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Objective: This study assessed the push-out bond strength (POBS) of an epoxy resin-based sealer in oval-shaped root canals after a final irrigation protocol using XP-endo Finisher and ultrasonic activation. Materials and methods: Thirty oval-shaped human root canals were prepared with Reciproc R25 and a final irrigation regimen using 5.25% sodium hypochlorite and 17% ethylenediaminetetraacetic acid (EDTA) was performed. The teeth were divided into three groups (n = 10) according to the final irrigation activation technique: no activation (control), ultrasonic activation and XP-endo Finisher activation. Specimens were filled only with AH Plus sealer and the POBS test was used to measure the bond strength between the root canal dentine and AH Plus sealer. The data obtained from the POBS test were analysed using two-way analysis of variance and Tukey post-hoc tests (P < 0.05). Results: The POBS values decreased from the coronal to the apical direction (P < 0.05). There was a significant association between the activation technique and the root canal third (P < 0.05). In the coronal and middle third, XP-endo Finisher and ultrasonic activation showed higher POBS than the control group (P < 0.05). In the apical third, XP-endo Finisher showed higher POBS than ultrasonic activation (P < 0.05) and the control group (P < 0.001). Ultrasonic activation also showed higher POBS values in the apical third when compared to the control group (P < 0.05). Conclusions: The activation of root canal irrigants influenced POBS of root canal sealers in the different root thirds of oval-shaped canals. The use of XP-endo Finisher file resulted in better POBS than ultrasonic activation in the apical third. [ABSTRACT FROM AUTHOR]

The purpose of this study was to analyze the in vitro antimicrobial activity of sodium hypochlorite (1% and 5%) and chlorhexidine (0.12%, 0.5% and 1%). Bacterial samples (ATCC) of Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Porphyromonas gingivalis and Fusobacterium nucleatum were submitted to a contact test. Solutions were evaluated at different time intervals: immediately, 5 min, 15 min, and 30 min after contact and repeated 10 times. The results of the contact test showed that 0.12% chlorhexidine did not eliminate E. faecalis at any time interval, while 0.5% and 1% chlorhexidine and 1% and 5% sodium hypochlorite did. These results permit us to conclude that to obtain better antimicrobial activity, chlorhexidine in a concentration greater than 0.12% should be used.

Aim: The aim was to evaluate the bacterial reduction achieved by ProTaper Next (PTN) system in root canals contaminated with Enterococcus faecalis. ProTaper Universal (PTU) and WaveOne (WO) systems were used as references for comparison. Materials and methods: A hundred human mandibular premolars were selected and ninety-five were contaminated with E. faecalis for 4 weeks. Then the teeth were randomly divided into six groups (n = 15): PTN + 2.5% NaOCl; PTU + 2.5% NaOCl; WO + 2.5% NaOCl; PTN + saline solution; PTU + saline solution; and WO + saline solution. Positive and negative control groups were created with five specimens each. The irrigation volume was standardised for all experimental groups. Samples taken before (S1) and after (S2) chemomechanical procedures were cultured and the colony-forming units (CFUs) were counted. The paired t-test was used for intragroup analysis, and one-way ANOVA for intergroup analysis. When significant differences were found amongst the groups, the Tukey test was used. The significance levels were set at 5% (P < 0.05). Results: After root canal instrumentation (S2), there was a significant reduction in bacterial load in all groups (P < 0.01). The WO/saline solution group showed a lower level of bacterial reduction when compared with the other tested groups (P < 0.01). Groups irrigated with NaOCl showed a higher level of bacterial reduction when compared with saline solution irrigation (P < 0.01), with no statistical differences amongst the systems used (P > 0.05). Conclusion: The PTN system was as effective as PTU and WO in the removal of bacteria during root canal treatment. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the antibacterial efficacy and discolouration potential of antibiotic pastes containing macrogol. Seventy single‐rooted teeth were contaminated with a culture of Enterococcus faecalis for 30 days. Double (DAP) and triple antibiotic pastes (TAP) containing propylene glycol or macrogol as vehicles were applied. After 15 days, bacterial viability was compared. Change in teeth coronal colour was measured by a spectrophotometer. Statistical analysis was performed using anova and Tukey's test (P < 0.05). TAP containing clindamycin and propylene glycol was the only medicament that led to the presence of contamination, while the same combination of antibiotics containing macrogol did not result in bacterial growth (P < 0.05). Only the pastes containing minocycline in formulation resulted in coronal discolouration (P < 0.05). Both DAPs evaluated and the TAP containing clindamycin and macrogol showed to be the preferable options for regenerative endodontic therapy, as they were effective against E. faecalis biofilm and did not promote tooth discolouration. [ABSTRACT FROM AUTHOR]

