Rotary Endodontic Files Research Articles

Assessing Dentinal Microcracks using Micro-CT after Root Canal Preparation with Different Rotary Endodontic File Systems

ABSTRACT Objective: This study aimed to evaluate the propagation of dentinal microcracks in the mesiobuccal (MB) and mesiolingual (ML) canals following root canal preparation using two different rotary endodontic file systems, TruNatomy (continuous rotation) and MicroMega ONE RECI (reciprocating motion), using micro-computed tomography (micro-CT). Materials and Methods: Fifty freshly extracted human mandibular first and second molars were selected based on specific inclusion criteria. Root canal preparation was confined to the MB and ML canals in mesial roots of mandibular molars (Vertucci Type IV canal configurations) using TruNatomy and MicroMega ONE RECI systems. Pre- and post- preparation scans were taken for all the specimens using micro-CT to identify and measure dentinal microcracks. Statistical analysis was performed using a t-test and Fisher’s exact test, with significance set at P < 0.05. Results: The results indicated no statistically significant differences between the two systems in terms of microcrack formation or propagation. In the ML canal, 8.0% of teeth prepared with TruNatomy and 12.0% with MicroMega ONE RECI exhibited microcracks (P = 0.643). In the MB canal, microcracks were found in 12.0% of the TruNatomy group and 8.0% of the MicroMega ONE RECI group (P = 0.643). Both systems showed a significant increase in canal volume, but no significant differences between the instruments (P < 0.001). Conclusion: Both TruNatomy and MicroMega ONE RECI demonstrated similar outcomes regarding dentinal microcrack formation and propagation in the MB and ML canals, with no significant differences. Both systems were effective in enlarging the canals while preserving the natural canal anatomy. These findings suggest that the choice of instrumentation system can be guided by clinical ease and efficiency as both systems offer comparable mechanical effects on dentin integrity during root canal preparation.

Effect of Cross-sectional Designs on Torsional Resistance of Endodontic Nickel-Titanium Files: A Finite Element Study.

This study aimed to assess the influence of two key design parameters on the torsional resistance of endodontic rotary files: the ratio of the equivalent radius (re ) to the polar moment of inertia (J), or re /J ratio, and the percentage of the inner core area. Understanding these factors can guide the development of files with improved performance during root canal procedures. Finite element analysis was employed to simulate the behavior of rotary files under torsional loading conditions. This method allowed for the investigation of maximum shear stress across various cross-sections (D4-D16) of the files. The relationship between the re /J ratio and the maximum shear stress was also evaluated. To assess the impact of cross-sectional design modifications on stress distribution, the study analyzed files with progressively changing configurations. Regions situated outside the inner core circle experienced lower shear stress compared with a circular shaft. Furthermore, a strong linear correlation was observed between the maximum shear stress experienced by the file, the applied torque during operation, and the re /J ratio. Significantly, the study established a connection between the percentage of the inner core area and the torsional resistance of the file. Files with a larger inner core area exhibited a lower coefficient (C) within a newly derived torsional formula. This lower C value directly translated to a reduction in the maximum shear stress experienced by the file. In essence, files with a higher percentage of inner core area demonstrated enhanced torsional resistance, allowing them to withstand higher torsional loads encountered during root canal procedures. This study identified the re /J ratio and the percentage of inner core area as the most critical design factors influencing the torsional resistance of rotary files. Files with a lower re /J ratio and a larger inner core area experienced lower shear stress, resulting in enhanced torsional resistance and potentially reducing the risk of torsional fracture during use. These findings offer valuable insights for both clinicians selecting rotary files and manufacturers designing future iterations, ultimately contributing to improved safety and efficacy during root canal treatments.

In Vitro Research Methods Used to Evaluate Shaping Ability of Rotary Endodontic Files-A Literature Review.

