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Statement of Problem: How best to restore endodontically treated teeth is still unclear because many types of material and techniques are involved., Purpose: The purpose of this overview of systematic reviews of clinical studies was to assess the available evidence-based literature on the influence of associated clinical factors on the clinical performance (survival, failure rate, or success) of restored endodontically treated teeth., Material and Methods: PubMed, Scopus, and Web of Science were searched from inception until September 27, 2021, to identify systematic reviews. Two reviewers independently screened titles, abstracts, and full-text articles, and each reviewer extracted the data of half of the included studies. A single reviewer with an independent verifier completed the quality appraisal. A descriptive analysis of the collected data was made., Results: A total of 36 systematic reviews fulfilled the inclusion criteria. The factors most assessed were the type of coronal restorative technique (n=22) and type of post (n=22). The results indicated that metal and fiber posts seem to present similar clinical performance, 1-piece endodontic crowns could be a suitable restorative option, there is no evidence to confirm whether single crowns are better or worse than direct restoration, the maintenance of the coronal structure is a fundamental factor, and the ferrule effect is still a controversial topic. Most of the studies (n=30, 81%) presented a final Grading of Recommendations, Assessment, Development and Evaluations (GRADE) rating of "critically low.", Conclusions: The post type does not appear to influence the clinical performance of restored endodontically treated teeth. However, conclusive evidence to suggest how different materials or techniques for restoring coronal tooth structure affect the clinical performance of such restorations, as well as the impact of the ferrule effect, is still lacking., (Copyright © 2022 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Aim: To evaluate the bond strength (BS) and analysis of the adhesive interface in root canals filled with bioceramic gutta percha sealers and cones., Material and Methods: Ninety-six maxillary canines were divided into eight groups according to the endodontic sealer (AH Plus, AH Plus Bioceramic, Bio-C Sealer or Bio-C Sealer Ion +  and gutta percha cones (conventional or bioceramic) tested. They were analyzed using the BS test, failure pattern, analysis of the adhesive interface by scanning electron microscopy and confocal laser scanning microscopy. The BS data were compared between groups using the analysis of variance test with the Turkey post-test. The chi-square test was used to assess the type of failure and the non-parametric Mann-Whitney and Kruse-Wallis tests (P < 0.05)., Results: Analysis of variance showed higher BS values for the groups of bioceramic gutta percha cones in Bio-C Sealer Ion +  (8.38 ± 4.27), AH Plus Bioceramic (6.19 ± 3.28), Bio-C Sealer (5.70 ± 3.18), AH Plus (4.61 ± 2.11) and for conventional gutta percha cones in AH Plus sealers (4.26 ± 2.35), Bio-C Sealer Ion + (3.63 ± 2.29), Bio-C Sealer (2.94 ± 2.32) and AH Plus Bioceramic (1.19 ± 0.89) (P < 0.05). Relative to the type of failure and adaptation of the types of filling material, a higher percentage of mixed failures was observed (gaps between 1 µm-10 µm) for the group with bioceramic gutta percha cones (P < 0.001)., Conclusion: The bond between sealers and bioceramic gutta percha cones showed higher bond strength values and greater penetration into the dentin tubules., Clinical Relevance: The filling the root canal system with bioceramic sealers should be associated with bioceramic gutta percha cones., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

To investigate the influence of the remaining volume of a new intracanal medication based on bioceramic compounds on the bond strength (BS) and formation of an adhesive interface between calcium silicate-based and epoxy resin-based root canal sealers. For this purpose, the specimens were distributed according to the intracanal medication (n = 26): Bio-C Temp (BCT) and Ultracal XS (UXS). The roots were scanned in microCT, and after 7 days, the medication was removed. Then a new scan was performed to evaluate the volume of medication remaining. Subsequently, 40 specimens were redistributed into 2 subgroups (n = 10) and filled according to the sealer used: AH Plus (AHP) and Bio-C Sealer (BCS), to assess the bond strength by using the push-out test, and the adhesive interface by confocal laser fluorescence microscopy (CLSM) and scanning electron microscopy (SEM). The t test showed a smaller remainder of BCT (1.77 ± 0.86) compared with UXS (10.47 ± 5.78), irrespective of the root third evaluated. The BS showed that teeth with BCT + BCS had higher bond strength values (3.70 ± 1.22) when compared to the other groups: BCT + AHP (2.15 ± 1.07), UXS + BCS (3.18 ± 1.09) and UXS + AHP (2.11 ± 1.02) (p<0.001). The cervical third had higher BS when compared with the middle and apical thirds (p < 0.001), and higher number of adhesive failures. The adhesive interface in SEM and CLSM images showed better adaptation for the association between BCT + BCS. Intracanal medication and silicate-based endodontic sealer appeared to interact chemically by forming a biomineralizing layer, allowing for an increase in the bond strength and forming an adhesive interface between the materials, with no or less gap formation.

