Abstract Introduction The aim of the present study was to evaluate the physicochemical properties of a bioceramic root canal sealer, Endosequence BC Sealer. Radiopacity, pH, release of calcium ions ...(Ca2+ ), and flow were analyzed, and the results were compared with AH Plus cement. Methods Radiopacity and flow were evaluated according to ISO 6876/2001 standards. For the radiopacity analysis, metallic rings with 10-mm diameter and 1-mm thickness were filled with cements. The radiopacity value was determined according to radiographic density (mm Al). The flow test was performed with 0.05 mL of cement placed on a glass plate. A 120-g weight was carefully placed over the cement. The largest and smallest diameters of the disks formed were measured by using a digital caliper. The release of Ca2+ and pH were measured at periods of 3, 24, 72, 168, and 240 hours with spectrophotometer and pH meter, respectively. Data were analyzed by analysis of variance and Tukey test ( P < .05). Results The bioceramic endodontic cement showed radiopacity (3.84 mm Al) significantly lower than that of AH Plus (6.90 mm Al). The pH analysis showed that Endosequence BC Sealer showed pH and release of Ca2+ greater than those of AH Plus ( P < .05) during the experimental periods. The flow test revealed that BC Sealer and AH Plus presented flow of 26.96 mm and 21.17 mm, respectively ( P < .05). Conclusions Endosequence BC Sealer showed radiopacity and flow according to ISO 6876/2001 recommendations. The other physicochemical properties analyzed demonstrated favorable values for a root canal sealer.
Abstract Introduction The objective of this study was to assess the presence of voids in mesial root canals of mandibular molar teeth obturated by using the single-cone (SC) and continuous wave of ...condensation (CWC) obturation techniques, and results were analyzed by using micro–computed tomography. Methods Twenty-four mandibular molars with fully developed roots and mesial root curvature ranging from 25° to 35° were instrumented by using Reciproc R25 files, and then they were obturated by using the SC and CWC techniques. Specimens were scanned before and after obturation for micro–computed tomography analysis (voxel size, 17.42 μm). After volumetric analysis and tridimensional reconstruction of the root canals, data were analyzed by using analysis of variance and the Tukey test. Results No significant differences were observed between the 2 techniques in terms of total percentage volume of voids: CWC = 3.91% ± 0.72%; SC = 6.52% ± 1.16% ( P > .05). Only in the cervical third, CWC showed a significantly lower percentage of voids when compared with SC, namely 2.86% ± 0.94% vs 8.00% ± 1.86%, respectively ( P < .05). Conclusions The percentage volume of voids was similar in the 2 groups and was influenced by the obturation technique only in the cervical third.
Abstract Introduction The aim of the present work was to evaluate the resistance to flexural fatigue of Reciproc R25 nickel-titanium files, 25 mm, used in continuous rotation motion or reciprocation ...motion, in dynamic assays device. Methods Thirty-six Reciproc R25 files were divided into 2 groups (n = 18) according to kinematics applied, continuous rotary (group CR) and reciprocation motion (group RM). The files were submitted to dynamic assays device moved by an electric engine with 300 rpm of speed that permitted the reproduction of pecking motion. The files run on a ring’s groove of temperate steel, simulating instrumentation of a curved root canal with 40° and 5 mm of curvature radius. The fracture of file was detected by sensor of device, and the time was marked. The data were analyzed statistically by Student's t test, with level of significance of 95%. Results The instruments moved by reciprocating movement reached significantly higher numbers of cycles before fracture (mean, 1787.78 cycles) when compared with instruments moved by continuous rotary (mean, 816.39 cycles). Conclusions The results showed that the reciprocation motion improves flexural fatigue resistance in nickel-titanium instrument Reciproc R25 when compared with continuous rotation movement.
The introduction of automated instrumentation in endodontics represented a major advance in progress for this specialty, with improvements in the quality and predictability of root canal preparation ...and a significant reduction in procedural errors. In recent years, endodontic instruments have undergone a series of changes brought about by modifications in design, surface treatments, and thermal treatments. In addition, new movements have also been incorporated to offer greater safety and efficiency, optimizing the properties of the NiTi alloy, especially through eccentric rotary motion. An understanding of the mechanical properties of these new NiTi instruments and their effect on the clinical performance of root canal preparation is essential if dental practitioners are to select the instruments that provide optimal clinical outcomes, especially in curved or flattened canals. The objective of this literature review is to present and discuss the characteristics of the NiTi alloys used in the major instrumentation systems available in the market, as well as the influence of the metallurgical and mechanical properties of NiTi instruments and the movements that drive them, to enable more accurate and predictable planning of root canal preparation.
