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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. Microbiological samples from the root canals were collected and processed by the anaerobic technique for identification and counting of microorganisms after establishment of periapical reactions. RESULTS: Seventy-four cultivable isolates were recovered in sealed canals (Group I). Strict anaerobes accounted for 64.9% of all species isolated, and gram-negative microorganisms accounted for 55.4%. Microbial genera most frequently isolated were Prevotella, Fusobacterium, Peptostreptococcus, Streptococcus, Enterococcus, Clostridium, and Porphyromonas. Statistical analysis by Pearson chi-square or Fisher's test revealed positive association between sealed teeth and strict anaerobes (P < .05). In open canals (Group II), from a total of 58 cultivable isolates, 19% were strict anaerobes and 81% facultative anaerobes, with predominance of gram-positive species (75.8%). Genera most frequently isolated were Streptococcus, Propionibacterium, Staphylococcus, Neisseria, and Prevotella. CONCLUSION: Strict anaerobes were most frequently found in sealed teeth rather than in the teeth with canals left exposed to the oral cavity for 4 months. Therefore, the method that induced periapical inflammatory lesions by intentional oral exposure, followed by tooth sealing, produced root canal microbiota similar to the same found in humans. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the antimicrobial activity of calcium hydroxide (Ca(OH)2) combined with 2% chlorhexidine gluconate (CHX) gel against endodontic pathogens and to compare the results with the ones achieved by Ca(OH)2 mixed with sterile water and by CHX gel alone. Two methods were used: the agar diffusion test and the direct contact test. Ca(OH)2 + 2% CHX gel produced inhibitory zones ranging from 2.84 to 6.5 mm, and required from 30 seconds to 6 hours to eliminate all tested microorganisms. However, 2% CHX gel showed the largest microbial growth zones from 4.33 to 21.67 mm, and required 1 minute or less to inhibit all tested microorganisms. A paste of Ca(OH)2 plus sterile water inhibited only the microorganisms with which it was in direct contact and required from 30 seconds to 24 hours to kill all tested microorganisms. In conclusion, 2% CHX gel + Ca(OH)2 showed better antimicrobial activity than Ca(OH)2 manipulated with sterile water. [ABSTRACT FROM AUTHOR]

Objective: This systematic review aimed to assess the impact of Passive Ultrasonic Irrigation on the periapical healing rate of primary root canal treatment compared to conventional syringe irrigation., Methods: Registered a priori in the PROSPERO database, this review was conducted by two independent reviewers who performed an electronic search up to December 2023. The search included databases such as MEDLINE (PubMed), Scopus, Web of Science, Embase, LILACS, and the Cochrane Library, as well as grey literature. We included randomized clinical trials (RCTs) that focused on patients undergoing primary root canal treatments. The study compared intervention groups using PUI with control groups that did not use activation techniques. Periapical healing was assessed over follow-up periods of at least six months, utilizing either periapical radiographs or cone-beam computed tomography. To synthesize the findings, a meta-analysis and trial sequence analysis were conducted, employing the Relative Risk as the measure of effect, with a 95% confidence interval. The GRADE approach was utilized to assess the certainty of the evidence., Results: The meta-analysis incorporated three RCTs, involving 474 patients (501 teeth). The analysis revealed that PUI led to a higher rate of periapical healing compared to CSI (Relative Risk: 1.10; 95% Confidence Interval: 1.01-1.21, I² = 0%), with moderate certainty of evidence., Conclusions: Despite the limited number of high-quality RCTs, the findings showed a positive impact of PUI on periapical healing rates in primary root canal treatments, in comparison to CSI., Register: CRD42021290894., Competing Interests: Competing interests: The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to British Dental Association.)

Introduction: Nonsurgical root canal retreatment (NS-RCRT) becomes necessary when primary endodontic procedures fail. This study evaluates the efficacy of NS-RCRT using 2% chlorhexidine gel and foraminal enlargement techniques, aiming to assess whether these approaches enhance periapical healing outcomes and success rates compared to traditional NS-RCRT techniques reported in the literature., Methods: This retrospective cohort study analyzed 120 teeth diagnosed with persistent apical periodontitis, from 80 patients who underwent NS-RCRT between January 2014 and December 2018 at a specialist's private practice. Data were collected following the Preferred Reporting Items for Observational Studies in Endodontics 2023 guidelines. Periapical healing was evaluated using digital periapical radiographs by three calibrated examiners. The outcome of the treatment was analyzed through descriptive statistics and bivariate analyses, including the Chi-Square and Fisher's Exact tests. Treatment outcomes were deemed successful if they showed complete or incomplete repair and unsuccessful if no repair was observed., Results: The average follow-up period was 30 months. Under loose criteria, 92.50% (n = 111) of the teeth were categorized as successful, and 7.5% (n = 9) as unsuccessful. Bivariate analysis indicated that the radiographic restoration of apical transportation was the only factor that significantly influenced the outcome., Conclusions: NS-RCRT performed in a single visit using the foraminal enlargement technique and 2% chlorhexidine gel demonstrated high success rates and may be an effective alternative to tooth extraction. This method promoted periapical healing and could significantly improve NS-RCRT protocols. Further prospective studies are recommended to corroborate these findings., (Copyright © 2024 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Background/aim: This study assessed the epidemiology of luxation injuries with or without dental fractures in patients attending the outpatient clinic of a Brazilian dental school over the past decade., Material and Methods: We reviewed clinical records from a specialized center for dental trauma care in Brazil, focusing on patients who experienced at least one traumatic dental injury (TDI) in a permanent tooth between 2012 and 2022. The extracted data included sex, age, etiology, time between trauma occurrence and the search for initial care, TDI classification, and the need for endodontic treatment. The statistical analysis involved Pearson's chi-squared and Fisher's exact tests at a 5% significance level., Results: The 366 analyzed clinical records included 166 patients (350 teeth) with luxation injuries. Men (n = 102) showed a higher prevalence of luxation injuries than women (n = 64). Extrusive luxation prevailed (n = 99 patients and 208 teeth). Patients with luxation injuries sought care promptly after dental trauma incidents (p = .02) and demonstrated a higher incidence of endodontic treatment (p < .0001) than those without luxation injuries. Lateral luxation was notably associated with traffic accidents (p < .0001). The combination of luxation injuries and tooth fractures did not correlate with a higher need for endodontic treatment (p > .05)., Conclusions: Age and trauma etiology seemed to have influenced the epidemiological profile of luxation injuries. Additionally, these injuries affected the time to seek initial care and the need for endodontic treatment., (© 2024 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objectives: This prospective randomized multicenter clinical trial (PRMCT) investigated postoperative pain after single-visit root canal treatments in teeth affected by pulp necrosis (PN), and asymptomatic apical periodontitis (AAP) (with apical radiolucent areas) or normal periradicular tissues (without apical radiolucent areas) comparing different instruments' kinematics and apical instrumentation limits., Methods: Before chemomechanical preparation, 240 patients/teeth were randomly distributed into four groups (n = 60) according to the instruments' kinematics (rotary or reciprocating) and apical instrumentation limits (with or without intentional foraminal enlargement [IFE]). After that, specimens were submitted to the same irrigation and obturation techniques, and the patients were referred to undergo the definitive restorations. No medication was prescribed, but the patients were instructed to take either paracetamol (750 mg every 6 h for three days) or ibuprofen (600 mg every 6 h for three days) in pain cases. Postoperative pain incidence and levels were assessed at 24-, 48-, and 72 h following treatment completion according to a verbal rating scale (VRS) following a score. The Kolmogorov-Smirnov test was applied to assess the normality of the data. Mann-Whitney U, Chi-square, Friedman's ANOVA, and Friedman's multiple 2 to 2 comparison tests were employed to identify potential significant statistical differences among the variables in the study groups (P < .05)., Results: Significant statistical differences were only observed among the groups considering tooth, periradicular status, and the occurrence of overfilling (sealer extrusion) (P < 0.00). Patients with teeth instrumented through rotary kinematics and without IFE experienced lower rates of postoperative pain; however, this difference was relevant only at 24 h (P < 0.05)., Conclusions: Postoperative pain was lower after using a rotary file system (Profile 04) inserted up to the apical constriction (AC). However, this finding was just statistically meaningful at 24 h., Trial Registration: This PRMCT was approved by the Human Research Ethics Committee of the Paranaense University - UNIPAR, Francisco Beltrão, PR, Brazil (CAAE. 46,774,621.6.0000.0109) on 02/09/2021. It was registered at The Brazilian Registry of Clinical Trials - ReBEC (RBR-3r967t) on 01/06/2023, was performed according to the Principles of the Helsinki Declaration and is reported following the Consolidated Standards of Reporting Trials Statement., (© 2024. The Author(s).)

