIC = 62.5 µg/mL) were evaluated and compared to chlorhexidine dihydrochloride (CDH), the positive control. PC-EO was obtained by hydrodistillation with the use of a Clevenger-type apparatus whereas its chemical composition was analyzed by gas chromatography-flame ionization detection (GC-FID) and gas chromatography-mass spectrometry (GC-MS). Viridiflorol (17.9%), β-caryophyllene (11.8%), 1,8-cineole (10.8%) and β-selinene (8.6%) were the major constituents found in PC-EO, which exhibited high antibacterial activity against all endodontic pathogens under investigation. Therefore, PC-EO, a promising source of bioactive compounds, may provide therapeutic solutions for the field of endodontics.

Detection of Red complex bacteria, P. gingivalis, T. denticola and T. forsythia in infected root canals and their association with clinical signs and symptoms

Aim:This study aimed to investigate the association between endodontic clinical signs and symptoms and the presence of Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia employing polymerase chain reaction (PCR).Materials and Methods:Microbial samples were obtained from 60 cases with necrotic pulp with primary teeth infections. DNA extracted from samples were analyzed for endodontic pathogens by using species-specific primers.Results:P. gingivalis/T. denticola were detected in 15 symptomatic teeth associated with periapical lesions. T. forsythia/T. denticola were found in 16 symptomatic teeth associated with pain and swelling. P. gingivalis was detected in 9 teeth which were associated with pain, 2 with tenderness on percussion, and 15 with periapical lesions. Statistically significant associations were found between T. forsythia as well as T. denticola in relation to clinical findings of pain and swelling. (P < 0.05). Red complex bacteria showed no statistical significant association with the presence of signs and symptoms.Conclusion:Prevalence of P. gingivalis, T. denticola, and T. forsythia suggested association of these bacteria with symptomatic infected pulp and periradicular diseases.

Comparative evaluation of antimicrobial efficacy of sesame oil irrigants on Enterococcus faecalis – An in vitro study

Introduction: During chemo-mechanical preparation, irrgants play a vital role for eradication of endodontic pathogens. Due to the shortcomings of the current irrgants used, a need has come to find out whether herbal irrigants has better cytological acceptance and whether there is a decrease in biomedical waste. With the growing trends of using herbal extracts and oils as an alternate to conventional irrigants as an antimicrobial agent, the main objective of this study was to test sesame oil itself and its combination with various agents for its antimicrobial efficacy on Enterococcus faecalis (EF).Aim: The antimicrobial efficacy of edible sesame oil and sesame oil mixture on EF using agar diffusion test.Materials and Methods: Forty-five extracted single teeth with single canal configuration were decoronated from each tooth at the cementoenamel junction and the orifices of canals were enlarged with Gates Glidden drill size number 4. EF colonies were adjusted to 1.5 × 108 colony forming unit (CFU)/ml. Crystal violet staining and observation under stereomicroscope (BX-63 Olympus DIC) were performed to check the 100% purity of culture. The inoculated specimens were divided into three groups (n = 15). The three groups are as follows: Group A was irrigated with 5.25% sodium hypochlorite (NaOCl); Group B was irrigated with edible sesame oil; and under Group C was irrigated with prepared sesame oil mixture. After 3 weeks, following the use of F4, 2 ml experimental irrigant was left undisturbed for 60 s. A volume of 20 ml of the all three irrigants were used. Absorbent paper points of sizes similar to the last apical file size used, i.e., 40.06 (F4) were placed in the canals for 5 min and transported for microbial assessment. CFUs were checked after 24 h on blood agar plates.Statistical Analysis: The intergroup statistical comparisons were performed using one-way analysis of variance (ANOVA) with Tukey's post hoc test for multiple group comparisons (P < 0.05). The intragroup comparisons were performed using r ANOVA in each study group (P < 0.01).Results: The intergroup comparison of the mean CFUs of EF on blood agar plates was significantly higher in for edible sesame oil (13.30 ± 1.64) compared to NaOCl (9.40 ± 1.24) and sesame oil mixture (7.60 ± 1.43).Conclusion: The present study confirmed the in vitro antimicrobial efficacy of prepared sesame oil mixture compared to 5.25% NaOCl and edible sesame oil.