Introduction: The purpose of this study was to evaluate the impact of conservative endodontic cavities (CECs) on root canal preparation, restoration, and biomechanical behavior of teeth prepared using different shaping systems and restorative materials., Methods: Ninety upper premolars with a bifurcated root were matched based on morphology and randomly assigned to a control group (n = 10) or 1 of the following experimental groups (n = 40): traditional endodontic cavity and CEC. Teeth were subdivided according to instrumentation (n = 10) as follows: ProTaper Universal (Dentsply Maillefer, Ballaigues, Switzerland), Reciproc (VDW GmbH, Munich, Germany), Reciproc Blue (VDW GmbH), and Hyflex EDM (Coltene/Whaledent, Altstätten, Switzerland). After canal obturation, teeth were restored using temporary material, conventional composite, regular bulk fill composite, or bulk fill flow combined with conventional composite. Before and after preparation and after obturation, the teeth were scanned using micro-computed tomographic imaging. Canal transportation (CT), the percentage of untouched canal surfaces (UCSs), voids in restoration (VRs), and residual filling material in the pulp chamber were evaluated. Finite element analysis, fracture resistance, and the failure pattern were recorded. The data were analyzed using analysis of variance and the Tukey and chi-square tests., Results: CECs had greater CT, percentage of filling material, and VRs compared with traditional endodontic cavities (P < .0001). The highest CT and UCSs were observed in CEC with ProTaper Universal. Bulk fill flow combined with conventional composite showed a lower percentage of VRs compared with other restorative materials (P < .05). Finite element analysis, fracture resistance, and failure pattern revealed similar behaviors in all groups (P > .05) ., Conclusions: CECs had a negative impact on root canal centralization, UCSs, cleaning of the pulp chamber, and percentage of VRs. Controlled memory instruments were the most adequate for the root canal preparation of CECs. The endodontic cavity did not influence the biomechanical behavior of restored teeth., (Copyright © 2021 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: Light transmitted deep into the root canal is an important parameter to increase bonding of the cement to the post and dentin. Glass fiber posts seem to be an option to increase transmitted light, but literature on the light transmittance profile and power transmission to deep canal regions is lacking., Purpose: The purpose of this in vitro study was to evaluate light delivered by 2 types of fiberglass posts submitted to different surface treatments and to evaluate the bond strength., Material and Methods: Whiteposts and Superposts were allocated to 4 groups: no surface treatment, surface treatment with 24% hydrogen peroxide, surface treatment with silane, and surface treatment with 24% hydrogen peroxide plus silane. The total light transmitted by the posts was measured by using an integrating sphere to collect the diffuse light. The light profile that was laterally delivered to the post was measured with a power detector equipped with an optical fiber probe. The bond strength was measured with the push-out test. Scanning electron microscopy was used to evaluate the surface treatments. The light transmission data were analyzed by using a generalized linear model and the Bonferroni test and the bond strength values were evaluated by using ANOVA and the Tukey test (α=.05)., Results: The cervical third presented the highest transmission (74.1% for Whiteposts and 74.6% for Superposts), followed by the middle (20.9% for Whiteposts and 20.4% for Superposts) and apical (5.0% for both Whiteposts and Superposts) thirds. Superposts led to higher bond strength than Whiteposts (9.73 ±5.89 and 8.48 ±4.99 MPa, respectively). Surface treatment with silane and hydrogen peroxide plus silane afforded similar bond strength (11.4 ±6.4 and 10.7 ±5.6 MPa, respectively), which was higher as compared with the bond strength obtained after surface treatment with hydrogen peroxide. For both post types, the bond strength decreased from the cervical (12.2 ±6.0 MPa) to the middle (9.7 ±5.0 MPa) and apical (6.5 ±3.6 MPa) thirds., Conclusions: Light transmission and bond strength decreased from the cervical to the apical third. Surface treatment impacted bond strength; light transmission through Whiteposts was slightly higher than light transmission through Superposts., (Copyright © 2020 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Statement of Problem: The mechanical behavior of ceramic endocrowns is unclear., Purpose: The purpose of this in vitro and 3-dimensional finite element analysis (3D-FEA) study was to evaluate the mechanical behavior of endodontically treated teeth restored with ceramic endocrowns made by using different computer-aided design and computer-aided manufacturing (CAD-CAM) systems., Material and Methods: Sixty mandibular human molars were endodontically treated, prepared for endocrowns, and divided into 4 groups (n=15) according to the following various ceramic systems: leucite-based glass-ceramic (LC group), lithium disilicate-based glass-ceramic (LD group), glass-ceramic based on zirconia-reinforced lithium silicate (LSZ group), and monolithic zirconia (ZR group). After adhesive bonding, the specimens were subjected to thermomechanical loading and then to fracture resistance testing in a universal testing machine. The failure mode of the specimens was qualitatively evaluated. Three-dimensional FEA was performed to evaluate the stress distribution in each group. Data were analyzed by using a 1-way ANOVA and the Tukey HSD test (α=.05)., Results: Statistically significant differences among the groups were observed (P<.05). The outcomes of the LC, LD, and LSZ groups were similar (1178 N, 1935 N, and 1859 N) but different from those of the ZR group (6333 N). The LC and LD groups had a higher ratio of restorable failures, while LSZ and ZR had more nonrestorable failures. Fractographic analysis indicated a regular failure pattern in the ZR group and irregular failure patterns in the other groups. Three-dimensional FEA revealed similar values and stress pattern distributions among the groups., Conclusions: The mechanical performance of monolithic zirconia was better than that of the other ceramic endocrowns considered in this research; however, monolithic zirconia presented a higher rate of catastrophic tooth structure failure., (Copyright © 2019 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Introduction: Nonsurgical endodontic retreatment continues to be a challenge in endodontics, particularly when dealing with a complex tooth anatomy. This study evaluated the efficacy of passive ultrasonic irrigation (PUI) and the GentleWave system as supplementary techniques to remove remaining filling materials from oval-shaped root canals., Methods: Twenty distal roots of human mandibular molars with single and oval-shaped canals were shaped with R40 (40.06) instrument and filled with gutta-percha and AH Plus sealer using warm vertical obturation. Initial filling material removal was performed with R50 (50.05) instrument, followed by the use of PUI (n = 10) or GentleWave system (n = 10). Micro-computed tomographic images were obtained after obturation, initial material removal, and after the use of PUI and GentleWave. The volume of remaining filling material was calculated for the entire canal as well as for the coronal, middle, and apical thirds. Statistical analyses were performed by using analysis of variance, Kruskal-Wallis and Mann-Whitney tests. P ≤ .05 was considered significant., Results: The use of PUI and GentleWave as supplementary techniques significantly reduced the volume of remaining filling material after initial instrumentation (P < .05). However, none of these techniques was able to render canals free from filling materials. PUI showed better performance by removing 18% of the remaining filling material, whereas the GentleWave system was able to remove approximately 10% (P = .02)., Conclusions: The use of supplementary techniques optimized filling material removal after initial instrumentation. PUI enhanced the overall cleaning of the root canal system during endodontic retreatment in oval-shaped canals., (Copyright © 2020 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Introduction: Endodontically treated teeth have an increased risk of biomechanical failure because of significant loss of tooth structure. The biomechanical behavior of endodontically treated teeth restored was evaluated using different extensions of endocrowns inside the pulp chamber by in vitro and 3-dimensional finite element analysis (FEA)., Methods: Thirty mandibular human molars were endodontically treated. Standardized endocrown preparations were performed, and the teeth were randomly divided into 3 groups (n = 10) according to different endocrown extensions inside the pulp chamber: G-5 mm, a 5-mm extension; G-3 mm, a 3-mm extension; and G-1 mm, a 1-mm extension. After adhesive cementation, all specimens were subjected to thermocycling and dynamic loading. The survival specimens were subjected to fracture resistance testing at a crosshead speed of 1 mm/min in a universal testing machine. All fractured specimens were subjected to fractography. Data were analyzed by 1-way analysis of variance and the Tukey post hoc test (P < .05). Stress distribution patterns in each group were analyzed using FEA. Qualitative analyses were performed according to the von Mises criterion., Results: After dynamic loading, a survival rate of 100% was observed in all groups. For static loading, statistically significant differences among the groups were observed (P < .05) (G-5 mm = 2008.61 N, G-3 mm = 1795.41 N, and G-1 mm = 1268.12 N). Fractography showed a higher frequency of compression curls for G-5 mm and G-3 mm than for G-1 mm. FEA explained the results of fracture strength testing and fractography., Conclusions: Greater extension of endocrowns inside the pulp chamber provided better mechanical performance., (Copyright © 2018 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Computer-aided design and computer-aided manufacturing (CAD-CAM) technology may be used to produce custom intraradicular posts, but studies are lacking. The purpose of this in vitro study was to evaluate the flexural properties (strength and modulus), failure mode, superficial morphology, and roughness of two CAD-CAM glass fiber posts (milled at different angulations) compared with a commercially available prefabricated glass fiber post. Three groups were tested (n = 10): PF (control group)- prefabricated glass fiber post; C-Cd-diagonally milled post; and C-Cv-vertically milled post. A 3-dimensional virtual image was obtained from a prefabricated post, which guided the posterior milling of posts from a glass fiber disk (Trilor Blanks; Bioloren). Surface roughness and morphology were evaluated using confocal laser microscopy. Flexural strength and modulus were evaluated with the 3-point bend test. Data were submitted to one-way analysis of variance followed by the Student-Newman-Keuls post hoc test (α = 0.05). The fractured surfaces were evaluated with scanning electron microscopy. The superficial roughness was highest for PF and similar for the experimental groups. Morphological analysis shows different sizes and directions of the glass fibers along the post. The flexural strength was highest for PF (900.1 ± 30.4 > C-Cd - 357.2 ± 30.7 > C-Cv 101.8 ± 4.3 MPa) as was the flexural modulus (PF 19.3 ± 2.0 GPa > C-Cv 10.1 ± 1.9 GPa > C-Cd 7.8 ± 1.3 GPa). A CAD-CAM milled post seems a promising development, but processing requires optimizing, as the prefabricated post still shows better mechanical properties and superficial characteristics., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Aim: To evaluate the effect of ultrasonic and sonic activation of two root canal sealers on interfacial adaptation and push-out bond strength (BS) to root canal dentine., Methodology: The root canals of seventy-eight roots of maxillary canines were prepared with NiTi rotary instruments under irrigation with 2.5% NaOCl and 17% EDTA. Canals were filled by lateral condensation of gutta-percha and AH Plus (n = 39) or MTA Fillapex (n = 39). Three subgroups (n = 13) were formed according to sealer activation: no activation (NA), sonic activation (SA, 20 s) and ultrasonic activation (US, 20 s). In three specimens of each subgroup, 0.1% rhodamine B was added to the sealer. Three 1-mm-thick slices were obtained from each root third. The first and second were used for push-out BS test and the third for a qualitative analysis of interfacial adaptation (gaps) and voids by confocal laser scanning microscopy (CLSM). Intratubular penetration of rhodamine B-labelled sealer was also assessed by CLSM. Data were analysed by two-way anova and Tukey's test (α = 0.05)., Results: AH Plus (2.58 ± 1.21) had higher push-out BS than MTA Fillapex (1.45 ± 0.71) (P = 0.000). UA (2.64 ± 1.44) had higher BS (P = 0.000) than NA (1.58 ± 0.73) and SA (1.83 ± 0.85), which did not differ significantly from each other (P = 0.3303). The coronal third had higher BS (2.48 ± 1.49) than the middle (2.08 ± 0.94) (P = 0.0003) and apical (1.48 ± 0.58) (P = 0.00) thirds. For both sealers, UA was associated with a more homogeneous filling material with better interfacial adaptation and greater quantity, density and length of tags in dentinal tubules. When UA was used, the tags had similar quantity, density and length to those formed without activation, but interfacial gaps and voids were observed., Conclusion: Ultrasonic activation was associated with higher BS values, deeper intratubular penetration and greater interfacial adaptation to root dentine than sonic activation and no activation techniques, AH Plus had higher BS values than MTA Fillapex irrespective of the type of activation., (© 2017 International Endodontic Journal. Published by John Wiley & Sons Ltd.)