Background: Dental caries is the most common oral disease worldwide, and it is estimated to affect 2.3 billion people, with at least 530 million of them being schoolchildren with decayed primary teeth. This condition can rapidly evolve into irreversible pulp inflammation and pulp necrosis and thus requiring endodontic intervention. Photodynamic therapy (PDT) is a supplementary method to conventional pulpectomy and is used to improve the protocol used for disinfection., Aim: The main objective of this study was to evaluate through a systematic review the efficacy of supplementary PDT on the pulpectomy of primary teeth. This review was registered a priori on the PROSPERO database (CRD42022310581)., Design: Two independent and blinded reviewers carried out a comprehensive search in five databases: PubMed, Cochrane, Scopus, Embase, and Web of Science. Eligible studies were randomized and nonrandomized clinical trials that evaluated in vivo microbiological load or clinical outcomes after using supplementary PDT in infected primary teeth., Results: After the selection process, four studies met the inclusion criteria and were included in this study. Data regarding the sample characteristics and PDT protocols were retrieved. All included trials used phenothiazinium salts as photosensitizer agents. Only one study observed a significant difference in the in vivo microbiological load reduction outcome when performing PDT on primary teeth. The remaining studies all discussed the possible benefits of this intervention; however, none observed a significant difference in this outcome., Conclusion: In this systematic review, moderate-to-low certainty of the available evidence was observed, and thus, no significant conclusions can be drawn from the findings., (© 2023 BSPD, IAPD and John Wiley & Sons Ltd.)

Introduction: Persistent apical periodontitis after root canal treatment may require surgical retreatment when non-surgical options are ineffective or impractical due to anatomical challenges or iatrogenic errors. Endodontic microsurgery (EMS) is a precise technique that aims to overcome extraradicular biofilm and root morphology issues. Photodynamic therapy (PDT) is an emerging supplementary disinfection approach that utilizes a photosensitizer agent and light to eliminate microorganisms through oxidative reactions., Report: A 60-year-old male with persistent apical periodontitis in a left maxillary first molar underwent non-surgical root canal retreatment followed by surgical reintervention due to anatomical complexities. During surgery, PDT was performed using a novel curcumin-based photosensitizer agent. After the procedure, the tooth was retrofilled with bioceramic cement, and photobiomodulation was applied to enhance tissue healing. One year post-surgery, the patient exhibited complete periradicular repair and remained asymptomatic., Discussion: EMS is considered a last resort to salvage an endodontically treated tooth and has shown moderate success rates. PDT has demonstrated promise in improving periapical healing and reducing microorganisms. In this case, curcumin, diluted with 2 % chlorhexidine gel, served as an effective photosensitizer agent with antimicrobial properties. Moreover, performing photobiomodulation aided in cell recovery and reduced postoperative discomfort., Conclusion: The proposed EMS treatment protocol with PDT using curcumin yielded positive outcomes in this case report. Further randomized clinical trials are necessary to assess the efficacy of this approach in EMS. Additionally, further research on curcumin-based photosensitizer agents encapsulated in nanoparticles and enhanced antimicrobial agents is recommended to refine this treatment protocol for routine use., Competing Interests: Declaration of competing interest The authors declare there is no conflict of interests., (Copyright © 2024. Published by Elsevier B.V.)

