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Shaping Ability of Three Different Rotary Nickel Titanium Systems An In Vitro StudyAim: The aim of the study was to compare the changes in transportation and changes in curvature after instrumentation in WaveOne Gold (WOG) system and One Curve (OC) system. Protaper Next (PTN) system was used as reference for comparison.Material and Methods: A Sixty-five human mandibular first molars were selected. Teeth were randomly allocated into three groups (n=15): Group 1: PTN; Group 2: WOG; Group 3: OC. Cone beam computed tomography (CBCT) were taken for all specimens before instrumentation. Pre instrumentation evaluation for angle of curvature was done using Schneider method. Also, transportation was evaluated using Gambill’s method. After instrumentation, radiographs (CBCT) were taken and changes in transportation and curvature were measured using Planmecca Romexis software. One-way ANOVA was used to compare between different groups, followed by Tukey’s Post Hoc test for multiple comparisons.Results: After root canal instrumentation, regarding transportation, Results showed significant difference between all groups at 6mm level as PTN group showed highest transportation (P=0.09). While there’s insignificance between 3mm and 9 mm level. As for changes in curvature, there was insignificant difference between groups (P=0.46).Conclusion: Single file system respected the original canal anatomy compared with multi-sequence file system.

Background: During mechanical preparation of the primary root canal, the original anatomy of the tooth should be preserved and the instrument should be perfectly balanced centrally into the canal space for reducing the probability of canal transportation. The aim of this research was to compare canal transportation and canal centring ability in primary root canals using ProTaper Next (Dentsply Mailfair,), AF baby (Fanta), and Kidzo Elephant (Endostar, Poldent Sp.) files. Materials and methods: Eighteen root canals were randomly divided into 3 experimental groups (n = 6 in each group). Instrumentation was performed using ProTaper Next, Fanta AF baby, and Kidzo Elephant files in groups 1, 2, and 3, respectively. During the instrumentation procedure, the irrigation of 2 mL of 1.5% sodium hypochlorite between each file was done, followed by 5 mL of 17% ethylenediaminetetraacetic acid as a final irrigating solution. Cone-beam computed tomography images were obtained before and after instrumentation. Each group was evaluated for transportation and centring ratios. Results: On comparing all the tested groups within each root canal level canal transportation, the results revealed a statistically nonsignificant difference in the buccolingual direction (P > 0.05). Meanwhile, in the mesiodistal direction, group 1 showed a statistically highly significant difference compared to groups 2 and 3 at the cervical level (P < .01). However, in both middle and apical root canal levels, there was a statistically nonsignificant difference amongst all groups (P > 0.05). Regarding the centring ability comparison of the 3 groups within each root canal level, there was a statistically nonsignificant difference amongst all groups (P > 0.05) in both buccolingual and mesiodistal directions. Conclusions: The ProTaper Next regular rotary file and the paediatric rotary files showed no difference in canal transportation and centring ability in the buccolingual direction, while in the mesiodistal direction at the cervical root canal level, the ProTaper Next showed high transportation liability.

Introduction Sudden fracture of instruments without previous warning signs, which occurs due to cyclic and torsional fatigue, represents the biggest problem and one of the most difficult complications during endodontic therapy. The aim of this research was to check the influence of diameter of the instruments on the appearance of cyclic fatigue in simulated canals in full rotation. Material and Method The study analyzed 24 ProTaper Universal instruments (12 instruments with a diameter of 25 and 12 instruments with a diameter of 30) and 24 ProTaper Next instruments (12 instruments with a diameter of 25 and 12 instruments with a diameter of 30). The instruments were tested in an artificial canal stuffed in a metal block at an angle of 45° and a corner radius of 5 mm. The operating time of each instrument until fracture was measured, and then the number of cycles to fracture (NCF) was calculated. The length of the fractured fragments (FL) was measured with a Vernier caliper. Results The number of cycles to fracture was higher (p < 0.001) in instruments of the ProTaper Universal group of diameter 25 (367.83 ± 17.00) compared to instruments of diameter 30 (329.33 ± 12.86) of the same group. The number of cycles leading to the fracture in instruments of the ProTaper Next group of diameter 25 (1189.33 ± 18.97) was higher (p < 0.001) compared to instruments of the same group of diameter 30 (971.08 ± 15.26). Conclusion Obtained results indicated that with an increase in the diameter of rotating endodontic instruments, there is a decrease in the resistance to cyclic fatigue.

Aim: The aim of this study was to compare and evaluate the severity of PEP using ProTaper Gold (PTG), ProTaper Next (PTN), and F-One rotary files in single-visit endodontic (SVE) treatment. Materials and Methods: In a randomized factorial clinical trial, 150 patients indicated for endodontic treatment in maxillary molars and mandibular molars were selected. They were separated into three groups: Group 1 (PTG), Group 2 (PTN), and Group 3 (F-One). SVE treatment was done under local anesthesia. The intensity of PEP was assessed using the Visual Analog Scale (VAS) after 24, 48, 72 h, and 1 week. Finally, the data were tabulated and statistically analyzed using SPSS software. VAS was analyzed using analysis of variance test with Scheffe's post hoc test. Results: PEP was less in Group 3 (F-One) and Group 2 (PTN) as compared to Group 1 (PTG) at 24.48 h which is statistically significant (P < 0.05), whereas the difference between PTN and F-One was statistically insignificant. Conclusion: All file systems showed PEP, but the intensity of pain was minimum in F-One single rotary file system followed by PTN and PTG Multi-file systems.