Abstract Introduction The aim of this study was to compare the efficacy of passive ultrasonic irrigation (PUI) and the EndoVac (EV) System (Discus Dental, Culver City, CA) in hard tissue debris ...removal and its influence on the quality of the root canal filling with the aid of micro–computed tomographic scanner. Methods Twenty-four mandibular molars were subjected to 4 microtomographic scannings (ie, before and after instrumentation, after final irrigation, and after obturation) using the SkyScan 1176 X-ray microtomograph (Bruker microCT, Kontich, Belgium) at a resolution of 17.42 μm. Mesial canals were prepared using R25 Reciproc instruments (VDW GmbH, Munich, Germany) and divided into 2 groups according to the final irrigation method: the PUI group ( n = 12) and the EV group ( n = 12). All specimens were filled with the continuous wave of condensation technique. CTAn and CTvol software (Bruker microCT) were used for volumetric analysis and 3-dimensional model reconstruction of the root canals, hard tissue debris, and the filling material. Data were statistically analyzed using the Student t test. Results Analysis of the micro–computed tomographic scans revealed debris accumulated inside the root canals, occupying an average of 3.4% of the canal's volume. Irrigation with PUI and the EV system reduced the volume of hard tissue debris in 55.55% and 53.65%, respectively, with no statistical difference between them ( P > .05). Also, there was no difference among the groups with regard to the volume of filling material and voids ( P > .05). Conclusions PUI and the EV system were equally efficient in the removal of hard tissue debris and the quality of root canal filling was similar in both groups, with no influence from the irrigation method.
The aim of this study was to evaluate the root canal shaping effect of ProTaper Gold (PTG) versus ProTaper Next (PTN) instrumentation systems, and of a manual #15 K-type file (K15) versus the ...ProGlider (PG) mechanized instrument for glide path creation, in severely curved mesial canals. Twenty-four mandibular molars with two separate mesial canals were anatomically matched using computed tomographic scanning, and then divided into two groups (n=12) according to the glide path instrument used, either K15 or PG. In all teeth, the PTG system was used to prepare the mesiobuccal canal, and the PTN, the mesiolingual canal. The teeth were scanned by computed microtomography, before and after root canal preparation, and the values of the initial volume, final volume, volumetric variation, untouched walls, and canal transportation variables were determined. The data were analyzed using the two-way ANOVA test, and the Tukey test for multiple comparisons. There was no significant difference among the study groups regarding volumetric variation or root canal transportation, either in the cervical, middle or apical thirds, or in the entire root canal (p>0.05). In the apical third, the percentage of untouched walls was significantly higher in groups using K15 than in those using PG (p<0.05), namely 33.144% and 23.285%, respectively, irrespective of the instrumentation system. In the other regions, there was no difference between K15 and PG regarding this variable. It was concluded that PG was associated with a lower rate of untouched walls in the apical region than K15.
Abstract Introduction Cleaning and shaping without making procedural errors have always been a challenge in endodontics, particularly when the root canals are curved. Several rotary instruments have ...been developed to minimize such errors. The purpose of this study was to compare the shaping ability of 2 rotary file systems, BioRace (BR; FKG, La Chaux-de-Fonds, Switzerland) and ProTaper Next (PTN; Dentsply Maillefer, Ballaigues, Switzerland), during the preparation of curved root canals in extracted teeth using micro–computed tomographic imaging. Methods A total of 20 first and second human mandibular molars with 2 separate mesial canals were scanned before and after root canal preparations using the SkyScan 1176 X-ray microtomograph (Bruker microCT, Kontich, Belgium) at a resolution of 17.42 μm. Canals were prepared using the BR and PTN systems. The percentage of dentin removed after preparation, root canal volume increase, untreated canal walls, structure model index, degree of canal transportation, and centering ability were also measured. Results There were no significant differences between the 2 groups in the removed dentin after preparation and determination of the root canal volume, percentage of untreated canal walls, structure model index, degree of canal transportation, and centering ability ( P > .05). Conclusions In conclusion, within the limitations of this ex vivo study, instrumentation of moderately curved mesial roots with 2 independent root canals and foramina using the BR and PTN rotary file systems were equally effective. Both instrumentation systems caused negligible procedural errors with minimal apical transportation.
