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PURPOSE: Using X-ray micro-computed tomography (micro-CT), the aim of this study was to measure the porosity of two tricalcium silicate sealers (EndoSequence BC and NeoSealer Flo) applied using three obturation techniques (single-cone, warm-vertical, and cold-lateral) to six single-rooted human teeth. METHODS: Six extracted, single-rooted human teeth were shaped with ProTaper Next rotary files and obturated with EndoSequence BC or NeoSealer Flo sealers and gutta-percha (GP) using one of the three techniques above. Micro-CT was used to map the full length of the canals. Deep learning cross-sectional segmentation was used to analyze image slices of the apical (0-2 mm) and coronal (14-16 mm from the apex) regions (n = 230-261 per tooth) for the areas of GP and sealer, as well as porosity. Median (%) with interquartile range of porosity were calculated , and the results were statistically analyzed with the Kruskal-Wallis test. RESULTS: In the apical region, EndoSequence BC had significantly fewer pores than NeoSealer Flo with the single-cone obturation (% median-interquartile range, IQR: 0.00-1.62) and warm-vertical condensation (5.57-10.32) techniques, whereas in the coronal region, NeoSealer Flo had significantly fewer pores than EndoSequence BC with these two techniques (0.39-5.02) and (0.10-0.19), respectively. There was no significant difference in porosity between the two sealers for the cold-lateral condensation technique in both the apical and coronal regions. CONCLUSION: For optimal obturation, the choice of technique and sealer is critical.

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INTRODUCTION: We compared the effects of heat on the physicochemical properties of recently developed calcium silicate-based sealers (CSBSs), including BioRoot Flow, BioRoot RCS, and AH Plus Bioceramic sealer, with those of the epoxy-resin-based sealer (ERBS) AH Plus. METHODS: The flow, film thickness, setting time, and solubility of sealers were evaluated at 37 °C and 100 °C using ISO 6876/2012. Furthermore, pH and calcium ion release were evaluated at these temperatures. In addition, the mass change in sealers at a high temperature was assessed via thermogravimetric analysis. Then, the chemical composition and components of the sealers were analyzed using a scanning electron microscope and Fourier-transform infrared spectroscopy (FTIR). RESULTS: BioRoot Flow, AH Plus Bioceramic, and AH Plus complied with ISO standards in terms of flow and film thickness, both before and after heat application. However, BioRoot RCS exhibited significantly increased film thickness at 100 °C. The setting times of all sealers were significantly reduced at 100 °C. The solubility of CSBS was >3%, exceeding the ISO 6876/2012 standard, both before and after heat exposure. Conversely, the solubility of AH Plus complied with the standard, regardless of the thermal condition. For 4 weeks, CSBS showed a significantly higher pH than AH Plus at both 37 °C and 100 °C. After heat treatment, calcium release decreased in Bioroot RCS and BioRoot Flow, while AH Plus showed no significant differences before and after treatment. However, CSBS consistently exhibited significantly higher calcium release than AH Plus at both temperatures. An FTIR analysis revealed that the chemical composition of the sealers did not change at the high temperature, whereas a thermogravimetric analysis demonstrated a >5% weight reduction in CSBS and a 0.005% weight reduction in AH Plus at 100 °C. CONCLUSIONS: BioRoot Flow, AH Plus Bioceramic, and AH Plus possess favorable physicochemical properties, which make them suitable for application under thermal conditions. At a high temperature, BioRoot RCS did not exhibit changes in its chemical composition. However, its film thickness was increased, and pH and solubility were reduced. Therefore, caution is needed when it is applied at high temperatures, such as during the warm obturation technique.