Association of specific microorganisms with endodontic signs and symptoms. A comparative study

Aim:The study aimed to evaluate the association of root canal microorganisms red complex and E. facealis with endodontic clinical signs and symptoms using polymerase chain reaction.Materials and Methods:Bacterial samples were obtained using sterile paper points from the teeth of 100 subjects divided into two groups; Group I: 50 individuals with primary tooth infections and Group II: 50 individuals with failed endodontic treatment having the secondary infection. DNA extracted from samples was analyzed for endodontic pathogens by using species-specific primers.Results:The pain was noticed in 66%, (33 of 50 subjects) in primary infection and 60% (30 of 50) in a secondary infection. A statistically significant association between pain and E. faecalis bacteria observed both in primary infection and secondary infection (P < 0.05). Tenderness on percussion was associated with 40% cases in Group I and 70% cases in Group II. The red complex accounted for 94% of cases associated with tenderness on percussion in primary infection while 86% of cases associated with secondary infection with a statistically significant association (P < 0.05).Conclusion:Prevalence of red complex bacteria and E. faecalis suggested the association of studied bacteria with symptomatic infected pulp and periradicular diseases.

In vitro evaluation of antimicrobial effect of Myristica fragrans on common endodontic pathogens.

Complete elimination of microorganisms from the root canals is the important key for the successful endodontic treatment. Constant emergence of resistant strains and adverse effects of synthetic drugs has led to the search of effective herbal alternatives. Nutmeg (Myristica fragrans) is one such spice used for its various medicinal activities. To evaluate the antimicrobial effect of M. fragrans on common endodontic pathogens of primary tooth. Essential oil of nutmeg was extracted by hydrodistillation method, and its phytoconstituents were determined by thin-layer chromatography (TLC), high-performance TLC, and gas chromatography-mass spectrometry analysis. Minimum inhibitory concentration of essential oil against standard strains of common endodontic pathogens (Escherichia coli, Staphylococcus aureus, Enterococcus faecalis, Streptococcus mutans, Candida albicans, Lactobacillus casei, Actinomyces viscosus, Prevotella intermedia, and Porphyromonas gingivalis) was determined by serial tube dilution method. Essential oil of M. fragrans was effective against all tested endodontic microorganisms. The active components of essential oil of nutmeg such as myristicin, myristic acid, trimyristin, elemicin, and safrole have good antimicrobial activity and are effective against endodontic microorganisms. M. fragrans can be used as an effective medicament in the treatment of endodontic infections.

Synthetic Human β Defensin-3-C15 Peptide in Endodontics: Potential Therapeutic Agent in Streptococcus gordonii Lipoprotein-Stimulated Human Dental Pulp-Derived Cells.

Human β defensin-3-C15, an epithelium-derived cationic peptide that has antibacterial/antifungal and immuno-regulatory properties, is getting attention as potential therapeutic agent in endodontics. This study aimed to investigate if synthetic human β defensin-3-C15 (HBD3-C15) peptides could inhibit inflammatory responses in human dental pulp cells (hDPCs), which had been induced by gram-positive endodontic pathogen. hDPC explant cultures were stimulated with Streptococcus gordonii lipoprotein extracts for 24 h to induce expression of pro-inflammatory mediators. The cells were then treated with either HBD3-C15 (50 μg/mL) or calcium hydroxide (CH, 100 μg/mL) as control for seven days, to assess their anti-inflammatory effects. Quantitative RT-PCR analyses and multiplex assays showed that S. gordonii lipoprotein induced the inflammatory reaction in hDPCs. There was a significant reduction of IL-8 and MCP-1 within 24 h of treatment with either CH or HBD3-C15 (p < 0.05), which was sustained over 1 week of treatment. Alleviation of inflammation in both medications was related to COX-2 expression and PGE2 secretion (p < 0.05), rather than TLR2 changes (p > 0.05). These findings demonstrate comparable effects of CH and HDB3-C15 as therapeutic agents for inflamed hDPCs.

Antimicrobial efficacy of photodynamic therapy, diode laser, and sodium hypochlorite and their combinations on endodontic pathogens.

