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The objective of this in vitro study was to evaluate the shear bond strength (SBS) of several universal adhesives to dentin treated with sodium hypochlorite (NaOCl), and NaOCl followed by ethylenediaminetetraacetic acid (EDTA). Adhese Universal, Scotchbond Universal, Prime & Bond Elect, Prime & Bond Active, and Optibond XTR were included in the study. SBS values were determined in self-etch mode with no pretreatment of the dentin, after a 20-minute exposure of the dentin to 6% NaOCl, and after a 20-minute exposure to NaOCl followed by a one-minute exposure to 17% EDTA. Experimental groups were repeated using a total-etch technique (except Optibond XTR). Adhesives in self-etch mode had significantly reduced SBS following dentin exposure to NaOCl (P <.05), while with a total-etch technique, only Prime & Bond Active was affected (P <.05). SBS in self-etch mode when NaOCl exposure was followed by EDTA were equal to or higher than negative control values (P <.05). For total-etch groups, Adhese Universal was negatively affected by NaOCl + EDTA exposure (P <.05). Prime & Bond Elect exhibited lower SBS following NaOCl + EDTA exposure when compared to just NaOCl exposure but was not different from the negative control (P <.05). For the adhesives tested, the use of 17% EDTA following NaOCl exposure negated the negative effects of NaOCl on SBS in self-etch mode. When used in total-etch mode, results varied significantly, with some adhesives performing better or worse depending on the specific testing condition. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate changes in geometry following root canal preparation using R-Motion instruments with different apical sizes and tapers. Fifty-four mesial canals of mandibular molars with single curvature of angles ranging between 20° and 30° were stratified into 3 groups according to their internal anatomy (R-Motion 25/.06, 30/.04, Reciproc Blue) (n = 18 per group). Micro-computed tomography was used to standardize the samples before instrumentation and, after instrumentation, to assess canal transportation, changes in canal volume and centering ability. Canals were irrigated with 17% EDTA and sodium hypochlorite, and the final rinse included subsonic agitation of these solutions. Measurements were analyzed automatically using the Dragonfly software (Come, Montreal, Canada) and were confirmed by a technician and an endodontist, based on a previously validated methodology. The results were analyzed using the Kruskal-Wallis's and Mann-Whitney's tests. The level of statistical significance was set at 5%. Significant differences were found in the coronal third for canal transportation, with Reciproc Blue R25 having greater values compared with both R-Motion instruments (P <.05) and greater changes in volume when compared with R-Motion 30/.04 (P <.05). R-Motion of apical size and taper 25/.06 and 30/.04 were associated with similar changes in geometry following root canal preparation in curved mesial canals of mandibular molars, whereas Reciproc Blue was associated with greater canal transportation in the coronal root third. [ABSTRACT FROM AUTHOR]

This study systematically reviewed literature regarding the effect of different concentrations of sodium hypochlorite (NaOCl) used during root canal treatment (RCT) on postendodontic pain (PEP) and rescue analgesia. Following registration with PROSPERO (CRD42023388916), a search was conducted using PubMed, Scopus, Web of Science, and Embase databases. Randomized controlled trials of patients receiving RCT which assessed PEP at different time intervals were included. Following data extraction and Cochrane risk of bias assessment 2, meta-analyses were performed to evaluate PEP during the first 48 hours along with rescue analgesic intake. The certainty of the evidence was evaluated using the Grading of Recommendations, Assessment, Development, and Evaluation approach. Five randomized controlled trials with 674 patients were included. One study exhibited a low risk of bias, while 4 raised some concerns. Patients treated with low concentrations of NaOCl (≤3%) were significantly less likely to report PEP at 24 hours (OR = 2.32; [95% CI, 1.63–3.31]; P <.05) and 48 hours (OR = 2.49; [95% CI, 1.73–3.59]; P <.05) as compared with high concentrations of NaOCl (≥5%). Furthermore, with low concentrations of NaOCl, significantly lesser moderate-severe PEP was reported at 24 hours (OR = 2.32; [95% CI, 1.47–3.62]; P <.05) and 48 hours (OR = 2.35; [95% CI, 1.32–4.16]; P <.05) and lesser analgesia was needed (OR = 2.43; [95% CI, 1.48–4.00]; P <.05). While PEP can be influenced by several factors, low certainty evidence suggests that when NaOCl is used as an irrigant during RCT, PEP may be less likely with lower concentrations of NaOCl. Moderate certainty evidence indicates that lesser analgesia may be required with lower concentrations of NaOCl. These results should be cautiously interpreted. [ABSTRACT FROM AUTHOR]

Nickel-titanium rotary endodontic files have been commercially available for decades, but more recent innovations have introduced heat-treated and surface-treated files. This study investigated the corrosion properties of various nickel-titanium files in normal saline and sodium hypochlorite (NaOCl). Ten different file brands of size 40 with a 0.04 taper were subjected to electrochemical testing in 0.9% NaCl (saline) and 5.25% NaOCl at room temperature. The Open Circuit Potential (OCP) was observed for 1 hour followed by a cyclic polarization test from −300 to 700 mV and back to −300 mV (vs OCP). Nonparametric ANOVA and a pairwise comparison (P <.05) were used for statistical analysis of the OCP at 1 hour and the corrosion current (Icorr) obtained via the cyclic polarization test. Significant differences (P <.05) were found between files with respect to OCP and Icorr in both solutions. Nine files exhibited significantly greater (P <.05) Icorrs in NaOCl than in saline. Conversely, pitting corrosion was observed in the saline solution but not NaOCl. Weak and/or moderate correlations existed between OCP and Icorr measures in the 2 solutions. Significant differences in electrochemical properties were observed among the 10 brands of files. Overall, there was not a clear trend between conventional, heat-treated, or surface-treated files among OCP or Icorr in either solution. [ABSTRACT FROM AUTHOR]

The aim of this study was to compare the outcome and prognostic factors for partial and full pulpotomy in the management of mature teeth with spontaneous symptomatic pulpitis. The study was a parallel double-blind randomized clinical trial; 200 carious mature permanent teeth with spontaneous symptomatic pulpitis were randomized using a block randomization technique to either partial pulpotomy (n = 99) or full pulpotomy (n = 101). Intraoperative assessment of the pulp under magnification was performed, hemostasis was achieved with a 2.5% sodium hypochlorite moist pellet, and NeoPUTTY (Avalon Biomed, Bradenton, FL) was the pulpotomy material. Preoperative pain levels were recorded and re-evaluated after 1 week. Clinical and radiographic evaluation was performed after 6 and 12 months. Data were analyzed using the chi-square test, the Wilcoxon rank test, and regression analysis. At 1 week, immediate failure occurred in 4 cases in partial pulpotomy, and 196 of 200 subjects reported pain relief and were satisfied with the treatment with no significant difference. At 6 months, 6 teeth failed in the partial pulpotomy group and 1 tooth in the full pulpotomy group, with a higher success rate for full pulpotomy (98.96 vs 89.69, P =.003). At 12 months, the recall rate was 98% (96/200). Full pulpotomy was more successful than partial pulpotomy (98.98% [98/99] vs 84.53% [82/97], P <.001). Multivariate analysis revealed that the odds of success for full pulpotomy were 13.6 times higher than partial pulpotomy. Increased age and higher time to hemostasis were significantly associated with decreased odds of success. Full pulpotomy has a higher success rate than partial pulpotomy in the management of spontaneous symptomatic pulpitis. Hemostasis within 4 minutes in partial pulpotomy can be set as the cutoff point beyond which further tissue removal is indicated. [ABSTRACT FROM AUTHOR]

In endodontic treatment, it is important to remove or inactivate biofilms in the root canal system. We investigated the effects of different concentrations and application times of sodium hypochlorite (NaOCl) on the viability of bacteria in ex vivo polymicrobial biofilms of different maturation levels. Polymicrobial biofilms were prepared from dental plaque samples and grown for 1, 2, and 3 weeks under anaerobic conditions on collagen-coated hydroxyapatite discs as an ex vivo biofilm model. The biofilms were then exposed to NaOCl at concentrations ranging from 0.1% to 2% for 1 or 3 minutes. The control group was exposed to sterile distilled water. Viability staining was performed and examined by confocal laser scanning microscopy to determine the percentage of biofilm bacteria killed by NaOCl. Scanning electron microscopy was also performed to visually examine the biofilms. Application of NaOCl at 0.5%–2% for both 1 and 3 min killed significantly more bacteria when compared to the controls (P <.05). Cell viability tended to be lower after the application of NaOCl for 3 minutes than that for 1 minute. Our experiments using an ex vivo model showed that within the range of 0.1%–2% of NaOCl, higher NaOCl concentrations and longer application times were more effective in killing biofilm bacteria, and that mature biofilms were more resistant to NaOCl than younger biofilms. [ABSTRACT FROM AUTHOR]

