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Copyright of Dental Press Endodontics is the property of Dental Press International and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Dental Press Endodontics is the property of Dental Press International and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Introduction: The success of endodontic treatment is based on microbial reduction promoted by the interaction of chemical and mechanical procedures. Photodynamic therapy (PDT) is used as an adjunct to conventional treatment, with significant microbial reduction. This study aimed to evaluate the influence of passive ultrasonic irrigation (PUI) of the photosensitizer (PS) used in PDT on microbial reduction in the root canal system. Materials and Methods: Forty-five mesiobuccal root canals from extracted human mandibular molars that were inoculated with standard strains of Enterococcus faecalis, Candida albicans, and Streptococcus mutans for 21 days were selected. The root canals were prepared using the ProTaper Next system and randomly divided into 3 groups (n=15): 1) PDT: PDT alone; 2) PUI+PDT: PUI followed by PDT; and 3) PUI/PS+PDT: PUI of the PS followed by PDT. Microbiological samples were collected from the canals before and after using the protocols described above. The data were analyzed by analysis of variance (Tukey's test) at a significance level of 5%. Results: Microbial counts before PDT, PUI+PDT, and PUI/PS+PDT did not differ significantly (P>0.05), showing methodological standardization in the microbial contamination of the root canal system. There was a significant reduction in microbial counts after PDT (61.05%), PUI+PDT (65.04%), and PUI/PS+PDT (68.58%) (P<0.01), but with no statistically significant difference between the three groups (P>0.05). Conclusion: Based on the present findings, it was concluded that the combination of PUI with PDT or PS activation did not influence microbial reduction achieved by PDT alone. [ABSTRACT FROM AUTHOR]

Introduction: Successful endodontic treatment requires an effective coronal sealing to prevent the penetration of saliva and microorganisms into the root canal system. We aimed to investigate the sealing capacity of Maxxion R, Intermediate Restorative Material (IRM), Mineral Trioxide Aggregate-like material (Biodentine), White Cimpat, Flow Resin and Z250 Resin against Enterococcus (E.) faecalis infiltrates, when used as coronalsealants after endodontic treatment. Materials and Methods: Sixty-six roots of adult lower premolars were randomly divided into 6 experimental groups with 10 roots each (n=10), and two control groups (positive and negative) with three roots each. The root canals were instrumented to ProTaper F3 file, irrigated with 2.5% NaOCl and 17% EDTA, and filled using Tagger's Hybrid technique with AH-Plus cement. After removing 2 mm of the coronal third filling with a Gates Glidden #6 drill, the cervical portion of each of the sixty roots was sealed with a 2 mm-thick plug, plus the respective material being tested in this study. All roots were fitted to silicone devices (Eppendorf) with cut extremities and sterilized with ethylene oxide; experimental procedures were performed in a laminar flow chamber for aseptic chain maintenance. All specimens were inoculated with E. faecalis, and the culture medium was renewed every 3 days for 60 days. Medium turbidity was evaluated daily. The obtained data were subsequently submitted to analysis of variance (ANOVA-R) complemented by Student's t-test at a significance level of 5%. Analyzes of variance were calculated using the SAS system GLIMMIX procedure. Results: Biodentine (56.90), Z250 Resin (54.90) and White Cimpat (53.30) resisted contamination for a longer time compared to Maxxion R (51.30), Flow Resin (50.70), and IRM (48.70) over a period of 60 days. Conclusion: Biodentine, Resin Z 250 and White Cimpat presented the lowest infiltration averages when compared to the other tested materials. [ABSTRACT FROM AUTHOR]