Abstract Introduction This study compared the combined use of sodium hypochlorite (NaOCl) and chlorhexidine (CXH) with citric acid and CXH on dentinal permeability and precipitate formation. Methods ...Thirty-four upper anterior teeth were prepared by rotary instrumentation and NaOCl. The root canal surfaces were conditioned for smear layer removal using 15% citric acid solution under ultrasonic activation and a final wash with distilled water. All teeth were dried, and 30 specimens were randomly divided into three equal groups as follows: positive control group (PC), no irrigation; 15% citric acid + 2% CHX group (CA + CHX); and 1% NaOCl + 2% CHX group (NaOCl + CHX). All roots were immersed in a 0.2% Rhodamine B solution for 24 hours. One-millimeter-thick slices from the cementum-enamel junction were scanned at 400 dpi and analyzed using the software ImageLab (LIDO-USP, Sao Paulo, Brazil) for the assessment of leakage in percentage. For scanning electron microscopy analysis, four teeth, irrigated for NaOCl + CHX samples, were split in half, and each third was evaluated at 1,000× and 5,000× (at the precipitate). Results Using the analysis of variance test followed by the Bonferroni comparison method, no statistical differences between groups were found when analyzed at the cervical and medium thirds. At the apical third, differences between the PC and NaOCl + CHX ( p < 0.05) and CA + CHX and NaOCl + CHX could be seen ( p < 0.05). Conclusion The combination of 1% NaOCl and 2% CHX solutions results in the formation of a flocculate precipitate that acts as a chemical smear layer reducing the dentinal permeability in the apical third.
This study evaluated the apical sealing ability and bioactivity of an experimental gutta-percha containing niobium phosphate bioglass. Thirty-six human premolars were endodontically prepared and ...divided into three groups: GPC-filling with conventional gutta-percha; GBC-filling with bioceramic gutta-percha (EndoSequence BC); GNB-filling with experimental gutta-percha containing niobophosphate. Teeth were stored in tubes containing 2 mL of simulated body fluid (SBF) solution in an oven for 30 days. Then, the samples were immersed in lanthanum nitrate solution and analyzed for apical nanoleakage (NI) with a scanning electron microscope (SEM/EDS) and transmission electron microscope (TEM). Gutta-percha specimens were immersed for 28 days (SBF) and analyzed in SEM/EDS and X-ray diffraction (XRD) to assess bioactivity. NI data originated from the SEM/EDS were analyzed using the Kruskal-Wallis test (α = 5%). NI data originated from TEM and bioactivity were descriptively reported. Statistical analysis did not detect a significant difference between groups (
= 0.13) for NI. In the bioactivity analysis, an abundant layer of hydroxyapatite was identified only in the surface of the GNB group samples. The gutta-percha containing niobophosphate bioglass promoted an apical sealing similar to EndoSequence BC, in addition to demonstrating bioactivity through the deposition of hydroxyapatite on the surface of the material after immersion in SBF.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
Abstract Introduction This study aimed to compare, using digital subtraction radiography, apical transportation in mesiobuccal root canals of extracted human maxillary molars instrumented with ...ProTaper Universal F3 and F4 files (Dentsply Maillefer, Ballaigues, Switzerland) with and without the prior creation of glide paths using the PathFile system and to compare, using cone-beam computed tomographic imaging, remaining dentin thickness (RDT) after complete preparation. Methods Forty mesiobuccal roots with curvatures of 20°–35° were used. In group A, glide paths were created with PathFile #1, #2, and #3 to the working length; in group B, no glide paths were used. All canals were instrumented up to F4 to the working length. Digital subtraction radiographic images were obtained in buccolingual and mesiodistal directions. Apical transportation associated with F3 or F4 was calculated based on the difference between the tip of the first and the last instrument analyzed in each group. RDT was calculated based on cone-beam computed tomographic images. Results Apical transportation was higher after F4 regardless of the use of the PathFile system. No statistically significant differences between groups A and B were observed in apical transportation after instrumentation with F3 or F4 ( P > .05). Group A showed greater RDT values at 2 (buccal and mesial walls, P < .05) and 3 mm (buccal and distal walls, P < .05) from the apex but not at 1 mm. Conclusions The use of the PathFile system before root canal preparation with ProTaper Universal F3 and F4 did not influence apical transportation but was associated with greater RDTs at 2 and 3 mm from the apex.
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