Bacteria In Root Canals Research Articles

PORÓWNANIE SKUTECZNOŚCI DEZYNFEKCJI SYSTEMU KANAŁOWEGO WYKONYWANEJ Z ZASTOSOWANIEM ORAZ BEZ STOSOWANIA KOFERDAMU

Endodontic treatment consists in necrotic pulp removal, proper root canal preparation, and sealed obliteration. The effectiveness of treatment depends on careful root canal disinfection of existing bacteria. Modern endodontics recommends the use of a rubber dam, not only to protect the patient from endodontic instrument aspiration, but also to protect root canals from bacteria existing in saliva. The aim of the study is a comparison of root canal disinfection among patients treated with and without rubber dam protection. Endodontic treatient of 36 patients who came to the Department of Conservative Dentistry and Endodontics was performed. 36 teeth were qualified to the treatment. In 17 patients the whole treatment was done with rubber dam protection. In the other 19 (II group) the treated tooth was isolated only by cotton rolls. After chamber trepanation, and after chemo-mechanical root canal preparation, samples of root canal bacteria were taken. After 24h incubation, the density of bacterial suspension was checked using a spectrophotometer. In both groups of patients very similar results were obtained: a high density of bacterial suspension in samples taken before treatment, and a significantly lower density in samples taken after chemo-mechanical root canal preparation. In our research the use or lack of use of a rubber dam does not change the effectiveness of root canal disinfection.

Efficacy of 4 Irrigation Protocols in Killing Bacteria Colonized in Dentinal Tubules Examined by a Novel Confocal Laser Scanning Microscope Analysis

IntroductionThe aim of this study was to determine the efficiency of 4 irrigation systems in eliminating bacteria in root canals, particularly in dentinal tubules. MethodsRoots of human teeth were prepared to 25/04, autoclaved, and inoculated with Enterococcus faecalis for 3 weeks. Canals were then disinfected by (1) standard needle irrigation, (2) sonically agitating with EndoActivator, (3) XP Endo finisher, or (4) erbium:yttrium aluminum garnet laser (PIPS) (15 roots/group). The bacterial reduction in the canal was determined by MTT assays. For measuring live versus dead bacteria in the dentinal tubules (4 teeth/group), teeth were split open and stained with LIVE/DEAD BackLight. Coronal, middle, and apical thirds of the canal dentin were scanned by using a confocal laser scanning microscope (CLSM) to determine the ratio of dead/total bacteria in the dentinal tubules at various depths. ResultsAll 4 irrigation protocols significantly eliminated bacteria in the canal, ranging from 89.6% to 98.2% reduction (P < .001). XP Endo had the greatest bacterial reduction compared with other 3 techniques (P < .05). CLSM analysis showed that XP Endo had the highest level of dead bacteria in the coronal, middle, and apical segments at 50-μm depth. On the other hand, PIPS had the greatest bacterial killing efficiency at the 150-μm depth in all 3 root segments. ConclusionsXP Endo appears to be more efficient than other 3 techniques in disinfecting the main canal space and up to 50 μm deep into the dentinal tubules. PIPS appears to be most effective in killing the bacteria deep in the dentinal tubules.

Comparative evaluation of antimicrobial effect of herbal root canal irrigants (Morinda citrifolia, Azadirachta indica, Aloe vera) with sodium hypochlorite: An in vitro study.

Aim and Objectives:Successful root canal treatment involves the complete elimination of microorganism from the root canal and the three-dimensional obturation of the canal space. Enterococcus faecalis is the most commonly found bacteria in failed root canal. Chemical irrigation of canals along with biomechanical preparation helps in the elimination of microorganisms. The present study was aimed to evaluate the antimicrobial effect of herbal root canal irrigants (Morinda citrifolia, Azadirachta indica extract, Aloe vera) with sodium hypochlorite (NaOCl).Materials and Methods:The bacterial E. faecalis (ATCC) culture was grown overnight in brain heart infusion (BHI) broth and inoculated in Mueller–Hinton agar plates. Antibacterial inhibition was assessed using agar well diffusion method. All five study irrigants were added to respective wells in agar plates and incubated at 37°C for 24 h. Bacterial inhibition zone around each well was recorded. Results were tabulated and statistically analyzed using Statistical Package for the Social Sciences software for Windows, version 19.0. (IBM Corp., Armonk, NY.Results:Highest inhibitory zone against E. faecalis was seen in NaOCl fallowed by M. citrifolia and A. indica extract, and the least by A. vera extract.Conclusion:Tested herbal medicine (A. indica extract, M. citrifolia, A. vera) showed inhibitory zone against E. faecalis. Hence, these irrigants can be used as root canal irrigating solutions.