This study compared disinfection and shaping after root canal preparation with either XP-endo Shaper or TruNatomy instrument systems, supplemented by ultrasonic activation of sodium hypochlorite (NaOCl) with either stainless-steel (SS) or nickel-titanium (NiTi) inserts. Mesial roots from mandibular molars with Vertucci class II configuration were divided into 2 groups (n = 24) based on anatomically paired micro-computed tomography (micro-CT) analyses. Pre and postpreparation micro-CT scans were obtained to evaluate the shaping performance. The canals were contaminated with a mixed bacterial culture for 30 days and then subjected to preparation with either XP-endo Shaper or TruNatomy instruments using NaOCl irrigation. Supplementary ultrasonic activation of NaOCl was conducted using either an SS (TruNatomy group) or NiTi (XP-endo Shaper group) insert. Bacteriological samples were taken from the canals before preparation (S1), after preparation (S2), and after the supplementary approach (S3). Bacterial reduction was evaluated using a quantitative real-time polymerase chain reaction. Preparation with both instrument systems significantly reduced bacterial counts (P <.01). After preparation, 36% (TruNatomy) and 35% (XP-endo Shaper) were negative for bacteria. These values increased to 59% and 65% after ultrasonic activation with the SS and NiTi inserts, respectively. The quantitative data in S2 showed that XP-endo Shaper promoted a significantly higher bacterial reduction than TruNatomy (P <.05). No significant intragroup differences were observed after ultrasonic activation (P >.05), probably because the SS insert promoted a significantly higher S2-to-S3 reduction than the NiTi insert (P <.01). Micro-CT analysis revealed no significant differences in the unprepared areas between the groups (P >.05). The XP-endo Shaper caused a significantly higher bacterial reduction than TruNatomy in Vertucci class II canals. Better antibacterial results after ultrasonic activation were observed for the SS ultrasonic inserts than for the NiTi inserts. [ABSTRACT FROM AUTHOR]

The efficacy of sodium hypochlorite (NaOCl) as an intracanal irrigant is widely debated in endodontic therapy. This study aimed to analyze and compare the penetration abilities of different modes of NaOCl application and assess the impact of various agitation strategies on promoting root canal cleanliness. This study included 168 single-rooted mandibular premolars that were randomly divided into 8 groups. The 2 modes of application of 5% NaOCl evaluated were intracanal heating and preheating, and the agitation strategies included ultrasonic, sonic, and manual dynamic agitations. The samples were sectioned and observed at a magnification of 1000 × under a scanning electron microscope. The analysis of variance test showed a statistically significant difference among the various groups of agitation (P <.05). The post hoc Tukey test confirmed that preheated NaOCl with ultrasonic agitation, intracanal-heated NaOCl with sonic agitation, and manual dynamic agitation had significantly higher debris scores of 1, 4, and 5, respectively, in the apical third of the canal. The results indicated that the combination of intracanal-heated NaOCl and ultrasonic agitation is an effective method for reducing debris in the root canal system. These findings highlight the importance of considering both the mode of application and the agitation strategies when optimizing the use of NaOCl as an intracanal irrigant in endodontic therapy. [ABSTRACT FROM AUTHOR]

The obturation quality of the mandibular molar mesial canals and isthmuses with two thermoplastic techniques, ultrasonic vertical condensation (UVC) and continuous wave of condensation (CWC), was evaluated using computed microtomography (μCT). Thirty-six human mandibular molars had been previously scanned and analyzed using μCT for mesial roots with morphologically similar isthmuses for this study. Coronal access and confirmation of foraminal patency were performed, and the actual length of the teeth was established using a clinical microscope (40X magnification). The canals were prepared using ProTaper Gold instruments up to #F3, with 2.5% sodium hypochlorite as the irrigant solution, followed by a passive ultrasonic irrigation protocol. The specimens were randomly divided into the UVC and CWC groups based on the obturation technique to be used. Obturation was performed with #F3 gutta-percha cones cemented using AH Plus Jet sealer. The μCT scans were performed after 15 days, and the images were evaluated by a calibrated examiner blinded to the experimental groups to determine the filling rate of the entire canal area, including the main canal and isthmus. Student's t -test was used for statistical analysis; P values ≤0.05 were considered significant. Neither of the thermoplastic obturation techniques achieved complete filling of the canals (86.3% for UVC and 91.4% for CWC), with a statistically significant difference between them (P =.029). Under the conditions of the study, it can be concluded that none of the techniques completely filled the canal/isthmus of the mandibular molars; however, the CWC exhibited better performance. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate pulp tissue dissolution ability of sodium hypochlorite (NaOCl) when mixed with tetrasodic etidronate (Na 4 HEBP) and disodic ethylenediaminetetraacetate (Na 2 EDTA) under controlled flow. Bovine pulp tissue was extracted from the lower incisors of 10 bovine jaws. Pulp specimens were standardized in size (1 × 3 × 10 mm), blotted dry, and weighed (initial weight [T0]: mean (SD) = 31.98 (1.18) mg). Specimens from the same jaw were randomly assigned to 2 control (n = 3 each) and 4 experimental groups (n = 10 each): NC (negative control/distilled water), PC (positive control/6%NaOCl), G1 (3%NaOCl), G2 (3%NaOCl-17% Na 2 EDTA), G3 (3%NaOCl-18% Na 4 HEBP), and G4 (3%NaOCl-9% Na 4 HEBP). Distilled water and NaOCl were provided using a delivery pump under a continuous controlled rate (1 mL/min). A second pump alternately delivered either Na 2 EDTA or Na 4 HEBP at the same rate with a 30-second programmed interval. Percentage of tissue weight loss was calculated at 2, 5, and 10 minutes (T2, T5, and T10) and compared among groups with analysis of variance. Free available chlorine and pH were controlled at T0 and T10. No tissue remained in PC at T5. No dissolution occurred in NC. There were no significant differences in the percentage of weight loss among experimental groups at any point of time. Some remnant tissue was found in G3 (1.4% ± 2.4) and G4 (1.6% ± 2.3) at T10, whereas nothing was left in G1 and G2. The controlled delivery of Na 2 EDTA and Na 4 HEBP did not alter tissue dissolution ability of NaOCl when fresh solutions were mixed in the root canal. [ABSTRACT FROM AUTHOR]

To evaluate the antimicrobial activity of Triton irrigation versus 4% sodium hypochlorite (NaOCl) utilizing a direct contact test and an extracted tooth model. In the first experiment, a direct contact test was conducted to compare bacterial DNA removal and microbial diversity changes following irrigation with 4% NaOCl or Triton. Hydroxyapatite and dentin discs were inoculated with subgingival human-derived dental plaque for 2 weeks utilizing the Center for Disease Control biofilm reactor and subsequently challenged with the root canal irrigants for 5 minutes. In the second experiment, teeth contaminated with a multispecies biofilm (n = 24) were assigned into two treatment groups, NaOCl or Triton irrigation. Samples were obtained for quantitative real-time polymerase chain reaction and next-generation sequencing analysis before and after instrumentation. The Shannon and Chao1 indices were used to measure alpha diversity. The Bray–Curtis dissimilarity and ANOSIM was used to measure beta diversity. Differences in abundances of genera were evaluated using Kruskal–Wallis test with Bonferroni corrections. The direct contact test revealed no significant differences in the bacterial load based on 16S rRNA gene molecules/μL, reads, or differences in the Shannon index among groups. In the extracted tooth model, a bacterial load reduction of log 10 3.08 ± 0.69 and 2.76 ± 0.91 were found for NaOCl and Triton, respectively (P =.348). Next-generation sequencing showed fewer reads, lower Chao1, and beta diversity values when pretreatment and post-treatment samples were assessed in both experimental groups (P <.0001). The Kruskal–Wallis analysis found that 17 genera of bacteria were over-represented in minimal values in the Triton post-treatment group, 14 of these genera represented less than 1% of the microbial community. Both irrigants had limited antimicrobial activity in the direct contact test. When used in conjunction with mechanical instrumentation both irrigants were able to reduce the bacterial DNA load and diversity in comparison with pretreatment communities. The NaOCl irrigation, followed by ethylenediaminetetraacetic acid flush, was more effective in decreasing DNA counts from low-abundance organisms. [ABSTRACT FROM AUTHOR]