Aim: To evaluate the efficacy of four final irrigation protocols on the reduction of hard-tissue debris accumulated within the mesial root canal system of mandibular first molars using micro-CT analysis., Methodology: Forty mesial roots of mandibular molars with a single and continuous isthmus connecting the mesiobuccal and mesiolingual canals (Vertucci's Type I configuration) were selected and scanned at a resolution of 8.6 μm. Canals were enlarged sequentially using WaveOne Small and Primary instruments activated in reciprocating motion without intracanal irrigation to allow debris to accumulate within the mesial root canal system. Then, specimens were anatomically matched and distributed into four groups (n = 10), according to the final irrigation protocol: apical positive pressure (APP), passive ultrasonic irrigation (PUI), Self-adjusting File (SAF) and XP-endo Finisher (XPF). The final irrigation procedures were performed over 2 min using a total of 5.5 mL of 2.5% NaOCl per canal. Reconstructed data sets were coregistered, and the mean percentage reduction of accumulated hard-tissue debris after the final irrigation procedures was compared statistically between groups using the anovapost hoc Tukey test with a significance level set at 5%., Results: Reduction of accumulated hard-tissue debris was observed in all groups after the final irrigation protocol. Overall, PUI and XPF groups had higher mean percentage reductions of accumulated hard-tissue debris (94.1% and 89.7%, respectively) than APP and SAF groups (45.7% and 41.3%, respectively) (P < 0.05). No significant differences were found when comparing the results of PUI and XPF groups (P > 0.05) or APP and SAF groups (P > 0.05)., Conclusions: The PUI technique and XP-endo Finisher instrument were associated with significantly lower levels of AHTD compared with conventional irrigation and the modified SAF system protocol in mesial root canals of mandibular molars., (© 2016 International Endodontic Journal. Published by John Wiley & Sons Ltd.)

This study evaluated the removal of filling material with ProTaper Universal Rotary Retreatment system (PTR) combined with solvents and the influence of solvents on the bond strength (PBS) of sealer to intraradicular dentin after canal reobturation. Roots were endodontically treated and distributed to five groups (n = 12). The control group was not retreated. In the four experimental groups, canals were retreated with PTR alone or in combination with xylol, orange oil, and eucalyptol. After filling material removal, two specimens of each group were analysed by SEM and µCT to verify the presence of filling remnants on root canal walls. The other roots were reobturated and sectioned in 1-mm-thick dentin slices that were subjected to the push-out test. Data were analysed by two-way ANOVA and Tukey's test (α = 0.05). SEM and µCT analysis revealed that all retreatment techniques left filling remnants on canal walls. The control group (3.47 ± 1.21) presented significantly higher (p < 0.05) PBS than the experimental groups. The groups retreated with PTR alone (2.59 ± 0.99) or combined with xylol (2.54 ± 0.77) and orange oil (2.32 ± 0.93) presented similar bond strength (p > 0.05), and differed significantly from the group with eucalyptol (1.89 ± 0.63). The solvents reduced the PBS of the sealer to dentin and no retreatment technique promoted complete removal of filling material.

Introduction: Metallic antibacterial nanoparticles have been shown to provide distinct antibacterial advantage and antibiofilm efficacy when applied in infected root canals. The purpose of this study was to evaluate the influence of incorporating zinc oxide nanoparticles (ZnO-Np) on the physicochemical properties of Grossman sealer., Methods: Grossman sealer was prepared according to its original formula. Additionally, 4 experimental sealers were prepared by replacing the zinc oxide component of the powder with ZnO-Np (average size of 20 nm) in different amounts (25%, 50%, 75%, and 100%). Characterization of the setting time, flow, solubility, dimensional changes, and radiopacity were performed according to American National Standards Institute (ANSI)/American Dental Association (ADA) Specification 57. Scanning electron microscopic and energy-dispersive X-ray spectroscopic analyses were conducted to assess the ultrastructural and chemical characteristics of experimental sealers subjected to the solubility test. Statistical analyses were performed with analysis of variance and post hoc Tukey-Kramer tests with a significance level of 5%., Results: A statistically significant difference in the setting time was observed among groups (P < .05), but only 25% ZnO-Np sealer complied with ANSI/ADA requirements. There was a significant difference in the flow characteristics between the control and 25% and 75% ZnO-Np experimental sealers (P < .05), but all sealers conformed to ANSI/ADA standardization; 25% ZnO-Np sealer showed significantly less solubility (1.81% ± 0.31%) and dimensional change (-0.34% ± 0.12%) than other sealers (P < .05). All sealers showed ultrastructural changes with increasing solubility., Conclusions: ZnO-Np decreased the setting time and dimensional changes characteristic of Grossman sealer; 25% ZnO-Np improved the physicochemical properties of Grossman sealer in accordance with ANSI/ADA requirements., (Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Objective: The aim was to evaluate the influence of Er,Cr:YSGG laser irradiation associated with different final irrigation protocols on the bond strength of epoxy resin-based root canal sealer to root dentin, on the dentin/filling material interface and in the temperature variation during irradiation., Methodology: Ninety-six maxillary canines were prepared with K3 rotary system up to #45/0.02 instrument, irrigating with distilled water between files. The specimens were randomly assigned to three groups-final irrigation (distilled water, 1% NaOCl, and 17% EDTAC) and four subgroups (n = 8)-laser parameters (non-irradiated, 2 W/20 Hz, 3 W/20 Hz, and 4 W/20 Hz). During irradiation, the temperatures were measured on the outer root dentin wall in the three thirds, and root apex. Canals were filled with lateral condensation of AHPlus sealer and gutta-percha cones. Two slices from each third were submitted to a push-out test in Instron machine and the failure mode was analyzed. One slice from each third was analyzed by confocal laser microscopy to evaluate the percentage of the perimeter of the root canal cross-section with sealer tags and depth of tags. Data were analyzed by ANOVA, Kruskal-Wallis, and Tukey's tests (P < 0.05)., Results: Er,Cr:YSGG laser irradiation increased sealer bond strength to dentin, regardless of the final irrigation. The highest values were obtained for 3 W (4.02 ± 1.32) and 4 W (4.18 ± 0.98) powers and different from the non-irradiated group (2.64 ± 0.58) (P < 0.05). The 2 W irradiation produced similar results to 3 W and 4 W when associated with 17% EDTA. Final irrigation with 17% EDTAC provided higher bond strength (4.01 ± 1.02) compared with distilled water (3.11 ± 1.09) and 1% NaOCl (3.47 ± 1.18) (P < 0.05). The cervical third (4.01 ± 1.21) presented significantly higher bond strength than the apical third (3.04 ± 0.89). There was a greater percentage of adhesive and mixed failure. In the groups irradiated with 3 W [21.1 (14.1-27.7)] and 4 W [17.8 (11.9-23.7)], a greater depth of filling material tags was observed compared with the non-irradiated group [12.9 (9.0-20.0)]. The greatest percentage of canal perimeter with sealer tags was observed in the irradiated groups, with no difference among them (P > 0.05). The temperature rise was proportional to the increase of laser power., Conclusions: Er,Cr:YSGG laser irradiation increased the bond strength of an epoxy resin-based sealer to root dentin, with greater formation of sealer tags for all tested powers, especially when combined with 17% EDTAC final irrigation; temperature rise during irradiation remained below the critical threshold biologically accepted. Lasers Surg. Med. 48:985-994, 2016. © 2016 Wiley Periodicals, Inc., (© 2016 Wiley Periodicals, Inc.)

This study evaluated the fracture strength of endodontically treated teeth submitted to reconstructive techniques through dynamic and static tests. Forty human anterior teeth were divided into 4 groups (n=10): GNW (non-weakened) - root restored with glass fiber post (GFP), GW - weakened root restored with GFP, GDA - weakened root restored with direct anatomic GFP, and GIA - weakened root restored with indirect anatomic GFP. The teeth were endodontically treated considering that experimental groups (GW, GDA and GIA) simulated weakened roots for restoration with GFP using different techniques. The GFP was luted with resin cement and the coronal portion was restored with composite resin and metallic crowns. All samples were submitted to chewing simulation at 60 cycles/min in a total of 300,000 cycles. The survival samples were further exposed to compressive loading at a crosshead speed of 1.0 mm/min in a universal testing machine. The load was applied at 135° to the long axis of the tooth until failure. Data were analyzed by ANOVA (a=0.05). After chewing simulation were observed: GNW: 100% of survival roots; GW: 70% of survival roots, and GDA and GIA: 80% of survival roots. The mean fracture strength values (N) were 280.6 (GNW), 239.0 (GW), 221.3 (GDA), and 234.1 (GIA) without significant difference among the groups (p=0.7476). The results suggested similar fracture strength in both weakened and non-weakened teeth regardless the reconstructive technique of root internal wall. Higher incidence of catastrophic fracture was observed in weakened teeth without restoration of the root internal wall.