Strains of Enterococcus faecalis differ in their ability to coexist in biofilms with other root canal bacteria.

To investigate the relationship between protease production and the ability of Enterococcus faecalis strains to coexist in biofilms with other bacteria commonly recovered from infected root canals. Biofilms with bacteria in mono-, dual- and four-species communities were developed in flow chambers. The organisms used were Lactobacillus salivarius, Streptococcus gordonii and Actinomyces naeslundii and E. faecalis strains, GUL1 and OG1RF. Biovolume and species distribution were examined using 16S rRNA fluorescence in situ hybridization in combination with confocal microscopy and image analysis. The full proteome of the E. faecalis strains was studied using two-dimensional gel electrophoresis. Spots of interest were identified using tandem mass spectroscopy and quantified using Delta 2D software. All bacteria formed biofilms and an anova analysis revealed that the biofilm biomass increased significantly (P ≤ 0.01) between 6 and 24 h. L. salivarius, S. gordonii and A. naeslundii formed mutualistic biofilm communities, and this pattern was unchanged when E. faecalis GUL1 was included in the consortium. However, with OG1RF, L. salivarius and S. gordonii were outcompeted in a 24-h biofilm. Proteomic analysis revealed that OG1RF secreted higher levels of proteases, GelE (P = 0.02) and SprE (P = 0.002) and a previously unidentified serine protease (P = 0.05), than GUL1. Different strains of E. faecalis can interact synergistically or antagonistically with a consortium of root canal bacteria. A possible mechanism underlying this, as well as potential differences in virulence, is production of different levels of proteases, which can cause detachment of neighbouring bacteria and tissue damage.

KÖK KANAL PATOJENLERİNİN TESPİTİNDE KULLANILAN TANI YÖNTEMLERİ

Nowadays, it is known that endodontic infections are polymicrobial and there are 3-12 kinds of bacteria in an infected root canal. Flare-ups, periapical destructions and persistent endodontic infections related bacteria and the identification of these bacteria are highly important and topical issues in endodontics. Microscopy, culture and antibiotic susceptibility testing, immunological and molecular biological methods have been used to detect pathogens in root canal. Today, in vitro DNA replication is provided by moleculer methods in three stages named denaturation, primer binding and extension of primers, thus millions of copies of a gene can be achieved by PCR. The aim of this review is to provide information about the methods used to determine the root canal pathogens and to introduce the molecular genetic methods. Especially, it is aimed to discuss the gene targets for microbial identification, PCR and its derivates for specific use, the advantages and disadvantages of PCR for microbial identification

Isolation of Alkaline-tolerant Bacteria from Primary Infected Root Canals

IntroductionAlkaline-tolerant bacteria in primary infected root canals could have enhanced survival capacity against antimicrobials commonly used in root canal treatment. The aims of this study were to isolate and characterize alkaline-tolerant bacteria before endodontic treatment (S1), after chemomechanical root canal preparation (S2), and after calcium hydroxide dressing (S3). MethodsBacteriologic samples were obtained from 43 primary infected root canals. Samples were inoculated into culture media at a pH of 9 and incubated anaerobically. The identities of bacterial isolates were determined by 16S ribosomal RNA sequencing. ResultsAll S1 samples were culture positive, with 70% harboring bacteria tolerating a pH of 9. Gram-positive bacteria Pseudoramibacter alactolyticus and Streptococcus spp were the most frequently isolated strains with a prevalence of 54%. Of 13 culture-positive S2 samples, 8 isolates tolerated a pH of 9, namely Streptococcus sanguinis, Enterococcus faecalis, Enterobacter cancerogenus, Streptococcus oralis, and Fusobacterium nucleatum. Seven of these 8 isolates (88%) were correspondingly isolated at S1. All 3 culture-positive S3 samples tolerated a pH of 9, namely S. sanguinis and E. faecalis, which were also isolated in the corresponding S1 and S2 samples. ConclusionsWe showed that the presence of alkaline-tolerant Streptococcus and Enterococcus spp in primary infected root canals could lead to their persistence during and after root canal treatment and could pose a challenge to current treatment efficacy.