Sterilization of the root canal system is of prime importance for a successful root canal therapy. Lasers and photodynamic therapy (PDT) have become the latest choice to eradicate microorganisms in the root canal. To evaluate and compare the antimicrobial activity of diode laser, photodynamic therapy, and sodium hypochlorite along with their combinations on endodontic pathogens: Enterococcus faecalis and Streptococcus mutans. A total of 120 uniradicular teeth were stored in 5.2% NaOCl solution to remove organic residues and the crowns were sectioned at the cemento-enamel junction (CEJ) to obtain root canal length of 15 mm. Canals were shaped using step-back technique up to #40 K-file and were autoclaved. The selected teeth (specimen) were randomly divided into two equal groups with sixty teeth being inoculated with E. faecalis (Group E) and remaining sixty teeth with S. mutans (Group S). Further, the groups were subdivided according to the disinfection technique used. Ten teeth from each subgroup were disinfected with a diode laser, photo activated disinfection (PAD), sodium hypochlorite, a combination of sodium hypochlorite and diode laser, a combination of sodium hypochlorite and photo activated disinfection respectively. Ten teeth in each group served as control without any disinfection. The treated specimens were transferred to test tubes containing 5 ml sterile Luria Bertani broth, incubated and the bacterial count, optical density in each root specimen was calculated and compared. The pairwise comparison of colonies across the subgroups was done by the Kruskal-Wallis test and within the subgroups was carried out using the Mann-Whitney U test. The statistical implication was tested at 5% and the study was performed using SPSS 18.0 ver. (SPSS Inc.). A significant reduction (98%) in the E. faecalis count was observed when the NaOCl was used in combination with the diode laser or PAD. PAD along with 3% NaOCl presents the advantage of utilizing a lower wavelength laser beam. Hence, PAD in combination with NaOCl can be an alternative and better option for root canal disinfection for both the endodontic pathogens, E. faecalis and S. mutans.

A New Combination with D-Cateslytin to Eradicate Root Canal Pathogens

The success of endodontic treatments depends on the elimination of intracanal pathogens. Since irrigation and instrumentation can only partially eliminate bacteria, the use of intracanal medicaments is suggested to improve the eradication of the root canal pathogens. Antimicrobial peptides derived from Chromogranin A display bacteriolytic activities and are potentially excellent candidates to be combined with conventional intracanal medicaments. In this study, we combined D-Cateslytin (D-Ctl), together with calcium hydroxide (Ca(OH)2) to test for enhanced antimicrobial properties against Enterococcus faecalis. Antimicrobial activities were determined by broth dilution assays, stability of D-Ctl was assessed by HPLC and MTT tests were used to evaluate cytotoxicity. A saturated solution of Ca(OH)2 (1.7 mg/mL) was able to inhibit 58% (± 5%) of E. faecalis growth, while the combination of both 0.85 mg/mL of Ca(OH)2 and ½ MIC of D-Ctl was able to fully inhibit its growth. D-Ctl was stable against the proteases secreted by E. faecalis and showed no toxicity on human gingival fibroblasts. Besides E. faecalis, this combination was also effective in completely killing other endodontic pathogens: Parvimonas micra, Prevotella intermedia, Fusobacterium nucleatum and Candida albicans. In conclusion, D-Ctl combined with Ca(OH)2 eradicates several endodontic pathogens and could be used as an innovative intracanal medicament to reduce endodontic failures.

Smear Layer Removal and Microhardness Alteration Potential of a Naturally Occurring Antioxidant - An In Vitro Study.

