Canal Aberrations Research Articles

Shaping outcomes of Reciproc Blue and Rotate in roots canals with band-shaped isthmuses: micro-CT study.

This study assessed the outcome of shaping the mesial roots of mandibular first molars containing band-shaped isthmuses with an isthmus floor located at the apical third with Reciproc Blue and Rotate instruments in terms of canal transportation, canal aberrations and unprepared apical canals. Pair-matched mesial roots of mandibular first molars according to their isthmus location (distance from apical foramina) and size were constructed based on quantitative measurements (length, major and minor diameter at isthmus roof and floor) on preoperative micro-CT scanning (n = 10). The pair-matched specimens were prepared either using Reciproc Blue R25 (25.08v) or Rotate (15.04, 20.05, 25.06) instruments and then subjected to a second micro-CT scanning. Micro-CT scans were analysed to evaluate the canal transportation at the apical foramen and isthmus floor levels and the frequency of procedural errors (separated instruments, artificial canal preparation, cross shaping and unprepared apical canals). Canal transportation values were compared using Mann-Whitney U, and the distribution of procedural errors was compared with chi-square tests with a 5% significance threshold. Greater transportation values were detected in the apical foramen level compared to the isthmus floor in both groups. No significant difference was detected between Rotate and Reciproc Blue groups in terms of absolute transportation values and the incidence of procedural errors (p > .05). Preparation of mesial root canals containing a band-shaped isthmus at the apical portion with Reciproc Blue and Rotate instruments caused transportation of the original canal position at the isthmus floor and the apical foramen levels and resulted in procedural errors. This ex vivo micro-CT study using controlled pair-matched specimens showed that presence of a band-shaped isthmus complicates canal preparation procedure irrespective of the preparation systems.

Comparative Evaluation of a Dynamic Navigation System versus a Three-dimensional Microscope in Retrieving Separated Endodontic Files: An In Vitro Study

IntroductionThis study aimed to compare the effectiveness of a dynamic navigation system and a three-dimensional microscope in retrieving broken rotary Nickel-Titanium files when using trepan burs and the extractor system. Materials and MethodsThirty maxillary first bicuspids with 60 separate roots were split into 2 comparable groups based on a comprehensive cone beam computed tomography analysis of the root length and curvature. After standardized access opening, glide paths, and patency attainment with the K file (sizes 10 and 15), the teeth were arranged on 3D models (three per quadrant, six per model). Subsequently, controlled-memory heat-treated Nickel-Titanium rotary files (#25/0.04) were notched 4 mm from the tips and fractured at the apical third of the roots. The C-FR1 Endo file removal system was employed under both guidance to retrieve the fragments, and the success rate, canal aberration, treatment time, and volumetric changes were measured. The statistical analysis was performed using IBM SPSS software at a significance level of 0.05. ResultsThe microscope-guided group had a higher success rate than the dynamic navigation system guidance, but the difference was insignificant (P > .05). In addition, the microscope-guided drills resulted in a substantially lower proportion of canal aberration, shorter time to retrieve the fragments and less change in the root canal volume (P < .05). ConclusionAlthough dynamically guided trephining with the extractor can retrieve separated instruments, it is inferior to three-dimensional microscope guidance regarding treatment time, procedural errors, and volume change.

T-Endo MUST ve WaveOne Gold'un Rehber Yol Eğeleri ile Şekillendirme Yeteneklerinin Karşılaştırılması: İn Vitro Çalışma

Objective: The aim was to compare the shaping ability and the canal straightening of T-Endo MUST and WaveOne Gold reciprocal file systems with glide path files in resin J-shaped root canals. Material and Methods: Two groups (n=17) were established. TEM tg (13/.04) + TEM M25 (25/.06) and WOG Glider (15/.02) + WOG Primary (25/.07) were used to prepare the resin simulated canals. A series of preoperative and postoperative images were taken by a digital camera and they were superimposed. The curvature angles and the amount of resin removed from both the inner and the outer wall of the canal into the level of 7 mm from the apical point, with a 1 mm increment were measured. The data were evaluated with independent samples Student's t-test with 5% significance interval. Results: There was no statistically difference between TEM and WOG reciprocal files (p>0.05). No instrument fracture or canal aberrations were inspected during canal preparation. Conclusion: Within the limitation of this present study, TEM and WOG files maintained the original canal curvature in curved canals. They produced conservative shapes with lower foramen transportation.