In this article, we present a literature review of methods used to measure the shaping ability of endodontic rotary files, including the selection of endodontic sample type (extracted teeth versus simulated blocks) and an imaging evaluation method. This review was conducted as background research to identify concerns that arise when designing research studies in this domain and propose how the field can plan more systematic studies going forward. A literature search was conducted using PubMed, MEDLINE, Embase, ScienceDirect, Scopus, and e B-on databases, including studies published in English from January 2010 to June 2024. Only studies that specified in vitro or ex vivo methods for evaluating the endodontic performance of NiTi rotary files on canal transportation and centering ability were considered. A total of 86 studies met the inclusion criteria from an initial pool of 651. Of these, 67 studies used extracted teeth, while 20 utilized simulated root canals in resin blocks. For evaluation methods, 55 studies employed Micro-Computed Tomography and Cone-Beam Computed Tomography (MCT + CBCT), 30 used Double Digital Images/Radiographs/Photographs (DDIR + DDIP) with software analysis, 1 used both DDIR and MCT, 1 used high-precision nano-CT, and 1 used a digital single-lens reflex (DSLR) camera. The findings indicate that the MCT method and its advanced variations appear superior in many cases for evaluating the quality of root canal instrumentation due to their ability to provide detailed three-dimensional images. We also discuss the pros and cons of other evaluation methods, including CBCT and DDIR. Finally, we identify important factors to consider for optimizing future cross-study comparisons. This work highlights the importance of being familiar with shaping ability assessment methods as new instruments are introduced to the market.

Influence of Torque on Cutting Efficiency of Heat Treated NiTi Alloy Endodontic Rotary Files

Influence of Torque on Cutting Efficiency of Heat Treated NiTi Alloy Endodontic Rotary Files

Comparative evaluation of pediatric endodontic rotary file systems to bending and torsion tests: A finite element analysis

Background and objectiveThe introduction of Paediatric NiTi instruments has transformed the field of paediatric endodontics. However, no studies are available on the mechanical behaviour of these files, wherein Finite Element Analysis (FEA) was found to play a major role. The objective of this study is to evaluate the mechanical behavior of three commercially available pediatric endodontic rotary file systems to bending and torsion stress analysis test through Finite Element Analysis (FEA). MethodsA Finite Element Analysis study was performed on three commercially available pediatric endodontic rotary files (Pro AF baby, Kedo SG and Neoendo pedoflex) available for cleaning and shaping the narrow root canals of the deciduous teeth to bending and torsion tests with the boundary conditions according to ISO 3630-1 specifications. ResultsIn the bending analysis, Pro AF baby files were found to withstand the complete bending tests without yielding with a maximum von Mises stress of 1366 MPa, and Kedo SG, Neoendo Pedoflex file exhibited maximum von Mises stress of 2296 MPa, 1971 MPa. Under torsion tests Kedo SG exhibited maximum stress distribution, while Neoendo Pedoflex and Pro AF baby files exhibited similar stress distribution. ConclusionPro AF baby file effectively withstood the rigorous 45 -degree bending examination without experiencing yielding, while Kedo SG file exhibited higher flexibility. Under torsional resistance test, all the three instruments exhibited similar stress distribution under the yield limit. In summary, the mechanical behaviour (bending and torsion) of pediatric rotary file systems were influenced by design of the files.

Effect of repetitive up-and-down movements on torque/force generation, surface defects and shaping ability of nickel-titanium rotary instruments: an ex vivo study