Introduction: EDTA plays a crucial role in regenerative endodontic therapy (RET) because of its significant biological effects. However, EDTA is also recognized as the preferred anticoagulant for hematologic tests. Thus, this study aimed to assess the influence of different EDTA activation techniques on the morphology of blood clots after conditioning the root canal dentin., Methods: Forty extracted human teeth were prepared to simulate immature teeth and divided into the following 5 groups: (1) saline solution (negative control), (2) EDTA 17% + saline solution (CNI), (3) CNI + ultrasonic activation, (4) CNI + Easy clean activation, and (5) CNI + XP-endo Finisher activation. After irrigation, the roots were cleaved, and the root canals were filled with human blood to clot formation. The morphology and density of erythrocytes, platelets, and the fibrin network were observed using a scanning electron microscope. The fibrin network density was classified using a 4-point scale. Data were analyzed using the Friedman test and the Kruskal-Wallis test with Bonferroni adjustment (α = 5%)., Results: All groups exhibited consistent blood clot morphology characterized by a high density of erythrocytes, platelets, and white blood cells throughout the entire length of the root canal. The negative control group showed statistically significant high scores of fibrin density compared with the CNI group in all root thirds (P < .05). However, there was no statistical difference in the scores for the fibrin network density between the groups irrigated with EDTA with and without activation (P > .05)., Conclusions: EDTA may impair the fibrin network formation compared with the saline group. However, EDTA activation did not significantly change the effects on the blood clot in contact with the conditioned intraradicular dentin., (Copyright © 2023 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Dental referrals to the Endodontics Specialty Clinic (ESC) are routine owing to the complexity of endodontic treatments. To obtain a better prognosis for treatment, students/dentists must perceive their technical limits. This study sought to investigate the referrals of patients to the ESC from different clinics of the Piracicaba Dental School, State University of Campinas - SP, Brazil, and check: a) the demographic profile of patients and the most commonly affected tooth; b) the clinic with the largest number of referrals; c) the reasons for referrals; d) the complexity of the cases; e) and the difficulty in assessing the referred cases based on the classification provided by the American Association of Endodontists (AAE) and Souza-Filho. The study sample consisted of patients' electronic dental referral records from February 2015 to June 2019. A total of 1,707 patients were referred to the ESC during the study period, and 62.4% were female. Lower molars were the most frequently involved teeth (34.8%), and 60.7% of the cases were referred due to the presence of root curvature. The AAE classification showed prevalence of highly difficult cases (71.3%), whereas Souza-Filho classification demonstrated a high rate of class III cases (85.8%). This study highlights the difficulties encountered by undergraduate students before or during endodontic treatments, reinforcing the need for clear criteria for selecting cases appropriate for each education level, thus improving endodontic treatment prognosis.

The objective of this study was to investigate the presence of culturable bacteria, endotoxins (LPS) and lipoteichoic acid (LTA) levels in teeth with normal vital pulp (NVP) with intact crowns (IC) and those with coronal restoration (CR) limited to the enamel level. A total of 20 teeth indicated for endodontic treatment due to prosthetic reasons were selected. Samples were collected from the root canals. The levels of cultivable bacteria, LPS and LTA were assessed. Statistical analyses were performed at significance level set at 5%. None of the teeth presented microbial growth. In the IC group, the LPS levels were limited to the lowest concentration of LPS. On the contrary, higher LPS and LTA levels were detected in teeth with CR. It was concluded that teeth with NVP and IC were negative for bacteria, LPS and LTA; while teeth with CR were positive for bacterial virulence factors., (© 2023 Australian Society of Endodontology Inc.)

Introduction: This retrospective cohort study aimed to estimate the success rate (SR) of primary root canal treatment on teeth with a diagnosis of pulp necrosis (PN) and asymptomatic apical periodontitis (AAP) when using 2% chlorhexidine gel as an auxiliary chemical substance and foraminal enlargement instrumentation technique., Methods: This study evaluated 178 patients with 206 teeth submitted to primary root canal treatment performed by graduate residents in endodontics. The inclusion criteria were patients who underwent treatment over a period of 1-7 years on teeth with a diagnosis of PN and AAP. The SR was evaluated clinically and radiographically and categorized considering strict (complete resolution of the periradicular lesion) or loose (reduction in the size of the existing periradicular lesion) criteria. Cases of clinical and/or radiographic absence of repair were classified as a failure. Two calibrated examiners independently assessed treatment outcomes using ImageJ software (National Institutes of Health, Bethesda, MD)., Results: The SRs were 81.1% (95% confidence interval, 75.7%-86.4%) and 87.4% (95% confidence interval, 82.8%-91.9%) when considering the strict or loose criteria, respectively. Females had a higher SR when strict criteria were applied. Also, the SR was significantly reduced when there was an increase in the patient's age., Conclusions: Teeth with a diagnosis of PN and AAP and treated with 2% chlorhexidine gel and foraminal enlargement achieved substantial SR. Sex and age were prognostic factors that played a significant role in the SR. Future randomized controlled trials should further investigate the effects of foraminal enlargement and 2% chlorhexidine gel as an auxiliary chemical substance., (Copyright © 2023 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Aim: To comparatively analyse the levels of culturable bacteria, endotoxins (LPS), tumour necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β) and substance P in teeth with symptomatic irreversible pulpitis (SIP) and vital normal pulp (VNP) tissues., Methodology: Thirty-two patients were included (20 teeth with SIP and 12 teeth with VNP tissues) in this cross-sectional study. Samples were collected from the full length of the root canals (microbial analysis) and periapical tissues (2 mm beyond the apex for immunological analysis), using sterile absorbent paper points. The levels of culturable bacteria (culture method), endotoxins (LAL Pyrogent 5000), TNF-α, IL-1β and substance P (ELISA) were assessed. The Mann-Whitney test was used for comparisons between the levels of CFU/mL, LPS, TNF-α, IL-1β and substance P in the SIP and VNP groups. The statistical analysis was performed with the significance level set at 5%., Results: Culturable bacteria were recovered from all teeth with SIP. On the other hand, no positive cultures were observed in the VNP tissues group (p > .05). The levels of LPS were approximately four times higher in teeth with SIP than in teeth with VNP tissues (p < .05). Higher levels of TNF-α and substance P were detected in teeth with SIP (p < .05). On the other hand, no difference in the levels of IL-1β was detected between the two groups (p > .05)., Conclusion: Teeth with symptomatic irreversible pulpitis present higher levels of culturable bacteria, endotoxins, TNF-α and substance P than those with vital normal pulp tissues. On the other hand, the levels of IL-1β were similar in teeth from both groups suggesting reduced implications of this inflammatory mediator in the early stages of infection., (© 2023 British Endodontic Society. Published by John Wiley & Sons Ltd.)