Introduction Root canal preparation is one of the most important active phases in the treatment of infected and noninfected teeth. Nickel-titanium (NiTi) instruments are increasingly used in endodontic therapy due to their superior properties compared to those made of stainless steel. The aim of this research was to perform an analysis and comparison of cyclic fatigue in ProTaper Universal and ProTaper Next rotary NiTi instruments in full rotation in simulated canals. Material and methods Twelve ProTaper Next and twelve ProTaper Universal instruments were analyzed in the study. The instruments were tested in an artificial canal stuffed in a metal block at an angle of 45° and a corner radius of 5 mm. The operating time of each instrument until fracture was measured and the number of cycles to fracture (NCF) calculated. Results ProTaper Next instruments showed greater resistance to cyclic fatigue compared to ProTaper Universal. The NCF value was significantly higher in ProTaper Next (1,296.83±20.2) instruments (p

Objectives: This study was aimed to evaluate the cause-effect relationship between canal preparation with ProTaper Next (PTN) and ProTaper Gold (PTG) using optimum torque reverse (OTR) motion or continuous rotation and dentinal crack formation. Materials and Methods: Fifty distobuccal roots of human maxillary first molars were divided into five groups; Group I: PTG Full rotation, Group II: PTG in OTR, Group III: PTN Full rotation, Group IV: PTN in OTR, Group V: unprepared (control group). After mechanical preparation, the distobuccal roots were sectioned horizontally at 3, 6, and 9 mm from the apex. Images were captured using a stereomicroscope at 25X to determine the presence or absence of dentinal cracks. Friedman test was used to compare between root sections followed by Wilcoxon signed-rank test for pairwise comparison. Kruskal–Wallis test was used to compare between tested rotary systems followed by pairwise comparison with Dunn Bonferroni correction (α = 0.05). Results: Crack development was significantly higher in PTG using OTR motion 36.7% followed by PTN using OTR 33.3%, while the control group showed no cracks. PTG and PTN with full rotation showed crack development with 23.3% and 13.3%, respectively. Conclusions: The type of motion kinematics used during mechanical preparation have an impact on dentinal crack formation. Nickel-titanium instruments with larger taper tend to induce more cracks.

Aim: The aim of the study is to evaluate and compare the quantity of apical debris extrusion from the root canals during biomechanical preparation by various rotary (reciprocating, Protaper Next [PTN] continuous) and manual hand filing system and by means of Crown-Down and Step Back techniques. Materials and Methods: Eighty mature, human mandibular premolars with single canals were randomly divided into four groups of twenty teeth each. Each group was instrumented using one of the four instrumentation systems: Group A: WaveOne, Group B: PTN, Group C: Hand file with Crown Down, Group D: Hand file with Step Back. Extruded debris was collected in preweighed Eppendorf tubes and the extruded irrigant was evaporated. The weight of the dry extruded debris was established by comparing the pre and post-instrumentation weight of Eppendorf tubes for each group. Results: Mean comparison of groups in different instrumentation by ANOVA presented that hand file with Step-Back technique is showed maximum amount of apical extrusion debris and continuous rotary file system showed the minimum amount of extrusion debris (P < 0.001). Conclusions: The current ex vivo study demonstrated reciprocating single file WaveOne and continuous rotary multiple file system lead to significantly less debris extrusion than manual hand file techniques. Reciprocating single file WaveOne extruded more debris than continuous rotary PTN multiple file system. More amount of debris was extruded in the group with Step-Back hand filing than Crown-Down technique.

Objectives: The aim of this in vitro study was to investigate the torsional fatigue resistance of different rotary files in straight and curved positions at a simulated intracanal temperature. Methods: Forty-eight size #25 files from ProTaper Universal (PTU), ProTaper Next (PTN) and ProTaper Gold (PTG) were tested for torsional resistance in both straight and curved (90 degrees) positions (n = 8 each). The experiment was conducted at a simulated intracanal temperature of 35 ± 1 °C. The torque gauge was reset before every use, and uniform torsional stress was applied by rotating the file clockwise at a speed of 40 rpm until fracture. Torque failure values were recorded, and fractured surfaces were tested using a scanning electron microscopy (SEM). Statistical analysis of the data was completed using one-way ANOVA and post-hoc test (LSD) in order to compare between the tested systems in each file position. Student’s t-test was also performed to compare between the two positions in each rotary system, and significance level was set at 5%. Results: In the straight position, torsional resistance of PTN was significantly lower than that of PTU and PTG (p 0.05). In the curved position, torsional resistance was found to be comparable among all systems (p > 0.05). Within each system, the curved position resulted in a significantly lower torsional resistance when compared to the straight position (p

Background. This study aimed to compare the cyclic fatigue resistance of ProTaper Next, Hyflex CM, 2Shape, and TF-Adaptive nickel-titanium endodontic file systems with various alloy properties and production methods and investigate the fractured cross-sectional surface of files due to cyclic fatigue by scanning electron microscopy (SEM). Methods. A total of 120 instruments were used (n=30). For standardization, #25/.06 apical diameter and taper angle were selected for each file system. The experiment of files was subjected to a static cyclic fatigue model. The time for files’ failure was recorded with a digital chronometer and multiplied by the rotation speed to calculate the number of cycles. Kolmogorov-Smirnov, one-way ANOVA, and post hoc Bonferroni analysis were used for statistical analysis. Statistical significance was set at P