This preliminary in vitro study evaluated the simulated retention force of O-rings used for mini-implant overdenture treatment and the effect of mechanical fatigue corresponding to 6 months of wear. A mandibular overdenture analog device was attached to two mini-implants and underwent a tensile strength test before and after the application of insertion-removal and simulated masticatory cycles. Insertion-removal cycles led to a retention loss of 24%, whereas masticatory cycles did not influence retention. Micro-CT scans showed minor deformation following mechanical cycling, but the changes were milder than those observed in similar clinical specimens. Both experimental loading methods led to physical changes in the O-rings, which explains in part the similar clinically observed wear.

The aim of this study was to assess the influence of sealer and light-curing unit on regional bond strength of resin composite to the weakened roots. Ninety roots of incisors were experimentally weakened, subjected to biomechanical preparation and filled with either Endofill, AH Plus or MTA Fillapex The roots were desobturated e reinforced with resin composite and fiber post light-activated with one of the light sources: halogen at 600 mW/ cm2 (QTH-600), LED at 800 mW/ cm2 (LED-800) and LED at 1500 mW/ cm2 (LED-1500). The roots were sectioned in slices from cervical, middle and apical root-reinforcement regions and analyzed by push out test, scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). Bond strength data were analyzed using three-way ANOVA and Tukey´s test (α=0.05). Specimens filled with AH Plus had higher bond strength, followed by MTA Fillapex and Endofill (p<0.05). For light-curing unit, LED-1500 presented superior bond strength than LED-800, which was higher than QTH-600 (p<0.05). The cervical region had the greatest mean values (p<0.05) while apical part showed the lowest bond strength (p<0.05). CLMS revealed remaining filling material in the dentinal tubules for all groups. The eugenol-containing sealer (Endofill) compromised the push-out bond strength of composite resin to the root dentin. Bond strength was favored in the cervical region, and when LED-1500 was used.

Root canal irrigants are used to minimize the negative effects of smear layer on endodontic sealer retention. The aim of this study was to evaluate the efficacy of agitation of 17% ethylenediaminetetraacetic acid (EDTA) with ultrasonic, 1064-nm Nd:YAG and 980-nm diode laser on the retention of an epoxy-based sealer to the root canal walls. Forty single-rooted bovine teeth were instrumented with ProTaper rotary system and divided into four groups according to the final irrigation protocol (n = 10): (1) 17% EDTA (control); (2) 17% EDTA with 50-s ultrasonic agitation; (3) 17% EDTA with 50-s diode laser (2-W) agitation; and (4) 17% EDTA with 50-s Nd:YAG (1.5-W) laser agitation. After endodontic filling with gutta-percha F5 master cone and Sealer 26, the roots were sectioned at the cervical, middle, and apical root thirds to obtain 1.5-mm slices. Push-out tests were performed using a universal testing machine at a 1 mm/min crosshead speed. Data were analyzed using two-way ANOVA and Tukey's tests (α=0.05). Apical root thirds had significant higher retention values than cervical and middle thirds (p < 0.05). EDTA with 1064-nm Nd:YAG or 980-nm diode laser presented the highest retention values and was significantly different from EDTA with ultrasonic agitation and EDTA only (p < 0.05). Adhesive failures were predominant to EDTA only group. Mixed failures were predominant to all agitation groups. 1064-nm Nd:YAG and 980-nm diode laser EDTA agitation enhanced the retention of the epoxy-based sealer to the root canal walls compared with that due to EDTA only or EDTA with ultrasonic agitation.

The aim of the present study was to evaluate the bond strength (BS) of root canal fillings to root dentin using the reciprocating file-matched single-cone or lateral compaction techniques with resin-based and calcium-silicate-based sealers. Maxillary canine roots were prepared and filled using one of the following approaches: Reciproc R40 file and R40 single cone, WaveOne Large file and Large single cone, or ProTaper up to F4 file with lateral compaction. The root filling was performed using AH Plus, Epiphany SE or MTA Fillapex (n = 10). Three 1-mm-thick slices were obtained from each third of each root. Two slices were subjected to a push-out test, and the other slices were prepared for scanning electron microscopy (SEM) to examine the dentin-sealer interface. Data (in MPa) from the push-out tests were analyzed using a two-way ANOVA and Tukey's test (p < 0.05). Failure modes (adhesive, cohesive or mixed) were evaluated at ×25 magnification. The single-cone techniques resulted in lower BS values than the lateral compaction technique. For lateral compaction, AH Plus and Epiphany SE showed the highest and lowest BS values, respectively. Slight differences were observed between sealers when the single-cone techniques were used. A tendency to reduce the BS toward the apical third was observed. Adhesive failures were predominant for all experimental conditions. A closer adaption of the filling material on the root dentin was observed for the AH Plus and lateral compaction techniques. The Reciproc and WaveOne techniques were associated with lower BS values than the lateral compaction technique. However, the effect of the root canal filling technique appears to be sealer-dependent.

Introduction: This study evaluated filling material removal from distal oval-shaped canals of mandibular molars with rotary, reciprocating, and adaptive motion systems by using micro-computed tomography., Methods: After cone-beam computed tomography scanning, 21 teeth were selected, prepared up to a size 40 file, root filled, and divided into 3 groups (n = 7) according to the filling material removal technique: group PTUR, ProTaper Universal Retreatment combined with ProTaper Universal F2, F3, F4, and F5 files; group RP, Reciproc R50 file; and group TFA: TF Adaptive 50.04 files. The specimens were scanned preoperatively and postoperatively to assess filling material removal by using micro-computed tomography imaging, and the percent volume of residual filling material was calculated., Results: The statistical analysis showed the lowest percent volume of residual filling material at the coronal third in all groups (P < .05). There was no significant difference among the systems in the coronal third (P > .05). In the middle third, group TFA (31.2 ± 10.1) showed lower volume of residual filling material than group RP (52.4 ± 14.1) (P < .05). In the apical third, groups TFA (44.8 ± 20.6) and PTUR (48.6 ± 16.8) presented a lower percent volume of filling material than group RP (70.6 ± 7.2) (P < .05), as confirmed by the qualitative analysis., Conclusions: The use of the adaptive motion increased the amount of root filling removed in the middle and apical thirds compared with the reciprocating motion. However, no technique was able to completely remove the filling material from the canals., (Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

The aim of this study was to compare the stress distribution in radicular dentin of a maxillary canine restored with either a glass fiber post, carbon fiber post or an experimental dentin post using finite element analysis (3D-FEA). Three 3D virtual models of a maxillary canine restored with a metal-ceramic crown and glass fiber post (GFP), carbon fiber post (CFP), and experimental dentin post (DP) were obtained based on micro-CT images. A total of 180 N was applied on the lingual surface of the incisal third of each tooth at 45 degrees. The models were supported by the periodontal ligament fixed in three axes (x=y=z=0). The von Mises stress (VMS) of radicular dentin and the intracanal posts was calculated. The structures of all groups showed similar values (MPa) and distribution of maximum von Mises stress. Higher stress was found in the apical third of dentin while the posts presented homogeneous stress distribution along the axis. The fiber and dentin posts exhibited similar stress values and distribution. Thus, the experimental dentin post is a promising restorative material.

This study aimed to evaluate the performance of the Wave One, Easy ProDesign Logic and One Shape systems in the preparation of long oval root canals. Forty-two mandibular incisors were randomized into three groups: Group I, Wave One Primary (WO) (#25.08); Group II, Easy ProDesign Logic (EPL) (#25.06) and Group III, One Shape (OS) (#25.06). Micro-computed tomography scans were obtained pre- and post-preparation of the samples. Instrument fractures or loss of working length did not occur in any of the groups. There was a statistically significant difference in total root canal volume between the WO and EPL (p<0.05) and OS systems (p<0.05) The mean percentages of instrumented canal area in the middle thirds were 76.9% in the WO, 62.3% in the EPL and 71.8% in the OS (p>0.05). The OS system had the strongest correlation between volume increase and instrumented area (R=0.63). The WO, EPL and OS systems presented mean preparation times of 2.13 min, 0.54 min, and 2.21 min (p<0.05), respectively. All three systems enabled the safe preparation of long oval root canals. The WO system most effectively increased root canal volume, but it did not affect the instrumented areas. The OS system had the strongest correlation between volume increase and instrumented area, while the EPL system was the fastest.