Shaping ability of three nickel-titanium rotary instruments in simulated L-shaped canals: OneShape, Hero Shaper, and Revo-S

BackgroundShaping ability of a file plays an important role during instrumentation in an endodontic treatment. This study aimed to compare the shaping ability of OneShape (OS), Hero Shaper (HS), and Revo-S (RS) instruments in simulated L-shaped canals.MethodsForty-eight simulated L-shaped canals were prepared to an apical size of 25 using OS, HS, and RS (all from Micro-Mega SA, Besançon, France), (n = 16 canals/group) systems. The amount of resin removed after each canal's preparation was measured and compared after producing a composite image made from the superimposition of pre and post-instrumented canals. Canal aberrations and the preparation time were also recorded. The data were statistically analysed by using ANOVA, Tukey, and Chi-square tests.ResultsOne file fractured during instrumentation in the RS group. A significant difference was found at the apical end of the prepared simulated canal between the groups, with RS showing the least amount of resin removal from the inner side of the canals and HS showing the highest amount of resin removal from the outer side (P < 0.05). Regarding the total width of the canals after preparation, a significant difference was found between the groups at the apical end and the straight portion of the canals, and RS removed the least amount of resin at the straight portion of the canals (P < 0.05). No statistically significant differences were found between the different instruments regarding canal aberrations' incidence (P > 0.05).ConclusionsAll of the files showed a tendency to straighten the canals, whereas OS files maintained the original canal curvatures well.

A Comparative Evaluation of Canal Transportation and Centering Ability of Three Different Ni-Ti File Systems - An In Vitro CBCT Study

Successful root canal therapy depends on many factors. One of the most important steps in any root canal treatment is biomechanical preparation. Additionally, respecting the original shape of the canal is of the same importance. Otherwise, canal aberrations such as transportation will be created. Purpose: To evaluate the canal transportation and canal centering ability of ProTaper Next (PTN), TruNatomy (TN), and Neohybrid (NH) file systems using cone-beam computed tomography. Materials and methods: Thirty extracted single-rooted mandibular premolars were decoronated and divided into three experimental groups, with ten in each group. Group I - ProTaper Next (PTN), Group II - TruNatomy (TN), and Group III - Neohybrid (NH) file systems. Cone-beam computed tomographic pre-scan were taken, followed by biomechanical preparation with the respective file systems. Post CBCT scans were taken and compared with pre-scans for canal transportation and canal centering ability at the levels of 3, 6, and 9mm. The data obtained were statistically analyzed. Results: Using One way ANOVA and Post hoc analysis, canal transportation at the level of 6mm from the apex, group II and group III have shown statistical significance compared to group I, and no statistically significant differences were seen at the levels of 3mm and 9mm. There is no statistically significant difference in canal centering ability among the three groups at the levels of 3,6, and 9mm from the apex. Conclusion: Under the in vitro conditions of the study, ProTaper Next (PTN), Trunatomy (TN), and Neohybrid (NH) rotary systems have shown similar behavior concerning canal transportation and canal centering ability.

Shaping ability of three thermally treated nickel-titanium systems in S-shaped canals.

This study aimed to compare the shaping ability of ProTaper Next (PTN), HyFlex EDM (HEDM) and One Curve (OC) systems manufactured via different thermal treatment methods in simulated S-shaped canals. Sixty S-shaped canals in clear resin blocks were enlarged to a final apical size of 25 using PTN, HEDM and OC instruments (n = 20 canals/group). Composite images were obtained by superimposing pre- and post-preparation images. The amount of removed resin was measured perpendicularly to the canal surface in 22 points. Prepared canal width and canal transportation at different levels were determined. Canal aberrations were also recorded. Data were statistically analysed using analysis of variance, the Kruskal-Wallis and the chi-square tests at a 0.05 significance level. OC produced the most conservative enlargement and better maintained particularly the apical curvature of the S-shaped canals than HEDM and PTN. OC and HEDM better maintained the canal terminus and coronal curvature than PTN.