Introduction: It is well-known in the field of endodontics that the presence of a smear layer in the root canals can harbor bacteria and limit the penetration of irrigating solutions and intracanal medications into the dentinal tubules which, in turn, causes the failure of endodontic treatment. Removing the entire smear layer throughout the root canal is essential for the success of endodontic treatment and these chemical agents that facilitate the removal of the smear layer are called chelating agents. Ethylenediaminetetraacetic acid (EDTA), being the most widely used chelating agent, brings about increased reduction in the microhardness of the root dentin, thereby making it friable.N-acetyl cysteine (NAC) is naturally occurring antioxidant that has various beneficial properties for the human being. Several studies have been done in determining the antimicrobial efficacy of NAC against various endodontic pathogens and concluded NAC to be advantageous. The chelating property of NAC has been utilized in heavy metal detoxification, where it binds to the metal ion and removes them from the human system. However, this chelating property has not been explored in the field of endodontics.Aim: This study was aimed to compare the ability of N-acetyl cysteine with the conventional chelating agent in the removal of the smear layer and in altering the microhardness of root dentin.Materials and Methodology: A total of 84 single-rooted human mandibular premolars with relatively similar dimension and morphology, freshly extracted with closed apices, were collected from adult patients. The crowns of all specimens were cut transversally at the cementoenamel junction (CEJ) with the double-faced diamond disc at low speed, with water coolant, to obtain a 12 mm root length. The root canals were randomly divided into three equal groups according to the final irrigation solutions: Group I: 17% EDTA, Group II: 20% NAC, and Group III: distilled water (control). They were then randomly divided into two parts: scanning electron microscope (SEM) analysis for the extent of smear layer removal and microhardness evaluation using the Vicker’s hardness test.Results: The smear layer removal ability of EDTA and NAC were more effective in the coronal and middle thirds of the root canal. However, both groups showed less smear layer removal in the apical region. Specimens treated with distilled water showed the least reduction in the smear layer throughout the length of the root canals. Regarding the evaluation of microhardness, both EDTA and NAC had a significant reduction in root dentin microhardness. However, the percentage of dentin microhardness reduction was significantly more in the EDTA group (p < 0.05) than N-acetyl cysteine in the coronal, middle, and apical third of the root canals.Conclusion: The chelating property of NAC is equally effective to that of EDTA in the smear layer from the root canal, and it induced a significantly lesser reduction in microhardness of root dentin than EDTA.

Raman Spectroscopic Characterization of Endodontic Biofilm Matrices

Endodontic persistent infections are often mediated by bacterial biofilms. This mode of bacterial growth is characterized by the presence of a matrix mainly composed of extracellular polymeric substances (EPSs) that protect the encased microorganisms. To establish better control and disinfection protocols, elucidation of the main components of biofilm matrices present in endodontic infections is required. The aim of the present study was to characterize the principal components ofE. faecalis,A. naeslundii, and dual-species biofilm matrices by means of Raman spectroscopy and confocal scanning laser microscopy (CSLM) techniques. The total biomass of biofilms was quantified via crystal violet assays, and the monospecies biofilms showed higher biomass than the dual-species biofilms. Raman spectroscopy and confocal laser scanning microscopy were used to identify the biochemical composition and structure of the biofilm matrices. Spectra originating from the biofilms of two endodontic pathogens show the presence of carbohydrates, proteins, fatty acids, and nucleic acids in all samples; however, variation in the levels of expression of these biomolecules allows spectroscopic differentiation of the biofilms using principal component analysis. This study is the first attempt to identify the composition of monospecies and dual-species biofilms of endodontic origin. Our data provides an important approach to the understanding of molecular dynamics of endodontic infections.

Antimicrobial Activity of Probiotics against Endodontic Pathogens:- A Preliminary Study

AbstractIntroduction: The purpose of this study was to evaluate the antibacterial effectiveness of probiotics lactobacilli group and Bifidobacterium against Enterococcus faecalis and Candida albicans in both planktonic stage and biofilm stage. Materials and Methods: Phase 1 of the study was conducted by agar well diffusion method. About 0.5 ml of test pathogen culture was inoculated on 20 ml of molten agar and allowed to solidify. 4–5 circular wells of diameter 8–10 mm were punched in each poured plates and 150 μl of diluted test samples were added to the wells. Phase 2 was deferred antagonism test, wherein purified culture of pathogen strain was streaked at right angle to the original producer growth and incubated at 37°C for 24 h. Zone of inhibition was measured for both the phases. Phase 3 biofilm stage evaluation was conducted by mixing 9 ml of 30% poloxamer 407 and De Man, Rogosa and Sharpe (MRS) broth in a test tube with 500 μl of either pathogen, together with 500 μl of test probiotic strains and incubated (37°C, 48 h), followed by serially diluting the mixture by 1 ml into 9 ml sterile saline till 108 dilutions for evaluation of colony-forming unit/ml counts. Controls were endodontic pathogens in 30% poloxamer with MRS broth and no probiotics. Results: Results were evaluated and statistically analysed using one-way analysis of variance and unpaired t-test. In the planktonic stage, probiotics showed inhibitory activity against endodontic pathogens with valid statistical significance (P < 0.05), while there was no activity by deferred antagonism method. In biofilm stage, all three probiotics showed growth reduction for E. faecalis, while lactobacilli group showed reduction in C. albicans colonies. Conclusion: This preliminary study suggested that probiotics are effective for preventing the growth of endodontic pathogens in vitro. Poloxamer could be utilised as an ideal delivery vehicle for probiotics.