BackgroundThe screw-in effect is a tendency of a nickel-titanium (NiTi) rotary endodontic file to be pulled into the canal, which can result in a sudden increase in stress leading to instrument fracture, and over-instrumentation beyond the apex. To reduce screw-in force, repeated up-and-down movements are recommended to distribute flexural stress during instrumentation, especially in curved and constricted canals. However, there is no consensus on the optimal number of repetitions. Therefore, this study aimed to examine how repeated up-and-down movements at the working length affect torque/force generation, surface defects, and canal shaping ability of JIZAI and TruNatomy instruments.MethodsAn original automated root canal instrumentation device was used to prepare canals and to record torque/force changes. The mesial roots of human mandibular molars with approximately 30˚ of canal curvature were selected through geometric matching using micro-computed tomography. The samples were divided into three groups according to the number of up-and-down movements at the working length (1, 3, and 6 times; n = 24 each) and subdivided according to the instruments: JIZAI (#13/0.04 taper, #25/0.04 taper, and #35/0.04 taper) or TruNatomy (#17/0.02 taper, #26/0.04 taper, and #36/0.03 tape) (n = 12 each). The design, surface defects, phase transformation temperatures, nickel-titanium ratios, torque, force, shaping ability, and surface deformation were evaluated. Data were analyzed with the Kruskal-Wallis and Dunn’s tests (α = 0.05).ResultsThe instruments had different designs and phase transformation temperatures. The 3 and 6 up-and-down movements resulted in a smaller upward force compared to 1 movement (p < 0.05). TruNatomy generated significantly less maximum torque, force, and surface wear than JIZAI (p < 0.05). However, TruNatomy exhibited a larger canal deviation (p < 0.05). No statistical differences in shaping ability were detected between different up-and-down movements.ConclusionsUnder laboratory conditions with JIZAI and TruNatomy, a single up-and-down movement at the working length increased the screw-in force of subsequent instruments in severely curved canals in the single-length instrumentation technique. A single up-and-down movement generated more surface defects on the file when using JIZAI. TruNatomy resulted in less stress generation during instrumentation, while JIZAI better maintained the curvature of root canals.

Comparing the impact of various sterilization methods on the cyclic fatigue resistance, bending strength, and torsional fatigue properties of NiTi rotary files

This study aimed to evaluate the influence of various sterilization techniques on the cyclic fatigue resistance, bending strength, and torsional fatigue resistance of Tornado Blue and Race Evo rotary endodontic file systems. Both the file systems underwent a series of 15 cycles of sterilization according to the following study groups: control group (G1; i.e., without treatment), chemical sterilization with 5.25% sodium hypochlorite (G2), dry heat sterilization (G3), glass beads sterilization (G4), and steam autoclaving (G5). Each group consisted of 8 samples (n = 8/group). Statistical analysis was performed using a two-way ANOVA and Tukey’s tests (p ≤ 0.05). Mean values for the number of cycles between both files were 1291 ± 52.79 rpm and 2095 ± 52.91 rpm for Tornado Blue and Race Evo, respectively. The torsional fatigue resistance was 8.00 ± 0.85 NCF and 10.70 ± 0.85 NCF and the bending strength was 486.94 ± 20.97 gf and 564.17 ± 20.97 gf for Tornado Blue and Race Evo, respectively. The results showed no significant difference in the mechanical properties followed by different sterilization protocols. However, a significant difference was observed in tested properties between the two file systems (p ≤ 0.05). The outcome is reassuring for clinicians that the essential process of routine sterilization at clinics seems safe with regards to mechanical integrity of the endodontic files.

Electrochemical Properties of Nickel-Titanium Rotary Endodontic Instruments

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

In Vitro Comparison of Cyclic Fatigue Resistance of ProTaper Next and TruNatomy Endodontic Rotary Files.

The purpose of this comparative in vitro study was to investigate the cyclic fatigue resistance (CFR) of two different rotary endodontic file systems, namely, TruNatomy and ProTaper Next filing systems. A stainless steel artificial canal with a 60° curvature angle and a 5 mm radius of curvature was used to simulate clinical settings to carry out the test. Twenty ProTaper Next X2 files and 20 TruNatomy Prime files were used to run a total of forty instruments until a fracture occurred, and the amount of time it took for the fracture to occur was taken into account. The files were driven by an endodontic motor set when the settings were adjusted according to the manufacturer's recommendations. A digital meter was employed to record the duration until fracture occurrence, thus ensuring precision. The TruNatomy files had a larger mean cycle fatigue life, which indicates that they have a higher resistance. Given the constraints of this in vitro testing, the CFR of TruNatomy files was found to be significantly higher than that of ProTaper Next files.