Background: A smile is considered one of the most important soft skills in social interaction. And discolored teeth may effect this. It is known that some photosensitizer agents (PS) used in photodynamic therapy (PDT) during root canal treatment could play a significant role in tooth color change, and thus the main objective of this systematic review is to address whether performing PDT can influence tooth color change and to synthesize the most effective methods to remove PS from the root canal system., Methods: This study followed the PRISMA 2020 statement, and the protocol was registered at the Open Science Framework. Two blinded reviewers searched five databases up to November 20th, 2022: Web of Science, PubMed, Scopus, Embase, and the Cochrane Library. The eligibility criteria were studies that investigated tooth color change after PDT in endodontics., Results: A total of 1695 studies were retrieved, and 7 were included in the qualitative analysis. All the included studies were in vitro evidence and investigated five different PS: methylene blue, toluidine blue O, malachite green, indocyanine green, and curcumin. Besides curcumin and indocyanine green, the remaining agents all caused tooth color change, and no method employed was effective in fully removing these PS from inside the root canal system CONCLUSIONS: Even though the findings showed that curcumin and indocyanine green did not influence tooth color change, the present evidence should be interpreted with caution since it is based on laboratory studies with questionable methods, and all efforts should be employed to avoid this undesirable side effect during clinical practice., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Objective: The objective of this study was to evaluate the microbiological profile of root canals indicated for endodontic retreatment due to secondary endodontic infections evidenced by the presence of chronic apical periodontitis (G1) or for prosthetic reasons, without clinical and radiographic signs of endodontic reinfection (G2)., Methods: Microbiological samples were collected from thirty teeth (N=30) out of which 15 were indicated for retreatment due to the presence of chronic apical periodontitis (G1) and 15 were indicated exclusively for prosthetic reasons (G2). Samples were collected from root canals before (S1), after chemomechanical preparation (S2), and after 30 days of intracanal medication composed of calcium hydroxide and 2% chlorhexidine gel (S3). The molecular analysis was performed using Nested-PCR for the detection of 17 bacterial species. The efficacy of each stage of the retreatment in reducing the microbial load was verified by counting colony-forming units (CFU). The statistical analysis considered a significance level of 5%., Results: The results showed that bacteria were detected in 100% of the cases in S1, in both groups, by Nested PCR. The most frequently found species in S1 in both groups were Enterococcus faecalis, Fusobacterium nucleatum, Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, and Parvimonas micra. The microbial load of G1 was higher than G2 in the initial samples (S1). Endodontic retreatment was effective in reducing the microbial load in G1 and G2. Statistically significant associations were found between specific bacteria and clinical signs and symptoms., Conclusion: It was concluded that the microbial community present in the root canal of teeth indicated for endodontic retreatment is mixed and heterogeneous. G1 and G2 differ in the number of species per case and microbial load., Clinical Relevance: Endodontic retreatment was effective in reducing the microbial load. Statistically significant associations were found between specific bacteria and clinical signs and symptoms., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

This study aimed to assess the traumatic dental injuries (TDIs) in permanent dentition among patients who attended at the outpatient clinic of a Brazilian dental school, during the last 20 years, and to investigate factors associated with the severity of these injuries. Clinical records of patients who attended a specialized center for dental trauma care in Brazil presenting at least one TDI in a permanent tooth, between the years 2000 and 2019, were reviewed. The data recorded were sex, age, affected arch, etiology, number, and type of the teeth affected, and classification and severity of the TDIs. The diagnosis and classification of the TDIs were based on the guidelines of the International Association of Dental Traumatology (IADT). The severity of each patient's injuries was defined as mild, moderate, or severe. Descriptive statistics, chi-square and multinomial regression analyses were used to evaluate the results. The significance level was set at 5%. A total of 837 clinical records were included, totaling 2357 teeth. Males were more prevalent than females. The patients' age ranged from 5 to 71 years. The most common traumas were avulsion (n=512) and uncomplicated enamel-dentin fracture (n=488). Univariate analyses showed that there was a statistically significant association between age group (p=0.004), etiology (p=0.000) and number of teeth affected (p=0.000) with severity of dental trauma. In conclusion, TDIs that occurred in Piracicaba and region are epidemiologically similar to those found worldwide, and that more severe injuries are related to age range, etiology and number of teeth affected.

Objective: To evaluate the effectiveness of supplemental photodynamic therapy for improving the bacterial removal and the levels of lipopolysaccharide (LPS) and lipoteichoic acid (LTA) by conducting a clinical trial., Methodology: Twenty-four root canals with pulp necrosis and periapical lesion were selected and randomly divided into conventional group using endodontic treatment with chemo-mechanical preparation (CMP) alone (n = 12) and a group using antimicrobial photodynamic therapy (aPDT) after CMP (n = 12). The samples were collected before and after CMP (conventional group) and after photodynamic therapy (aPDT group). A photosensitizer (0.005% methylene blue) was applied to the root canal for 3 minutes after CMP, whereas aPDT was performed by using a red laser with a power of 30Mw and energy density of 9J/cm 2 for 90 s per root canal. Culture technique was performed to determine the bacterial colony forming units. LPS and LTA levels were quantified by using limulus amoebocyte lysate (LAL) assay and enzyme-linked immunosorbent assay (ELISA), respectively., Results: All samples showed growth of viable bacteria on Fastidious Anaerobe Agar (FAA), with an average of 5.19 × 10 5 CFU/ mL. CMP was effective in decreasing viable bacteria (p < 0.05), whereas there was a significant decrease (p < 0.05) in the samples treated with aPDT compared to those submitted to CMP. LPS and LTA were detected in all initial samples, with mean values of 20.561 EU/mL and 430.91 pg/mL, respectively. Both CMP and aPDT groups significantly decreased the levels of LPS and LTA (p < 0.05), with a statistical difference between the groups regarding aPDT (p < 0.05)., Conclusion: Photodynamic therapy as an adjunct to CMP proved to be effective in improving root canal disinfection and reducing the LPS and LTA levels in teeth with primary endodontic infection., Competing Interests: Declaration of Competing Interest The authors have declared that no conflict of interest exists., (Copyright © 2023. Published by Elsevier B.V.)