Background. This study aimed to evaluate the effects of repeated sterilization cycles on the surface alterations of various nickel-titanium instruments, including ProTaper Next (PTN), TF Adaptive (TFA), HyFlex CM (HCM), and 2Shape (2S). Methods. Twenty-four new NiTi files of four different alloys were selected. The instruments in each group were divided into two equal groups, as follows: control and sterilization. The first group was chosen as the control without applying any sterilization procedure, while in group 2, five cycles of sterilization procedures were applied. The surface topographies were evaluated using scanning electron microscope (SEM) and atomic force microscope (AFM). The root mean square (RMS) and maximum height (MH) values and three-dimensional images were recorded. The data were analyzed with the Shapiro-Wilk test, one-way ANOVA, and post hoc Tukey tests. The statistical significance level was set at P≤0.05. Results. Before the experiment, HCM demonstrated the highest RMS value, and 2S showed the lowest. After the procedures, the RMS and MH values deteriorated on the surface of PTX, TFA, and 2S (P0.05). Conclusion. The initial irregularity on the surface did not affect the rate of alteration. The HCM files demonstrated superior surface properties after several cycles of sterilization. The PTN, TFA, and 2S presented similar surface responses after five cycles of autoclave sterilization.

Background. This research aimed to investigate and compare the amount of apically extruded debris after root canal preparation using ProTaper Next, ProTaper Gold, and TruNatomy systems. Methods. Forty-five extracted mandibular premolar teeth with single canals with similar lengths were used. The root canals were prepared using ProTaper Next (Dentsply Maillefer, Ballaigues, Switzerland), ProTaper Gold (Dentsply Maillefer, Ballaigues, Switzerland), or TruNatomy (Dentsply Maillefer, Ballaigues, Switzerland) files. Apically extruded debris during preparation was gathered into preweighed Eppendorf tubes. Then the Eppendorf tubes were incubated at 70°C for five days. The Eppendorf tubes were weighed again to determine their final weight plus the extruded debris. Results. The TRN system resulted in significantly less debris extrusion than the PTN system (P0.05). Conclusion. All the instrumentation systems caused apical extrusion of debris. However, the TRN system resulted in significantly less debris extrusion than the other systems.

Background: During the biomechanical preparation of the root canal by rotary file systems, stress is generated within the canal, which leads to dentinal microcrack formation. Such defects are evaluated only under the microscope. Aim: The present study aimed to evaluate dentinal microcrack formation after instrumentation with ProTaper Next (M-wire), Revo S (conventional NiTi), and WaveOne Gold (Gold-wire) file systems under the stereomicroscope. Materials and Methods: Forty single-rooted teeth free from any defect were selected and divided into four groups (Control, PTN, RS, and WOG). Experimental groups were instrumented with file system used in the study, and the control group were left unprepared. Samples were further decoronated and sectioned at 3 mm, 6 mm, and 9 mm from the apex perpendicular to the long axis and examined under a stereomicroscope at ×25 for different types of microcracks (no fracture, complete fracture, partial fracture, and other fracture). Statistical Analysis Used: Data analysis was done by the Chi-square test using the SPSS version 17.0 software. A two-sided (α = 2) P < 0.05 (P < 0.05) was considered statistically significant. Results: The null hypothesis was rejected. There was a statistically significant difference between the groups. All file systems created microcracks in the root dentin. WOG group showed an incidence of 66.7% for no fracture, PTN group had 40% for other fracture, and RS group had 60% for complete fracture. Conclusion: Single file system WOG with gold wire technology proves to be the best choice for canal preparation among the tested groups in terms of least dentinal crack formation.

Aim: The present study aimed to evaluate and compare the microcrack formation in apical root dentin as a result of root canal preparation with different nickel–titanium (NiTi) rotary systems. Materials and Methods: Sixty extracted mandibular premolar teeth with single canals were used. Apical 1 mm of roots was flattened perpendicular to the tooth axis. Forty-five teeth were prepared using ProTaper Next (PTN), ProTaper Gold (PTG), or TruNatomy files. Fifteen teeth were left unprepared as the negative control group. Images of apical surfaces of roots were obtained using a stereomicroscope at × 20 magnification. The presence of microcracks was noted with the help of the images. The data were analyzed with a Chi-square test using MiniTab 17 Statistical Software. Results: There was a statistically significant difference between the PTN and TruNatomy groups (P < 0.05). There was no statistically significant difference between the PTG group and other groups (P > 0.05). Conclusion: Whereas all rotary files created microcracks in the apical root dentin, TRN caused fewer microcracks than other NiTi rotary systems.

Aim: The aim is to compare the apical extrusion of debris during endodontic instrumentation with continuous rotation and reciprocating motion. Materials and Methods: Sixty extracted single-rooted mandibular premolar human teeth were randomly assigned to four groups of 15 teeth each. The canals were then instrumented with the following instrument systems: ProTaper Next (PTN; Dentsply Maillefer, Ballaigues, Switzerland), 2Shape (TS; MicroMega, Besancon, France), Reciproc Blue (RB; VDW, Munich, Germany) and WaveOne Gold (WOG; Dentsply Sirona, Ballaigues, Switzerland). Apically extruded debris during instrumentation was collected into pre-weighed Eppendorf tubes. The Eppendorf tubes were then stored in an incubator at 70°C for 5 days. The weight of the dry extruded debris was established by subtracting the pre-instrumentation weight from postinstrumentation weight of the Eppendorf tubes. The data were analyzed using one-way analysis of variance and Tukey's Post hoc tests. Results: Among the instruments tested in the present study, the least amount of extrusion of debris was seen with TS rotary file system (Group IA) followed by RB (Group IIA) and WOG (Group IIB) (P < 0.05), the results, however, were not found to be statistically significant between them. The maximum amount of debris extrusion was observed with PTN (Group IB) with a statistically significant difference when compared to TS, RB, and WOG file system (P > 0.05). Conclusion: All instruments were associated with apical extrusion of debris with TS rotary file system associated minimum extrusion and PTN, resulting in maximum extrusion of debris.

