Evaluating the Impact of Ultrasonic Irrigation on Bacterial Levels and Activity Following Chemomechanical Procedures.

Introduction: This single-arm interventional trial aimed to investigate the efficacy of ultrasonic irrigation as a supplementary disinfection approach after chemomechanical procedures (CMP) using molecular techniques based on ribosomal RNA (rRNA) and rRNA genes (referred to as DNA).

Methods: Samples were collected from 35 single-rooted teeth with radiographic evidence of apical periodontitis. Samples were taken after gaining root canal access (S1), (S2), and ultrasonic irrigation (S3).

Metatranscriptome and Resistome of the Endodontic Microbiome.

Introduction: In this study, we used metatranscriptomics for the first time to investigate microbial composition, functional signatures, and antimicrobial resistance gene expression in endodontic infections.

Methods: Root canal samples were collected from ten teeth, including five primary and five persistent/secondary endodontic infections. RNA from endodontic samples was extracted, and RNA sequencing was performed on a NovaSeq6000 system (Illumina).

Enhancing Antibiotic Efficacy in Regenerative Endodontics by Improving Biofilm Susceptibility.

Introduction: Various strategies have been researched to enhance the susceptibility of biofilms, given their tolerance to antibiotics. This study evaluated the effect of the anti-microbial peptide nisin in association with antibiotics used in regenerative endodontics, exploring different treatment times and biofilm growth conditions.

Methods: A mixture of 10 bacterial species was cultivated on dentin specimens anaerobically for 21 days.

Antibiofilm Activity of LL-37 Peptide and D-Amino Acids Associated with Antibiotics Used in Regenerative Endodontics on an Ex Vivo Multispecies Biofilm Model.

The antimicrobial peptide LL-37 and D-amino acids (D-AAs) have been proposed as antibiofilm agents. Therefore, this study aimed to test the antimicrobial effect of antibiofilm agents associated with antibiotics used in regenerative endodontic procedures (the triple antibiotic paste—TAP: ciprofloxacin + metronidazole + minocycline). An endodontic-like biofilm model grown on bovine dentin discs was used in this study.

Nature and Prevalence of Bacterial Taxa Persisting after Root Canal Chemomechanical Preparation in Permanent Teeth: A Systematic Review and Meta-analysis.

Introduction: Culture-independent molecular studies have shown a broad spectrum of bacterial taxa that persist after chemomechanical procedures (CMP). Therefore, this study systematically reviewed these reports to explore the prevalence of bacteria in post-instrumentation samples of root canals from permanent teeth, especially of as-yet-uncultivated/difficult-to-culture bacteria.

Methods: Electronic databases were searched from 2007 to January 2021.

Antibacterial Effect of Sodium Hypochlorite and EDTA in Combination with High-Purity Nisin on an Endodontic-like Biofilm Model.

Antimicrobial peptides have been proposed as antibiofilm agents. Therefore, we evaluated the effect of endodontic irrigants combined or not with the antimicrobial peptide nisin against an endodontic biofilm model composed of eleven bacterial species. Biofilms were grown on hydroxyapatite discs for 3, 15 and 21 days and treated with 1.

Identification of Fusobacterium nucleatum in primary and secondary endodontic infections and its association with clinical features by using two different methods.

Objective: Fusobacterium nucleatum is an important oral pathogen involved in endodontic infections. This study aimed to assess the frequency of Fusobacterium nucleatum in primary and secondary endodontic infections and its associations with the clinical features in a Brazilian population by using both culture and nested PCR methods.

Methods: A total of 100 microbial samples from patients with primary (n=50) and secondary endodontic infections (n=50) were analyzed by using culture and nested PCR methods.

Antibacterial Effect of High-Purity Nisin Alone and in Combination with D-Amino Acids or Chlorhexidine in an Endodontic-Like Biofilm Model.

New strategies to eradicate endodontic biofilms are needed. Therefore, we evaluated the effect of high-purity nisin alone and in combination with D-amino acids (D-AAs) or chlorhexidine (CHX) against an "endodontic-like" biofilm model. Biofilms were grown on hydroxyapatite discs for 64 h and treated with nisin, eight D-AAs mixture, nisin + eight D-AAs, 2% CHX, and nisin + 2% CHX.