Background: Photodynamic therapy (PDT) is an adjunctive treatment that aims to inactivate microorganisms through an oxidative reaction produced by irradiating a photosensitizing agent. The quest for improved root canal disinfection has sought supplementary methods when performing chemomechanical procedures. From this perspective, PDT protocols were proposed as an auxiliary approach in endodontics. Thus, the aim of this study was to investigate publication metrics and research trends related to this scope., Methods: This review is reported in accordance with the PRISMA 2020 recommendations. Two blinded and independent reviewers systematically searched five electronic databases until December 2021. The acquired bibliometric parameters were analyzed through descriptive statistics and graphical mappings with VOSViewer software., Results: The search retrieved 342 studies from 84 journals originating from 33 countries. About 85% of the included studies were published over the last decade. Most of the available evidence is laboratory-based (74.5%), and the main clinical outcomes evaluated were microbiological load reduction and postoperative pain. Mayram Pourhajibagher is the researcher with the most publications as the first author (n = 16). Tehran University of Medical Sciences carried out the highest number of studies (n = 29), and Photodiagnosis and Photodynamic Therapy is the journal that most published on the theme (n = 111)., Conclusions: This bibliometric analysis mapped and discussed the scientific progress and publication metrics in PDT in endodontic research. Additionally, future perspectives were highlighted and should focus on discovering new photosensitizer agents, standardizing optimal photoactivation protocols, and conducting more clinical-oriented research., (Copyright © 2022. Published by Elsevier B.V.)

Introduction: The objective of this study was to investigate the action of photodynamic therapy on pain control after endodontic treatment in asymptomatic teeth with a primary infection, within a single visit., Methods: Sixty (60) single-rooted teeth with pulp necrosis and periapical lesions were selected and randomly divided into two (2) groups (n = 30), according to the protocol; a control group (CG) and a group using photodynamic therapy (aPDT). The canals were instrumented with Reciproc files # 25 up to 40 along the entire length of the canal, using 2% chlorhexidine gel as the auxiliary chemical substance, followed by irrigation with sterile saline. aPDT consited of 0.005% methylene blue as photosensitizer, using AsGaAl diode laser, 660 nm wavelength, 100 mW of power and 9 J of energy, using optical fibers with 365 μm in diameter. The canals were filled with Endomethasone N cement., Results: Pain intensity was assessed at 8, 12, 24, 48, 72 h and 1 week after endodontic treatment using a visual analogue scale. The level of pain was classified as none (0), mild (1-3), moderate (4-7) or severe (8-10). The data were at a significance level of 5%. There was a statistically significant difference (p<0.05) in the periods of 8, 12, 24, 48 and 72 h between the control group and the aPDT group. After 1 week, there was no statistically significant difference., Conclusions: It is concluded that photodynamic therapy had a significant effect on decreasing post-endodontic treatment pain in teeth with necrotic pulp and asymptomatic periapical lesions., (Copyright © 2021. Published by Elsevier B.V.)

Introduction: The objective of this study was to monitor the effects of chemomechanical preparation (CMP) performed with 6% sodium hypochlorite and calcium hydroxide-based intracanal medication (ICM) on the levels and diversity of bacteria, endotoxins (lipopolysaccharides [LPS]), and lipoteichoic acid (LTA) in root canals of teeth with symptomatic irreversible pulpitis., Methods: Samples were collected from 10 teeth with symptomatic irreversible pulpitis before CMP (S1), after CMP (S2), and after ICM (S3). The levels of bacteria, LPS, and LTA were assessed by using checkerboard DNA-DNA hybridization, LAL Pyrogent 5000, and enzyme-linked immunosorbent assay, respectively. Wilcoxon test, repeated-measures analysis of variance, and Tukey post hoc test were used for statistical analysis at a significance level of 5%., Results: Forty species were detected at S1. Two species were eliminated after CMP and 5 after ICM. Resistant and pain-related species were detected in the root canals. Higher levels of culturable bacteria were detected at S1. However, CMP and ICM effectively reduced the microbial load in the root canals. Higher levels of LPS and LTA were detected at S1. CMP was effective in reducing both LPS and LTA (P < .05). ICM produced additional reduction in the levels of LPS (P > .05) and LTA (P < .05)., Conclusions: Chemomechanical preparation using 6% sodium hypochlorite and calcium hydroxide-based intracanal medication were effective in reducing the levels of bacteria, LPS, and LTA in teeth with vital pulp and irreversibly inflamed pulp., (Copyright © 2021 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Background/aim: Dental trauma (DT) occurs frequently in children and adolescents. Therefore, understanding the factors associated with its occurrence in these age groups is important to establish specific preventive measures. The aim of this study was to investigate the relationships of lip coverage, overjet, and open bite to dental trauma in Brazilian children and adolescents., Material and Methods: The review protocol was registered in the PROSPERO database (CRD42020156290) and the bibliographic search was performed in nine electronic databases until July 2020. The studies included were observational, performed in Brazil, with healthy children and adolescents (0-19 years old), and without the restriction of date or language. Two reviewers assessed the individual risk of bias of the eligible studies with a standardized checklist. The meta-analyses were stratified by dentition stage and age range using fixed or random effects, odds ratio (OR) as the effect measure, and 95% confidence interval. The heterogeneity across studies was assessed with the I² test and the GRADE approach assessed the certainty of evidence., Results: The search presented 2493 initial results, from which 55 met the eligibility criteria and were included. Most studies (67%) presented a low risk of bias and were published between 2000 and 2019. Children and adolescents with inadequate lip coverage are 1.86-2.36 times more likely to suffer from DT, while those with increased overjet are 1.94-3.11 times more likely. Children with primary dentitions and anterior open bites are 1.76 (95% CI: 1.20-2.59) times more likely to suffer from DT. The certainty of evidence varied from very low to moderate., Conclusions: Inadequate lip coverage, increased overjet, and anterior open bite are associated with the occurrence of dental trauma in Brazilian children and adolescents., (© 2021 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objectives: This study aimed to detect the presence of specific bacteria and to evaluate the levels of lipopolysaccharides (LPS) and lipoteichoic acid (LTA) in symptomatic necrotic root canals associated with acute apical abscess (symptomatic group - GI). It also aimed to compare the findings with those presented by asymptomatic necrotic root canals (asymptomatic group - GII) in the different stages of the endodontic treatment., Materials and Methods: Microbiological samples were collected from 20 root canals, including purulent collection from acute apical abscesses, before and after chemo-mechanical preparation (CMP) preparation (CMP) with chlorhexidine gel 2% and after 30 days of intracanal medication (ICM) with (Ca[OH] 2 ) + chlorhexidine. The culture method was used to evaluate the efficacy of CMP and ICM. Nested PCR was used to detect the presence of 17 specific bacteria. Levels of LPS were measured by using limulus amebocyte lysate, whereas enzyme-linked immunosorbent assay was used for the quantification of LTA., Results: CMP was effective in reducing the microbial load in both groups (P < 0.05). LPS levels were higher in GI than in GII (P < 0.05). There was a significant reduction in the LPS levels after CMP and ICM (P < 0.05) in GI and GII. LTA levels were significantly reduced in GI after ICM and in GII after CMP and ICM (both P < 0.05). Fusobacterium nucleatum and Enterococcus faecalis were frequently identified in both groups, alone or in combination with each other., Conclusion: Different species were detected in all stages of the endodontic treatment. CMP was able to reduce bacterial content and the levels of LPS, but not of LTA in the symptomatic group. High levels of LPS were correlated with spontaneous pain and pain to percussion in the symptomatic group., Clinical Relevance: This clinical study showed that chemo-mechanical preparation was able to reduce bacterial load and levels of LPS, but not of LTA in the symptomatic group. Elevated levels of LPS were correlated with the presence of symptomatology., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Introduction: More data are needed before affirming that single-visit approaches are effective and safe for regenerative endodontic procedures (REPs). This study compared clinical and radiographic outcomes of REPs between interappointment dressing or single-visit protocols., Methods: Twenty young patients presenting traumatized immature teeth with pulp necrosis were divided into 2 groups. Teeth were submitted to 6% sodium hypochlorite and 2% chlorhexidine irrigation and to 17% EDTA use before blood clot induction. In the interappointment dressing group (n = 11), calcium hydroxide was used with 2% chlorhexidine gel for 21 days before scaffold induction. In the single-visit group (n = 9), the scaffold was induced during the only appointment. Patients were followed up for 24 months. Primary, secondary, and tertiary outcomes were assessed by 3 independent evaluators. Preoperative and follow-up radiographs were assessed for quantitative measurements of the apical diameter, root width, root length, and cervical barrier placement and compared between groups using the t test or Mann-Whitney U test. Categoric variables were assessed with the G test and the Fisher exact test and continuous variables with the Mann-Whitney U test. Statistical significance was set at 5%., Results: One tooth showed persistence of infection. No difference was observed in cervical barrier placement (P > .05); between groups regarding primary, secondary, and tertiary outcomes (P > .05); and in parameters of quantitative radiographic outcomes (P > .05)., Conclusions: Completing REPs with an interappointment dressing or a single-visit protocol presented similar clinical and radiographic outcomes. A single-visit protocol of REPs using 6% sodium hypochlorite, 2% chlorhexidine, and 17% EDTA permitted satisfactory outcomes in necrotic immature permanent teeth., (Copyright © 2021 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