Aim: This study aims to evaluate and compare the canal transportation and centering ability of two nickel–titanium file systems, ProTaper Next and WaveOne Gold, in comparison with ProTaper Universal in mesiobuccal canals of maxillary molars using micro-computed tomography. Materials and Methods: Seventy-five permanent maxillary first and second molars having mesiobuccal canals with curvatures between 20° and 30° were selected and subjected to pre-operative micro-computed tomographic scans. They were then divided into three groups (n = 25) based on the file system to be tested: Group 1-ProTaper universal (control), Group 2: ProTaper Next, and Group 3-WaveOne Gold. Access cavities were prepared, following which each specimen was instrumented using the specific file system. Post-instrumentation micro-computed tomographic scans were then carried out for each specimen. Pre- and post-instrumentation measurements of mesiobuccal canals were performed using the ImageJ 1.8.0 software. Canal transportation and centering ratio were calculated at three cross-section levels that corresponded to 3-mm, 6-mm, and 9-mm distance from the apical end of the root. The data obtained were then subjected to statistical analysis using ANOVA and Tukey's post-hoc tests. Results: It was seen that WaveOne Gold caused the least overall canal transportation and exhibited the highest centering ability, followed by ProTaper Next and ProTaper Universal, though the difference was not significant. Furthermore, there was no significant difference between the canal transportation and centering ability of ProTaper Universal, ProTaper Next, and WaveOne Gold at all three levels. Conclusion: None of the systems evaluated exhibited perfect centering ability and zero canal transportation. All file systems caused root canal transportation and minor changes in the root canal anatomy.

Background: Under axial loading, there is stress concentration around the cervical areas especially in the premolars because of their location in the arch. Aim: To evaluate and compare flexural fracture resistance of mandibular premolars after instrumentation with ProTaper®Universal, ProTaper Next®, OneShape®, and WaveOne® endodontic file systems. Methods: Seventy-five mandibular premolar teeth with single straight canals were divided into five different groups (n = 15): Group A: Control, Group B: ProTaper Universal (PTU), Group C: ProTaper Next (PTN), Group D: OneShape, Group E: WaveOne. The teeth were instrumented as per the manufacturer's instructions. After obturation and core placement, the teeth were placed in a customized jig mounted on a universal testing machine where force was applied at 45° on the buccal cusp and the force required to fracture the teeth was noted. Results: Amongst all the instrumented groups, WaveOne showed the highest resistance to fracture (1065.56 ± 175.05) and the control group was 1104.13 ± 188.42. All groups showed a significant difference in the fracture load values with the control group. However, there was a statistically significant (P < 0.05) difference seen with WaveOne vs PTU and WaveOne vs OneShape. Conclusions: Root canals instrumented with reciprocating motion have better flexural fracture resistance than continuous rotary motion. Mandibular premolars when instrumented with ProTaper Universal and OneShape endodontic files showed similar fracture resistance, proving that dentin removal does not depend on the number of files used.

Aim: This study aimed to comparatively evaluate the influence of working length (WL) determined by three different electronic apex locators (EALs) on the apical extrusion of debris following the instrumentation with a rotary NiTi instrumentation system. Methodology: Forty extracted human maxillary or mandibular premolar teeth with single root and canal were selected. Standardized access cavities were prepared, and the samples were divided into four groups according to the method used to determine the WL: Group I (n = 10) – actual working length (AL), Group II (n = 10) – Root ZX mini, Group III (n = 10) – CanalPro™, and Group IV (n = 10) – Propex Pixi™. Each specimen was held in a test apparatus to evaluate the apical extrusion of debris during instrumentation. Instrumentation of all the specimens was done using ProTaper Next till the size X3. The apically extruded debris was collected and calculated by subtracting the initial weight of the tube from the weight of the tube containing dried debris. The apically extruded debris weight score was calculated and tabulated and was subjected to statistical analysis using one-way ANOVA and post hoc Tukey test. Results: Group II and Group III exhibited similar results and exhibited significantly less apical extrusion of debris compared to Groups I and IV. Conclusion: WL determined by EAL (Root ZX mini and CanalPro) showed lesser apical extrusion of debris than AL determination.

Abstract Background The aim of this study is to compare the torsional resistance of the available ProTaper rotary systems, namely, ProTaper Universal (PTU), ProTaper Next (PTN), and ProTaper Gold (PTG). Methods A total of 195 files from the three systems distributed into 13 groups (PTU-S1, PTU-S2, PTU-F1, PTU-F2, PTU-F3, PTG-S1, PTG-S2, PTG-F1, PTG-F2, PTG-F3, PTN-X1, PTN-X2 and PTN-X3) were subjected to torsional fatigue until failure. The torsional test was performed according to ISO 3630-1, where each file was placed in a straight position to eliminate the influence of cyclic fatigue. The Kruskal–Wallis test was conducted to compare the mean maximum torques and angular deflections at fracture for the groups, and the Mann–Whitney test was performed for pairwise comparisons. The significance level was set at 0.05 and the fractured surfaces were examined under a scanning electron microscope. Result Among the tested files, PTG-S1 had the lowest torsional fatigue resistance, whereas PTU-F2 and PTU-F3 had the highest torsional resistance. The scanning electron microscope showed typical features of torsional failure. Conclusion The new ProTaper systems (PTG and PTN) did not show improved torsional resistance in comparison with PTU.