Aerosol generation in a dental setting is a critical concern, and approaches that aim at decreasing bacterial load in aerosols are of high priority for dental professionals. The objectives of this study were to evaluate the relative effect of various endodontic procedures on the generation and dissemination of aerosols and the effect of 0.1% sodium hypochlorite (NaOCl) in dental unit waterlines (DUWLs) on the bacterial load in the generated aerosols in a clinical setting. The study was completed in 2 phases. The classic passive sampling technique using brain-heart infusion agar plates was used. Agar plates were strategically placed throughout the operatory at predefined locations. In phase 1, to evaluate the effect of different endodontic procedures on the generation and dissemination of aerosols, we collected a total of 38 samples. After baseline collection, test samples were collected during vital pulp therapy (VPT) full pulpotomy (n = 10), nonsurgical root canal therapy (NSRCT, n = 10), surgical root canal therapy (SRCT, n = 10), and incision and drainage (n = 8) procedures. Bacterial growth was expressed as colony-forming units at 48 hours after sample collection. Data were analyzed using 1-way analysis of variance with the Tukey multiple comparison post hoc test. In phase 2, to evaluate the effect of 0.1% NaOCl in the DUWL on the bacterial load in the generated aerosols, a total of 30 samples were collected. All procedures including VPT (n = 10), NSRCT (n = 10), and SRCT (n = 10) were performed with 0.1% NaOCl in the DUWL. Bacterial growth was expressed as colony-forming units at 48 hours after sample collection. Data were analyzed using 2-way analysis of variance with the Tukey multiple comparison post hoc test. All endodontic procedures generated aerosols at all tested locations, except incision and drainage. Aerosols were disseminated as far as 3 m from the patient's head with no significant difference between various locations (P >.05). VPT procedures generated the maximum number of aerosols compared with NSRCT and SRCT. Adding 0.1% NaOCl to DUWLs significantly reduced the bacterial load in the generated aerosols in all treatment groups compared with groups treated with untreated waterlines (P <.05). No significant difference was noted in the bacterial load between all groups with treated waterlines (P >.05). All tested endodontic procedures led to the generation and dissemination of contaminated aerosols, and the addition of 0.1% NaOCl as a biocide to the DUWL led to a statistically significant reduction in the bacterial load. [ABSTRACT FROM AUTHOR]

This study evaluated the bacterial reduction promoted by root canal preparation using irrigation with sodium hypochlorite (NaOCl) alone, associated with etidronic acid (1-hydroxyethane 1,1-diphosphonic acid [HEDP]) or alternated with citric acid, and after a supplementary agitation step. Extracted mandibular premolars were selected and distributed into 3 groups based on anatomically paired micro–computed tomographic analyses. The canals were contaminated with Enterococcus faecalis for 30 days and then subjected to chemomechanical preparation with a reciprocating instrument under irrigation with NaOCl alone, mixed with HEDP (NaOCl/HEDP), or alternated with citric acid (NaOCl/CA). A supplementary agitation step with the XP-endo Finisher was performed in all groups. Intracanal bacteriological samples were taken before (S1) and after preparation (S2) and after the supplementary approach (S3). DNA was extracted from the samples and subjected to quantitative real-time polymerase chain reaction. Intragroup analyses revealed a substantial bacterial reduction from S1 to S2 or S3 in all groups (P <.01). The supplementary agitation resulted in S2-to-S3 bacterial reduction of 6%, 68%, and 80% in the NaOCl, NaOCl/HEDP, and NaOCl/CA groups, respectively. Irrigation with NaOCl alone resulted in 53% and 47% of samples negative for bacteria in S2 and S3, respectively. Corresponding figures for NaOCl/HEDP were 75% and 85%, and 44% and 72% for NaOCl/CA. Intergroup analyses of S2 samples showed that NaOCl/HEDP was significantly more effective than the other 2 in reducing the bacterial levels (P <.05). After the supplementary approach, both NaOCl/HEDP and NaOCl/CA were significantly more effective than NaOCl alone (P <.05), with no significant differences between them (P >.05). Both the freshly combined NaOCl/HEDP solution and the alternate use of NaOCl and citric acid followed by XP-endo Finisher agitation resulted in significantly higher intracanal bacterial reduction than NaOCl alone. [ABSTRACT FROM AUTHOR]

The retrievability of calcium silicate–based sealers (CSSs) during nonsurgical retreatment has been equivocal. This study compared the retrievability of 3 different CSSs using 1 of 3 different solutions or no solution. A total of 130 extracted teeth with a straight canal were decoronated to a standardized root length. The canals were instrumented to 35/.04 and divided into 3 groups (BC: EndoSequence BC sealer; EBC: EdgeBioceramic; NEO: NeoSEALERFlo), and each group was further divided into 4 subgroups (6% sodium hypochlorite; 5% acetic acid; carbonated water; no solution). After sealer placement, each master gutta-percha cone was placed intentionally 2 mm short of the working length (WL) to ensure the apical 2 mm was filled only with sealer. After storage for 21 days at 37°C and 100% humidity, retreatment was performed until apical patency was obtained. The operator was blinded to the CSS and solution used. Data were analyzed using analysis of variance to compare apical patency rates and the mock chair-times. Overall success rates for apical patency in BC, EBC, and NEO were 63.64%, 69.77%, and 100%, respectively. There was significantly higher apical patency rate in NEO than BC and EBC. The chair-time for NEO was significantly shorter than BC (P <.05) and EBC sealer (P <.001). There was no significant difference in the chair-time between BC and EBC sealer groups. BC, EBC, and NEO sealers in a straight canal were consistently retrievable when no solution was used. Compared with no solution, the retrievability of BC, EBC, and NEO decreased when solutions were used. [ABSTRACT FROM AUTHOR]

IntroductionNisin, a broad-spectrum bacteriocin, has recently been highlighted for its biomedical applications. To date, no studies have examined the antimicrobial and antibiofilm properties of high-purity (>95%) nisin (nisin ZP) on Enterococcus faecalis and biofilms formed by this species. We hypothesize that nisin can inhibit E. faecalis and reduce biofilm biomass, and combinations of nisin and sodium hypochlorite (NaOCl) will enhance the antibiofilm properties against E. faecalis biofilms.MethodsUsing broth cultures, disc diffusion assays, and biofilm assays, we examined the effects of nisin on various E. faecalis growth parameters and biofilm properties (biovolume, thickness, and roughness). Confocal microscopy was used in conjunction with Imaris and Comstat2 software (Kongens Lyngby, Copenhagen, Denmark) to measure and analyze the biofilm properties.ResultsNisin significantly decreased the growth of planktonic E. faecalis dose dependently. The minimum inhibitory concentrations against E. faecalis strains OG-1 and ATCC 29212 were 15 and 50 μg/mL, and the minimum bactericidal concentrations were 150 and 200 μg/mL, respectively. A reduction in biofilm biovolume and thickness was observed for biofilms treated with nisin at ≥10 μg/mL for 10 minutes. In addition, the combination of nisin with low doses of NaOCl enhanced the antibiofilm properties of both antimicrobial agents.ConclusionsNisin alone or in combination with low concentrations of NaOCl reduces the planktonic growth of E. faecalis and disrupts E. faecalis biofilm structure. Our results suggest that nisin has potential as an adjunctive endodontic therapeutic agent and as an alternative to conventional NaOCl irrigation.

The purpose of this study was to evaluate the impact of different sodium hypochlorite (NaOCl) irrigation protocols on organic tissue dissolution in the periapical region of simulated immature permanent teeth. Eight single-rooted premolars and 48 samples of porcine palatal mucosa were used. Acrylic resin prototypes were constructed, placing the tissue in close contact with the dental apices. Specimens were then divided into 6 groups (n = 8): 2 control groups of normal saline irrigation with (NS/WA) or without (NS/NA) ultrasonic activation and 4 experimental groups of 1.5% and 2.5% NaOCl irrigation with (NaOCl 1.5%/WA and NaOCl 2.5%/WA) or without (NaOCl 1.5%/NA and NaOCl 2.5%/NA) activation. Root canals were irrigated with 20 mL of the solution for 5 minutes distributed over 4 irrigation cycles. In each cycle, after irrigation, the solution was either kept stagnant or activated for 30 seconds and then replaced. Specimens were weighed on a precision balance before and after the irrigation protocols. Tissue dissolution was measured by the difference between the initial and final weights. One-way analysis of variance was applied followed by the Tukey honestly significant difference test (α = 0.05). The NS/NA and NS/WA groups had mean weight reductions similar to the 1.5% NaOCl/NA group (P >.05) and lower than the others (P <.05). The 2.5% NaOCl/NA and 2.5% NaOCl/WA groups had the highest mean weight loss (P <.05), whereas the 1.5% NaOCl/WA group had intermediate values (P <.05). Periapical tissue dissolution occurred in all groups, with a greater impact observed with 2.5% NaOCl with or without ultrasonic activation. [ABSTRACT FROM AUTHOR]