This study compares the clinical success rate and continued radiographic root development of apexification and regenerative endodontic procedure in traumatised immature permanent teeth, and proposes a method to evaluate apical convergence, namely apical angle. Clinical and radiological data were collected from 44 treated teeth (22 with apexification and 22 with regenerative endodontic procedure). The preoperative and follow-up periapical radiographs were analysed to calculate the percentage changes in root length, root width, apical diameter and apical angle. The success rates for complete healing with apexification and regenerative endodontic procedure were 86.36% and 95.45%, respectively. Radiographically, regenerative endodontic procedure showed significantly greater percentage changes in root width only (P < 0.05). Apexification and regenerative endodontic procedure provide satisfactory outcomes concerning clinical success rates. Continued root development in regenerative endodontic procedure was similar to apexification, except for root width. Apical angle allowed us to assess the convergence of the root canal walls., (© 2020 Australian Society of Endodontology Inc.)

Aim: This cross-sectional study aimed to investigate the microbial profile and to quantify the levels of endotoxins (LPS) and lipoteichoic acid (LTA) present in periapical lesions associated with root filled teeth and those that had received root canal retreatment. It also aimed to investigate the association between microorganisms and their virulence factors with clinical and radiographic features., Methodology: Patients with periapical lesions in teeth with post-treatment endodontic disease following primary root canal treatment (n = 19) and unsuccessful root canal retreatment (n = 13) were treatment planned for endodontic microsurgery, where the periapical lesions were collected. Clinical and radiographic data were also collected. For microbiological analysis, nested polymerase chain reaction was used to detect 17 bacterial species. Levels of LPS and LTA were determined using limulus amebocyte lysate and enzyme-linked immunosorbent assays, respectively. The Student t-test or Wilcoxon-Mann-Whitney tests were applied to compare the data on LPS and LTA with clinical and radiographic features. The associations between the clinical and radiographic features and the bacterial species were analysed using the Fisher's exact test. A significance level of 5% was adopted., Results: Bacterial DNA, LPS and LTA were detected in all samples. Parvimonas micra was the most commonly detected species in all groups, followed by Enterococcus faecalis, Fusobacterium nucleatum and Porphyromonas endodontalis. The type of endodontic treatment, whether a primary root canal treatment or retreatment, was not associated with the presence of any bacterial species in periapical lesions. The levels of LPS and LTA in periapical lesions of root filled teeth were not significantly different from those that had been retreated. Associations between the levels of LPS and LTA with clinical signs and symptoms were found. No association was found between specific bacteria and clinical features., Conclusion: Periapical lesions associated with teeth after primary root canal treatment and retreatment had similar polymicrobial composition. The levels of LPS and LTA in periapical lesions associated with teeth after primary root canal treatment and retreatment were similar, and both were associated with the same symptomatology., (© 2020 International Endodontic Journal. Published by John Wiley & Sons Ltd.)