Optimization of difficult endodontic treatment with nickel-titanium files in martensitic and austenitic phase

INTRODUCTION. Nickel-titanium alloys and cutting-edge design of endodontic files continue to revolutionize. In addition to variations in the design of nickel-titanium files, manufacturers have implemented several proprietary manufacturing processing procedures to improve their mechanical properties.AIM. The aim of the study was to improve the quality of mechanical instrumentation of highly curved root canals based on the data of laboratory and experimental analysis of rotary endodontic instruments made of nickel-titanium alloys of various modifications.MATERIAL AND METHODS. As part of the research, the following endodontic rotary files systems were studied during instrumentation of curved root canals: group 1 – Mtwo (VDW); group 2 – Race Evo (FKG), group 3 – Ultrataper next (Eurofile). A metallographic analysis of the instruments was performed, a morphological structure of the root dentin after instrumental was examined by scanning electron microscopy, as well as the amount of extruded debris was studied.RESULTS. Groups 2 and 3 showed significant deterioration after three applications. Mtwo files showed a statistically higher amount of surface damage after five uses (p &lt; 0.05). The smallest amount of extruded debris was found in the group 2, while the largest number of root dentin irregulations was found in the groups 1 and 3 (p &lt; 0.001).CONCLUSIONS. A different degree of the surface damage of the instruments was revealed, depending on the number of treated root canals. The safest and most effective endodontic system for the mechanical preparation of curved root canals is the Race EVO.

Evaluation of cyclic fatigue behavior of RACE EVO rotary Files: In-vitro comparative study

IntroductionComparative evaluation of the newly introduced; RACE EVO file system to the currently well-performing file systems like HyFlex EDM OneFile, Vortex Blue, ProTaper Gold (PTG) with regards to the cyclic fatigue resistance. Materials&Methods.The endodontic rotary files under evaluation were segregated into four groups as follows:; RACE EVO, PTG, Vortex Blue, and HyFlex EDM OneFile. A detailed physical analysis of the cyclic fatigue resistance was performed in 15 files of each type (n = 60). Under the test conditions of 37 °C the test samples were subjected to continuous motion at the manufacturer recommended speed within an artificial curved canal until it fractured. For all the test samples, with the recording of time of fracture, calculation was done for number of cycles to fracture (NCF). In addition, the length of the fractured segment was determined. The fractured surface was further evaluated with scanning electron microscopic (SEM) images. ResultsHighest significance for NCF was seen in HyFlex EDM OneFile followed by the Vortex Blue, PTG, and; RACE EVO (p < 0.05) by analyzing the data statistically. Significant differences among the lengths of the fractured segments were evident among tested files, ranging between 4.73 and 6.3 mm (p < 0.05) with HyFlex EDM OneFile uniquely differentiating from the others showing the fracture at 6.3 mm. The common features of cyclic fatigue failure was further substantiated by SEM images. ConclusionsCompared to the HyFlex EDM OneFile, Vortex Blue, and PTG files; RACE EVO demonstrated significantly lower resistance to cyclic fatigue.

Local Elements Content on Working Surfaces of Five Different New Ni-Ti Rotary Endodontic Files: SEM-EDS Study

Objective: To assess diversity of local elements content within working surfaces of five different new Ni-Ti rotary endodontic files.&#x0D; Methods: Energy dispersive spectrometry (EDS) for local elements content analysis was held within three specific areas of working surfaces of the files identified over received SEM images: 1) with pronounced visible signs of impurities; 2) with slightly visible signs of impurities; 3) with no visible signs of impurities. EDS procedure was provided with the use of EDS-detector. Local elements content data at the three above-mentioned specific areas of files’ working surfaces was presented in means of weight percent (wt%), normalized to 100%, and was automatically calculated by the SEM-EDS software.&#x0D; Results: Expressiveness of visible signs of impurities present over working surfaces of the files demonstrated correlation with nickel (r=-0.62, p &lt; 0.05) and titanium (r=-0.49, p &lt; 0.05) content at analyzed areas, while also with carbon (r=0.57, p &lt; 0.05) and oxygen (r=0.50, p &lt; 0.05) content at analyzed areas. Odds ratio for possibility to register traces of one of the following elements N, Na, Mg, Al, Si, S, Cl, Cr, Fe, Ca at the working surface of endodontic file under condition of present pronounced visible signs of impurities was found to be at the level of OR=12.5 (95% CI: 1.08; 143.44; p=0.04).&#x0D; Conclusions: None of the analyzed files was free of impurities over their working surface. Carbon, oxygen, nickel, and titanium were the most prevalent elements observed along working surfaces of five new different endodontic files, while some instruments were characterized with the presence of tungsten, silicon, aurum, iron, chromium, magnesium and nitrogen, maximum level of which at selected areas with pronounced visible signs of impurities outreach 10% weight percent values.