Root canal preparation is an important process in endodontic therapy. Root canals can be shaped in continuous motion by rotary instruments using a crown-down technique and a single length technique (simultaneous technique) as well. Most rotary systems require a crown-down approach to minimize torsional loads and to reduce the risk of instrument fracture. The most known of these are ProTaper Universal and ProTaper Gold (Dentsply Sirona). On the other hand, there are also on the market rotary systems that shape the canal in a single length technique. These are ProTaper Next (Dentsply Sirona) and Mtwo (VDW). These instruments are used without early coronal enlargement and are led up to the working length without apical pressure. This work has the aim to compare the ability of two techniques to prepare uniform tapered the root canals and to maintain the original shape of curved canals during preparation.

PurposeThe purpose of the present study is to assess the rate of newly formed microcrackscomparatively during root canal instrumentation by using ProTaper Next, Reciproc,and Self-Adjusting File systems using micro-computed tomography.Subjects and MethodsThirty mesial roots of mandibular molars were randomly assigned to 3 experimentalgroups (n = 10) as follows, ProTaper Next, Reciproc and Self-Adjusting File system.Preoperative and postoperative scans were obtained at the isotropic resolution of13.68 μm. Cross-section images were examined to identify the presence of newlyformed dentinal microcracks.ResultsThe Self-Adjusting File and Reciproc systems caused a higher rate of new microcrackformation than the ProTaper Next group (p < 0.001). There were also significantdifferences in the new microcrack formation between Reciproc and Self-AdjustingFile groups (p < 0.001).ConclusionReciproc and Self-Adjusting File systems caused a higher rate of newly formedmicrocraks compared to ProTaper Next system.

Context: The presence of smear layer and debris can prevent the irrigant and sealer from penetrating the dentinal tubules thereby compromising the seal of the root canal filling. Aim: This study aims to evaluate the efficacy of XP-endo Finisher with ProTaper Next and HyFlex in smear layer and debris removal. Materials and Methods: Thirty-two extracted mandibular premolar teeth were selected and sectioned at the cementoenamel junction. The roots were then randomly divided into 4 groups. In group 1 and 2, canals were instrumented with X2 ProTaper Next (25 0.06 taper). In group 3 and 4, canals were instrumented with HyFlex system (25 0.06 taper). The canals in group 2 and 4 were further finished with XP-endo Finisher. Irrigation was carried out using 3% sodium hypochlorite during instrumentation, and 17% ethylenediaminetetraacetic acid was used as the final rinse. The roots were then split longitudinally. The canal wall was observed under the scanning electron microscope in coronal, middle, and apical thirds at a magnification of ×400 and ×1000 for evaluation of debris and smear layer, respectively. Photomicrographs were taken, and qualitative assessment for debris and smear layer removal was done. Statistical Analysis Used: The results were analyzed using Kruskal–Wallis test and Mann–Whitney U-test. Results: Lower debris and smear layer scores were seen in canal thirds instrumented with ProTaper Next and XP-endo Finisher (P < 0.01). Conclusion: The use of XP-endo Finisher as an adjuvant during shaping and cleaning produced cleaner root canal walls.

Aim: The aim of this study is to compare canal transportation and centering ratio using of Protaper Next (PTN) (Dentsply Maillefer, Ballaigues, Switzerland) and Revo-S (RS) (MicroMega, Besancon Cedex, France) compared to Protaper Universal (PTU) (Dentsply Maillefer, Ballaigues, Switzerland) nickel-titanium rotary file systems in curved root canals using cone-beam computed tomography. Materials and Methods: Ninety maxillary mesiobuccal first molar uncalcified canals with mature apex, curvature of 20°–45° (the Estrela method) and minimum 20-mm length were selected. The samples were randomly divided into three groups of 30 teeth each, respectively, Group I PTU, Group II PTN, and Group III RS Rotary systems and Instrumented according to the manufacturers' instructions. Pre- and post-instrumentation cone-beam tomographic scan was performed in same position to calculate canal transportation and centering ability at 2 mm, 5 mm, and 8 mm from the root apex. Statistical analysis was performed with ANOVA and Post-hoc Tukey test. Results: PTU had maximum mean canal transportation and minimum mean centering ratio at all levels, whereas PTN showed minimum mean canal transportation and maximum mean centering ratio. The results were statistically significant. Conclusions: In terms of canal transportation and centering ratio in the middle and coronal third of the root, PTN and RS performed better than PTU. However, in apical third, PTN performed best among all other groups.

Purpose The purpose of the present study is to assess the rate of newly formed microcracks comparatively during root canal instrumentation by using ProTaper Next, Reciproc, and Self-Adjusting File systems using micro-computed tomography. Subjects and Methods Thirty mesial roots of mandibular molars were randomly assigned to 3 experimental groups (n = 10) as follows, ProTaper Next, Reciproc and Self-Adjusting File system. Preoperative and postoperative scans were obtained at the isotropic resolution of 13.68 μm. Cross-section images were examined to identify the presence of newly formed dentinal microcracks. Results The Self-Adjusting File and Reciproc systems caused a higher rate of new microcrack formation than the ProTaper Next group (p < 0.001). There were also significant differences in the new microcrack formation between Reciproc and Self-Adjusting File groups (p < 0.001). Conclusion Reciproc and Self-Adjusting File systems caused a higher rate of newly formed microcraks compared to ProTaper Next system.