The aim was to compare the compressive strength of dentin after irrigation with different concentrations of sodium hypochlorite (NaOCl). A total of 259 extracted human tooth roots with no root caries or previous endodontic treatment were collected. They were sorted by size and length, and assigned to 7 groups (n = 37): negative control (no instrumentation, no irrigant), positive control (saline irrigant), 1%, 2.5%, 4%, 5.25%, and 10% NaOCl. A total of 13 mL NaOCl or saline (in 1-mL increments) was used per canal while being instrumented to #35 files (approximately 13 minutes). EDTAC (15%) was then used to remove the smear layer (2 minutes), followed by NaOCl as a final rinse. The roots were sectioned into 2-mm-thick disks and subjected to compression testing. There was a significant difference between the negative control group and all instrumented groups (P <.05). The positive control group was significantly different from the 5.25% group (P <.05) and had a low P value when compared with the 2.5% group and the other higher concentrations (P ≅.1). When the NaOCl groups were compared with each other, there was a significant difference between 1% NaOCl and all higher concentrations (P <.05), but no significant difference when 2.5% NaOCl was compared with higher concentrations. A concentration of 1% NaOCl had the least effect on the compressive strength of dentin and this was significantly different from all higher concentrations tested. Therefore, the use of concentrations of NaOCl above 1% should be reconsidered. [ABSTRACT FROM AUTHOR]

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. 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%. 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). 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. [ABSTRACT FROM AUTHOR]

Extrusion of sodium hypochlorite (NaOCl) is a very rare accident with the most common complications including pain, swelling, and hematoma. It can occur even if procedural guidelines, predisposing conditions, and risk factors are taken into consideration. A 59-year-old female patient was admitted to the endodontics department to treat a left maxillary first premolar (World Dental Federation tooth 24). The medical history included osteoporosis and systemic medication with alendronate. Initially, the diagnosis was "symptomatic irreversible pulpitis" with "normal apical tissues." During instrumentation of the buccal canal, accidental extrusion of 2.5% NaOCl occurred into the periapical tissues, resulting from misinterpretation of the working length, and caused severe pain and bleeding. The canal was immediately flushed using copious irrigation with saline solution. An analgesic and corticosteroid were prescribed. At 3 and 7 days, ecchymosis and slight hematoma were observed extraorally in the area of the affected tooth and an intraoral ulceration at the apex of the affected tooth. At 15 days, minimal signs of ecchymosis were observed, and the treatment was resumed. At 30 days after the accident, there was complete remission of the sequelae. The clinical, radiographic, and tomographic assessment after 1 month, 1 year, and 8 years showed favorable case evolution. During the 8-year follow-up, the patient maintained the systemic use of alendronate. It can be concluded that NaOCl extrusion is an accident that causes patients and clinicians to experience an unpleasant consequence. The radiographic working length should always be determined carefully. A successful outcome can be achieved in patients who take alendronate. [ABSTRACT FROM AUTHOR]

Introduction: The purpose of this study was to evaluate effect of cryotreated and warm sodium hypochlorite (NaOCl) on postoperative pain in patients with symptomatic irreversible pulpitis and symptomatic apical periodontitis., Methods: Sixty-six individuals with preoperative pain scores of ≥54 mm on the Heft Parker Visual Analogue Pain Scale (HP-VAS) diagnosed with symptomatic irreversible pulpitis and symptomatic apical periodontitis as per the American Association of Endodontists guidelines in mandibular molars were included. The preparation of the access and the root canals was instrumented and irrigated in accordance with a standard protocol. Based on the temperature of the final irrigant, the root canals were then randomly assigned to 3 groups and 3% NaOCl was irrigated: control (at 25°C), cold NaOCl (2°C), and warm NaOCl (60°C) (n = 22/group). Root canal treatment was completed at the same visit. Pre- and postoperative pain assessment at 6, 24, 48, and 72 hours was conducted using the HP-VAS, and analgesic consumption was noted. Suitable statistical tests were used to analyze the data., Results: In comparison with the other 2 groups, the cold NaOCl group had a lower HP-VAS score at all follow-up intervals. Between groups, there was a statistically significant difference in postoperative pain scores at 6 and 72 hours (P < .05). None of the subjects experienced any postoperative discomfort at 72 hours in the control and cold NaOCl groups., Conclusion: Patients treated with cold NaOCl as the final irrigant experienced significantly less postoperative pain at 6 hours when compared with room temperature and warm NaOCl., (Copyright © 2024 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

The aim of this study was to evaluate the postoperative pain in patients after endodontic treatment using 8.25% sodium hypochlorite (NaOCl) compared with other concentrations and 2% chlorhexidine (CHX). In this double-blind randomized trial, 180 patients were evaluated who underwent a single session of endodontic treatment under irrigation with 2.5%, 5.25%, or 8.25% NaOCl or 2% CHX solutions. The presence of postoperative pain was assessed 24, 48, and 72 hours after treatment and recorded using the visual analog scale (VAS). A descriptive analysis, logistic regression, and Wald test were performed. Altogether 169 patients participated, of whom 107 were women, and the mean age was 38.1 ± 14.4 years. No significant differences occurred between the irrigants and the pain outcomes, not even for the use of postoperative pain medication and responses to VAS (P >.05). In the multivariate model including irrigants, after 24 hours or at any time, a significant difference (P <.05) remained in preparation time ≥10 minutes and the presence of overfilling. Also, in relation to the VAS, the overfilling presented significantly different results (P <.05). There was no significant difference in the presence of postoperative pain between the 8.25% NaOCl and the other irrigation solutions. However, the extended preparation time and the overfilling material were responsible for the increase of postoperative pain. [ABSTRACT FROM AUTHOR]

This ex vivo study compared the disinfection and shaping abilities of 2 preparation protocols in C-shaped canals. Mandibular second molars with type I C-shaped canals were pair matched based on micro–computed tomographic (micro-CT) analysis and distributed into 2 groups. The canals were contaminated with a mixed bacterial culture and prepared using 2 protocols, both with 2.5% sodium hypochlorite irrigation: XP-endo Shaper (FKG Dentaire, La Chaux-de-Fonds, Switzerland) supplemented with XP-endo Finisher (FKG Dentaire) (XP-E) and BioRaCe (FKG Dentaire) supplemented with a Hedström file (Dentsply/Sirona, Tulsa, OK) (BR-Hed). Micro-CT scans and intracanal bacteriologic samples were taken before (scan #1 and sample 1) and after preparation (scan #2 and sample 2) and after the supplementary step (scan #3 and sample 3). Canal shaping was evaluated by micro-CT imaging, and disinfection was assessed by quantitative polymerase chain reaction. Micro-CT data from the XP-E (n = 21) and BR-Hed (n = 23) protocols revealed no significant differences between groups regarding shaping parameters (canal volume, surface area, structure model index, and prepared walls) after preparation and after the supplementary step (P >.05). All these parameters significantly increased after each preparation step (P <.05), except for structure model index changes after the XP-endo Finisher (P >.05). Bacteriologic data from the XP-E (n = 21) and BR-Hed (n = 22) groups showed that 14 (66.7%) and 10 (45.5%) S2 samples still had detectable bacteria, respectively. The corresponding figures for supplementary steps with the XP-endo Finisher and Hedström file were 11 (52.4%) and 10 (45.5%), respectively. Bacterial counts in sample 1 significantly decreased in samples 2 and 3 in both groups (P <.01). Intragroup comparison between sample 2 and sample 3 showed a 66% reduction in counts after using the Hedström file and 18% after using the XP-endo Finisher (P >.05 for both groups). The quantitative bacterial reduction was not different between groups (P >.05). The XP-endo Shaper and BioRaCe systems have similar disinfecting and shaping abilities in C-shaped canals. Supplementary steps with the Hedström file and the XP-endo Finisher were similarly effective in improving shaping, but this was not sufficient to enhance disinfection. About half of the cases, in both groups, still harbored detectable amounts of bacteria. [ABSTRACT FROM AUTHOR]

Hydrogen peroxide (H 2 O 2) and sodium hypochlorite (NaOCl) solutions are similar in that they contain oxidizing agents with a bleaching effect. NaOCl solutions are stable at a high pH, at which they also exert increased cleansing/proteolysis. On the other hand, H 2 O 2 solutions are natively acidic, yet gain bleaching power on organic stains when alkalized. It was investigated whether alkalizing a H 2 O 2 solution would also let it dissolve soft tissue or increase its bleaching power on blood-stained dentin. The stability of alkalized H 2 O 2 solutions was assessed by iodometric titration. Soft tissue dissolution was investigated on porcine palatal mucosa. The bleaching effect (ΔL∗) after 60 minutes of exposure was monitored in blood-stained human dentin using a calibrated spectrophotometer. To compare similar molarities, 2.5% H 2 O 2 solutions were used here, and 5.0% NaOCl was used as the positive control, whereas nonbuffered saline solution served as the negative control. Adding alkali (NaOH) to the H 2 O 2 solutions rendered them unstable in a dose-dependent manner. A H 2 O 2 solution of pH 11.1 was chosen for the main experiments (tissue dissolution and bleaching effect) and compared with a native counterpart (pH = 4.7). Alkalizing the H 2 O 2 solution had no discernible effect on its soft tissue dissolution or bleaching power (P =.75 compared with the native H 2 O 2 solution). The NaOCl solution of similar molar concentration had a considerably (P <.001) higher tissue dissolving and bleaching effect under current conditions. The proteolytic/bleaching effects of NaOCl solutions are unique and cannot be achieved by altering the pH of peroxide solutions. [ABSTRACT FROM AUTHOR]