This study evaluates the effect of two thermoplastic obturation systems (MicroSeal and Obtura II) on bond strength of different sealers to intraradicular dentin. Sixty root canals of human canines were prepared using ProTaper rotary files (crown-down technique) and irrigated with 2.5% sodium hypochlorite and 17% EDTA. The root canals were filled by MicroSeal, Obtura II, or lateral compaction techniques using AH Plus and Epiphany SE. 1.5 mm thick root slices were subjected to the push-out test. ANOVA and Tukey's test showed that the bond strength values (MPa) observed in the groups obturated with MicroSeal (2.96 ± 2.72) and Obtura II (2.68 ± 2.18) did not significantly differ from each other (p > 0.05) but were significantly higher than that observed in the group obturated with lateral condensation (2.01 ± 1.48; p < 0.05). There were no statistically significant differences in strength (p > 0.05) among the root canal thirds (cervical: 2.44 ± 2.03; middle: 2.50 ± 2.27; and apical: 2.70 ± 2.34). Adhesive failures were predominant (60%) in all groups. In conclusion, MicroSeal and Obtura II techniques, using AH plus sealer, increased the resistance to displacement of the filling material, when compared with lateral compaction. Moreover, when used with Epiphany SE, these obturation systems did not affect the bond strength of the material to root dentin.

The aim of this study was to evaluate the effects of different root canal filling techniques on the bond strength of epoxy resin-based sealers. Sixty single-rooted canines were prepared using ProTaper (F5) and divided into the following groups based on the root filling technique: Lateral Compaction (LC), Single Cone (SC), and Tagger Hybrid Technique (THT). The following subgroups (n = 10) were also created based on sealer material used: AH Plus and Sealer 26. Two-millimeter-thick slices were cut from all the root thirds and subjected to push-out test. Data (MPa) was analyzed using ANOVA and Tukey's test (α = 0.05). The push-out values were significantly affected by the sealer, filling technique, and root third (p < 0.05). AH Plus (1.37 ± 1.04) exhibited higher values than Sealer 26 (0.92 ± 0.51), while LC (1.80 ± 0.98) showed greater bond strength than THT (1.16 ± 0.50) and SC (0.92 ± 0.25). The cervical (1.45 ± 1.14) third exhibited higher bond strength, followed by the middle (1.20 ± 0.72) and apical (0.78 ± 0.33) thirds. AH Plus/LC (2.26 ± 1.15) exhibited the highest bond strength values, followed by AH Plus/THT (1.32 ± 0.61), Sealer 26/LC (1.34 ± 0.42), and Sealer 26/THT (1.00 ± 0.27). The lowest values were obtained with AH Plus/SC and Sealer 26/SC. Thus, it can be concluded that the filling technique affects the bond strength of sealers. LC was associated with higher bond strength between the material and intra-radicular dentine than THT and SC techniques.

Introduction: Current push-out experimental methods used in endodontic research should be improved. This study introduced a novel dentin push-out bond strength model that uses micro-computed tomography (μCT)., Methods: Roots filled with gutta-percha cones and different resin-based sealers (n = 10) were sectioned transversely to obtain two 2-mm-thick slices per root third. The first slice was subjected to a push-out test by using a material testing stage fitted inside a μCT scanner. The apparatus was scanned before and after the test to evaluate areas of filling material ruptures. The images provided by μCT were also used to generate models for a 3-dimensional finite element analysis. Confocal laser scanning microscopy was used to assess failure modes after the test and to measure interfacial gaps in slices not subjected to push-out. Bond-strength and gap data were statistically analyzed (P < .05)., Results: Proper coefficients of variation (average less than 30%) were observed for all the experimental conditions. The finite element analysis helped explain the results of bond strength and root-filling ruptures. A significant, moderate, indirect correlation was observed between the bond strength and gaps., Conclusions: The micromechanical model with the μCT images resulted in a consistent root-filling bond strength evaluation., (Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

The present study evaluated the reliability of FEA on the results of different mechanical properties (E and v) of materials. Two 3D models of a maxillary canine with endodontic treatment, intracanal post, composite resin core and restored with porcelain-fused-to-metal crown were generated according to micro-CT images. Two groups with different E and ν values for porcelain, metal coping alloy, resin cement and composite resin were established. The materials' properties for group GL were based on literature data, while for group GIE the impulse excitation technique was used. A load of 180 N was applied at 45° on the incisal third of the lingual surface of the canine tooth. All models were supported by the periodontal ligament (x=y=z=0). The von Mises stress (VMS) was calculated. The stress values revealed differences between the groups for both VMS distribution and value. The porcelain (GL: 5.966 MPa; GIE: 7.478 MPa), metal coping (GL: 3.811 MPa; GIE: 0.973 MPa) and core (GL: 4.771 MPa; GIE: 0.026 MPa) were significantly affected. In conclusion, this study showed that the determination of mechanical properties (E and ν) of materials is essential for the reliability on the results of FEA.

Statement of Problem: The restoration of weakened roots with glass fiber posts (GFPs) remains a challenge., Purpose: The purpose of this study was to evaluate the stress distribution of endodontically treated teeth with weakened radicular walls restored with different protocols by 3-dimensional finite element analysis (3D-FEA)., Material and Methods: The following 4 models of endodontically treated maxillary canines restored with metal ceramic crowns were simulated on the basis of computed microtomographic images to characterize the groups: GNW (control), a nonweakened root restored with a GFP; GW, a weakened root restored with a GFP; GDA, a weakened root restored with a direct anatomic GFP; and GIA, a weakened root restored with an indirect anatomic GFP. Loads of 180 N were applied to the lingual surface on the incisal third of the teeth at 45 degrees. The models were supported by a periodontal ligament and fixed in 3 axes (x=y=z=0). The von Mises stress (VMS) was calculated., Results: All models exhibited VMS concentrations at the loading area and were distributed along the proximal surfaces of the root. The GFP exhibited a homogeneous stress distribution, and similar VMS distributions were observed in all of the reconstructive techniques., Conclusions: Similar stress distributions were observed in the endodontically treated teeth, regardless of root weakness and the reconstructive technique for the radicular walls., (Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.)

Objective: The purpose of this study was to analyze the effects of agitation of 17% ethylenediaminetetraacetic acid (EDTA) with 1064 nm Nd:YAG and 980 nm diode laser on root dentin microhardness and superficial roughness (with confocal laser scanning microscopy [CLSM])., Background Data: Root canal irrigants are used in an attempt to minimize the negative effects of smear layer., Materials and Methods: Twenty-five bovine roots were sectioned longitudinally and divided into five groups (n=10 each): (1) deionized water, (2) 17% EDTA, (3) 17% EDTA with 60 sec manual agitation, (4) 17% EDTA with 50 sec diode laser (2 W) agitation, and (5) 17% EDTA with 50 sec Nd:YAG (1.5 W) laser agitation. Microhardness and superficial roughness values were calculated before and after the procedures at the cervical, middle, and apical root thirds. Microhardness was statistically analyzed using two way ANOVA, paired t test, and Tukey's tests (α=0.05). Roughness was statistically analyzed using Kruskal-Wallis, paired t test, and Student-Newman-Keuls tests (α=0.05%)., Results: Statistically significant differences in microhardness and roughness were observed between the deionized water group and others. EDTA with 1064 nm Nd:YAG or 980 nm diode laser presented the lowest microhardness and the highest roughness values and was significantly different from EDTA with manual agitation and EDTA only (p<0.05). However, there were no differences in microhardness or dentin roughness between the root thirds (p>0.05). CLSM analysis showed that the control samples exhibited smoother surfaces than that of the EDTA groups., Conclusions: Nd:YAG 1064 nm and 980-nm diode laser EDTA agitation caused greater reduction in microhardness and increased roughness of root dentin than EDTA only or EDTA with manual agitation.