Combinations of bacterial species associated with symptomatic endodontic infections in a Chinese population.

To use microarrays to detect 11 selected bacteria in infected root canals, revealing bacterial combinations that are associated with clinical symptoms and signs of primary endodontic infections in a Chinese population. DNA was extracted from 90 samples collected from the root canals of teeth with primary endodontic infections in a Chinese population, and the 16S rRNA gene was amplified by polymerase chain reaction (PCR). The PCR products were hybridized to microarrays containing specific oligonucleotide probes targeting 11 species, and the arrays were screened with a confocal laser scanner. Pearson's chi-squared test and cluster analysis were performed to investigate the associations between the bacterial combinations and clinical symptoms and signs using SAS 8.02. Seventy-seven samples (86%) yielded at least one of the 11 target species. Parvimonas micra (56%), Porphyromonas endodontalis (51%), Tannerella forsythia (48%), Prevotella intermedia (44%) and Porphyromonas gingivalis (37%) were the most prevalent taxa and were often concomitant. The following positive associations were found between the bacterial combinations and clinical features: P. endodontalis and T. forsythia with abscess; P. gingivalis and P. micra with sinus tract; P. gingivalis and P. endodontalis or P. micra and P. endodontalis with abscess and sinus tract; and the combination of P. endodontalis, P. micra, T. forsythia and P. gingivalis with sinus tract (P < 0.05). Various combinations of P. micra, P. endodontalis, T. forsythia and P. gingivalis may contribute to abscesses or sinus tracts of endodontic origin with bacterial synergism in a Chinese population.

Evaluation of antibacterial effect of irrigant solutions (titanium tetra fluoride, green tea, sodium hypochlorite, normal saline) using real-time quantitative – polymerase chain reaction

Removal of bacteria from the pulp system by instrumentati on of an infected root canal, will be significantly reduced the number of bacteria, but it is well documented that instrumentation alone can-not clean and kill all bacteria found on the root canal walls. Antibacterial irrigants are needed to kill the remaining microorganisms. The aims of this study was to assess antibacterial effect of titanium tetrafluoride (TiF4) solution and brewing green tea against root canal bacteria and to compare with sodium hypochlorite and normal saline through microbiological and molecular studies. Materials and methods: Microbiologica l study was carried out to determine the concentration of titanium tetrafluoride and brewing green tea at which they exert antibacterial effect against ten swabs that had been taken from necrotic root canals that were incubated aerobically and anaerobically by paper disk diffusion test, whilemolecular study carried out among Forty children in which the antibacterial effect of titanium tetrafluoride and brewing green tea compared with sodium hypochlorite and normal saline were assessed by real time polymerase chain reaction using SYBR Green. Results: The microbiological study results showed that TiF4 achieved maximum antibacterial effect at concentration 5% against aerobic and anaerobic bacteria while green tea exhibited antibacterial effect when brewed for 20 minutes at concentration 100mg/1ml against staphylococcus aureus, but not active against other microorganisms like Escherichia coli and streptococcus. While results of molecular study illustrated that sodium hypochlorite remained the most effective endodontic irrigant solutions followed by titanium tetrafluoride then green tea while normal saline showed no antibacterial effect. Statistically titanium tetrafluoride, green tea and sodium hypochlorite have significant differences compared to normal saline. Conclusions: This study revealed that, titanium tetra fluoride and brewing green tea can be used as antibacterial