The present study evaluated the effect of passive ultrasonic activation (PUI) of EDTA solution followed by conventional irrigation with 2 concentrations of sodium hypochlorite (NaOCl) on smear layer removal. Fifty single-root mandibular premolars were chemomechanically prepared with ProTaper Universal (Dentsply Maillefer, Ballaigues, Switzerland) nickel-titanium rotary instruments and 1% NaOCl. The roots were cleaved, and the dentin surfaces were analyzed with scanning electron microscopy operated at a low vacuum. Images were obtained from previously demarcated areas in each root canal third. The teeth were reassembled and distributed into 5 groups according to the final irrigation protocols (n = 10): group 1, EDTA/PUI + 1% NaOCl; group 2, EDTA/PUI + 5% NaOCl; group 3, EDTA/CI + 1% NaOCl; group 4, EDTA/CI + 5% NaOCl; and group 5 (negative control), saline solution/PUI. After irrigation, the teeth were reseparated and prepared for conventional high-vacuum scanning electron microscopy of the same dentin surface that was previously analyzed. The amount of debris was classified using a 4-point scoring system. Data were analyzed with Kruskal-Wallis and Dunn tests at α = 0.05. Groups 1 and 2, which used PUI and different concentrations of NaOCl, were not significantly different; however, they differed significantly from group 3 (P <.05). With respect to canal cleanliness at different root thirds, all groups showed the worst cleaning at the apical third. PUI activation of the EDTA irrigant is required when canal debridement is performed with EDTA and a lower concentration of NaOCl. [ABSTRACT FROM AUTHOR]

This study aimed to assess whether ultrasonic activation (UA) or the EasyClean (EC; BassiEndo, Belo Horizonte, BH, Brazil) or EDDY (ED; VDW, Munich, Germany) systems used to promote agitation of the irrigating solutions during the final irrigation step can lead to smear layer formation in the apical third of the root canal. Thirteen premolars were instrumented with the Reciproc R40 file (VDW) and embedded in silicone, forming a closed irrigation/aspiration system. The teeth were cleaved, and 4 indentations were made on the inner buccal wall of the canal to standardize the observation sites. All the specimens were cleaned in an ultrasonic bath and evaluated under environmental scanning electron microscopy, thus constituting the control group. The same specimens were reassembled, submitted to final irrigation using UA or the ED or EC systems, and classified using a 4-level scoring system. The data were analyzed using the kappa, Pearson, and Kruskal-Wallis tests (P <.05). Smear layer formation occurred in all of the experimental groups and at all apical levels. At 3 and 4 mm, all of the experimental groups had significantly higher levels of smear layer formation than the control group. At 2 mm, the level of smear layer formation in the UA group was significantly higher than that of the control group, and there were no significant differences among the EC, ED, and control groups. At 1 mm, there were no significant differences between the ED and control groups, and the levels of smear layer formation in the EC and UA groups were significantly higher than that of the control group. There were no significant differences between the ED and EC groups at any of the apical levels. The smear layer formation occurred in all of the specimens submitted to final irrigation, irrespective of the technique used. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the effect of the continuous wave of condensation technique (CWCT) and the thermoplastic gutta-percha injection (TGI) technique on the messenger RNA (mRNA) expressions of heat shock proteins (HSPs) and mineralized tissue–associated proteins of the immortalized mouse cementoblasts (OCCM.30). Crowns of human premolar teeth with single and straight canals were removed. The root canals were prepared up to the ProTaper Next X5 file (Dentsply Maillefer, Ballaigues, Switzerland) in combination with 2 mL 2.5% sodium hypochlorite solution. Roots (12 ± 2 mm height) were sterilized (121°C for 20 minutes) and placed vertically to the cell culture dishes using a tissue culture insert by opening holes according to the root diameter after the removal of 1 mm from the apex for appropriate adaptation to the petri dish surfaces. Six groups were created: control 1 (without teeth), control 2 (with teeth), AH Plus (Dentsply DeTrey, Konstanz, Germany), single-cone obturation (SC), CWCT, and thermoplastic gutta-percha injection technique (TGI). The viability of the OCCM.30 cells was analyzed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide cell viability experiments at 24 and 96 hours. The mRNA expression of HSP27 , HSP70 , and HSP90 and mineralized tissue markers (bone sialoprotein, osteocalcin, runt-related transcription factor 2, type I collagen, and alkaline phosphatase) was evaluated by real-time polymerase chain reaction. Reduced OCCM.30 cell viability was observed in all groups except the control groups. When the SC technique and CWCT and TGI groups were compared, it was observed that heat had a significant negative effect on cell viability (P <.05). A reduction in the mRNA expressions of HSP27 , HSP70 , and HSP90 was recognized in all test groups when compared with the control 1 group (P <.01). When the warm gutta-percha techniques were compared with the SC technique, a decrease in mRNA expression of HSP27 and HSP90 was noted (P <.01). The HSP70 transcript was similar in the CWCT group and the SC group. Higher HSP70 mRNA expression was observed in the TGI group compared with the SC group. In all groups except the control 1 group, bone sialoprotein, osteocalcin, runt-related transcription factor 2, type I collagen, and alkaline phosphatase mineralized tissue markers were affected, but this negative effect was higher in the heat-treated groups (P <.05). Within the limitations of this study, it was concluded that warm gutta-percha techniques reduced the mRNA expressions of the genes for HSPs and mineralized tissue–associated proteins of cementoblasts. Further animal studies are needed to clarify the effect of heat on the behavior of cementoblasts histologically in short- and long-term periods. [ABSTRACT FROM AUTHOR]

This study assessed the cleaning, shaping, and disinfection abilities of 2 instrumentation systems in molar root canals using a novel correlative analytical approach. The root canals from extracted mandibular and maxillary molars with apical periodontitis were pair matched according to anatomic similarities as determined by micro–computed tomographic analysis and prepared with either XP-endo Shaper (FKG Dentaire, La Chaux-de-Fonds, Switzerland) (n = 16) or Reciproc Blue (VDW, Munich, Germany) (n = 16) instruments and 2.5% sodium hypochlorite irrigation. Pre- and postpreparation micro–computed tomographic scans were used to identify and calculate the unprepared surface areas (shaping), which were histobacteriologically evaluated for the presence of residual bacteria (disinfection) and pulp tissue remnants (cleaning) in each canal third. Unprepared canal surface areas for XP-endo Shaper and Reciproc Blue in the full canal length were approximately 26% and 19% (P <.05), respectively (30% and 23% in the apical part of the canal, P >.05). Preparation with Reciproc Blue resulted in 37.5% canals free of bacteria in all sections examined and 56% in the apical sections only. XP-endo Shaper resulted in 44% canals free of bacteria in all sections, and 56% in the apical part of the canal only. Pulp tissue remnants were not observed in 31% (all canal sections) and 50% (apical canal sections) of specimens from both instrument systems. No significant differences were observed between instruments when comparing the amount of pulp tissue remnants and the number of cases negative for bacteria and tissue remnants (P >.05). Although the Reciproc Blue instrument had superior shaping ability in comparison with XP-endo Shaper, both systems performed similarly in cleaning and disinfecting root canals. Irregular canals and difficult-to-reach areas were not thoroughly cleaned and disinfected by any of the tested systems. [ABSTRACT FROM AUTHOR]

Root canal treatment of immature necrotic teeth is a major challenge in current endodontics. The effect of inflammatory mediators, such as prostaglandin, on the modulation of stem cells of the apical papilla (SCAP) is not completely understood. The aim of this study was to investigate the role of prostaglandin E 2 (PGE 2) on SCAP activation by Escherichia coli lipopolysaccharide (LPS) in vitro. SCAP cultures were established and characterized. Increasing concentrations of lipopolysaccharide (0.1–10 μg/mL) were used to investigate cyclooxygenase-2 (COX-2/ PTGS2) and PGE 2 receptors (EP1–4) gene expression. Then, SCAP were treated with a COX-2 inhibitor (indomethacin) before treatment with different concentrations of LPS. The levels of the chemokine CCL2/monocyte chemoattractant protein 1 and interleukin (IL)-6 were detected in cell supernatants (24 hours) by enzyme-linked immunosorbent assay. Data analysis was performed using analysis of variance followed by the Tukey post test. The expression of COX-2 was up-regulated in the group treated with LPS at 1μg/mL compared with that in the control group. EP1–4 were detected in all experimental conditions at similar levels. SCAP treated with indomethacin presented a down-regulation in the production of LPS-induced CCL2 and the secretion of IL-6. SCAP showed increased COX-2 (PTGS2) gene expression induced by LPS and a PGE 2 -dependent production of IL-6 and CCL2. [ABSTRACT FROM AUTHOR]