Resumen Objetivo: Comparar el tiempo empleado por los instrumentos TruNatomy Medium y ProTaper Next X3 para penetrar hasta la longitud de trabajo la masa de obturaciones realizadas con GuttaCore Primary y sellador en conductos curvos simulados. Materiales y métodos: Se prepararon 20 conductos curvos simulados con instrumentos rotatorios WaveOne Gold Primary y se obturaron con GuttaCore Primary y AH Plus. Las muestras fueron divididas en dos grupos de 10 cada uno. Grupo 1: El material de obturación fue penetrado hasta la longitud de trabajo con instrumentos TruNatomy Medium. Grupo 2: El material de obturación fue penetrado hasta la longitud de trabajo con instrumentos ProTaper Next X3. Se registraron los tiempos de penetración requeridos para cada grupo y los valores obtenidos fueron analizados mediante la prueba t de Student. Resultados: Los instrumentos ProTaper Next X3 penetraron la masa del material de obturación más rápidamente que los instrumentos TruNatomy MediumTM. Las diferencias observadas entre ambos instrumentos fueron estadísticamente significativas (P

Resumen Objetivo: Evaluar radiográficamente 162 tratamientos endodónticos realizados ex vivo en premolares inferiores y superiores humanos mediante el empleo del sistema ProTaper Next por parte de alumnos de grado de una cátedra de endodoncia de una universidad argentina. Materiales y métodos: Se evaluaron 162 tratamientos endodónticos realizados ex vivo durante los años 2017, 2018 y 2019 (54 por cohorte) en premolares inferiores y superiores humanos por alumnos de grado de la cátedra de Endodoncia I de la Escuela de Odontología de la Universidad del Salvador / Asociación Odontológica Argentina. Para la instrumentación fue empleado el sistema ProTaper Next. La muestra se tomó de forma aleatoria. En un programa de presentación de computadora se incluyeron las radiografías periapicales pre- y posoperatoria para su evaluación. Un evaluador externo analizó las imágenes radiográficas de los tratamientos y los categorizó como correctos o incorrectos teniendo en cuenta tres requisitos excluyentes: la conformación de la preparación quirúrgica, el límite apical y la homogeneidad de la obturación. Para el análisis estadístico, se utilizó la frecuencia relativa (intervalo de confianza 95%) y la prueba de chi-cuadrado. Resultados: La evaluación radiográfica de los tratamientos endodónticos realizados mostró un número considerable de tratamientos correctos. Los resultados para cada cohorte (años 2017, 2018 y 2019) fueron del 96,3% (87,2-99,5%), el 94,4% (84,6-98,8%) y el 98,2% (90,1-99,9%) respectivamente. El porcentaje global de tratamientos correctos fue del 96,3% (92,1-98,6%). La diferencia entre las cohortes no fue estadísticamente significativa (P>0,05). Conclusión: El empleo del sistema ProTaper Next por parte de estudiantes de grado evaluados mostró resultados radiográficamente satisfactorios en la instrumentación ex vivo de conductos radiculares de premolares inferiores y superiores humanos. Palabras clave: Dientes ex vivo, evaluación radiográfica, ProTaper Next, tratamiento endodóntico. Abstract Aim: To evaluate radiographically, 162 endodontic treatments performed ex vivo by three cohorts of students from a school of dentistry in Argentina, using ProTaper Next rotatory system in mandibular and maxillary human premolars. Materials and methods: 162 mandibular and maxillary human premolars received endodontic treatment by undergraduate students from the Department of Endodontics I of the School of Dentistry USAL/AOA. The treatments were performed ex vivo during the academic years 2017, 2018 and 2019 (54 teeth were chosen for each cohort) using the rotatory system ProTaper Next. The samples were taken randomly. Pre and postoperative radiographs were included in a computer presentation program for its evaluation. An external examiner analysed the radiographic images by the shape of the preparation, the apical limit, and the homogeneity of the obturation, considering the treatments well obturated (correct) or ill obturated (incorrect). To be considered correct the case had to meet all the requirements. The statistic calculations used in this study were: relative frequency (confidence interval 95%) and the chi-square test. Results: The radiographic evaluation showed a considerable number of endodontic treatments correctly done using ProTaper Next system. The percentages for each cohort were 96.3% (87.2-99.5%), 94.4% (84.6-98.8%) y 98.2% (90.1-99.9%) for years 2017, 2018 y 2019 respectively. Global percentage of correctly endodontic treatments was 96.3% (92.1-98.6%). The difference between the cohorts was not statistically significant (P>0.05). Conclusion: The use of ProTaper Next by the dental students evaluated showed satisfactory results in the ex vivo instrumentation of mandibular and maxillary human premolar root canals. Key words: Endodontic treatment, ex vivo teeth, ProTaper Next, radiographic evaluation.

Abstract Background Comparison of the shaping ability of advanced nickel-titanium (Ni-Ti) instruments is of great interest to the field of endodontics. However, the models used to study canal preparation still lack uniformity, relevance to reality and complexity. The aim of this study was thus to compare the shaping abilities of the ProTaper Next (PN) and WaveOne (WO) Ni-Ti instruments in three-dimensional (3D)-printed teeth, which may overcome the present defects of most real teeth and model teeth including 3D S-shaped canals. Methods Six teeth and their corresponding 3D-printed replicas were prepared using the same kind of Ni-Ti instrument. The pre- and post-preparation volumes, surface areas and transportation of the canals were measured to compare the teeth with their replicas. Twenty 3D-printed teeth with S-shaped canals were used to support the preparation study. The S-shaped canals were then scanned to measure their volumes and surface areas. Next, the two kinds of instruments were used to prepare the 3D-printed canals (n = 10 per group). The volume and surface area of the canals, the transportation along the two curvatures and the percentage of unprepared surface area were measured. Micro-CT and VGstudio2.2 (VG2.2) software were used to perform scans and collect data throughout the research. The paired-samples T test and Kruskal-Wallis H test were used for statistical analysis. Results There was no significant difference between the real canals and the printed ones post-preparation (P > .05). The printed S-shaped root canals had a unified shape, with a small standard deviation and range. The WO group had higher mean values for the volume and superficial area measurements compared with the PN group (P .05). PN caused less transportation at the apical curve than WO did (P