Biofilm in endodontics: A review

Endodontic disease is a biofilm-mediated infection, and primary aim in the management of endodontic disease is the elimination of bacterial biofilm from the root canal system. The most common endodontic infection is caused by the surface-associated growth of microorganisms. It is important to apply the biofilm concept to endodontic microbiology to understand the pathogenic potential of the root canal microbiota as well as to form the basis for new approaches for disinfection. It is foremost to understand how the biofilm formed by root canal bacteria resists endodontic treatment measures. Bacterial etiology has been confirmed for common oral diseases such as caries and periodontal and endodontic infections. Bacteria causing these diseases are organized in biofilm structures, which are complex microbial communities composed of a great variety of bacteria with different ecological requirements and pathogenic potential. The biofilm community not only gives bacteria effective protection against the host's defense system but also makes them more resistant to a variety of disinfecting agents used as oral hygiene products or in the treatment of infections. Successful treatment of these diseases depends on biofilm removal as well as effective killing of biofilm bacteria. So, the fundamental to maintain oral health and prevent dental caries, gingivitis, and periodontitis is to control the oral biofilms. From these aspects, the formation of biofilms carries particular clinical significance because not only host defense mechanisms but also therapeutic efforts including chemical and mechanical antimicrobial treatment measures have the most difficult task of dealing with organisms that are gathered in a biofilm. The aim of this article was to review the mechanisms of biofilms’ formation, their roles in pulpal and periapical pathosis, the different types of biofilms, the factors influencing biofilm formation, the mechanisms of their antimicrobial resistance, techniques to identify biofilms.

Bakteri dominan di dalamsaluran akar gigi nekrosis (Dominant bacteria in root canal of necrotic teeth)

One disease that often affects the pulp is necrotic teeth, which are caused by some irritants. Most major irritants aremicrobes, such as bacteria. This study aimed to determine the type of bacteria in the necrotic root canal. Samples wereobtained from fifteen patients with necrotic teeth in Conservation Clinic of Dental Hospital, Faculty of Dentistry,Hasanuddin University. Specimens of bacteria from samples taken using paper points were inserted into the root canal.The specimens identified in the Laboratory of Microbiology, Faculty of Medicine. The results showed that there areseven types of bacteria that vary in number, most are gram-positive facultative anaerobic bacteria Actinomyces spp. Itwas concluded that Actinomyces spp. is the dominant species of bacteria on the necrotic tooth root canal.

In vitro activity of photoactivated disinfection using a diode laser in infected root canals

Objective. To investigate the lethal activity of photoactivated disinfection (PAD) on Enterococcus faecalis (ATCC 29212) and mixed populations of aerobic or anaerobic bacteria in infected root canals using a diode laser after the application of a photosensitizer (PS). Materials and methods. First, the bactericidal activity of a low power diode laser (200 mW) against E. faecalis ATCC 29212 pre-treated with a PS (toluidine blue) for 2 min were examined after different irradiation times (30 s, 60 s and 90 s). The bactericidal activity in the presence of human serum or human serum albumin (HSA) was also examined. Second, root canals were infected with E. faecalis or with mixed aerobic or anaerobic microbial populations for 3 days and then irrigated with 1.5% sodium hypochlorite and exposed to PAD for 60 s. Results. Photosensitization followed by laser irradiation for 60 s was sufficient to kill E. faecalis. Bacteria suspended in human serum (25% v/v) were totally eradicated after 30 s of irradiation. The addition of HSA (25 mg/ml or 50 mg/ml) to bacterial suspensions increased the antimicrobial efficacy of PAD after an irradiation time of 30 s, but no longer. The bactericidal effect of sodium hypochlorite was only enhanced by PAD during the early stages of treatment. PAD did not enhance the activity of sodium hypochlorite against a mixture of anaerobic bacteria. Conclusions. The bactericidal activity of PAD appears to be enhanced by serum proteins in vitro, but is limited to bacteria present within the root canal.