Mixtures of clodronate with sodium hypochlorite (NaOCl) better maintain free available chlorine (FAC) than etidronate-hypochlorite mixtures. This research aimed to compare organic tissue dissolution and residual FAC between clodronate and etidronate mixtures. Additionally, clodronate-hypochlorite mixtures lose no FAC over several hours. The second aim was to examine how well such mixtures dissolve organic material 6 hours from mixing. Soon after mixing, porcine palatal mucosa samples were added to 32°C solutions containing 0.26 mol/L clodronate and 5% NaOCl (0.26 mol/L-5% NaOCl), 0.26 mol/L etidronate-5% NaOCl, 5% NaOCl, 0.26 mol/L clodronate, 0.26 mol/L etidronate, or phosphate-buffered saline. Weights and FAC, where applicable, were recorded initially and at 15 minutes. FAC was measured by iodometric titration. Secondly, 6 hours after mixing, mucosa was added to 0.26 mol/L clodronate-2.5% NaOCl, 2.5% NaOCl, 0.52 mol/L clodronate-5% NaOCl, 5% NaOCl, or phosphate-buffered saline. Sample weights at 0, 5, 10, and 15 minutes were recorded. Analysis of variance was used for statistical analyses (α <.05). Soon after mixing, 0.26 mol/L clodronate-5% NaOCl dissolved mucosa as well as 5% NaOCl and better than 0.26 mol/L etidronate-5% NaOCl compared with which it retained more FAC. At 6 hours after mixing, 0.26 mol/L clodronate-2.5% NaOCl dissolved organic material as well as 2.5% NaOCl. However, 0.52 mol/L clodronate-5% NaOCl dissolved less mucosa than 5% NaOCl. Soon after mixing, clodronate mixtures better dissolve organic material than etidronate mixtures and have higher residual FAC. Six hours from mixing, 0.26 mol/L clodronate-2.5% NaOCl mixtures dissolve organic material similarly to controls. [ABSTRACT FROM AUTHOR]

The goal of regenerative endodontic treatment (RET) is to regenerate the pulp-dentin complex in immature teeth with pulp necrosis. There is no consensus in using RET in previously treated teeth. This article reports on long-term outcomes of RET in previously treated immature teeth. Previously treated immature teeth with signs/symptoms of failure were included. After local anesthesia and rubber dam isolation, the root canal filling material was removed without the use of chemical solvents. The root canals were irrigated with 6% sodium hypochlorite using an EndoVac (Kerr Endodontics, Culver City, CA), and a creamy mix of metronidazole and ciprofloxacin was placed in the canals for 4 weeks. At the second visit, the antibiotic dressing was removed using 17% EDTA. Bleeding was induced into the root canal space, and SynOss Putty (Collagen Matrix Inc, Oakland, NJ) was placed. Bioceramic putty was placed over the SynOss Putty, and the teeth were restored at a subsequent visit. Five teeth in 4 patients were included. The patients' ages ranged from 14–46 years. Recall examinations were performed from 20 to 72 months with an average of 54.4 months. The apical openings of the teeth ranged from 1–3.7 mm. All teeth were functional and asymptomatic at the recall visits. All periapical lesions resolved with partial or complete mineralization of the root canals, and all teeth showed partial to complete apical closure at the follow-up visits. RET can be a viable option for nonsurgical retreatment of immature teeth. This article adds a new perspective to the field of regenerative endodontics. [ABSTRACT FROM AUTHOR]

Introduction: The aim of this study was to ascertain the current trends in regenerative endodontic procedures (REPs) among clinicians, including case selection criteria and clinical protocols., Methods: An online questionnaire consisting of provider demographics, case selection criteria for REPs, and clinical protocols was made available to members of the American Association of Endodontists and members of the Endolit website. Data were analyzed using the Fisher exact test., Results: Two hundred seventy-two responses were analyzed (64.6% were men and 34.7% were women). Of those, 44.5% of respondents practiced in the United States, and 55.5% practiced outside of the Unites States. Most respondents (85.4%) reported performing REPs in their practice, and 92.2% were using sodium hypochlorite as one of their disinfecting irrigants. Calcium hydroxide was the most commonly used intracanal medicament (68.4%), and the majority of respondents use a blood clot alone as the scaffold (73.5%). Most (93%) of the providers reported using a bioceramic material for coronal capping. Practitioners outside the United States were found to be more likely to use adjunctive irrigation activation (P = .003). Younger practitioners preferred REPs over apexification (P = .01). Practitioners outside the United States were more likely to perform an REP in 1 visit (P = .006). Men were found to be more likely to always instrument the canal walls (P = .031). Women were found to be more likely to use manual irrigant activation, whereas men were more likely to use sonic activation (P = .043)., Conclusions: There is significant heterogeneity within REPs regarding case selection and clinical protocol. Notable differences were observed from the reported findings of REPs from 5 years ago., (Copyright © 2023 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

This study aimed to investigate the effect of the immersion of standardized dentin bars in 5% sodium hypochlorite (NaOCl) solutions at 60°C and 80°C on their viscoelastic properties using dynamic mechanical analysis. Eighteen intact teeth were used to produce 99 dentin bars of standard dimensions (12 × 1 × 2 mm) and randomly allocated to 6 groups (n = 15 each) for immersion in (1) saline at 26°C, (2) saline at 60°C, (3) saline at 80°C, (4) NaOCl at 26°C, (5) NaOCl at 60°C, and (6) NaOCl at 80°C. The bars were individually tested using dynamic mechanical analysis at baseline and after every 10 minutes of immersion in the test medium, up to 40 minutes. The effects of media, temperature, duration of exposure, and aspect ratio of bars on the storage modulus and tan delta were investigated using generalized estimating equations. There was a significant interaction between the test medium and the duration of immersion (P <.05). The storage modulus of specimens immersed in NaOCl at 60°C or 80°C decreased significantly (P <.0001) over time of exposure, but the changes in other groups were minimal and insignificant. The tan delta of specimens immersed in saline 80°C (P <.05), NaOCl at 60°C (P <.05), or 80°C (P <.0001) increased significantly over the time of exposure, but the change in NaOCl at 26°C was minimal. Other groups displayed negligible changes. NaOCl at 60°C or 80°C significantly reduced the elastic behavior but increased the hysteresis of dentin under cyclic loading. [ABSTRACT FROM AUTHOR]

This ex vivo study evaluated the intracanal bacterial reduction promoted by chemomechanical preparation using a single-file technique varying the volume, concentration, and retention time of sodium hypochlorite (NaOCl) irrigation in comparison with a multifile system. Palatal roots from extracted maxillary first molars were selected and anatomically matched based on microcomputed tomographic analysis for group distribution. The canals were contaminated with a fresh mixed bacterial culture grown in anaerobiosis and recently obtained from a tooth with apical periodontitis. Specimens were divided into 4 groups of 24 each according to the following preparation protocols: REC-6LOW (Reciproc R50 instrument [VDW, Munich, Germany], 6% NaOCl, low irrigant volume), REC-2.5LOW (R50, 2.5% NaOCl, low irrigant volume), REC-2.5HI (R50, 2.5% NaOCl, high irrigant volume), and BR-2.5HI (BioRaCe [FKG Dentaire, LaChaux-de-Fonds, Switzerland], 2.5% NaOCl, high irrigant volume). The total time of preparation was recorded. Intracanal bacteriologic samples were taken before and after preparation; DNA was extracted and subjected to quantitative polymerase chain reaction. Bacteria were detected in 22 initial samples from the REC-2.5LOW group and in 23 from the other groups. Intragroup analysis showed that all tested preparation protocols were highly effective in significantly reducing the intracanal bacterial counts (P <.001). Intergroup comparison of bacterial reduction levels revealed a statistically significant difference between BR-2.5HI and REC-2.5LOW (P <.05). Counts of bacteria were 2.5 times significantly higher in REC-2.5LOW compared with BR-2.5HI. No other significant differences were found in quantitative findings (P >.05). The concerted effects of multiple instruments, the high volume of irrigation, and the long retention time of NaOCl irrigant had a positive influence on intracanal disinfection during chemomechanical preparation. • Bacterial reduction was compared between a single-file and a multifile system. • All protocols produced a highly significant intracanal bacterial reduction. • Counts of bacteria were 2.5 times significantly higher in the REC-2.5LOW group when compared with the BR-2.5HI group. • Disinfection was better with multiple instruments, high volume, and longer sodium hypochlorite exposure. [ABSTRACT FROM AUTHOR]