Aim: The aim of the study was to evaluate the effect of different irrigation solutions on cyclic fatigue of ProTaper Next (PTN) rotary files. Materials and Methods: A total of 50 files were divided into 5 groups according to the environment in which cyclic fatigue test was carried out as follows: chlorhexidine (CHX) 2%, ethylenediaminetetraacetic acid 17%, saline, sodium hypochlorite 6%, and air (control group). A specially designed testing device was assembled utilizing an artificial canal made of a heat-resistant glass tube. The tube had a 1.2 mm diameter, an angle of curvature of 60°, and a radius of curvature 6 mm. Before each fatigue test, the tube was filled with fresh irrigation solution except air group, which was left dry. The mean number of cycles to failure was counted then fractography and length of broken segment were analyzed after failure. Statistical analyses were performed using one-way ANOVA test. Results: The CHX group was the most resistant to cyclic fatigue compared to all groups (P < 0.05). No significant difference was found between all other solutions or dry group (P > 0.05). Fractographic analysis of all groups showed signs of a fatigue failure. A crack site was seen followed by a striation area leading to a dimples overload area. The length of broken segments was not significantly different among all groups (P = 0.37). Conclusion: Although liquid media may function as lubrication, all irrigants except CHX failed to increase the fatigue life of PTN files when compared to dry conditions.

Background. The aim of this study was to compare the dentinal defects caused by Reciproc, TF Adaptive and ProTaper Next NiTi rotary file systems during the retreatment procedure. Methods. A total of 150 mandibular incisors with straight and single root canals were included in the present study. All the root canals were prepared up to an apical diameter 0.40 mm using stainless steel files. Thirty teeth were randomly stored as the negative control group. A total of 120 specimens were obturated with gutta-percha and AH Plus sealer using vertical compaction technique. Thirty specimens with root canal filling were randomly separated for the only-filled group. Then the teeth were randomly divided into 3 groups; Reciproc, TF Adaptive and ProTaper Next. The retreatment procedure was performed with these NiTi files. Then 150 specimens were cut perpendicular to tooth axis at 3-, 6-, and 9-mm distances from the apex, and examined to determine the presence of any cracks at ×25 under a stereomicroscope. Chi-squared test was used at 5% significance level. Results. All the tested NiTi file systems were found to cause significantly more dentinal defects compared to unprepared and only-filled groups (P0.05). No correlation was found between the slice levels and the dentinal defect distribution (P>0.05). Conclusion. Within the limitations of present study, all the tested NiTi file systems were found to cause significantly more dentinal defects compared to unprepared and only-filled groups.

Purpose: The aim of this study was to compare the cleanliness of root canal walls after retreatment using ProTaper Next (PTN), ProTaper Universal Retreatment (PTR) nickel-titanium (NiTi) systems and Hedström hand files in curved mesial canals of mandibular molar teeth and the time required for gutta-percha and sealer removal. Materials and Methods: Ninety mandibular molar teeth with curved mesial roots were instrumented up to #35.04 with Mtwo NiTi rotary instruments and obturated using the continuous wave of condensation technique. Removal of gutta-percha and sealer was performed using one of the following: PTN and PTR NiTi systems and Hedström hand files. Samples were placed on the VistaScan phosphor plates in the mesio-distal direction and the radiographs were taken. The digital radiographs were analyzed using AutoCAD software. Also, the total time required for gutta-percha removal was calculated by a chronometer. Results: The total retreatment time was significantly shorter in the PTN and PTR groups compared with the manual group (p

Aim: The aim of this study was to compare the canal transportation and canal centering ability in the preparation of curved root canals after instrumentation with V-Taper 2H, ProTaper Next (PN), and Hyflex CM files using cone-beam computed tomography (CBCT). Materials and Methods: Thirty mesiobuccal canals of mandibular molars with an angle of curvature ranging from 20 to 40 were divided according to the instrument used in canal preparation into three groups of ten samples each: V-Taper 2H (Group 1), PN (Group 2), and Hyflex CM (Group 3). The teeth were instrumented according to manufacturer's guidelines up to 30 no. apical preparation. Canals were scanned using a CBCT scanner before and after preparation to evaluate the transportation and centering ratio at 3 mm, 6 mm, and 9 mm from the apex. The amount of transportation and centering ability was assessed. The three groups were statistically compared with analysis of variance and post hoc Tukey test. Results: All instruments maintained the original canal curvature with significant differences between the different files. Data suggested that V-Taper 2H files presented the best outcomes for both the variables evaluated. V-Taper 2H files caused lesser transportation and remained better centered in the canal than PN and Hyflex CM files. However, it was seen that PN caused less transportation in apical level than Hyflex CM. Conclusion: The canal preparation with V-Taper 2H showed lesser transportation and better centering ability than PN and Hyflex CM.