Antibacterial Activity of Zinc Oxide Nanoparticles on the Growth of Enterococcus Feacales, Candida and Total Root Canal Microbiota (in Vitro Study)

Severalendodontic irrigants,medication can eliminate endodontic pathogens,the possible development of resistant bacterial species, the anatomic complexity of the root canal system and limitation of cleaning and shaping protocols making the achieving of complete elimination of the pathogens is difficult. Antimicrobial nanoparticles show promising effect against pathogens The concept of using nanoparticles in endodontics as a new treatment modality was developed recently and their antibacterial efficacy against endodontic pathogens was evaluated by several researchers in many in vitro studies. The aim of this study to evaluate the antimicrobial activity of zinc oxide nanoparticles against E.feacales, candida and total root canal microbiota.30 patients diagnosed with necrotic root canal and failed endodontic treatments was selected, microorganisms were isolated from root canals andcultured, After identification and isolation of bacterial species, agar diffusion method was used to assess the antibacterial action of ZNO NPs, Zones of inhibition (no growth of bacteria) were examined around the wells containing ZNO NPs & diameters of the zones were measured in mm. The mean of inhibition zones was measured and statistically analyzed among groups using ANOVA. Znonps showed increase in diameter of the inhibition zone as the concentration increased, 2% concentration showed the larger inhibition zone, When comparing between the diameter of the inhibition zone of the ZNO NPs on the bacteria using F-test for all concentration the result was highly significant except for 0.25% concentration it was non-significant. It can be conclude that the zinc oxide nanoparticles in different concentrations have inhibition effects on E. feacales, candida, T. aerobic and T. anaerobic, the sensitivity of the bacteria to ZnO NPs increase with increasing of the concentration.

An In vitro Evaluation of Antimicrobial Efficacy of new Nano-zinc Oxide Eugenol (NZOE)

Introduction: This interventional in-vitro study aimed to evaluate the antimicrobial activity of a new Nano Zinc OxideEugenol (NZOE) sealer in comparison with AH26 and Pulpdent common root canal sealers against endodontic pathogens. Methods: The antimicrobial efficacy of three sealers(NZOE, AH26 and Pulpdent) against Enterococcus faecalis (ATCC 29212), Escherichia coli (ATCC 25922), Streptococcus mutans (ATCC700610), Candida albicans (ATCC 90028), and Staphylococcus aureus (ATCC 25923) were evaluated by Direct Contact Test (DCT) at five different time intervals 0, 2, 14, 48 hours and 7 days. The results were statistically analyzed using SPSS software and Kruskal–Wallis at 5% significance level. Results: All three tested sealers had antimicrobial activity against microorganisms involved in this study. Fresh NZOE sealer eliminated all microorganisms tested, except the strain of E. faecalis colony which was reached to zero after 2 hours. However, AH26 and Pulpdent failed to completely kill all of the E. faecalis colony during the entire observation period. Also, NZOE showed a significant antimicrobial action (P<0.05) in comparison with other two sealers by effectively eliminating the Candida albicans colonies at zero time and 7 days. Conclusion: Highest antimicrobial effect of NZOE sealer was shown followed by Pulpdent sealer and AH 26 against Candida albicans and Enterococcus faecalis.