Abstract Introduction The aim of this study was to evaluate the effect of 2 different concentrations of sodium hypochlorite on healing and postoperative pain after primary endodontic treatment. Methods One hundred mandibular molars with pulp necrosis and chronic apical periodontitis were randomly assigned to 2 treatment groups: high-concentration (HC) 5% sodium hypochlorite and low-concentration (LC) 1% sodium hypochlorite. Root canal treatment was performed using a standardized protocol. Canals were prepared using equal volumes of respective irrigants after each instrument change. After chemomechanical preparation, the final flush was performed with 5 mL 17% EDTA solution followed by 5 mL 5% or 1% sodium hypochlorite depending on the group. All patients were asked to record the degree of pain on a visual analog scale every 24 hours for 1 week. At the second visit, canals were obturated, and the teeth were restored permanently. Clinical and radiographic evaluations were performed every 3 months for 12 months. The data collected were statistically analyzed. Results Eighty-six teeth were available for evaluation at the 1-year follow-up. The overall healing rate observed was 76.7%. Greater healing was observed in the HC (81.4%) group compared with the LC group (72.1%), but the difference was not statistically significant (P >.05). No significant differences in pain incidence and pain scores were found between the 2 groups (P >.05), with lower values reported in the LC group. Conclusions The use of LC or HC sodium hypochlorite did not result in a significant difference in the clinical outcome. [ABSTRACT FROM AUTHOR]

Abstract Introduction The aim of this study was to evaluate the effect of different temperatures of sodium hypochlorite (NaOCl) on the cyclic fatigue resistance of the heat-treated file systems. Methods The cyclic fatigue resistance of Reciproc 25 (VDW Dental, Munich, Germany), Reciproc Blue R25 (VDW), WaveOne Primary (Dentsply Maillefer, Ballaigues, Switzerland), WaveOne Gold Primary (Dentsply Maillefer), and One Shape (25.06; Micro Mega, Besançon, France) was tested in the following conditions: control (no immersion), immersion in distilled water (DW) at 37°C ± 1°C, immersion in DW at 60°C ± 1°C, immersion in NaOCl at 37°C ± 1°C, and immersion in NaOCl at 60°C ± 1°C. The immersion period was 5 minutes for all conditions. A stainless steel artificial canal with a curvature of 60° and a 5-mm radius was used. The time to failure and fragment lengths were recorded for each instrument, and data were subjected to statistical analysis. Results Reciproc Blue showed greater cyclic fatigue resistance in all conditions compared with the other systems (P <.05). Immersion in NaOCl at 60 °C negatively affected all instruments' cyclic fatigue resistance except Reciproc Blue. Immersion in DW at 60 °C increased the cyclic fatigue resistance of Reciproc Blue. Heat-treated files presented higher fatigue resistance than traditional files. Conclusions A high temperature of NaOCl affected the cyclic fatigue life of the file systems. Instruments produced with heat treatment presented a longer fatigue life. Highlights • RB presented higher cyclic fatigue resistance following 60°C NaOCl treatment. • NaOCl at 60°C caused corrosion and drastic effect on cyclic fatigue resistance. • Heat-treated alloys presented better cyclic fatigue resistance. [ABSTRACT FROM AUTHOR]

Abstract Introduction Tetrasodium etidronate (Na 4 etidronate) and tetrasodium EDTA (Na 4 EDTA) are chelators that can combine with sodium hypochlorite (NaOCl) as a 1-mix endodontic irrigant in a process called continuous chelation. The therapeutic window of these mixtures is determined by the chemical reaction between NaOCl and the chelator. At room temperature, this window is 60 minutes for Na 4 etidronate and 30 minutes for Na 4 EDTA. Because reaction kinetics are influenced by heat, this study assesses the influence of heating to an intracanal temperature of 35°C on the therapeutic window in continuous chelation. Methods The loss of free available chlorine (FAC) in NaOCl mixtures with Na 4 etidronate or Na 4 EDTA was determined by iodometric titration at 23°C ± 0.7°C (23°C) and 34.6°C ± 0.3°C (35°C) at 1, 20, 40, and 60 minutes after mixing. The pH and temperature of the mixtures were measured. Results At 23°C, 18% Na 4 etidronate/5% NaOCl solutions at 20, 40, and 60 minutes lost 4%, 9% and 18% FAC, and at 35°C, they lost 20%, 68% and 92% FAC; 5% Na 4 EDTA/2.5% NaOCl solutions at 20, 40, and 60 minutes at 23°C lost 88%, 94%, and 97% FAC, and at 35°C, they lost 96%, 99%, and 100%. Decreases in FAC were accompanied by pH declines. Conclusions The effect of heating to 35°C from a room temperature of 23°C on 18% Na 4 etidronate/5% NaOCl solutions reduces its therapeutic window to 20 minutes. Solutions of 5% Na 4 EDTA/2.5% NaOCl are not useful in the continuous chelation technique. Tracking pH changes could be used to estimate NaOCl degradation. Highlights • Heat accelerates the fall in free available chlorine in continuous chelation. • Heat reduces the therapeutic window in continuos chelaton. • Tetrasodium EDTA mixtures are unsuitable for continuous chelation. • Decreases in free available chlorine parallel declines in pH. • pH measurements can estimate the use life of continuous chelation mixtures. [ABSTRACT FROM AUTHOR]

Abstract Introduction Mineral trioxide aggregate (MTA) has been used in pulp capping of cariously exposed mature permanent teeth with promising results. The search for alternative materials that seal better and set faster than MTA and do not stain is ongoing. Biodentine (Septodont, St Maur-des-Fossés, France) exhibits these advantages but has not been tested yet for a prolonged duration in mature teeth. This study aimed to evaluate the clinical performance of Biodentine and white MTA (Angelus, Londrina, Brazil) in cariously exposed mature permanent teeth. Methods This was a prospective longitudinal randomized controlled study of 68 vital permanent teeth with deep caries. Patients were randomly allocated into 2 study arms: Biodentine and MTA. Teeth were assessed clinically and radiographically before the procedure. Caries were excavated under local anesthesia; hemostasis was achieved after pulp exposure using sodium hypochlorite and capped with Biodentine or MTA. Clinical and radiographic follow-ups were performed by a blinded calibrated evaluator after 6 months and 1, 2, and 3 years. Results There were no significant differences in the overall success rate between Biodentine and MTA; it was 93.3% (Biodentine = 93.1% and MTA = 93.5%) at 6 months. The overall success rate increased to 96.2% (Biodentine = 96.0% and MTA = 100%) at 1 year and to 100% at 2 years. At the 3-year follow-up, it decreased to 93.8% (Biodentine = 91.7% and MTA = 96.0%). Conclusions Biodentine and MTA have favorable and comparable success rates when used as direct pulp capping or pulpotomy material in permanent mature teeth with carious exposure. The remaining tooth structure and durability of coronal restoration might affect significantly the long-term success of vital pulp therapy. [ABSTRACT FROM AUTHOR]

Abstract Introduction SmearOFF (Vista Dental Products, Racine, WI) is an irrigation solution containing chlorhexidine (CHX), EDTA, and a surfactant. This study examined the chemical interaction of SmearOFF with sodium hypochlorite (NaOCl) on the dentin surface, specifically the formation of precipitate and/or parachloroanaline (PCA). Methods Dentin blocks prepared from human maxillary molars were mounted in resin. Dentinal tubules were exposed in a perpendicular orientation using an ultracryomicrotome. The blocks were divided into 2 groups: the CHX group, irrigation with 6% NaOCl, 17% EDTA, 6% NaOCl, and 2% CHX, and the SmearOFF group, irrigation with 6% NaOCl and SmearOFF. The dentin surface was analyzed with time-of-flight secondary ion mass spectrometry and X-ray photoelectron spectroscopy to determine the formation of precipitate or/and PCA on the surface of dentin. Results Precipitation with PCA and occlusion of the dentinal tubules were noted on the dentin surface in the CHX group. No precipitate and no PCA were detected on the surface of dentin in the SmearOFF group. Conclusions Interaction of SmearOFF with NaOCl on the dentin surface did not result in the formation of precipitate or PCA. Highlights • Patent dentinal tubules without precipitate were detected after final rinse with SmearOFF. • No PCA was detected after irrigation with NaOCl followed by SmearOFF. • SmearOFF may be a suitable irrigant to use after NaOCl irrigation. [ABSTRACT FROM AUTHOR]