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INTRODUCTION: This systematic review and meta-analysis aimed to evaluate the clinical and radiographic failure of nonsurgical endodontic treatment and retreatment for mature permanent teeth with or without apical periodontitis using the single-cone (SC) obturation technique with calcium silicate-based bio-ceramic (CSBC) sealers and to compare these failure rates to other sealer materials and obturation techniques. METHODS: A comprehensive search was conducted using MEDLINE (PubMed), Embase, Cochrane Library, Scopus, Web of Science, and gray literature up to March 2023. Two reviewers assessed the eligibility of the included studies. Eligible studies were critically appraised for risk of bias and quality of evidence. Subsequently, a meta-analysis of pooled data was conducted utilizing the RevMan software (P < .05) to evaluate the failure rate of non-surgical root canal therapy using CSBC sealers and SC obturation procedures. Separately, another analysis was conducted to compare those results with the outcome of nonsurgical root canal therapy using alternative obturation materials and methods. RESULTS: Five studies were included. The pooled failure rate for nonsurgical endodontic treatment and retreatment combined using CSBC sealers and SC obturation technique was 6.8% [95% confidence interval (CI) = (3%-12%), I2 = 46%]. A second analysis was conducted on the 3 included clinical trials to compare the outcomes of the intervention (CSBC sealers and SC obturation technique) and control groups (other sealers and other obturation techniques). This analysis found no significant difference between the 2 groups regarding clinical and radiographic failure of endodontic treatment and retreatment [Risk ratio = 0.71, 95% CI = (0.33, 1.51), I2 = 0]. This difference was also not statistically significant when the failure rate of primary root canal treatment and retreatment were separately analyzed [Combined Risk ratio of primary root canal treatment = 0.94, 95% CI = (0.46, 1.93), I2 = 0%; Combined Risk ratio of retreatment = 0.21, 95% CI = (0.001, 75.46), I2 = 0%]. CONCLUSIONS: The overall results of this systematic review and meta-analysis demonstrate that the SC obturation technique with CSBC sealer provides similar results compared to other obturation materials and techniques in facilitating the healing of apical periodontitis.

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Context: Bioceramic sealers have improved sealing ability by forming an interfacial apatite layer that chemically bonds the sealer and radicular dentin thus decrease apical leakage. Aim: This study aims to evaluate and compare the apical leakage of Cerafill RCS bioceramic sealer and gutta percha when used with three different obturating techniques. Materials and Methods: Thirty-four extracted single-rooted premolars were decoronated and prepared up to size F3. Then, the specimens were randomly divided into 3 experimental groups (n = 10) cold lateral obturation technique, warm vertical obturation technique, single-cone obturation technique, positive and negative control groups (n = 2), according to the obturation technique used along with a bioceramic sealer. To evaluate apical leakage, all specimens were mounted in a glucose leakage model and assessed at 7 and 14 days using an ultraviolet-visible spectrophotometer. Statistical Analysis: The results were subjected to ANOVA/Kruskal-Wallis ANOVA; followed by post hoc analysis using Bonferroni correction. Results: Significant differences were found in the cumulative leakage of all the three experimental groups. Significantly higher leakage was found in groups obturated using single-cone obturation technique as compared to warm vertical compaction technique at both 7 and 14 days. Conclusions: Warm vertical compaction showed a better sealing result than single-cone obturation techniques at all observation periods.

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Introduction: Tricalcium silicate-based cements exhibit several beneficial properties for dental health and biocompatibility, which can induce biomineralisation. Objectives: To assess the sealing ability and intratubular penetration of tricalcium silicate-based sealers using warm and cold obturation techniques. Materials and Methods: An electronic search was conducted in PubMed, Scopus, and Web of Science databases for endodontically treated teeth with bioceramics and their sealing capacity in root canal obturation published up to February 2023. Results: Of the 90 articles, 16 met the inclusion criteria, and only 10 were used for the meta-analysis, of which four addressed intratubular penetration, four addressed sealing capacity, and two addressed both variables. In the sealing capacity group, the meta-analysis concluded a standardised mean difference (SMD) of -1.31 in favour of the test group (warm) with a certain nonsignificant trend (p = 0.081); regarding intratubular penetration, the meta-analysis concluded an SMD = 2.34 in favour of the test group (warm) with significantly greater penetration (p = 0.032). Conclusion: The warm obturation technique introduced significantly greater intratubular penetration than the cold technique, along with a remarkably superior sealing capacity compared to the cold technique, approaching statistical significance.