Proteomic profile of root canal contents in teeth with post‐treatment endodontic disease

To characterize the proteome of 20 root canals in teeth with post-treatment endodontic disease using mass spectrometry and to correlate the identified proteins with clinical features. Twenty patients with radiographic evidence of apical periodontitis and need for root canal re-treatment were selected. Samples from the root canal contents were collected and processed using two-dimensional capillary nano-flow liquid chromatography and electrospray ionization tandem mass spectrometry. The acquired spectra were separately searched against specific protein database. The results obtained were analysed using descriptive statistics. Additionally, Pearson's chi-square test or one-sided Fisher's exact test, as appropriate, was chosen to examine the null hypothesis that there is no relationship between each clinical feature and the presence of specific microbial or human proteins. Significance levels were set at 5% (P<0.05). A total of 1153 human and 720 microbial UniProt accession numbers corresponding to proteins were recovered. The greater prevalence of proteins was related to biological functions, such as cellular and metabolic processes. A considerable number of microbial proteins with clinical relevance functions, such as pathogenesis/virulence, proteolysis, cell adhesion and drug resistance, were detected. Common endodontic pathogens related to post-treatment endodontic disease such as Enterococcus spp., Propionibacterium spp. and Streptococcus spp. were associated with 23, 40 and 94 distinct proteins, respectively. As for human proteins, many factors related to the immune system process were detected. No significant correlations were found between microbial and human proteins and the clinical features investigated (P>0.05). A considerable number of microbial and human proteins were identified using proteomic analyses, being mainly related to processes indicating cell viability. No significant correlation was found between proteins and clinical features. These findings suggest a network of important microbial pathogenic functions that may be responsible for the host immune system response.

Endodontic pathogens possess collagenolytic properties that degrade human dentine collagen matrix

To measure collagenolytic protease activity from Enterococcus faecalis and Micrococcus luteus and their ability to degrade human dentinal collagen. Proteases activity of E.faecalis ATCC 29212, ATCC 47077 and M.luteus towards generic and specific human matrix metalloproteinase (MMP) substrates was measured using a fluorimetric assay. The ability of the bacteria to degrade dentinal collagen was tested by quantifying the amount of hydroxyproline released into the media following incubation of the bacteria or heat-inactivated bacteria (HIN) with demineralized human dentine samples for 24h and by scanning electron microscopy (SEM). Multifactorial anova and Tukey's post hoc test were used to analyse the data (P<0.05). All strains had MMP-like activities, but with different substrate affinity; E.faecalis ATCC 29212, ATCC 47077 and M.luteus had the greatest affinity towards MMP-8 (7.75±0.88μmolL-1 /3×106 CFU), MMP-9 (33.86±5.16μmolL-1 /3×106 CFU) and generic MMP (26.08±4.48μmolL-1 /3× 106 CFU), respectively. The amount of hydroxyproline released from demineralized dentine was similar (P>0.05) for the three strains (range 1.8±0.17 to 2.38±0.39μg50μL-1 ) and was significantly higher (P<0.001) compared to their HIN counterparts (0.61±0.22μg50μL-1 ). SEM revealed increased collagen network degradation after incubation with bacteria versus HIN. Endodontic pathogens possess collagenolytic protease properties that enable them to degrade dentinal collagen, potentially compromising the restoration-tooth and sealer-tooth interfaces. These collagenolytic protease properties could facilitate the migration of pathogenic bacteria into the root canal system and explain in part their role in root canal infections.

Synergistic Effect of Newly Introduced Root Canal Medicaments; Ozonated Olive Oil and Chitosan Nanoparticles, Against Persistent Endodontic Pathogens.

This study was conducted to investigate the antimicrobial-biofilm activity of chitosan (Ch-NPs), silver nanoparticles (Ag-NPs), ozonated olive oil (O3-oil) either separately or combined together against endodontic pathogens. While testing the antimicrobial activity, Ch-NPs showed the least minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values exerting eightfold higher bactericidal activity than O3-oil against both Enterococcus faecalis and Streptococcus mutans as well as fourfold higher fungicidal activity against Candida albicans. Antimicrobial synergy test revealed synergism between O3-oil and Ch-NPs against the test pathogens (FIC index ≤ 0.5). Ch-NPs was superior at inhibiting immature single and mixed-species biofilm formations by 97 and 94%, respectively. Both of O3-oil and Ch-NPs had a complete anti-fibroblast adherent effect. The safety pattern results showed that O3-oil was the safest compound, followed by Ch-NPs. The double combination of Ch-NPs and O3-oil reduced the mature viable biofilm on premolars ex vivo model by 6-log reductions, with a fast kill rate, indicating potential use in treating root canals. Therefore, the double combination has the potential to eradicate mature mixed-species biofilms and hence it is potent, novel and safe.