Detection of bacteria in endodontic samples and its association with defined clinical signs and symptoms of endodontic infection

Introduction : The role of bacteria in pulpal and periradicular lesions is well established. However, the association of bacterial species with signs and symptoms of endodontic infection is not well elucidated. The purpose of this study was to investigate the types of bacterial species in infected root canals (using MicroSeq 500 16S ribosomal ribonucleic acid, rRNA) and the association of bacterial species with clinical signs and symptoms of different pulpal and periapical infections. Materials and Methods: Microbial samples were obtained from 92 adult patients (one tooth with single root canal for each patient). Clinical data including signs and symptoms were collected. Polymerase chain reaction (PCR) (MicroSeq 500 16S rRNA) was used to detect bacteria in the infected root canals. Results: A total of 179 bacterial species were identified. Actinomyces viscosus and Streptococcus sanguis were associated with the presence of pain. While Staphylococcus haemolyticus and Veillonella spp. were associated with pain of palpation, the pain to percussion was associated with Actinomyces spp., Actinomyces naeslundii, and Actinomyces viscosus. Also, Streptococcus mitis, Bacteroides spp., and Veillonella spp. were associated with periapical swelling. The presence of sinus tract was found to be significantly associated with Neisseria spp. and Staphylococcus haemolyticus. The wet canal was significantly associated with the presence of Propionibacterium acnes and Bacteroides spp. Conclusions: There are significant associations between the presence of some bacterial species with clinical signs and symptoms of infected root canals.

Effect of Thyme Water Extract on Commonly Found Oral and Root Canal Bacteria (A Comparative Study)

Back ground and objectives: Bacteria and their products play an essential role in the pathogenesis of pulpo-periapical disease. The purpose of this study was to compare the anti-microbial activity of thyme water extract on selected bacterial isolates and culti- vated root canal swabs in comparison with different concentrations of sodium hypochlorite (NaOCl). M aterials and Methods: Clinical isolates of Staphylococcus aureus , Moraxella catarrhalis , and Klebsiella pneumoniae were selected. Microbiological samples from infected root canals were taken from forty five male and female patients in age group of 15-45 years old during the first visit of root canal therapy. Antibacterial assay were done by agar well diffusion method and microdilution assay. Re sults: The best antimicrobial activity for thyme extract was noticed at Moraxella catarrhalis and failed to show any significant effect on Klebsiella pneumoniae . The results revealed that 2% sodium hypochlorite are more effective than thyme water extract, on evaluated bacterial isolates and swabs. Co nclusion: From bacteriological point of view, it could be demonstrated that water extracts of thyme (infusion method), may be useful for root canal irrigation with their antibacterial effect.

Bacterial analysis of combined periodontal-endodontic lesions by polymerase chain reactiondenaturing gradient gel electrophoresis

We used denaturing gradient gel electrophoresis (DGGE) to compare bacterial profiles in periodontium and root canals of teeth with combined periodontal-endodontic lesions. Samples of dental plaque and necrotic pulp were collected from thirteen extracted teeth with advanced periodontitis. Genomic DNA was extracted for polymerase chain reaction (PCR) analysis using universal bacterial primers. The PCR products were then loaded onto DGGE gels to obtain fractionated bands. Characteristic DGGE bands were excised and DNA was cloned and sequenced. The number of bands, which indicates the number of bacterial species, was compared between dental plaques and necrotic pulp tissues from the same tooth. Although the difference was statistically significant (P < 0.01), there was no positive correlation; similarity (Dice coefficient) was 13.1% to 62.5%. Some bacteria species were present in both the periodontal pockets and root canals of the same tooth; however, periodontal bacteria did not always invade the root canals, and some bacteria in root canals were not present in periodontal pockets of the same tooth. In some teeth, unique bacteria in root canals had not passed from periodontal pockets. A basic local alignment search tool (BLAST) sequence search in Genbank indicated that new bacteria species were present in periodontal pockets and root canals. Their characteristics must thus be further analyzed.