Comparative Evaluation of Single Rotary File System and Sequential Multi-file Rotary Systems on Time for Biomechanical Preparation and Obturation Quality in Single-visit Pulpectomy Protocol: A Double-blind Randomized Clinical Trial.

Single-visit pulpectomy (SVP) protocol with rotary files is highly recommended for the treatment of teeth with irreversible pulpitis. Various rotary endodontic files specially designed for use in the pediatric population are available. The aim is to clinically assess the parameters related to the time required for biomechanical preparation (TBMP) and quality of filling using a single file system vs a sequential multi-file system in infected primary mandibular molars. A total of 45 infected primary molars were allocated to three groups (two experimental groups (n = 15) and a control group. The first experimental group was instrumented using NiTi K-Flex files, the second group with a single file rotary system with variably variable (VV) taper, and the third with a sequential multi-file system with constant taper. Biomechanical preparation time was recorded and standardized digital radiograph (RVG) were taken pre- and postinstrumentation. The data recorded was sent for statistical analysis. There is a substantial reduction of TBMP in primary molars using single file VV taper and multi-sequential file constant taper. Obturation time for all three file systems was comparable and there were no differences between the three file systems used (p > 0.05). Multi-sequential file constant taper files showed a higher probability of optimal obturations and minimal voids followed by NiTi "K-Flex" files and single file system but the difference was nonsignificant (p > 0.05). However, using a rotary in primary teeth results in better canal shape, and less TBMP leading to a better quality of treatment in less time. Shetty B, Singh R, Patil V, et al. Comparative Evaluation of Single Rotary File System and Sequential Multi-file Rotary Systems on Time for Biomechanical Preparation and Obturation Quality in Single-visit Pulpectomy Protocol: A Double-blind Randomized Clinical Trial. Int J Clin Pediatr Dent 2023;16(S-3):S247-S252.

A new method to measure the mechanical properties of rotary endodontic Ni-Ti files: Measurement of 6-axis force/torque and automatic root canal preparation.

The purpose of this study was to develop a new instrument to measure the mechanical properties of rotary endodontic Ni-Ti files (ProTaper Gold F2, ProTaper Ultimate F2, and HyFlex EDM Onefile), and to evaluate the overall utility of the device. The instrument was capable of analyzing the 6-axis force/torque generated by the files during cyclic dynamic movement in a metal curved artificial root canal, and doing automatic cyclic dynamic filing in a resin root canal with a preset vertical force limit by adopting a negative feedback mechanism. By analyzing the 6-axis force/torque, we were able to estimate the position and contact points of the files in the curved root canal. ProTaper Gold showed the highest force/torque in all directions. HyFlex EDM had the highest hysteresis ratio, centering ratio value and NCF (number of cycles to fatigue fracture), while the lowest vertical force.

Comparative Evaluation of Stress Distribution Against the Root Canal Wall at Three Different Levels by Using TruNatomy, XP-endo Shaper, F360, and 2Shape Files-A Finite Element Analysis.