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OBJECTIVES: The aim of this research was to compare the penetration ability of calcium silicate-based sealers (iRoot SP and TotalFill BC HiFlow) and an epoxy resin-based sealer (AH Plus) into the lateral canals using the single-cone (SC) or continuous wave compaction (CW) obturation techniques. METHODS: Ninety single-rooted human teeth received canal instrumentation and diaphanisation before artificial lateral canals were created at 3 different root levels. The specimens were randomly allocated into 6 groups based on the combination of obturation technique and sealer used. Radiographic and photographic measurements evaluated the percentage of sealer penetration. Statistical analysis was performed to compare the penetration ability amongst different types of sealers, obturation methods, and root levels. RESULTS: Although TotalFill BC HiFlow sealer combined with the CW technique demonstrated greater sealer penetration at the coronal level (P < .05), the overall penetration ability of iRoot SP, TotalFill BC HiFlow, and AH Plus was not significantly different. The deepest sealer penetration was observed at the apical root level. CONCLUSIONS: All sealers showed similar penetration abilities into the lateral canals using the SC or CW techniques in vitro. Calcium silicate-based sealers have comparable penetration ability into lateral canals compared to epoxy resin-based sealers using SC or CW obturation techniques.

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Understanding the properties of endodontic sealers is vital for treatment planning. Calcium silicate-based sealers are important in modern endodontics. This study investigates the effect of heat on the physicochemical properties of new calcium silicate sealers, addressing concerns raised by clinicians seeking to combine their benefits with the gutta-percha obturation technique. Five endodontic sealers (AH Plus Bioceramic®, Total Fill® BC®, One-fil® Bioceramic, K-Biocer, Any-seal®) were evaluated. Each sealer (n = 16/group) was either kept at 37 °C or subjected to heat at 60 or 200 °C for 30 s. ISO 6876-2012 standards were used to measure setting time, flow, film thickness, and dimensional changes over time. SEM and EDS were utilized for surface and chemical analysis. Data analysis employed IBM SPSS Statistics version 26 with a 5% significance level for two-sided tests. The sealers' setting times were shortened by heat, except for Total Fill® BC with extended setting time. All sealers had significantly longer setting times than manufacturer specifications. Film thickness increased with temperature, while flow values decreased. K-Biocer sealer showed the highest flow (16.89 ± 0.57 mm) at 200 °C, while Total Fill® sealer had the lowest (15.32 ± 0.62 mm). Shrinkage was significant at 60 °C and 200 °C, with greater shrinkage at 200 °C. Heat caused surface deformations in all sealers. The 200 °C groups exhibited more voids in AH Plus Bioceramic®, Any-seal®, and One-fil® sealers, and higher void area in Total Fill®, One-fil®, and K-Biocer sealers (p value < 0.001). EDX analysis confirmed heat-induced chemical and elemental changes in all tested sealers. Elevated temperature affects the physicochemical properties and structure of the tested endodontic sealers. The consideration of endodontic sealer compatibility is essential when warm gutta-percha obturation techniques are used.

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Adequate root canal sealing is essential for the success of endodontic treatment. There are numerous techniques available; identifying simple and efficient techniques is important to provide good patient care. The purpose of the study was to compare the maximum penetration depth and the percentage of sealant penetration of an endodontic sealer into dentine tubules using cold lateral condensation, continuous wave, and hybrid techniques, and to contrast the effectiveness of two different tapered gutta-percha master cones (0.02 and 0.04). A sample of sixty single root teeth was used. Six experimental groups were formed from the three filling techniques and the two tapered master cones. Images were acquired using a confocal laser scanning microscope. In the apical root third, the penetration percentage was higher in the hybrid compared with the continuous wave technique. The results indicated a higher penetration depth of hybrid compared with cold lateral condensation in the middle and coronal thirds, and in the apical third, a higher penetration was identified in the hybrid group compared with the continuous wave group. No significant differences in penetration were found comparing 0.02 with 0.04 taper gutta-percha groups. The coronal cross-sections presented a higher penetration than the apical third sections. In conclusion, the hybrid technique a had higher maximum sealer penetration than the continuous wave in the apical third, and the coronal third hybrid and continuous wave had a higher penetration than cold lateral condensation.