Aim: To evaluate the use of a dissolved oxygen microsensor (DOMS) for assessing the viability and thickness of microbial biofilms on the apical external surface of contaminated human tooth roots., Methodology: Apical biofilm formation was evaluated in 15 roots contaminated in vitro with a polymicrobial mixture of Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa and Candida albicans for 7, 21 and 60 days and in three freshly extracted roots with associated radiographically visible periapical lesions. In each root, the thickness and viability (measured by the amount of dissolved oxygen) of biofilm formed on the apical 2 mm were examined with the DOMS. Scanning electron microscopy (SEM) was used as an auxiliary analysis to confirm the existence of the biofilms detected by the DOMS., Results: The DOMS detected dissolved oxygen on the biofilms formed on the three residual roots up to thickness of 375 μm, 480 μm and 1650 μm. In the 15 roots contaminated in vitro, the DOMS detected dissolved oxygen in six specimens up to thicknesses from 75 to 250 μm, and the intensity of the metabolic activity (biofilm thickness) was directly proportional to the contamination time. SEM confirmed the presence of biofilm in all roots., Conclusion: The dissolved oxygen microsensor allowed the measurement of the amount of dissolved oxygen in the biofilm, which is indicative of the intensity of the microbial metabolic activity (viability), correlating the results with biofilm thickness. The DOMS was effective in freshly extracted roots, but had limitations in roots contaminated in vitro after short periods (7 and 21 days) of contamination., (© 2014 International Endodontic Journal. Published by John Wiley & Sons Ltd.)

This study evaluated the bond strength of root-end filling materials to root-end cavities using a new methodology. Twenty maxillary central incisors were subjected to biomechanical preparation (#80 hand file) and sectioned transversally 2 mm short of the apex and 4 mm coronally to this point. The root cylinders were embedded in acrylic resin and positioned at 45° to the horizontal plane for preparation of root-end cavities with a diamond ultrasonic retrotip. Two groups (n=10) were formed according to the root-end filling material: MTA and Super EBA. A gutta-percha cone (#80) was tug-backed at the limit between the canal and the root-end cavity. The cavity was filled and the gutta-percha cone was removed after complete setting of the sealer. The specimens were placed in an Instron machine with the root-end filling turned downwards. The push-out shaft was inserted in the space previously occupied by the gutta-percha cone and run at a crosshead speed of 1.0 mm/min for pushing out the root-end filling material. Data were analyzed by ANOVA (α=5%). Super EBA (6.03±1.31) presented higher bond strength (MPa) than MTA (1.81±0.45) (p>0.05). There was a predominance of cohesive failures for Super EBA and mixed for MTA. The protocol of specimen preparation is effective and introduces a specific methodology for assessing bond strength of root-end filling materials to dentin. Among the materials, Super EBA presented the highest bond strength.

The endodontic preparation of curved and narrow root canals is challenging, with a tendency for the prepared canal to deviate away from its natural axis. The aim of this study was to evaluate, by cone-beam computed tomography, the transportation and centering ability of curved mesiobuccal canals in maxillary molars after biomechanical preparation with different nickel-titanium (NiTi) rotary systems. Forty teeth with angles of curvature ranging from 20° to 40° and radii between 5.0 mm and 10.0 mm were selected and assigned into four groups (n = 10), according to the biomechanical preparative system used: Hero 642 (HR), Liberator (LB), ProTaper (PT), and Twisted File (TF). The specimens were inserted into an acrylic device and scanned with computed tomography prior to, and following, instrumentation at 3, 6 and 9 mm from the root apex. The canal degree of transportation and centering ability were calculated and analyzed using one-way ANOVA and Tukey's tests (α = 0.05). The results demonstrated no significant difference (p > 0.05) in shaping ability among the rotary systems. The mean canal transportation was: -0.049 ± 0.083 mm (HR); -0.004 ± 0.044 mm (LB); -0.003 ± 0.064 mm (PT); -0.021 ± 0.064 mm (TF). The mean canal centering ability was: -0.093 ± 0.147 mm (HR); -0.001 ± 0.100 mm (LB); -0.002 ± 0.134 mm (PT); -0.033 ± 0.133 mm (TF). Also, there was no significant difference among the root segments (p > 0.05). It was concluded that the Hero 642, Liberator, ProTaper, and Twisted File rotary systems could be safely used in curved canal instrumentation, resulting in satisfactory preservation of the original canal shape.

Oral rehabilitation with dental implants has become a routine treatment in contemporary dentistry. The displacement of dental implants into the sinus membrane, a complication related to the maxillary sinus, is one of the most common accidents reported in the literature. The treatment for this complication is the surgical removal of the implant. A 60-year-old woman with three dental implants displaced into the maxillary sinus (one implant displaced into the left maxillary sinus and two implants displaced into the right maxillary sinus) underwent surgery for removal of the implants. The surgery to remove the implants was performed under local anesthesia through the Caldwell-Luc technique. The patient was subsequently administered antibiotic, anti-inflammatory, and analgesic drugs. The patient returned 7 days after the surgery for suture removal and is being regularly monitored to determine whether future rehabilitation of the edentulous area is necessary. In conclusion, surgical removal of the dental implant displaced into the maxillary sinus is the treatment of choice. This technique is appropriate because it allows the use of local anesthesia and provides direct visualization for the removal of the implants.

This paper describes two cases of instrument fragment removal from the apical thirds of root canals using a customized extractor and a modified needle technique, respectively. In case 1, a customized extractor was manufactured to remove a bur fragment located in the apical root canal of a maxillary central incisor. The use of this extractor enabled successful and conservative removal of the instrument fragment. In case 2, a modified injection needle was used as a trepan to gain access around an instrument fragment located in the curved apical portion of the mesiobuccal canal of a mandibular molar. A segment of steel wire was inserted into the needle lumen to engage the metallic fragment, enabling its removal with counter-clockwise rotation and a simultaneous pull-out motion. Alternative and creative methods are useful for the management of intracanal metallic fragments during root canal treatment.

This study aimed to evaluate, by means of scanning electron microscopy (SEM), the cleaning of flattened root canals, varying irrigation/aspiration protocols during biomechanical preparation. Thirdy human mandibular incisors were distributed into three groups (n = 10) according to the aspiration/irrigation protocols: conventional, conventional + brush, and apical negative pressure irrigation. Irrigation procedure was performed with 5 mL of 1% NaOCl at each change of instrument; final irrigation was conducted with 17% EDTA for 5 min. After biomechanical preparation, the roots were sectioned and prepared for SEM analysis. The images obtained were evaluated under 35× and 1,000× magnification by three calibrated examiners, following a double-blind design. All data were analyzed using Kruskal-Wallis and Dunn's post hoc tests (α = 0.05). Canals wherein the conventional method and apical negative pressure irrigation were employed revealed less debris, statistically different from the conventional + brush group (p < 0.05). Regarding the presence of smears, apical negative pressure irrigation was more effective in cleaning, showing lowest scores (p < 0.05), compared with the other tested protocols. Comparing each root canal third revealed that the apical portion was difficult to clean as all the tested protocols showed similar high scores (p > 0.05), both for the presence of debris and smear layer. In conclusion, although none of the studied irrigation/aspiration protocols have completely cleaned flattened root canals, apical negative pressure irrigation was more effective in smear layer removal, whereas the conventional + brush protocol was the least effective in removing the debris and smear layer.

This case report describes root canal filling performed over a large S1 ProTaper file fragment in a second mandibular molar with irreversible pulpitis. An S1 ProTaper file was fractured during the instrumentation of the mesiobuccal canal. Approximately 10 mm of file fragment remained in the apical and middle thirds of the canal. The obturation was performed over this fragment using thermomechanically compacted gutta-percha and sealer. Radiographic findings and the absence of clinical signs and symptoms at 3-year follow up indicated successful treatment. Cone-beam computed tomography images revealed absence of periapical lesion and details of intracanal file fragment related to root fillings and apex morphology. In this case, the presence of a large intracanal fractured instrument did not have a negative impact on the endodontic prognosis during the follow up evaluation period.