Analysis of Active Bacteria Persisting after Chemomechanical Procedures: An RNA- and DNA-based Molecular Study.

Introduction: Because active cells present higher abundance of ribosomal RNA (rRNA) than rDNA (rRNA genes), data obtained with rDNA-based quantitative polymerase chain reaction (qPCR) and rRNA-based qPCR (RT-qPCR) were correlated to search for active bacteria after chemomechanical procedures (CMP). In addition, the ability of both assays to detect bacteria in endodontic samples was evaluated.

Methods: Samples were taken from 40 teeth with primary endodontic infections before (S1) and after CMP (S2).

Investigation of Filifactor alocis in primary and in secondary endodontic infections: A molecular study.

Objective: Identification of specific bacteria in root canals (RCs) in distinct clinical conditions can support the comprehension of pathological processes. Thus, the objective of this clinical study was to investigate the presence of F. alocis in RCs of teeth with primary endodontic infection (PEI) and with persistent/secondary endodontic infection (SEI) by using molecular techniques.

Clinical and Molecular Microbiological Evaluation of Regenerative Endodontic Procedures in Immature Permanent Teeth.

Introduction: This study evaluated the bacterial levels after regenerative endodontic procedures and their correlation with the treatment outcome using molecular microbiology methods.

Methods: Root canal samples of 15 necrotic immature teeth were analyzed by quantitative polymerase chain reaction. Bacteria were counted before treatment (S1), after irrigation with 6% sodium hypochlorite (S2), and after intracanal dressing (S3) using either triple antibiotic paste (n = 7) or calcium hydroxide with chlorhexidine (n = 8).

Next-Generation Sequencing to Assess Potentially Active Bacteria in Endodontic Infections.

Introduction: Because active bacteria present a higher abundance of ribosomal RNA (rRNA) than DNA (rRNA gene), the rRNA/DNA ratio of next-generation sequencing (NGS) data was measured to search for active bacteria in endodontic infections.

Methods: Paired complementary DNA and DNA samples from 5 root canals of teeth with apical periodontitis were subjected to polymerase chain reaction with bar-coded primers amplifying the 16S rRNA gene hypervariable regions V4-V5. High-throughput sequencing was performed using MiSeq (Illumina, San Deigo, CA), and data were analyzed using Quantitative Insights Into Microbial Ecology and Human Oral Microbiome Database.

Effects of Contemporary Irrigant Activation Schemes and Subsequent Placement of an Interim Dressing on Bacterial Presence and Activity in Root Canals Associated with Asymptomatic Apical Periodontitis.

New tools for activating endodontic irrigants have evolved, yet their impact on root canal disinfection, in comparison to the passive placing of an inter-visit medication, have not yet been fully elucidated. The use of DNA- and rRNA-based methods may cast some new light on this issue, as they allow a comparison to be made between microbial presence and activity. Therefore, the aim of this single-arm intervention trial is to evaluate the antibacterial effect of endodontic procedures using both molecular methods.

Comparison of rRNA-based reverse transcription PCR and rDNA-based PCR for the detection of streptococci in root canal infections.

Objective: The rDNA-based method is unable to distinguish between alive and dead cells. Alternatively, bacterial viability can be assessed by molecular methods based on ribosomal RNA (rRNA). Therefore, this study aimed to detect viable streptococci in root canal samples using rRNA-based reverse transcription polymerase chain reaction (RT-PCR), compared to an rDNA-based PCR assay.

Evaluation of the Propidium Monoazide-quantitative Polymerase Chain Reaction Method for the Detection of Viable Enterococcus faecalis.

Introduction: One limitation of DNA-based molecular assays is their inability to distinguish between live and dead cells. A sample treatment with propidium monoazide (PMA) before DNA amplification has been proposed to overcome this problem. The aim of this in vitro study was to test different concentrations of PMA coupled with quantitative polymerase chain reaction (qPCR) for the detection of viable Enterococcus faecalis.

RNA-based Assay Demonstrated Enterococcus faecalis Metabolic Activity after Chemomechanical Procedures.

Introduction: Because ribosomal RNA (rRNA) indicates metabolic cell activity, this study aimed to evaluate the sensitivity of rRNA-based quantitative polymerase chain reaction (RT-qPCR) for the identification of active Enterococcus faecalis in root canals samples compared with a method based on ribosomal DNA (rDNA) (rRNA genes).