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The aim of the study was to evaluate the impact of kinematics and irrigation protocols on the extrusion of apical debris during removal of different obturation techniques. A total of 144 single-rooted teeth were instrumented and obturated with Thermafil+AH Plus, Thermafil+AH Plus Bioceramic and single gutta-percha cone+AH Plus Bioceramic. Samples were divided according to the retreatment kinematics: continuous rotation or Jeni motion. Each sub-group was subjected to conventional irrigation or irrigation activated by EDDY. Extruded debris was collected in Eppendorf tubes, weighted and retreatment time was digitally recorded. Data were analysed with two-way ANOVA (p < 0.05). Debris extrusion was not significantly different between all groups. EDDY activation system and CanalPro Jeni required significantly longer time compared with other groups to remove Thermafil+AH Plus and single cone+AH Plus Bioceramic. Within current limitations, obturation technique, irrigation protocol and kinematics tested had no influence on apical extrusion debris, while they significantly impacted the retreatment time.

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Lack of identification of the root canal results in root canal treatment failure, one of the most frequent causes of root canal treatment failure. To successfully treat root canals, it is crucial to have a detailed understanding of root canal configuration, including distinguishing traits and anatomical differences. The root canal in the C form arrangement is among the most important anatomical variances. Because of its distinctive highlight, the existence of fins or webs linking the different root canals - the C-shaped form of root canal has proven challenging to detect and manage. Any molar region may have this root canal arrangement, including the mandibular first molar, first premolar, and maxillary molars. Above all, mandibular second molars are where it is most usually discovered. This report discusses the uncommon maxillary first molar with an apically merged root. The importance of comprehending canal variations, which are C-shaped root canals, should be critically evaluated in light of the rise in the root canal treatment failure rate for the upper molars.

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OBJECTIVES: This study aims to assess the obturation efficacy of sealers placed with different techniques using microcomputed tomography (µCT) and assess the influence of µCT testing parameters on the obturation data obtained. MATERIALS AND METHODS: Incisors and mesial roots of lower molars with standardized root length were scanned using µCT, and one tooth of each type was 3D printed in acrylic. Two obturation techniques (warm vertical and single cone) and 4 sealer types (AH Plus, BioRoot RCS, Totalfill BC, and Bio-C Sealers) were assessed following storage in Hank's balanced salt solution for 3 and 6 months by assessing gap and void volume percentages on both natural and replica incisor and molar roots. The storage solution was analysed to assess calcium ion leaching. The influence of temperature, tooth positioning, and moisture content of the teeth while µCT scanning was also investigated. RESULTS: The obturation quality in the incisor group was the same using both natural teeth and replicas (p > 0.05). No changes in void volume were identified when comparing the same sealer using different obturation techniques. The premixed sealers used in single-cone obturation exhibited high void volume in the 3D printed replicas in the long term. The temperature, positioning, and moisture content of the teeth did not affect the outcome of µCT testing. CONCLUSIONS: BioRoot RCS, Totalfill BC, and Bio-C Sealers are suitable for obturation of both complex and simple root canal systems using different obturation techniques with BioRoot RCS exhibiting the highest calcium ion release. 3D printed acrylic teeth can be used to assess the obturation quality in uncomplicated root canal systems. µCT parameters had no significant effect on the µCT measurement. CLINICAL RELEVANCE: The single-cone obturation technique with hydraulic sealer is a simple technique that can be used for obturation of all root canal systems.