The aim of this in vitro study was to assess the stress distribution of novel endodontic rotary files of different cross sections and metallurgy against the root canal wall at three different levels by using finite element analysis. A total of 60 novel NiTi rotary files were included in this study after being scanned for any surface deformities using a scanning electron microscope. The scanned files were assigned into 4 groups of 15 samples each based on their metallurgy and design: Group A-TruNatomy, Group B-XP-endo Shaper, Group C-F360, and Group D-2shape files. ANSYS® 15 Workbench finite element software (Canonsburg, Pennsylvania, United States) was used to numerically analyse the stress created by computer-aided models of these instruments on the dentinal wall of a simulated root canal to test the mechanical behaviour of these files. All data were analysed using one-way ANOVA with post hoc Tukey analysis, the Shapiro Wilk test, and Levene's test. The significance level was set at 5%. XP-endo Shaper files employed minimal stress on the surface of dentine during instrumentation, and F360 files exerted maximum stress on the dentinal wall. However, no statistically significant difference was found among the groups in relation to the amount of stress produced at the distinct levels of the root canal wall (p>0.05). There was no discernible difference in stress generation among the four groups in the current investigation. Therefore, it can be inferred that the upgrade in design and metallurgy of rotary files has the potential to downgrade the stress during the shaping of the canal and the menace of instrument breakage during their clinical usage.

Comparative evaluation of stress distribution against the root canal wall at three different levels using novel NiTi rotary files - A finite element analysis.

Recent innovations in the physical and mechanical features of endodontic file systems have diminished the prospect of stress generation and fracture risk in novel endodontic files. The purpose of this research was to comparatively evaluate the stress distribution of recently introduced endodontic rotary files with distinct features and metallurgy at three different levels of the root canal wall by finite element analysis. Forty endodontic files were used in this experiment after being inspected through a scanning electron microscope for any surface deformities. Based on their metallurgy and design, the scanned files were divided into four groups, each with 10 samples: Group A-2Shape files, Group B-F360, Group C-One Curve, and Group D-TruNatomy. To assess the mechanical behavior of these files, the stress produced by computer-aided models of these instruments on the dentinal wall of a simulated root canal was numerically analyzed using ANSYS® 15 Workbench finite element software. A one-way ANOVA was used to assess all the raw data with post hoc Tukey analysis, the Shapiro-Wilk test, and Levene's test. F360 files exerted the maximum stress on the dentinal wall, while TruNatomy files exerted the least stress at all the distinct levels of dentinal walls. There was no statistically significant variation in the stress generated between the four groups. Therefore, it can be concluded that improvements in rotary file design and metallurgy have the potential to reduce the stress during canal shaping and the risk of instrument breakage during clinical use.

Evaluation of the stress generated during biomechanical preparation with nickel–titanium rotary endodontic file using finite element analysis

Introduction: Adequate biomechanical preparation of root canals is the essence of successful endodontic therapy. Roots with curved canal framework led to endodontic complexity. The hassles in the preparation of such complex canals have prompted the inauguration of nickel–titanium (Ni-Ti) instruments with properties of shape memory and superelasticity. They benefit root canal preparation with causing less aberration, yet intracanal separation due to fatigue remains a concern. The study was intended to evaluate and compare the stresses developed during biomechanical preparation with Ni-Ti rotary file in straight, moderate, and severely curved root canals using finite element analysis (FEA). Materials and Methods: Six real sizes, three-dimensional root models were designed in SolidWorks software with varying angles of curvature (2°–45°), and using the same software, ProTaper Gold F2 rotary file was developed. All the designed root models with the rotary file inserted into each model were subjected to FEA. ANSYS Software (version 17.2 Company, Commonwealth of Pennsylvania, USA) 2015 was used to simulating root canal shaping, and the stresses generated in all the root canal models were observed. Results: Highest mean stress was observed with 45° models which was 235.95 MPa, followed by a 30° simulated model showed 220.36 MPa and least stress of 125.22 MPa was observed with 2° models (P &gt; 0.05). Conclusions: Increased canal curvature has definitely resulted in generation of more amount of stress.

Comparative assessment of cleaning efficacy of two exclusive paediatric rotary files in root canals of primary teeth: An invitro study.