Abstract Introduction The present study aimed to evaluate the antibacterial effect of a new peptide, DJK-5, used alone or mixed together with EDTA on mono- and multispecies biofilms in dentin canals covered by a smear layer with or without preceding sodium hypochlorite (NaOCl) irrigation. Methods One hundred twelve dentin blocks (224 final specimens) were prepared and divided into 56 groups, and Enterococcus faecalis or multispecies bacteria were introduced into dentinal tubules by centrifugation. After 1 week of cultivation, a uniform smear layer was created on the surface of the dentin blocks, and the samples were exposed to sterile water, 17% EDTA, 2% or 6% NaOCl, 10 μg/mL DJK-5, or a mixture of 8.5% EDTA +10 μg/mL DJK-5 or were combined treated with the solution in the following sequence: 2% or 6% NaOCl +10 μg/mL DJK-5, 2% or 6% NaOCl + 8.5% EDTA +10 μg/mL DJK-5, 2% or 6% NaOCl + 8.5% EDTA + 10 μg/mL DJK-5. Specimens without a smear layer treated by 6% NaOCl or 10 μg/mL DJK-5 served as the positive control. The irrigant exposure time was 3 or 10 minutes. The antibacterial efficacy was determined by live/dead staining and confocal laser scanning microscopy. Results The smear layer reduced the antibacterial capacity of 6% NaOCl and 10 μg/mL DJK-5. The efficacy of 2% or 6% NaOCl followed by 10 μg/mL DJK-5 was superior to 10 μg/mL DJK-5 alone (P <.05) but inferior to 2% or 6% NaOCl + 8.5% EDTA + 10 μg/mL DJK-5 and 2% or 6% NaOCl + 8.5% EDTA + 10 μg/mL DJK-5 (P <.05). The mixture of 8.5% EDTA and 10 μg/mL DJK-5 had the same disinfection effectiveness as 10 μg/mL DJK-5 used alone (P <.05). Using 2% or 6% NaOCl before EDTA + peptide always resulted in the highest killing (P <.05). Conclusions The smear layer inhibits the disinfectant effect in dentin. Peptide DJK-5 showed a strong antibacterial effect against mono- and multispecies biofilms in dentin canals. The highest killing was measured when 6% NaOCl was followed by a mixture of EDTA and peptide DJK-5. Highlights • The mixture of EDTA and DJK-5, with or without preceding sodium hypochlorite irrigation, is used against mono- and multispecies biofilms inside infected dentin in the presence of the smear layer. • The smear layer reduced the antibacterial capacity of sodium hypochlorite and DJK-5. • DJK-5 in mixtures increases the killing of bacteria in dentin canal biofilm. • The peptide DJK-5 mixed with EDTA or used separately enhances the antimicrobial activity of the irrigation against bacteria in dentin canal biofilm. [ABSTRACT FROM AUTHOR]

Abstract Introduction We tested the cyclic fatigue resistance of heat-treated instruments immersed in sodium hypochlorite solution under different concentrations and temperature conditions. Methods Based on the irrigating solution's concentration and temperature, 135 ProTaper Gold (PTG; Dentsply Sirona, York, PA) F2 instruments were divided equally into 9 groups of 15. Cyclic fatigue testing was performed by using a block with artificial canals with a curvature angle of 60°, a curvature radius of 5 mm, and a curvature center 5 mm from the instrument tip. The block was fixed inside a water bath of distilled water, 2.5% sodium hypochlorite (NaOCl), or 5.25% NaOCl. The temperature was preset at 25°C, 37°C, or 60°C. The instrument was rotated at 300 rpm until fracturing occurred. The number of cycles to fracture was calculated, and the fragment length was measured. Fractured surfaces were examined via scanning electron microscopy. NCF data were analyzed statistically via Kruskal-Wallis and Mann-Whitney tests. All statistical analyses were performed using SPSS software Version 22 (IBM Corp, Armonk, NY) at a 5% significance level. Results The number of cycles to fracture of the PTG F2 was highest in distilled water at 25°C and lowest in 5.25% NaOCl at 60°C. Changing the irrigating solution from distilled water to NaOCl and increasing the surrounding temperature reduced the fatigue resistance. Conclusions NaOCl irrigating solution at different concentrations and temperatures influenced the cyclic fatigue resistance of PTG instruments. Future NiTi instrument failure studies should be conducted under simulated body temperature conditions in commonly used irrigating solutions. Highlights • Increasing the temperature of the sodium hypochlorite (NaOCl) solution to body temperature and above significantly decreased ProTaper Gold's resistance to cyclic fatigue. • The irrigant solution and simulated body temperature should be considered in future nickel-titanium instrument failure studies. • The irrigant temperature and concentration were shown to play a vital role in the cyclic fatigue resistance of endodontic instruments manufactured with heat-treated NiTi alloy. [ABSTRACT FROM AUTHOR]

Introduction Sodium hypochlorite (NaOCl) is the main irrigant to clean root canals. Decalcifying agents are advocated as additional means to condition the root dentin. The aim of this study was to evaluate the effect of alternating (EDTA) or continuous 1-hydroxyethane 1,1-diphosphonic (HEDP) chelation in conjunction with NaOCl irrigation on the pushout bond strength of Biodentine (Septodont, Saint Maur des Fosses, France). Methods Single root canals of 50 extracted, mature human teeth were divided into 5 groups ( n = 10) and enlarged using rotary instruments. Canals were irrigated with 5 mL irrigant after each instrument and then with 5 mL after mechanical preparation as follows: 2.5% NaOCl during and then 2.5% NaOCl, 17% EDTA, or 17% EDTA followed by 2.5% NaOCl after preparation. Continuous chelation with 2.5% NaOCl/9% Dual Rinse HEDP (Medcem GmbH, Weinfelden, Switzerland) during and after preparation. The control group was irrigated with water during and after preparation. Canals were then filled with Biodentine. A horizontal section of 1.5-mm thickness was taken from the middle root third, and a pushout bond test was performed. Data were statistically analyzed using 1-way analysis of variance/Tukey honest significant different test. Results The pushout bond strength of Biodentine was significantly higher when the root canal was irrigated with 2.5% NaOCl/9% Dual Rinse HEDP (19.6 ± 2.3 MPa) than with NaOCl alone (15.5 ± 1.5 MPa) or the NaOCl/EDTA sequences (15.7 ± 2.2 MPa and 16.9 ± 2.9 MPa) ( P < .05), which did not differ among each other ( P > .05). The lowest pushout bond strength values were found with water irrigation (11.5 ± 0.5 MPa) ( P < .05 to all other groups). Conclusions Irrigation with 2.5% NaOCl/9% Dual Rinse HEDP significantly improved the pushout bond strength of Biodentine to the root canal dentin. [ABSTRACT FROM AUTHOR]

Introduction This prospective study evaluated the outcome of Biodentine (Septodont, Saint Maur des Fosses, France) pulpotomy in young permanent teeth with carious exposure. Methods Twenty permanent molar teeth in 14 patients with carious pulp exposure were treated with Biodentine pulpotomy. The age of the patients ranged from 9–17 years (12.3 ± 2.7 years). A preoperative pulpal and periapical diagnosis was established. After informed consent, the tooth was anesthetized, isolated via a dental dam, and disinfected with 5% sodium hypochlorite before caries excavation. Full pulpotomy was performed by amputating the exposed pulp to the level of the canal orifices, hemostasis was achieved via a cotton pellet moistened with 2.5% sodium hypochlorite, a 3-mm layer of Biodentine was placed as the pulpotomy agent, a Vitrebond liner (3M ESPE, St Paul, MN) was applied, and the tooth was subsequently restored. Postoperative periapical radiographs were taken after placement of the permanent restoration. Clinical and radiographic evaluation was completed after 6 months and 1 year postoperatively. Pain levels were scored preoperatively and 2 days after treatment. Statistical analysis was performed using the Fisher exact test. Results Clinical signs and symptoms suggestive of irreversible pulpitis were established in all teeth and symptomatic apical periodontitis in 14 of 20 (70%). Two days after treatment, all patients reported complete relief of pain. All teeth were clinically successful at 6 months and 1 year postoperatively. Radiographically, immature roots showed continued root development; dentin bridge formation was detected in 5 of 20 teeth. Seven of 7 teeth with preoperative periapical rarefaction showed signs of healing; 1 tooth had signs of internal root resorption at 1 year with an overall success rate of 95% (19/20). Conclusions Young permanent teeth with carious exposure can be treated successfully with full pulpotomy using Biodentine, and clinical signs and symptoms of irreversible pulpitis are not a contraindication. [ABSTRACT FROM AUTHOR]