Aim: This study aims to evaluate and compare the incidence of dentinal defects induced by Hand Files, HyFlex CM, ProTaper Next (PTN), and One Shape during canal preparation. Materials and Methods: One hundred and fifty extracted mandibular premolar teeth with single root canal were selected. Specimens were then divided into five groups with thirty specimens each. Group I: Specimens were prepared with hand instruments. Group II: Specimens were prepared with HyFlex CM rotary files (Coltene) using a crown-down technique according to the manufacturer's instructions. Group III: Specimens were prepared with PTN rotary files (Dentsply) using a crown-down technique according to the manufacturer's instructions. Group IV: Specimens were prepared with One Shape Single file rotary system (MicroMega) using a crown-down technique according to the manufacturer's instructions. Group V: Specimens were used as a control and left unprepared. All roots were cut horizontally at 3, 6, and 9 mm from the apex. Sections were then viewed under stereomicroscope and dentinal defects were registered as “no defect,” “fracture,” and “other defects.” Statistical Analysis: Results of the study were subjected to Chi-square test. Results: Results were expressed as the number and percentage of defected, partially defected and roots with no defects in each groups. Conclusion: Hand files and One Shape file system caused less root defects compared to PTN and HyFlex file systems.

Amaç: Tek köklü dişlerden farklı eğe sistemlerini kullanarak kanal içi ilaç olan kalsiyum hidroksit’in (KH) uzaklaştırılmasının değerlendirilmesidir. Gereç ve Yöntemler: Bu çalışmada 30 adet tek köklü çekilmiş insan dişi kullanıldı. Kök kanalları ProTaper F4 eğesine kadar genişletildi. KH patı kök kanallarına çalışma uzunluklarında yerleştirildi. Köklerin koronal kısımlarına pamuk pelet ve geçici bir dolgu maddesi konularak kapatıldı. Daha sonra dişler distile su içinde 37oC’de 7 gün boyunca bekletildi. Sonrasında geçici dolgular kaldırıldı. Kök kanallarındaki KH’ın uzaklaştırılmasında kullanılan yönteme göre örnekler rastgele dört deney grubu (ProTaper Universal F4, ProTaper Next X4, Reciproc 40, WaveOne Large) ve kontrol grubu olmak üzere toplam 5 gruba (n=12) ayrıldı. Kökler bukko-lingual olarak ikiye ayrıldı ve kanal içerisinde kalan artık KH miktarı x 15 büyütmede stereomikroskop altında değerlendirildi. Veriler SPSS programında Cronbach alpha yöntemi ile istatistiksel olarak değerlendirildi. Bulgular: KH’in kök kanallarından tamamen uzaklaştırılamadığı görüldü. Reciproc eğe sistemi ile istatistiksel olarak diğer gruplardan daha fazla KH’i uzaklaştırıldığı belirlendi (P < 0.05). Kontrol grubunda diğer gruplardan daha az KH uzaklaştırılmasına rağmen ProTaper Universal, ProTaper Next ve WaveOne eğe sistemleriyle aralarında istatistiksel olarak anlamlı bir fark görülmedi (P > 0.05). Sonuç: Reciproc eğe sisteminin NaOCl ile birlikte kullanımı kök kanallarından KH’i uzaklaştırmada yalnızca NaOCl kullanımından veya ProTaper Universal, ProTaper Next ve WaveOne eğe sistemlerinden daha etkili olduğu görülmüştür. Ancak, kullanılan tekniklerin hiçbiri kök kanallarından KH’i tamamen uzaklaştıramamaktadır.

مقدمه: تغییر زاویه خمیدگی کانال خصوصا در کانال‏های خمیده جزء اتفاقات مرحله آماده‏سازی می‏باشد. فایل‏های چرخشی نیکل- تیتانیوم که برای آماده‏سازی کانال طراحی و عرضه شده اند، می‏توانند این مشکلات را کمتر کنند. همچنین مساله زمان در درمان ریشه بسیار اهمیت دارد. هدف از مطالعه حاضر مقایسه سه سیستم چرخشی Reciproc، ProTaper و ProTaper Next از لحاظ میزان تغییر زاویه خمیدگی و مدت زمان آماده‏سازی کانال ریشه دندان بود. مواد و روش‏ها: در این مطالعه از 45 بلوک رزینی با انحنای کانال بین 25 تا 35 درجه و طول 15 میلی‏متر استفاده شد. ابتدا از مسیر کانال در تمامی بلوک‏ها با استریو میکروسکوپ تصویر تهیه شد. سپس بلوک‏ها به سه گروه تقسیم شدند و هر گروه با یکی از سیستم‏های Reciproc، ProTaper و ProTaper next آماده‏سازی شدند. سپس تصاویر بعد از آماده‏سازی از تمامی بلوک‏ها تهیه شد و تصاویر قبل و بعد از آماده‏سازی تطابق داده شدند و با استفاده از نرم افزار فتوشاپ میزان تغییر زاویه خمیدگی محاسبه گردید. همچنین زمان فعال آماده‏سازی هر یک از گروه‏ها نیز محاسبه شده و داده‏ها، تست‏های آماری آنالیز واریانس و تعقیبی توکی در سطح معنی‏دار 5 درصد مورد انالیز قرار گرفت. یافته‏ ها: زمان آماده‏سازی با فایل‏های Reciproc با اختلاف معنی‏داری کمتر از دو گروه دیگر بود (034/0=P، 001/0>P). تغییرات زاویه کانال پس از آماده‏سازی در بین سه گروه تفاوت معنی‏داری نداشت. نتیجه گیری: مطابق یافته‏های این مطالعه، هر سه گروه فایل‏های چرخشی نیکل-تیتانیوم زاویه انحنای کانال را به میزان کمی تغییر می‏دهند و وسایل مطمئنی برای آماده‏سازی کانال‏های خمیده هستند. همچنین سیستم Reciproc زمان کمتری از دو گروه دیگر برای آماده‏سازی نیاز دارد که می‏تواند پروسه آماده‏سازی را تسریع کند.