Comparative Evaluation of Antimicrobial Activity of Quercetin against Endodontic Pathogens in Primary Molars

Comparative Evaluation of Antimicrobial Activity of Quercetin against Endodontic Pathogens in Primary Molars

Antibacterial Efficacy and Discoloration Potential of Endodontic Topical Antibiotics

IntroductionThe optimal concentration for the use of endodontic topical antibiotics is not known. The aims of this study were to determine the minimum bactericidal concentrations (MBCs) and minimum inhibitory concentrations (MICs) of metronidazole, ciprofloxacin, minocycline, Augmentin (GlaxoSmithKline, Research Triangle Park, NC), and tigecycline against common endodontic pathogens and to evaluate ex vivo the antibacterial efficacy and discoloration effect of triple antibiotic paste (TAP), Augmentin, and tigecycline at different concentrations using a slow-release hydrogel scaffold. MethodsUsing the Epsilometer test method (Etest; bioMérieux USA, St Louis, MO), MICs and MBCs of selected antibiotics were determined against Fusobacterium nucleatum, Porphyromonas gingivalis, Streptococcus intermedius, and Enterococcus faecalis. Biofilms of these bacterial species were then grown in extracted single-rooted teeth anaerobically for 3 weeks. Root canals were filled with TAP, Augmentin, and tigecycline at concentrations of 1 or 0.1 mg/mL in a degradable hydrogel scaffold or pure TAP at 1 g/mL for 7 days. Coronal discoloration was evaluated spectrophotometrically at 1, 2, and 3 weeks after dressing. ResultsMIC/MBC data showed significant efficacy of tigecycline, Augmentin, and minocycline compared with the other antibiotics (P < .05). Significant differences were found when comparing the log10 colony-forming units of all experimental groups (P < .05). TAP at 1 g/mL had no bacterial growth but caused the greatest discoloration. Hydrogel mixtures with TAP, Augmentin, or tigecycline at 1 mg/mL significantly reduced bacterial growth and the number of positive samples compared with those at 0.1 mg/mL (P < .05) with minimal discoloration. ConclusionsTAP, Augmentin, and tigecycline in a hydrogel at 1 mg/mL reduced bacterial growth significantly with minimal color change.

Expression patterns of oxyR induced by oxidative stress from Porphyromonas gingivalis in response to photo-activated disinfection.

IntroductionPorphyromonas gingivalis, an important endodontic pathogen, may be exposed to sublethal doses of photo-activated disinfection (sPAD) during root canal therapy. Such an exposure can affect bacterial survival and virulence features. In this study, we evaluated the effect of sPAD-related oxidative stresses on the expression of oxidative stress response gene (oxyR) in P. gingivalis clinical isolates surviving in vitro photodynamic treatment.Materials and methodsTo determine the sPAD, 16 clinical P. gingivalis isolates photosensitized with toluidine blue O (TBO), methylene blue (MB), and indocyanine green (ICG) were irradiated with specific wavelength and energy density of diode laser corresponding to the photosensitizers following bacterial viability measurements. The effects of sPAD on the expression ratio of oxyR of 16 clinical P. gingivalis isolates were then assessed using quantitative real-time PCR (qRT-PCR) assay.ResultsMaximum values of sPAD against P. gingivalis were 6.25, 15.6, and 25 μg/mL at fluencies of 171.87, 15.6, and 93.75 J/cm2, respectively, for TBO-, ICG-, and MB-sPAD (P>0.05). ICG-, MB-, and TBO-sPAD could increase the oxyR gene expression of the clinical P. gingivalis isolates 12.3-, 5.6-, and 8.5-fold, respectively. ICG-sPAD increased the expression of oxyR gene in clinical isolates of P. gingivalis ~1.5- and 2-fold higher than TBO- and MB-sPAD, respectively.ConclusionOur results showed that upregulation of oxyR during sPAD may lead to better survival and increased pathogenicity of P. gingivalis isolates. Therefore, selection of appropriate photo-activated disinfection dosage should be considered for the successful treatment of endodontic infection.