Paediatric rotary file systems have recently been developed for primary teeth use. To study the cleaning efficacies of two paediatric rotary endodontic files, the Prime PedoTM , and the Kedo-SG BlueTM against the standard H files. This invitro study included 54 freshly extracted primary molars, which were randomised into three groups (n = 18 each) and were prepared using either Kedo-SG BlueTM , Prime PedoTM or hand H files after injecting methylene blue dye into the canals. Pre- and post-operative cone beam computerised tomography (CBCT) was performed to assess change in root canal volumes. Methylene blue dye removal from canals was assessed using stereomicroscopy, and canal cleanliness was examined by scanning electron microscopy (SEM). Both Prime PedoTM and Kedo-SG BlueTM files reduced significantly less dentine when compared with conventional hand filing with Prime PedoTM removing the least amount of dentine. No significant difference was found in median SEM scores among the groups in the cervical, middle and apical thirds of the roots. Stereomicroscopic assessment of root canal cleanliness using dye removal technique shows a statistically significant difference existing between Kedo-SG BlueTM and hand H files groups. Prime PedoTM removed the least amount of dentine. Kedo-SG BlueTM performed significantly better than conventional hand filing with H files when the root canal cleanliness was assessed.

Comparative Evaluation of the Shaping Ability of the Recent, Fifth-generation ProTaper Next and Revo-S NiTi Rotary Endodontic Files Using Three-dimensional Imaging: An Imaging-based Study

Abstract Aim: The aim of the present study was to assess the shaping ability of the recent, fifth-generation ProTaper Next and Revo-S NiTi rotary endodontic files using three-dimensional imaging. Materials and Methods: For the present in vitro study, 100 freshly extracted mandibular first molars indicated for extraction due to periodontal reasons were collected, while samples were cleaned and the angle of curvature was determined using Weine’s method. The access cavity was prepared using Endo Access Kit, while samples were divided into four groups to be prepared by ProTaper Next and Revo-S rotary endodontic files with or without using Glide path. The canal preparations were done in conjunction with Endo Prep RC, while the shaping ability of the instruments was assessed on the basis of canal transportation and canal-centering ability as assessed from pre- and postoperative cone-beam computed tomography images acquired before and after instrumentation. Statistical analysis was done using the Statistical Package for the Social Sciences (SPSS) version 16.0 (SPSS Inc., Chicago, IL, USA). Kruskal–Wallis H-test was used to compare canal transportation and canal-centering ability of the two file systems among different groups. P &lt;0.05 was considered statistically significant. Results: Revo-S files when used with Glide path performed best at 2 mm distance from the apical portion of teeth with zero apical transportation in case of both mesiobuccal (MB) and mesiolingual canals. Furthermore, ProTaper Next files when used with or without Glide path showed higher canal-centering ability as compared to Revo-S files with the mean value being 0.83 ± 0.29 mm in either case when observed at 2 mm distance from the apical portion of teeth in case of MB canals. Conclusions: Within the limitations of the present study, the findings obtained in the study suggested that ProTaper Next files had optimal canal-centering ability within the canal as compared to Revo-S files.

Comparing the Incidence of Dental Defects in Oval Root Canals Prepared with Two Distinct Endodontic Rotary Files: An In Vitro Study

Objective: The purpose of this work is to compare the incidence of dentinal defects in oval root canals with two different file systems and examine and contrast the creation of dentinal cracks using a scanning electron microscope (SEM) and a stereomicroscope during the root canal preparation process. Material and Method: Three groups of 15 were created from the sixty extracted human mandibular premolars: two were experimental and one was control. The experimental groups underwent root canal therapy. Group I the control group, did not receive any preparations. Group II is the Waldent walflex file and group III is the Trunatomy (TRN) file. After sectioning the roots at 3, 6, and 9 mm from the apex, the surfaces were examined with a stereomicroscope and SEM. Results: The data were examined using the Chi-square test. There were no fissures in the untreated group. The area between 3mm and 6mm was where the cracks in Waldent Walflex were most evident. There was no statistically significant difference between the experimental groups at either the 6 mm or 9 mm levels (P &gt; 0.05). Conclusion: In conclusion, each rotary file utilized in the testing caused dentinal cracks. Compared to the Trunatomy file group, the Waldent walflex file group has more errors. The apical area of the samples had much more defects than the median and coronal regions.