Methods: Samples were taken from 18 teeth with persistent/secondary intraradicular infection before (S1) and after (S2) chemomechanical preparation. RNA and DNA were extracted, and complementary DNA was synthesized from RNA using RT-PCR.

Lineage variability in surface components expression within Porphyromonas gingivalis.

The periodontopathogen Porphyromonas gingivalis is represented by a spectrum of phenotypes ranging from commensals to pathogenic lineages. Capsule and fimbriae are considered key virulence factors in this specie, involved in colonization and host defenses evasion. Since these virulence traits may not be expressed by certain strains, we aimed to test the hypothesis that certain clusters or genotypes of P.

Analysis of genetic lineages and their correlation with virulence genes in Enterococcus faecalis clinical isolates from root canal and systemic infections.

Introduction: Enterococcus faecalis is a member of the mammalian gastrointestinal microbiota but has been considered a leading cause of hospital-acquired infections. In the oral cavity, it is commonly detected from root canals of teeth with failed endodontic treatment. However, little is known about the virulence and genetic relatedness among E.

Prevalence of traumatic dental injuries and associated factors among Brazilian schoolchildren.

Purpose: To assess the prevalence of traumatic dental injuries to permanent anterior teeth in 9- to 14-year-old schoolchildren attending public schools in Anápolis, Brazil, and to investigate the association between the occurrence of these injuries and the size of incisal overjet and type of lip coverage.

Materials And Methods: A cross-sectional survey and a two-stage cluster sampling technique were used. The sample size included 765 9- to 14-year-old schoolchildren.

Capsule locus polymorphism among distinct lineages of Enterococcus faecalis isolated from canals of root-filled teeth with periapical lesions.

Introduction: Although Enterococcus faecalis is a member of the normal microbiota, it is also a major cause of nosocomial infections. Some strains of E. faecalis produce capsule, which contributes to pathogenesis through evasion of host defenses, and its production is dependent on the capsule (cps) operon polymorphism.

Microbial analysis of canals of root-filled teeth with periapical lesions using polymerase chain reaction.

The objective of the present study was to investigate the presence of nine bacterial species in root-filled teeth associated with periapical lesions using a polymerase chain reaction analysis and to correlate these species with clinical features of the cases. DNA was extracted from 45 canal samples of root-filled teeth with periapical lesions. A PCR assay using species-specific primers of 16S rDNA and the downstream intergenic spacer region was used for microbial detection.

Gemella morbillorum in primary and secondary/persistent endodontic infections.

Objective: To investigate the presence of Gemella morbillorum by culture or nested PCR in primary and secondary/persistent endodontic infections.

Study Design: Microbial samples were taken from 50 cases with primary and 50 cases with secondary/persistent endodontic infections. Microbiologic techniques were used for culture and identification.

The outcome of endodontic treatment: a retrospective study of 2000 cases performed by a specialist.

The purpose of this study was to evaluate the treatment outcome of initial endodontic treatment and nonsurgical retreatment performed by an endodontic specialist in his private office. A total of 2,000 teeth were examined clinically and radiographically and the results were analyzed statistically by Pearson or Fisher's Exact test and multivariate logistic regression. The multivariate analysis evaluated joint associations among various factors, using logistic regression models.

Root canal microbiota of dogs' teeth with periapical lesions induced by two different methods.

Objective: The microbial composition was investigated in root canals of dogs' teeth with periapical lesions induced by 2 different methods: open versus sealed canals.

Study Design: Teeth from Group I (n = 16) were left open for a week, then sealed with composite resin for 120 days. The teeth from Group II (n = 16) were left open for the same period.

Molecular analysis of Filifactor alocis, Tannerella forsythia, and treponema denticola associated with primary endodontic infections and failed endodontic treatment.

The aim of this study was to investigate the presence of strict anaerobes such as Filifactor alocis, Tannerella forsythia, and Treponema denticola in primary and secondary root-infected canals with periapical lesions by molecular analysis and the association of these species with specific endodontic signs and symptoms. Microbial samples were taken from 100 root canals, 50 with necrotic pulp tissues (NPT, primary infection), and 50 with failed endodontic treatment (FET, secondary infection). DNA was extracted from the samples, which were analyzed for the presence of three endodontic pathogens using species-specific primers and PCR.