Purpose: To introduce a mapping method to characterize large dentin surfaces using digital microscopy and to discuss the advantages and possible applications of the method. Materials and Methods: Twenty unerupted third molars were sectioned transversally exposing coronal dentin surfaces. The microscopic mosaic method was used to generate a large field image with the resolution necessary to measure characteristics of dentin tubules. The AxioVision 4.7 software was used to control a motorized optical microscope and the process of acquiring approximately 400 small images to generate each dentin mosaic. An image analysis routine measured the number of tubules (NT) and the ratio between the total area of tubules and the area of the mosaic -- the area fraction (AF) -- of each mosaic. An automatic procedure transformed the mosaic image into a color map, providing a direct visual representation of tubule density through colors. The dentin maps were used for a comparative qualitative analysis of tubule density distribution of each sample. Results: The results for NT (92450 to 196029 tubules/sample) and AF (4.12% to 11.10%) demonstrated a wide variation among dentin samples. The maps confirmed the microstructure variety, also revealing strong local variations in tubule density within each sample. Conclusion: The mapping method was able to perform dentin morphology characterization and is a valuable tool for producing a baseline for dentin adhesion studies. The method could be also useful in determining the real contribution of dentin structures to the final adhesion quality. [ABSTRACT FROM AUTHOR]

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To assess the root canal system morphology of mandibular molars by means of micro‐computed tomography, one hundred and four mandibular first molars were investigated and the following were evaluated: Vertucci's classification, the presence of lateral canals and the number of apical foramina. Mesial root canal surface area and volume were obtained by the CTAn and CTvol software. The type of root canal isthmi was classified applying the Hsu & Kim and Fan criteria. The most frequent root canal configuration was Vertucci type IV (46.2%). Lateral canals were observed in all root canal thirds and the average number of apical foramina was 3.15 ± 1.77. Regarding the presence of isthmus, Types I and II were the most prevalent, according to Hsu & Kim and Fan et al. criteria, respectively. Mesial root canals of mandibular molars showed high morphology variability. [ABSTRACT FROM AUTHOR]

Aim: This study investigated the sealing ability produced by AH Plus (Dentsply DeTrey, Konstaz, Germany), EndoSequence BC sealer (Brasseler USA, Savannah, GA, USA), GuttaFlow (Coltène/ Whaledent, Altstätten, France) and MTA Fillapex (Angelus, Londrina, Brazil). Methdos: A total of forty-six single-root human canines were prepared and randomly divided into four experimental groups (n=10): MTA Fillapex, EndoSequence BC Sealer, AH Plus or GuttaFlow. Teeth with intact crowns served as negative controls (n=3) and teeth filled with only gutta-percha served as positive controls (n=3). Teeth were mounted in a two-chamber apparatus and exposed to Enterococcus faecalis. The number of days over a 60-days period was recorded for the appearance of turbidity in the lower chamber. Kaplan- Meier method was used to estimate the survival curves. The nonparametric log-rank test was used to compare the survival curves using a significance level of 0.05. Results: The results at the end of the observation time were further analyzed by chi-square testing. All positive controls leaked within 24 h, whereas none of the negative controls leaked after 60 days. EndoSequence BC Sealer and MTA Fillapex had significant less bacterial leakage (P<0.05) than the other tested sealers. No significant difference between AH Plus and GuttaFlow was observed (P>0.05). Conclusion: In conclusion, calcium-silicate based root canal sealers promoted improved sealing ability when compared to other endodontic sealers. [ABSTRACT FROM AUTHOR]

Introduction: The electronic method has been studied and improved aiming to add precision, speed and reliability of the measurement technique to determine the exact location of the working length. Currently, the root canal preparation recommends prior to determine the tooth length and consequent perform instrumentation of the apical portion, a previous preflaring of the cervical and middle thirds in various techniques. This procedure may provide a reduction in system impedance, leading to read errors by the apex locators. Objective: Investigate the influence of preflaring of the cervical and middle thirds on the accuracy of measuring the working length by apex locators. Material and methods: Twenty-five mesial roots of molars were used and had their crowns cut at the cemento-enamel junction. The actual measure of each root canal was performed and then the samples were embedded into a mixture of alginate, used as a conducting medium, where electronic measurements were taken with apex locator before and after pref laring of the canals with Gates-Glidden drills in descending order (#4, #3, #2). Measurements obtained by electronic method were then compared with the actual measurement of the root canal. The results were tabulated and submitted to the Student t test Results: The results show that there was no statistical significance (p<0.05) between the readings before and after preflaring. Readings closer to the foraminal ending occurred in the group after preflaring with Gates Glidden. Conclusion: It was concluded that preflaring with Gates Glidden drills were not able to influence significantly the accuracy of apex locator in determining the exact working length. [ABSTRACT FROM AUTHOR]

Objective: This study evaluated the antimicrobial efficacy of 2.5% and 5.25% NaOCl, 2% gel and liquid CHX and MTAD against Enterococcus faecalis biofilms on human dentin. Material and methods: E. faecalis biofilms grown on dentin matrix of 216 root sections were submerged in test irrigants for 1, 5, 15 and 30 minutes. The antimicrobial activity of the test irrigants were assessed through CFU counts. Biofilm formation over the dentin surface was ensured by SEM analysis. Results: Results showed no statistic difference among CHX gel, 2.5% and 5.25% NaOCl. However, the CHX liquid and MTAD were less effective than 2.5% and 5.25% NaOCl. Only CHX liquid and MTAD had differences in its efficacy depending on the time. Conclusion: The most effective irrigants in eliminating E. faecalis biofilms were 2.5% and 5.25% NaOCl and 2% CHX gel, at all the tested time intervals, in comparison to CHX liquid and MTAD. [ABSTRACT FROM AUTHOR]