Bacterial analysis of combined periodontal-endodontic lesions using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE)

Objective To compare the bacterial community profiles present in periodontium and root canals of the same tooth diagnosed as combined periodontal-endodontic lesions by using denaturing gradient gel electrophoresis (DGGE).Methods Samples were collected from 13 extracted teeth with advanced periodontitis,endodontic samples from root tip 1/3 root canal,and periodontal samples from the corresponding neighboring periodontium.Genomic DNA was collected for the following universal bacterial primersPCR.The PCR products were then loaded on the DGGE gels to gain separate bands.The typical DGGE bands were excised,PCR-cloned and sequenced.Results The number of bands,which was indicative of the number of bacterial species,was compared intra-group (periodontal and pulpal specimen from the same tooth).The difference was statistically significant (P＜0.01),but there was no positive correlation between them.The similarity (Dice Coefficient) between them was 13.1％-62.5％.Taxa identified through BLAST (≥98％ identity) were Campylobacter,Fusobacterium,Neisseria,et al in the periodontium,and Mogibacterium,Corynebacterium,Actinomyces,et al in the root canals.Conclusion Common bacteria existed between them,but not all of the periodontal bacteria would appear in neighboring root canal; and the bacteria in the root canal are not completely from neighboring periodontal tissue.The original bacteria in the root canals may resuscitate and enrich the bacterial community.In combined periodontal-endodontic lesions (periodontal source),it is probable that new species existed to be confirmed either in the periodontium or in the root canal. Key words: Combined periodontal-endodontic lesions; Denaturing gradient gel electrophoresis; 16S rDNA; Bacteria

Supplementing the Antimicrobial Effects of Chemomechanical Debridement with Either Passive Ultrasonic Irrigation or a Final Rinse with Chlorhexidine: A Clinical Study

IntroductionThe ability of 2 different approaches to supplement the antimicrobial effects of chemomechanical debridement in infected root canals was compared in vivo. MethodsSamples from necrotic root canals of teeth with apical periodontitis were taken at the baseline (S1), after preparation with rotary nickel-titanium BioRaCe instruments and 2.5% NaOCl irrigation (S2), and then after either passive ultrasonic irrigation (PUI) for activation of NaOCl (n = 13) or a final rinse with 2% chlorhexidine (CHX) (n = 14) (S3). The incidence of positive culture for bacteria and fungi as well as positive broad-range polymerase chain reaction (PCR) results for bacteria, fungi, and archaea was determined. ResultsAll S1 samples were positive for bacteria in all methods. Fungi were not detected, and archaea occurred in only one S1 sample. Treatment procedures were significantly effective in reducing the incidence of positive culture and PCR results. Although both supplementary approaches reduced the incidence of positive bacteriologic results when compared with postinstrumentation samples, reduction was not statistically significant (P > .05). There was no significant difference for intergroup comparisons either (P > .05). ConclusionsAlthough supplementary disinfection with either PUI or a final rinse with CHX can reduce the number of cases with positive culture and PCR results for bacteria, many cases still remain with detectable bacteria in the main root canal. Research on alternative or supplementary antimicrobial methods or substances should be encouraged.

Decreased Bacterial Adherence and Biofilm Growth on Surfaces Coated with a Solution of Benzalkonium Chloride

IntroductionSecondary biofilm formation by oral bacteria after breakdown/fracture of temporary or permanent restorations imposes a challenge to the outcome of root canal treatment. This study focuses on benzalkonium chloride (BAK) coating on dentin or polystyrene surfaces and its influence on the early adhesion and biofilm formation by oral and root canal bacteria. MethodsMicrobial adhesion and biofilm growth on surfaces coated with BAK were analyzed qualitatively with a dentin disk model and quantitatively with a mini-flow cell biofilm model. Cell viability and total biovolume were analyzed by the LIVE/DEAD technique. The repelling effect of surfaces coated with BAK was compared with NaOCl. Uncoated surfaces were used as controls. ResultsScanning electron microscope images in the dentin disk model revealed that very sparse biofilms were formed on NaOCl- and BAK-coated dentin surfaces. In contrast, biofilms formed on uncoated dentin were clearly visible as numerous irregularly distributed aggregates of rods and cocci. In the mini-flow cell system, confocal laser scanning microscope analysis confirmed that biofilms formed on NaOCl- and BAK-coated surfaces showed significantly less adhesion (2 hours) and biovolume accumulation (24 and 96 hours) compared with the uncoated controls (P < .01). Furthermore, cell viability assessments showed that on uncoated controls the viability measurements were high (>89%) as well as on BAK-coated surfaces (88% viable cells). However, cell viability was significantly reduced on NaOCl-coated surfaces (59% viable cells). ConclusionsThis study illustrates that surface coating with a surfactant solution containing BAK does not cause cell membrane damage but might interfere with cell mechanisms of adhesion. Investigations into the clinical utility of BAK as an antibiofilm medication are warranted.