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Background: There are few studies in the literature about the effect of obturation techniques on postoperative pain. Besides, GuttaFlow2 was used for the first time in this study regarding postoperative pain. This study aimed to compare the postoperative pain levels and incidence following single-visit root canal treatment with different canal filling techniques; cold lateral compaction (CLC), thermoplasticised solid-core carrier (GuttaCore) based filling and cold free-flow compaction (GuttaFlow2) technique. Methods: The patients (n = 93) having single-rooted teeth with a single canal diagnosed with asymptomatic irreversible pulpitis or single-rooted vital teeth with a single canal requiring endodontic treatment because of prosthetic reasons were enrolled in this study. Patients were randomized into three groups (n = 31) according to the obturation technique. A single operator performed all the treatments in a single visit. Data on obturation levels, postoperative pain and analgesic intake frequency were recorded at postoperative 6, 12 and 24 h and daily afterward until the 7th day. Postoperative pain was measured by visual analogue scale (VAS). The date were statistically analyzed with chi-squared tests (for the analyses of the categorical data), the nonparametric Kruskal-Wallis test (for the comparisons of VAS score) and with the Friedman test (for the assessments of the changes in VAS scores over time). Results: The GuttaCore group recorded the higher pain levels, except first 12 h, on the other hand, the GuttaFlow2 group recorded the lower pain levels at all time periods. Significant differences occurred among the groups during the first 4 days (p < 0.05), except at 12 h (p = 0.054). The patients in the CLC and GuttaFlow2 groups did not need to use the prescribed analgesic; however, one patient in the GuttaCore group used it once. Conclusions: Postoperative pain levels following root canal therapy were affected by the obturation technique especially first 4 days following obturation.

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OBJECTIVES: The aim of this cross-sectional retrospective study was to evaluate radiographically the technical quality of root canal treatment performed by undergraduate students using reciprocating NiTi instrumentation and single-cone obturation. METHODS: Endodontic treatment on 1102 teeth performed by undergraduate students from the School of Dentistry of the University of Santa Cecilia (Brazil) was evaluated. All root canal preparations were performed using Reciproc files and were irrigated with 1% NaOCl. The root canal was filled with gutta-percha, along with AH Plus sealer, using the single-cone obturation technique. The technical quality of the root canal treatment was evaluated based on immediate postoperative radiographs. Distance between the end of the filling and the radiographic apex, the filling density, and the taper of the root filling was assessed. Inter-examiner agreement statistic (Kappa) and Chi-square statistic test were used for statistical evaluation of the results. Differences were considered statistically significant when p < 0.05. RESULTS: Anterior teeth, maxillary premolars, and molars presented better results than mandibular premolars and molars (p < 0.05). Mandibular premolars presented a high incidence of a short length of obturation (33.34%) and mandibular molars presented a high incidence of overfilling (6.55%). The majority of the treatment analyzed (62.46%) fulfilled all the criteria showing acceptable working length, taper, and density of obturation. Instrument fractures occurred in eighteen root canals (0.81%). CONCLUSIONS: The use of NiTi reciprocating instruments with the single-cone obturation technique provided an acceptable quality of endodontic treatment in the majority of the cases performed by undergraduate students.

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AIM: To evaluate voids and sealing ability using a disposable syringe, endodontic pressure syringe, and Skinni syringe with NaviTip in primary molars with cone-beam computed tomography (CBCT). MATERIALS AND METHODS: The 15 extracted primary mandibular molars with at least one root ≥8 mm length and an equal number of mesiobuccal canals were divided into three groups, i.e., obturation using a disposable syringe, an endodontic pressure syringe, and a Skinni syringe with NaviTip, respectively. The evaluation of the apical seal was determined as the measurement between the apical end of the filling material and the radiographic apex. The quality of the filling was determined by the size, number, type, and location of voids present. Statistical analysis was done using the Chi-square test and post-hoc test. RESULTS: The endodontic pressure syringe score was the highest and statistically significant in obtaining apical seal (p = 0.013). Disposable syringe shows highest size of voids (p = 0.01) in which type I-voids (p = 0.04) and type S-voids (p = 0.07) were statistically significant. The location of voids was maximum at the middle third of the root (p = 0.016). CONCLUSION: The endodontic pressure syringe provided the best root canal obturation of primary molars, whereas the disposable syringe was least effective with the maximum number and size of voids. CLINICAL SIGNIFICANCE: Comparing the voids and sealing abilities of different obturating techniques with CBCT would help the pediatric practitioners for better outcome of obturation in primary teeth.