This review aims to evaluate whether root canal obturation with calcium silicate-based (CSB) sealers reduces the risk and intensity of endodontic postoperative pain when compared to epoxy resin-based (ERB) sealers. The review was registered at PROSPERO (CRD42020169255). Two independent reviewers conducted an electronic search in PubMed, Scopus, EMBASE, Web of Science, Cochrane Library and LILACS until November 2020 and included only randomized clinical trials with adult health participants undergoing root canal treatment. After selection, the JBI Critical Appraisal tool was used to assess the risk of bias. A fixed-effect meta-analysis was performed to summarize the results of pain risk and pain intensity at time intervals of 24 and 48 hours. Finally, the certainty of evidence was assessed using the GRADE approach. The search resulted in 1,206 records, of which five studies ( n = 421 patients) met the eligibility criteria and presented moderate to low risk of bias. There was no significant difference between groups in the risk of pain in the first 24 hours (relative risk or RR = 0.83, 95% confidence interval or CI: 0.60, 1.16, I 2 =) or 48 hours (RR = 0.56, 95% CI: 0.26, 1.21, I 2 =). Silicate-based sealers led to lower pain intensity only at 48 hours (mean and standard deviation = 0.37, 95% CI: 0.69, 0.05). All analyses revealed low heterogeneity ( I 2 < 25%). The evidence presented moderate level of certainty. Currently available evidence has shown that there is no difference between CSB and ERB sealers in the risk or intensity of postoperative pain., Competing Interests: None declared., (European Journal of Dentistry. This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial-License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/).)

Objective: Pulp revascularization is an effective treatment for immature necrotic teeth. Calcium hydroxide has been used in pulp revascularization as an intracanal medication due to its antimicrobial action and the non-exhibition of crown discoloration and cytotoxicity for stem cells from the apical papilla. Our study aimed to investigate the clinical success and quantitative radiographic changes of root development in immature traumatized teeth using calcium hydroxide plus 2% chlorhexidine gel as intracanal medication., Methodology: In this retrospective study, 16 patients were treated with a standardized pulp revascularization protocol. Calcium hydroxide and 2% chlorhexidine gel were manipulated in a 1:1 (v/v) ratio and inserted into root canals with Lentulo spirals (Dentsply Maillefer, Baillaigues, Switzerland). Patients were followed up for a period from 9 to 36 months for the evaluation of clinical and radiological data. Radiographic measurements of root length, root width, apical diameter, and MTA placement from the apex were quantified using software ImageJ. Wilcoxon test and t-test were used, according to nonparametric or parametric data, respectively, for changes over time in root length, root width, and apical diameter., Results: Fifteen teeth survived during the follow-up period (93.75%) and met the criteria for clinical success. Although the changes seem to be very small in many cases, significant increases in the average root length (14.28%, p<0.0001), root width (8.12%, p=0.0196), and decrease in apical diameter (48.37%, p=0.0007) were observed. MTA placement from the apex and age at the time of treatment was not significantly associated with the quantitative radiographic outcomes., Conclusions: Pulp revascularization in traumatized immature teeth treated with calcium hydroxide plus 2% chlorhexidine gel as intracanal medication had high success and survival rates, showing periodontal healing and resolution of signs and symptoms. However, concerning the continued root development, the outcomes can still be considered unpredictable.

Aim: The objective of this study was to evaluate the presence of microorganisms in the root canals (RC) of teeth submitted to endodontic retreatment due to prosthetic reasons and without evidence of apical periodontitis., Material and Methods: Twenty teeth referred to endodontic retreatment due to prosthetic reasons and without evidence of apical periodontitis were included in this study. Gutta-percha (GP) was collected from each third of the RC. After GP removal, microbial samples were also collected from the full extension of RC using paper points and files. The samples were cultivated in Fastidious Anaerobe Agar and the colony-forming units (CFU/mL) were counted. They were also semi-quantitatively analyzed by checkerboard DNA-DNA hybridization using 40 DNA bacterial probes., Results: Microorganisms were found in all samples. The coronal third of GP was more contaminated than the apical third (p ≤ 0.05). There was prevalence of Enterococcus hirae and Enterococcus faecalis in all RC thirds and also in the samples collected from the full extension of RCs., Conclusion: Microorganisms were found in all cases referred to endodontic retreatment due to prosthetic reasons and without evidence of apical periodontitis. Enterococcus was the genus most frequently detected., Clinical Significance: An endodontic retreatment should be considered before replacing a prosthesis.

Aim: To evaluate in a clinical trial the efficacy of reciprocating and ultrasonic activation of 6% sodium hypochlorite (NaOCl) in the microbial composition and reduction in microbial load as well as in levels of lipopolysaccharide (LPS) and lipoteichoic acid (LTA) in teeth with primary endodontic infections., Methodology: Samples were collected from 24 root canals with pulp necrosis and periapical lesions, before and after chemo-mechanical canal preparation. The teeth were randomly divided according to the activation protocol as follows: control group without activation (WA, n = 8), reciprocating activation group using Easy Clean tip (EC, n = 8) and ultrasonic activation group using Irrisonic insert (US, n = 8). Microbiological specimens were processed using a culture technique and microbiota composition was analysed using the checkerboard technique. The levels of LPS and LTA were quantified using limulus amebocyte lysate (LAL) and enzyme-linked immunosorbent assay (ELISA), respectively. The Fisher's exact test, Kruskal-Wallis, Dunn's and Wilcoxon's test with a significance level of P < 0.05 were used for statistical analysis., Results: All initial specimens had growth of viable bacteria in fastidious anaerobe agar (FAA), with an average of 10 5  CFU mL -1 , whereas only one case had such growth after chemo-mechanical canal preparation. LPS and LTA were recovered in 100% of the cases. Chemo-mechanical canal preparation significantly decreased the levels of LPS and LTA (P < 0.05), but no significant differences were found between the groups (P > 0.05). Through the checkerboard technique, bacteria were found in 100% of the initial specimens with concentrations between <10 5 and 10 6 . The most frequently identified microorganisms were Prevotella nigrescens and Enterococcus hirae. After chemo-mechanical canal preparation, many species were not detected in any of the three groups tested. A significant reduction occurred in Group US, followed by Groups EC and WA., Conclusions: Activation of 6% NaOCl reduced the levels of LPS and LTA with no differences between the groups. However, ultrasonic activation was associated with a greater reduction in microbial load within root canals., (© 2019 International Endodontic Journal. Published by John Wiley & Sons Ltd.)