Introduction: Maxillary premolars, may be more susceptible to fracture due to their anatomy; especially when there is loss of tooth structure. Therefore, it is necessary to evaluate materials and techniques that may increase fracture resistance during and post root canal treatment. This in vitro study aimed to evaluate root fracture resistance of maxillary premolars when filled with three root canal sealers as well as whether this resistance would be increased by passive ultrasonic irrigation (PUI). Methods and Materials: Sixty-four maxillary premolars with two roots were randomly divided into one negative control group (intact canals; n = 8), one positive control group (instrumented, unsealed canals; ti = 8), and six experimental groups (n = 8), which were instrumented with ProTaper Next rotaiy system up to X2 file and subdivided according to final irrigation (with or without PUI) and type of sealer used (AH-Plus [AH], MTA Fillapex [MTA], or EndoSequence BC Sealer [ES]). The specimens were subjected to fracture strength test in a universal testing machine at a speed of 1 mm/min until fracture. The maximum force required to induce fracture was recorded (N). The Kruskal-Wallis test and DUNN test were used for analysis. Results: The lowest force required to cause root fracture was observed in the positive control group (310.48 ±54.08 N); this was significantly different from the other groups (P< 0.05). There was no significant difference between experimental groups obturated with the same sealer, whether with or without PUI (AH with PUI: 558.80±87.12 N; AH without PUI: 508.75±97.55 N; MTA with PUI: 507.27± 174.55 N; MTA without PUI: 516.69±96.56 N; ES with PUI: 526.76± 143.97 N; ES without PUI: 628.40± 94.74 N) (P>0.05). There was also no significant difference between the experimental groups and the negative control group (P> 0.05). Conclusions: In this in vitro study PUI did not increase the fracture resistance of maxillary premolars, while AH Plus, MTA Fillapex, EndoSequence sealers increased fracture resistance of instrumented root canals. [ABSTRACT FROM AUTHOR]

Introduction: The success of endodontic treatment is based on microbial reduction promoted by the interaction of chemical and mechanical procedures. Photodynamic therapy (PDT) is used as an adjunct to conventional treatment, with significant microbial reduction. This study aimed to evaluate the influence of passive ultrasonic irrigation (PUI) of the photosensitizer (PS) used in PDT on microbial reduction in the root canal system., Materials and Methods: Forty-five mesiobuccal root canals from extracted human mandibular molars that were inoculated with standard strains of Enterococcus faecalis , Candida albicans , and Streptococcus mutans for 21 days were selected. The root canals were prepared using the ProTaper Next system and randomly divided into 3 groups ( n =15): 1) PDT: PDT alone; 2) PUI+PDT: PUI followed by PDT; and 3) PUI/PS+PDT: PUI of the PS followed by PDT. Microbiological samples were collected from the canals before and after using the protocols described above. The data were analyzed by analysis of variance (Tukey's test) at a significance level of 5%., Results: Microbial counts before PDT, PUI+PDT, and PUI/PS+PDT did not differ significantly ( P >0.05), showing methodological standardization in the microbial contamination of the root canal system. There was a significant reduction in microbial counts after PDT (61.05%), PUI+PDT (65.04%), and PUI/PS+PDT (68.58%) ( P <0.01), but with no statistically significant difference between the three groups ( P >0.05)., Conclusion: Based on the present findings, it was concluded that the combination of PUI with PDT or PS activation did not influence microbial reduction achieved by PDT alone., Competing Interests: None.

Introduction: The aim of this study was to evaluate the effectiveness of 2.5% sodium hypochlorite associated with 17% Ethylenediaminetetraacetic acid (NaOCl-EDTA), versus that of 1% peracetic acid (PA), in removing the smear layer, as assessed by scanning electron microscopy (SEM), and in exerting bactericidal action against Enterococcus faecalis ( E. faecalis ) , as assessed by the real-time polymerase chain reaction (real-time PCR)., Methods and Materials: Fifty-five extracted mandibular single-rooted premolars were selected, and divided into two experimental groups (NaOCl-EDTA and PA; n =25) and one control group (0.9% saline; n =5). Pre- and post-instrumentation samples were collected and assessed for the presence of E. faecalis using real-time PCR. The teeth were instrumented using hand files and the ProTaper Universal system (hybrid technique) for a standardized time of 7 min. A total of 20 mL of NaOCl followed by 5 mL of EDTA were applied during instrumentation in the NaOCl-EDTA group, whereas 20 mL of PA and 20 mL of saline were applied in the PA and control groups, respectively. An additional 5 mL of saline was applied in all the groups to neutralize the environment. A scoring system was used to conduct the SEM assessment. The results were submitted to the Kruskal-Wallis test, complemented by Dunn's test (SEM analysis) ( P <0.05)., Results: A significant microbial reduction was observed in both the PA and the NaOCl-EDTA groups ( P <0.05). In the PA group, the presence of a smear layer in the apical third was significantly greater than in the cervical third ( P <0.05); no significant differences were observed between the middle and cervical thirds, or between the middle and apical thirds ( P >0.05). In the NaOCl-EDTA group, the smear layer scores were significantly higher in the apical third than in the cervical and middle thirds ( P <0.05)., Conclusion: This in vitro study showed that there was no significant difference between PA and NaOCl-EDTA irrigation regimens regarding either antimicrobial action against E. faecalis or removal of the smear layer, except for greater removal in the middle third by the NaOCl-EDTA group., Competing Interests: ‘None declared’.