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OBJECTIVES: This study aimed to evaluate dentinal tubule penetration and the retreatability of EndoSequence BC Sealer HiFlow (HiFlow), iRoot SP, and AH Plus when using the single-cone (SC) or continuous wave condensation (CWC) technique. MATERIALS AND METHODS: Sixty-five single-rooted teeth were instrumented and randomly divided into 5 groups: group 1, AH Plus/CWC; group 2, iRoot SP/CWC; group 3, iRoot SP/SC; group 4, HiFlow/CWC; and group 5, HiFlow/SC. The ability to re-establish patency during endodontic retreatment was recorded, as was the time taken to reach the working length. Dentinal tubule penetration and remaining debris after retreatment were evaluated by confocal microscopy and scanning electron microscopy. Data were analyzed by Kruskal-Wallis test and Dunn's multiple comparisons test (α = 0.05). RESULTS: The HiFlow/CWC and iRoot SP/CWC groups required more time to reach the working length than groups that underwent the SC technique regardless of the sealer used (P < .05). The HiFlow/CWC group showed a significantly higher percentage of sealer penetration area than that of the iRoot SP/SC at 4 mm from the apex (P < .05) and penetrated deeper into dentinal tubules than iRoot SP/SC at both 8-mm and 12-mm levels (P < .05). Moreover, the HiFlow/CWC and HiFlow/SC groups demonstrated less remaining sealer along the canal wall than AH Plus/CWC group at 4-mm level (P < .05). CONCLUSIONS: HiFlow/CWC technique showed better performance in dentinal tubule penetration than that of iRoot SP/SC. Both HiFlow and iRoot SP combined with CWC technique groups required more retreatment time than the other groups. Furthermore, using HiFlow with either the CWC or SC technique left less remaining sealer at 4-mm level than using AH Plus with the CWC technique during retreatment. CLINICAL RELEVANCE: With favorable performance in dentinal tubule penetration and retreatability in endodontic retreatment, the combined use of EndoSequence BC Sealer HiFlow with the recommended continuous wave condensation technique may be a worthwhile choice in root canal treatment.

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The effects of different obturation techniques on calcium silicate-based sealer penetration in the presence of apically separated rotary files were evaluated. Forty-eight extracted mandibular incisors were used. ProTaper F2 rotary files were separated at the apical thirds. Samples were divided into four groups (n = 12) according to obturation technique used: (a) cold lateral compaction (CLC); (b) single cone; (c) bulk-fill (BF) without a core material; and (d) thermoplastic injection (TI). Specimens were sectioned horizontally at 1 and 3 mm from the apex and studied using a confocal scanning laser microscope. The maximum tubule penetration depth and percentage of penetration were measured. Data were statistically analyzed using parametric and nonparametric tests with a significance level of 5%. Regarding penetration depth, a significant difference was found at 1 mm (p < .05), while no significant difference was found at 3 mm (p > .05). At the 3 mm level, all of the obturation techniques showed similar penetration depths. Regarding penetration percentage, the values of the CLC and TI groups were statistically less when compared with the BF group at 1 and 3 mm levels, respectively (p < .05). Under the limitations of this in vitro study, results suggest that the obturation technique may present a significant effect on sealer penetration.

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Objective: This study was designed to evaluate the effects of an Erbium, Chromium:Yttrium-Scandium-Gallium-Garnet (Er,Cr:YSGG) laser on removing the filling residues and smear layer (SL) after retreatment using rotary files. Background: Er,Cr:YSGG laser has been proposed as an additional protocol to improve root canal cleaning and removal of the filling remnants. Methods: Eighty-four mandibular premolars were divided into six groups (n = 14). Groups 1, 2, and 3 were obturated using a cold lateral compaction technique, and groups 4, 5, and 6 were obturated using a thermoplasticized injectable technique. The retreatment procedures were performed in all of the groups using a rotary system before applying Er,Cr:YSGG laser at 1.5 W for groups 2 and 5, and at 3.0 W for groups 3 and 6. Then, the teeth were split longitudinally into two halves and observed under a stereomicroscope and a scanning electron microscope. The SL and residual filling materials were evaluated at the coronal, middle, and apical thirds of the root canal. The data were statistically analyzed using three-way analysis of variance and Tukey tests. Results: The 3.0 W Er,Cr:YSGG laser was significantly more effective in removing SL than the other retreatment procedures in the coronal and middle thirds, but there was no significant difference in the apical third (p > 0.05). However, carbonization was observed in some of the specimens in the 3.0 W laser groups. Conclusions: None of the retreatment procedures completely removed the filling remnants from the root canal. However, the additional use of lasers improved the canal cleaning after retreatment.