Development of a Multispecies Biofilm Community by Four Root Canal Bacteria

IntroductionThe development of multispecies biofilm models are needed to explain the interactions that take place in root canal biofilms during apical periodontitis. The aim of this study was to investigate the ability of 4 root canal bacteria to establish a multispecies biofilm community and to characterize the main structural, compositional, and physiological features of this community. MethodsFour clinical isolates isolated from infected root canals, Actinomyces naeslundii, Lactobacillus salivarius, Streptococcus gordonii, and Enterococcus faecalis, were grown together in a miniflow cell system. Simultaneous detection of the 4 species in the biofilm communities was achieved by fluorescence in situ hybridization in combination with confocal microscopy at different time points. The LIVE/DEAD BacLight technique (Molecular Probes, Carlsbad, CA) was used to assess cell viability and to calculate 3-dimensional architectural parameters such as biovolume (μm3). Redox fluorescence dye 5-cyano-2,3-ditolyl tetrazolium chloride was used to assess the metabolic activity of biofilm bacteria. ResultsThe 4 species tested were able to form stable and reproducible biofilm communities. The biofilms formed in rich medium generally showed continuous growth over time, however, in the absence of glucose biofilms showed significantly smaller biovolumes. A high proportion of viable cells (>90%) were generally observed, and biofilm growth was correlated with high metabolic activity of cells. The community structure of biofilms formed in rich medium did not change considerably over the 120-hour period, during which E. faecalis, L. salivarius, and S. gordonii were most abundant. ConclusionsThe ability of 4 root canal bacteria to form multispecies biofilm communities shown in this study give insights into assessing the community lifestyle of these microorganisms in vivo. This multispecies model could be useful for further research simulating stresses representative of in vivo conditions.

Rapid Quantification of Bacteria in Infected Root Canals Using Fluorescence Reagents and a Membrane Filter: A Pilot Study on Its Clinical Application to the Evaluation of the Outcomes of Endodontic Treatment

Objective. The bacterial examination has been performed during the course of the root canal treatment. In the present pilot study, the new developed method, using fluorescence reagents and a membrane filter, was applied to the detection and quantification of bacteria in infected root canals, in order to evaluate the outcomes of the treatment. Methods. Six infected root canals with periapical lesions from 5 subjects were included. Informed consent was obtained from all subjects (age ranges, 23–79 years). Samples from infected root canals were collected at the beginning of the treatment (termed #25 First), the end of the first day of treatment (termed #55 First), and the next appointment day (termed #55 Second). Then, the bacterial count (CFU) was measured using fluorescence reagents (4′,6′-diamidino-2-phenylindole and propidium iodide) and the polycarbonate membrane filter by Bioplorer. Results. The mean ± SD of CFU in the sample of “#25 First” was (1.0 ± 1.4) × 105. As the root canal treatment progressed, the CFU decreased as 7.9 × 103 (#55 First) and 4.3 × 102 (#55 Second). Conclusion. In the present pilot study, rapid detection and quantification of bacteria in infected root canals were found to be successfully performed using fluorescence reagents and a membrane filter (Bioplorer analysis).

Antimicrobial activity of a new nanobased endodontic irrigation solution: In vitro study

Aims: The purpose of this study was to introduce a nanosilver particle based endodontic irrigation solution and to evaluate its antimicrobial efficacy in comparison to 5.25% NaOCl. Materials and Methods: In an in vitro experiment the effect of the new irrigant against Enterococcus faecalis (ATCC: 29212) and Staphylococcus aureus (ATCC 25923), two most commonly isolated species of root canal space, was studied in different time intervals of 3, 5 and 15 minutes. Results: No growth of E. faecalis and S. aureus was observed in any of irrigant groups and any of different time intervals. Conclusion: These results indicate that the new irrigant is as effective as NaOCl in preventing the bacterial growth of common root canal bacteria.