Introduction: This study compared the bond strength, interfacial ultrastructure, and tag penetration of resin-based sealers applied to smear-free radicular dentin using 70% isopropyl alcohol as the active final rinse., Methods: Eighty root canals were prepared and assigned to 2 groups (n = 40) according to the drying protocol: paper points or 70% isopropyl alcohol. Then, roots were divided into 4 subgroups (n = 10) with respect to the sealer and obturation material: AH Plus (Dentsply De Trey GmbH, Konstanz, Germany) and gutta-percha (AH/GP), Hybrid Root SEAL (Sun Medical, Tokyo, Japan) and gutta-percha (HR/GP), Epiphany SE (Pentron Clinical Technologies, Wallingford, CT) and gutta-percha (EP/GP), and Epiphany SE and Resilon (EP/RS). Roots were sectioned, and the push-out test was performed. Failure modes were examined under stereomicroscopy and sealer penetration into the dentinal tubules under scanning electron microscopy. Data were statistically analyzed by 2-way analysis of variance post hoc Tukey tests with a significant level of 5%., Results: Overall, canals dried with isopropyl alcohol showed significantly higher bond strength values (2.11 ± 1.74 MPa) than with paper points (1.81 ± 1.73 MPa) (P < .05). The HR/GP group showed lower bond strength than the AH/GP group (P < .05) but higher than the EP/GP and EP/RS groups (P < .05). The most frequent type of failure was cohesive in the AH/GP and HR/GP groups and adhesive in the EP/GP and EP/RS groups. Scanning electron microscopic evaluation revealed better adaptation of the adhesive interface in the AH/GP and HR/GP groups in comparison with the EP/GP and EP/RS groups., Conclusions: A final rinse with EDTA and 70% isopropyl alcohol improved the bond strength and penetration of the sealers into dentinal tubules of the root., (Copyright © 2014 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Objective: The purpose of this study was to assess the bond strength of a restorative material to bleached dentin, pretreated with Er:YAG laser., Background Data: Laser irradiation for dental surface treatment may increase the bond strength of restorative material to tooth surface. There are no reports of using Er:YAG laser on dentin bleached with 35% hydrogen peroxide., Methods: Forty maxillary canines were sectioned, resulting in 80 fragments (5×5 mm) of intracoronary dentin that were divided into eight groups (n=10) according to the dental bleaching (present or not), surface conditioning (with or without laser) and the post-bleaching time to perform restoration (immediately or 7 days). The bleached specimens received two applications of 38% hydrogen peroxide. Er:YAG laser was applied for 20 sec with 400 mJ/15 Hz. Restorative procedure was performed using phosphoric acid, an adhesive system, and resin using a split Teflon matrix. The specimens were submitted to shear bond strength test and the data (MPa) were analyzed by ANOVA and Tukey's test (α=0.05)., Results: There were significant differences among the three factors (p<0.05). The highest values were obtained for unbleached specimens compared with bleached, for those treated with laser compared with those only conditioned with acid, and for those restored after 7 days compared with those having immediate restoration. In the interaction of factors, the bleached specimens treated with laser and restored immediately were statistically similar (p>0.05) to those bleached and restored after 7 days., Conclusions: Er:YAG laser can restore the bond strength of the dentin/restorative material interface even if the restoration is performed immediately after bleaching.

This study aimed to evaluate, by scanning electron microscopy (SEM), the cleaning of canal walls with moderate curvature subjected to biomechanical preparation with different final diameters using apical negative pressure irrigation. Thirty-two mesiobuccal roots of molars were divided into 4 groups (n=8) according to the instrument's final diameter: GI: 30.02, GII: 35.02, GIII: 40.02 and GIV: 45.02. Irrigating procedure was performed at each change of instrument with 1% NaOCl using the Endovac system. Final irrigation was conducted with 17% EDTA for 5 min. The SEM photomicrographs were evaluated under 35× and 1000× magnification, by three calibrated examiners, in a double-blind design. Data were submitted to Kruskal-Wallis and Dunn's post hoc tests (α=0.05). Canals instrumented with 30.02 and 35.02 final diameters showed more debris, statistically different from the other groups (p<0.05). Comparing each root canal third, for the cervical and apical portions no statistically significant difference (p>0.05) was found among the four groups. Regarding the presence of smear layer, canals with 30.02 final diameter showed the highest scores, statistically different from the 45.02 group (p<0.05) and similar to the 35.02 and the 40.02 groups (p>0.05). Although none of the studied diameters completely removed debris and smear layer, it may be concluded that instrumentation with higher final diameters was more effective in cleaning the root canals with moderate curvature.

This study assessed the influence of different endodontic chemical substances on the adhesion of the Epiphany SE/Resilon system (with and without resinous solvent) to radicular dentin walls, using the push-out test and scanning electron microscopy (SEM). Forty-eight root canals of human canines were prepared biomechanically with ProTaper rotary files (crown-down technique) and the radicular dentin was treated with either 17% EDTA, 2% chlorhexidine gel (CHX) or 2.5% NaOCl (control). The root canals were filled with Resilon cones and Epiphany SE sealer with and without resinous solvent. Six groups of eight canals each had their roots sectioned transversally to obtain 1-mm thick slices. Data were subjected to statistical analysis by ANOVA and Tukey's tests. The specimens treated with 17% EDTA (1.59 ± 0.91) presented higher bond strength (P < 0.05) than those treated with 2.5% NaOCl (0.93 ± 0.27) and 2% CHX (0.92 ± 0.22). Significantly higher bond strength (P < 0.05) was observed when the Epiphany SE was prepared with (1.37 ± 0.78) than without (0.92 ± 0.33) solvent. Adhesive failures were predominant in all groups. SEM analysis showed greater homogeneity of the filling mass when the solvent was added to the sealer. Treatment of root canal walls with 17% EDTA, and addition of a resinous solvent to Epiphany SE produced the highest adhesion to radicular dentin., (© 2014 Wiley Periodicals, Inc.)

Aim: To evaluate the bond strength of a resin-based sealer (AH Plus) to root canal dentine after the removal of a zinc oxide-eugenol-based sealer (Endofill), using different retreatment techniques., Methodology: The root canals of sixty-four maxillary incisors were prepared with ProTaper and filled with Endofill/gutta-percha. After thermocycling, the roots were randomly assigned according to the retreatment technique (n = 16): (A) ProTaper, (B) ProTaper/xylol, (C) ultrasound and (D) ultrasound/xylol and according to whether an operating microscope (OM) was used or not (n = 8): GI- direct vision (DV) and GII- indirect through the OM. Eight additional roots were instrumented and filled with AH Plus/gutta-percha (control). Roots were sectioned to obtain 1-mm-thick slices. Slices were used in the push-out test and in confocal microscopy. Data were submitted to anova and Tukey test (α = 0.05)., Results: The specimens filled under the OM (2.50 ± 0.90) had higher bond strength values of sealer to root canal walls (P < 0.05). The control group had superior mean adhesion values (4.75 ± 1.47) that were significantly different from the others (P < 0.05). Ultrasound/xylol (2.53 ± 1.00) was superior to ultrasound (2.23 ± 0.72) (P < 0.05), ProTaper (2.20 ± 0.69), ProTaper/Xylol (2.12 ± 0.65), which were similar (P > 0.05). Bond strength was different in all thirds (P < 0.05) and decreased in the following sequence: cervical (3.19 ± 1.18), middle (2.58 ± 1.21) and apical (1.87 ± 0.68). Confocal analysis revealed residues of Endofill in dentinal tubules when the removal protocol was carried out with ProTaper, but not from ultrasound combined with xylol., Conclusions: The OM was associated with higher bond strength values for filling material to root canals. The zinc oxide-eugenol-based sealer negatively affected the bond strength of AH Plus to root canal walls, regardless of the retreatment technique., (© 2013 International Endodontic Journal. Published by John Wiley & Sons Ltd.)

Aim: The percentage of Endofill remaining on canal walls after retreatment with different techniques was evaluated using confocal microscopy and qualitative analysis of the interface between the filling material/dentine., Methodology: Sixty-four root canals of incisors were prepared with ProTaper, filled with gutta-percha and Endofill mixed with 0.1% rhodamine B. The roots were thermocycled and distributed into groups according to the method of evaluation: GI - direct viewing (DV) and GII - operating microscope (OM) and according to the removal technique: A) ProTaper retreatment (PR), B) PR/xylol, C) ultrasound and D) ultrasound/xylol. The root canals were then refilled with gutta-percha and AH Plus with 0.1% fluorescein and sectioned at 2, 4 and 6 mm from the apex. The percentage of remaining Endofill was analysed by confocal microscopy. Additionally, 16 roots were prepared with a ProTaper F5 instrument and were filled with Endofill + 0.1% rhodamine B/gutta-percha (negative control group) (n = 8), and the positive control group (n = 8) were filled with AH Plus with 0.1% fluorescein/gutta-percha., Results: Three-way anova demonstrated differences in the method of evaluation, removal techniques and their interaction (P < 0.05). OM (26.15 ± 12.16%) had a smaller percentage of remaining sealer than DV (32.77 ± 14.47%). The Tukey's test revealed that ultrasound/xylol (15.77 ± 7.15%) led to lower percentages of remaining sealer, significantly different from the PR group (35.25 ± 13.63%), PR/xylol (33.03 ± 11.64%) and ultrasound (33.79 ± 11.71%), which were similar (P > 0.05). Qualitative analysis detected that ultrasound had lower remaining Endofill than PR, particularly when combined with xylol. Operating microscope resulted in lower residual sealer, regardless of the removal technique., Conclusions: None of the protocols was associated with complete removal of the filling material; however, the use of ultrasound/xylol under an OM provided better results., (© 2013 International Endodontic Journal. Published by John Wiley & Sons Ltd.)