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OBJECTIVE: To evaluate the bond strength of fiber posts to intraradicular dentine pretreated with two root canal obturation techniques and three postspace irrigation solutions. METHODS: A total of 96 human premolars were collected and treated with complete or partial root canal obturation techniques. The roots were further divided into three subgroups (n = 16) based on postspace irrigation solutions: 2.5% NaOCl, 37% phosphoric acid etching, and distilled water. The fiber posts were bonded with self-adhesive resin cement, and the roots were sectioned into three slices (cervical, middle, and apical regions) after 5,000 thermocycles. The push-out bond strengths were determined and subjected to analysis of variance (α = 0.05). A stereomicroscope was used to observe the failure modes of the specimens. RESULTS: The irrigation solution, root canal obturation technique, and root region had significant effects on bond strength (P < 0.001). The completely obturated root canals showed significantly lower bond strength than the partially obturated root canals. The 2.5% NaOCl treatment produced the highest bond strength among the three irrigation solutions. Among the root regions, the cervical part showed significantly greater bond strength than the middle and apical parts. The most common failure mode was mixed failure. CONCLUSION: The partial root canal obturation technique provided better bond strength of the fiber post to intraradicular dentine. Irrigation with 2.5% NaOCl solution and phosphoric acid etching before cementation improved the push-out bond strength of the fiber posts to intraradicular dentine.

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Endodontic residency programs across the U.S. vary in the exposure they provide to residents in procedures, protocols, and equipment. Having information on the range of clinical experiences provided in programs would be useful for program directors and for applicants who are seeking the best fit for their residency. The aim of this study was to collect information from residents in U.S. endodontic residency programs about the procedures and equipment they experienced in their programs. In January 2018, a 14-question survey was emailed to all 437 endodontic residents with an email address in the 2016-17 American Association of Endodontists Membership Directory. Survey items asked about the number of endodontic procedures, techniques employed, and products used in residents' programs. A total of 133 endodontic residents responded to all or part of the survey, for a 30% response rate. The majority reported completing 151-250 nonsurgical root canals, 26-50 nonsurgical retreatments, 0-10 surgical retreatments, and 0-10 regenerative endodontic procedures during their residencies. All respondents said they used a surgical operating microscope (SOM), and 82% reported using a multi-file rotary system for nonsurgical procedures. Respondents reported that the main instruments they used were Dentsply Sirona file systems, and the most commonly used obturation technique was warm vertical compaction/condensation, reported by 92% of respondents. These endodontic residents reported being exposed to a variety of procedures, products, and protocols during their residency. Based on information they provided, prospective endodontic residency applicants can expect to use the SOM for treatment, to gain extensive experience in primary nonsurgical endodontic treatment, and to not perform endodontic surgery during their first year of postgraduate training.

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OBJECTIVE: The purpose of this study was to evaluate the effect of immediate and delayed post space preparation on the sealing ability of two root canal obturation techniques by using micro-computed tomography imaging and a push-out test. METHODS: The root canals of 40 human maxillary premolar teeth were instrumented and divided into four groups: (A) single cone (SC) followed by immediate post space preparation, (B) continuous wave of condensation (CWC) followed by immediate post space preparation, (C) SC followed by delayed post space preparation, and (D) CWC followed by delayed post space preparation. Micro-CT scans were performed for volumetric analysis of voids and filling materials in the apical 4-mm portion. A push-out test was performed, and failure modes (adhesive, cohesive, or mixed) were assessed. Data were analyzed using the Kruskal-Wallis test and one-way analysis of variance. RESULTS: No significant differences were observed among the four groups in terms of the percentage volume of voids of the apical 4 mm or the bond strength of apical gutta-percha. CONCLUSIONS: The percentage volume of voids and bond strength of apical gutta-percha were similar and were not significantly influenced by the timing of post space preparation or the obturation technique.

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