Objective: The objective of this work was to investigate in vivo the effects of calcium hydroxide-based intracanal medication (ICM) on the levels of bacteria, pro-inflammatory cytokines (PICs), and matrix metalloproteinases (MMPs) in root canals and periradicular tissues of teeth with failure of the root canal treatment and apical periodontitis., Materials and Methods: Twenty infected root canals of single-rooted teeth were randomly assigned into two groups according to the irrigant used for chemomechanical preparation (CMP) (n = 10 per group): G1 - 2% chlorhexidine (CHX) gel and G2 - 6% sodium hypochlorite (NaOCl). Root canal contents were taken by using paper points before CMP (S1) and after 30 days of calcium hydroxide-based ICM (S2). Microbial reduction was calculated by means of colony-forming unit count (CFU/mL), with PICs and MMPs (pg/mL) being measured by using enzyme-linked immunosorbent assay (ELISA)., Results: Culturable bacteria (101.2 ± 79.2), PICs (IL-1β 1.2 ± 0.4 and TNF-α 8.8 ± 4.7), MMP-2 (803.7 ± 96.4), MMP-3 (453.9 ± 229.3), MMP-8 (245.9 ± 122.4), MMP-9 (129.4 ± 29.6), and MMP-13 (70.8 ± 12.8) were present in all S1 samples. After 30 days of ICM (S2), a 99.5% microbial reduction was observed, together with a significant reduction of PICs in all groups. Overall, it was observed a decrease in the levels of MMPs (S2), except MMP-13, which was found in increased levels after ICM (P < .05), independently of the groups., Conclusions: Calcium hydroxide-based intracanal medications have had a positive effect on the microbial reduction by decreasing the levels of PICs and MMPs. Both auxiliary chemical substances (i.e., 2% CHX and 6% NaOCl) presented similar effects when calcium hydroxide was used as intracanal medication., Clinical Relevance: Teeth with failure of the root canal treatment and apical periodontitis, and consequently with high levels of bacteria, PIC, and MMP, may present a better prognosis after a 30 days of a calcium hydroxide-based ICM.

This study aimed to evaluate the influence of different ethanol concentrations on dentin roughness, surface free energy, and contact angle between AH Plus and the root canal dentin. One hundred human maxillary anterior teeth were split longitudinally and 200 dentin specimens were polished to make the surface flatter and smoother. An acrylic bar was positioned between two dentin specimens and impression material was added to create a block, simulating an instrumented root canal space. Specimens were removed from the mold and cleaned in an ultrasonic bath for 10 min. Thereafter, dentin specimens were divided into four groups (n = 50) according to the drying methods used: a) wet: vacuum only, b) paper points: vacuum + absorbent paper points, c) 70% alcohol: 70% alcohol (1 min) + vacuum + absorbent paper points, and d) 100% alcohol: 100% alcohol (1 min) + vacuum + absorbent paper points. A rugosimeter and a goniometer were used to verify the roughness (Ra) and to measure the surface free energy and the contact angle between the AH Plus sealer and the root canal dentin. ANOVA and Tukey tests (α = 0.05) were used for statistical analysis. The 70% and 100% ethanol groups showed significantly decreased roughness as well as increased surface free energy in the root canal dentin when compared to the wet and paper point groups. In addition, ethanol significantly reduced the contact angle between the AH Plus sealer and the root canal dentin. Ethanol solutions (70% and 100%) provide better wettability of AH Plus sealer on dentin surfaces.

Aim: This clinical study was conducted to investigate the influence of 17% ethylenediaminetetraacetic acid (EDTA) ultrasonic activation after chemomechanical preparation (CMP) on eliminating/reducing oral bacterial lipopolysaccharides (known as endotoxins) and cultivable bacteria in teeth with pulp necrosis and apical periodontitis., Methodology: Samples were taken from 24 root canals at several clinical periods: S1 - before CMP; S2 - after CMP; S3 - after EDTA: G1 - with ultrasonic activation (n = 12) and G2 - without ultrasonic activation (n = 12). Root canals were instrumented using Mtwo rotary files. Culture techniques were used to determine the number of colony-forming units (CFU). Limulus amebocyte lysate (LAL) was used to measure endotoxin levels. Friedman's and Wilcoxon signed-rank tests were used to compare the amount of bacteria and endotoxin levels in each period (P < 0.05)., Results: Endotoxins and cultivable bacteria were recovered in 100% of the initial samples (S1). CMP was effective in reducing endotoxins and bacterial load (all with P < 0.05). Higher values of endotoxin reduction were achieved with EDTA ultrasonic activation [G1, 0.02 EU mL -1 (range 0.01-0.75)] compared with the no activation group [G2, 1.13 EU mL -1 (range 0.01-8.34)] (P < 0.05). Regarding bacterial reduction, no statistically significant difference was found in S3, regardless of the group (G1, G2, P > 0.05)., Conclusions: Chemomechanical preparation was effective in reducing bacteria and endotoxins, but could not completely eliminate them. The ultrasonic activation of EDTA was effective in further reducing endotoxin levels in the root canals of teeth with pulp necrosis and apical periodontitis., (© 2016 International Endodontic Journal. Published by John Wiley & Sons Ltd.)

Objective: The aim of this study was to investigate in vivo microorganisms detected in root-filled teeth with post-treatment apical periodontitis and quantify colony-forming units (CFU) during endodontic retreatment., Materials and Methods: Fifteen root-filled teeth had their previous gutta-percha removed and were randomly instrumented before being divided into three groups and medicated with either [Ca(OH)2 + 2% CHX gel], [Ca(OH)2 + 0.9% NaCl] or 2% CHX gel. Samples were taken after removal of gutta-percha (S1), after chemomechanical preparation using 2% CHX gel (S2), and after inter-appointment dressing (S3) for 7 or 14 days later. Cultivable bacteria recovered from infected root canals at the three stages were counted and identified by means of culture and PCR assay (16S rDNA). Quantitative data were statistically analyzed by using Mann-Whitney test in which pairs of groups were compared (P < 0.05)., Results: CFU counts decreased significantly from S1 to S2 (P < 0.05). No significant difference was found between S2 and S3 (P = 0.3093) for all three experimental groups. Chemomechanical preparation and intra-canal dressing promoted significant median reductions of 99.61% and 99.57%, respectively, in the number of bacteria compared to S1 samples. A total of 110 cultivable isolates were recovered by culture technique from 32 different species and 7 different genera. Out of the 13 target species-specific primer of bacteria analyzed, 11 were detected during endodontic retreatment., Conclusion: The great majority of taxa found in post-treatment samples were Gram-positive bacteria, although Gram-negative bacteria were found by molecular methods. Moreover, our results showed that gutta-percha removal and chemomechanical preparation are effective for root canal disinfection, whereas additional intra-canal dressing did not improve disinfection.