This study aimed to synthetize, characterize and evaluate the antimicrobial properties of silver nanoparticles to be used in the development of a root intracanal formulation. Silver nanoparticles (AgNPs) were obtained by reduction of silver nitrate with sodium borohydride and characterized by UV-Visible spectrophotometry, scanning electron microscopy (SEM) and dynamic light scattering (DLS). The antimicrobial activity of nanoparticle formulation was evaluated by determinations of the minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) against different bacterial species by the microdilution method, according to recommendations of the Clinical and Laboratory Standards Institute (CLSI). Three potential vehicles, hydroxyethylcellulose, Carbomer and polyethylene glycol were tested as carriers for formulations containing AgNPs. The efficiency of the synthesis method chosen to produce AgNPs was demonstrated by four characterization techniques. The nanoparticles showed antibacterial activity against all species tested. Incorporation of AgNPs into all experimental vehicles produced stable formulations but the one in hydroxyethylcellulose presented better physical proprieties. The results indicate that silver nanoparticles are potential antiseptic agents to be used in root canals and incorporation in adequate vehicles may favor a broader application.

The aim of this study was to assess the clinical, radiographic and microscopic features of a case series of ossifying fibroma (OF) of the jaws. For the study, all cases with OF diagnosis from the files of the Oral Pathology Laboratory, University of Ribeirão Preto, Ribeirão Preto, SP, Brazil, were reviewed. Clinical data were obtained from the patient files and the radiographic features were evaluated in each case. All cases were reviewed microscopically to confirm the diagnosis. Eight cases were identified, 5 in females and 3 in males. The mean age of the patients was 33.7 years and most lesions (7 cases) occurred in the mandible. Radiographically, all lesions appeared as unilocular images and most of them (5 cases) were of mixed type. The mean size of the tumor was 3.1 cm and 3 cases caused displacement of the involved teeth. Microscopically, all cases showed several bone-like mineralized areas, immersed in the cellular connective tissue. From the 8 cases, 5 underwent surgical excision and 1 patient refused treatment. In the remaining 2 cases, this information was not available. In conclusion, OF occurs more commonly in women in the fourth decade of life, frequently as a mixed radiographic image in the mandible. Coherent differential diagnoses are important to guide the most adequate clinical approach. A correlation between clinical, imaginological and histopathological features is the key to establish the correct diagnosis.

Introduction: Cleaning and shaping of root canals are essential steps for the success of endodontic therapy. The purpose of this study was to evaluate the tissue debridement efficacy of the self-adjusting file (SAF) protocol in the apical third of oval-shaped canals of mandibular incisors in comparison with a nickel-titanium rotary system preparation., Methods: Twenty-six single-rooted human mandibular incisor teeth were selected and assigned to a control (n = 4) and 2 experimental groups (n = 11) according to 1 of 2 instrumentation techniques, SAF and nickel-titanium rotary systems. After root canal preparation, the apical thirds of the specimens were submitted to histologic processing and analyzed by optical microscopy regarding the percentage of debris and uninstrumented root canal walls. The data were statistically compared by using unpaired t test with Welch's correction, and the level of significance was set at 5%., Results: The percentage of remaining debris and uninstrumented canal perimeter was significantly lower in SAF group (2.18 ± 2.71 and 12.33 ± 7.85, respectively) than in rotary group (13.11 ± 12.98 and 53.54 ± 15.95, respectively) (P < .05). In the SAF group most of specimens were completely free of debris, whereas in the rotary group 53% of the canals presented debris., Conclusions: SAF had significantly more contact to the dentin walls and removed more debris than rotary instrumentation in the apical third of mandibular incisors., (Copyright © 2013 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.)

Few reports have addressed the effects of diode laser irradiation at 980 nm on the morphology and fracture resistance of dentine. The purpose of this study is to evaluate the effects of 980-nm diode laser on the ultrastructure and fracture resistance of root dentine. The roots of 90 extracted canine teeth were divided into three groups according to the type of irrigating solution (water, NaOCl, and NaOCl/EDTA) and subdivided into three subgroups (n = 10) according to the amount of laser irradiation (without irradiation, 1.5 W/100 Hz and 3.0 W/100 Hz). The roots were filled with an epoxy resin-based sealer and gutta-percha and then subjected to a fracture resistance test. Data were analyzed by ANOVA and the Tukey test (p < 0.05). Additionally, 18 canine teeth were prepared using the same irrigation/irradiation protocols and evaluated by scanning electron microscopy (SEM). The SEM showed greater changes when the laser power increased, and the changes also varied according to the irrigating solution. A modified smear layer was observed in specimens that were treated with water and then laser-irradiated. The laser treatment did not alter the fracture resistance of roots treated with 1.5 W/100 Hz (246.3 ± 29.5 N) and 3.0 W/100 Hz (215.3 ± 25.1 N) laser power. The roots treated with NaOCl were more susceptible to fracture (199.4 ± 15.1 N) than those irrigated with water (254.2 ± 23.0 N) (p < 0.05). The 980-nm diode laser altered the morphology of the dentine but did not affect the fracture resistance of the roots.

Objective: To analyze the expression and distribution patterns of mature dendritic cells (mDCs) and immature DCs (imDCs) in radicular cysts (RCs), dentigerous cysts (DtCs), and keratocystic odontogenic tumors (KCOTs)., Materials and Methods: Forty-nine odontogenic cystic lesions (OCLs) (RCs, n = 20; DtCs, n = 15; KCOTs, n = 14) were assessed using the following markers: S100, CD1a and CD207 for imDCs; and CD83 for mDCs., Results: Almost all cases were S100, CD1a, and CD207 positive, whereas 63% were CD83 positive. RCs presented greater number of immunostained cells, followed by DtCs, and KCOTs. The number of S100+ cells was greater than both CD1a+ and CD207+ cells (P < 0.001), which showed approximately similar amounts, followed by lower number of CD83+ cells (P < 0.001) in each OCL type. Different from S100+ cells, both CD1a+ and CD207+ cells on the epithelium (P < 0.05) and CD83+ cells on the capsule (P < 0.05) were preferentially observed. In RCs, significant correlation was found between the thickness epithelium with S100+ and CD1a+ cells, and between the degree of inflammation with CD83+ cells., Conclusions: Dendritic cell populations in OCLs can be phenotypically heterogeneous, and it could represent distinct lineages and/or functional stages. It is suggested that besides DC-mediated immune cell interactions, DC-mediated tissue differentiation and maintenance in OCLs should also be considered., (© 2012 John Wiley & Sons A/S.)

Crystal-storing histiocytosis is a rare manifestation of plasma cell dyscrasia/monoclonal gammopathies and lymphoproliferative disorders, characterized by cytoplasmic accumulation of crystallized immunoglobulins in histiocytes. Nevertheless, some reported cases of crystal-storing histiocytosis raise the possibility that this lesion may also be reactive. Crystal-storing histiocytosis in the oral cavity is extremely rare; only one case affecting the tongue has been reported in the English-language literature. In this report, we discuss the case of a 38-year-old man who presented a persistent periapical lesion affecting the maxillary left lateral incisor. Histopathological analysis showed numerous crystal-laden histiocytes associated with a mild plasma cell infiltrate within a fibrous stroma. The plasma cells failed to show clonal light-chain restriction, and the patient had no associated hematologic disorder or systemic disease. Thus, this lesion was probably the result of hypersecretion of immunoglobulins by polyclonal plasma cells found in the periapical lesion. Crystal-storing histiocytosis should be considered in the differential diagnosis of periapical lesions., (Copyright © 2012 Elsevier Inc. All rights reserved.)