Shaping ability of ProTaper Next and Navigator EVO rotary nickel–titanium file systems in simulated L-shaped and S-shaped root canals

Objective: The objective of this study is to evaluate and compare the shaping ability of ProTaper Next (PTN) and Navigator EVO (N-Evo) rotary file systems in L- and S-shaped simulated resin root canals. Materials and Methods: A total of forty L-shaped (n = 20) and S-shaped (n = 20) resin block root canals were randomly assigned into four groups (n = 10) based on the PTN and N-Evo rotary file systems. Before the instrumentation, simulated root canals were filled with the India blue ink and preinstrumentation images were taken using a digital camera. Each canal was prepared to the standard working length 16 mm, 0.15 mm apical foramen diameter, and 0.2 initial tapers. After the canal preparation, red India ink was filled in each canal and postoperative images were obtained. The two images were superimposed, five points were selected, and canal widths were measured with image analysis software. Canal preparation time, file failure, and presence of aberrations were recorded and compared between the two systems. Descriptive statistics of mean and standard deviation and inferential statistics of Independent samples t-test and analysis of variance tests were applied to the data. Results: PTN file system showed significantly lesser preparation time (L-shape, 2.55 ± 0.38 min, and S-shape, 2.57 ± 0.44 min) in comparison to N-Evo file system (L-shape, 5.01 ± 0.37 min, and S-shape, 5.21 ± 0.30 min) (P Conclusions: N-Evo file system demonstrated better shaping ability compared to PTN in L- and S-shaped simulated canals. PTN file system prepared the canal in less time and maintained the original curvature. An almost similar number of canal aberrations found between tested file systems. However, three N-Evo files broke in L-shaped canals indicating possible limitation in this area.

Impact of new cross-sectional designs on the shaping ability of rotary NiTi instruments in S-shaped canals.

The aim was to compare the shaping ability of different rotary nickel-titanium instruments in simulated S-shaped canals. One hundred S-shaped canals in resin blocks were prepared to an apical size 25 using F6 SkyTaper (Komet), Silk Files .04, Silk Files .06, Prototypes .04, and Prototypes .06 (all Mani) (20 canals/group). Material removal was measured at 20 measuring points, beginning 1mm from the endpoint of preparation. Incidence of canal aberrations, preparation time, and instrument failures were also recorded. Statistical analyses were performed using ANOVA, Student-Newman-Keuls and Chi-square test. Pooled data of all measuring points revealed that canals instrumented with Prototypes .04 were significantly better centered than those prepared with all other instruments, while Prototypes .06 and both Silk Files performed significantly better than F6 SkyTaper (p < 0.05). The preparation time differed significantly between all groups and Prototypes .04 allowed the fastest preparation (p < 0.05). There was no statistically significant association between type of instrument and incidence of aberrations (p > 0.05). The cross-sectional design had a marked impact on the shaping ability of the instruments, and less tapered instruments maintained the original canal curvature better than instruments having greater tapers.

Comparison of the Shaping Ability of Endowave and K3 Rotary Nickel-Titanium Instruments in Simulated Canals

Abstract Objectives The aim of this study was to compare canal aberrations and transportation of Endowave and K3 rotary nickel-titanium files in simulated canals with 40-degree curvature. Materials and Methods Twenty simulated canals with 40-degree curvature were divided into two groups (each of 10). In one group, canals were instrumented with Endowave and in the other group with K3. Both systems were used in crown-down manner, and canals were prepared till apical size # 25/0.06 taper. The pre- and post-instrumentation radiographic scanned images were superimposed on each other using software movements and viewed for canal aberrations and transportation. Results are statistically analyzed using Student's t-test. Results In the canals prepared with Endowave files, one (10%) ledge was created whereas in the canals prepared with K3 files, one (10%) apical zip and elbow, one (10%) ledge, and two (20%) perforations were created. When two groups were compared, results were statistically insignificant (p &gt; 0.05) for the amount of resin removed from inner and outer aspect of the canal. Conclusions Endowave files revealed better results in terms of the canal aberrations compared to K3 files. The direction of transportation was generally toward the outer aspect with both files.

Performance of progressive and constant tapered instruments rotary systems at canal preparation

ABSTRACT Objective: The aim of this study was to compare the performance of two nickel-titanium rotary systems regarding the preparation time, final shape of canal, incidence of aberration, transportation, and fracture of instrument. Methods: A total of 40 simulated canals in resin blocks with 30o curves and a length of 17 mm were divided randomly into two groups: preparation with ProTaper and BioRaCe systems up to F5 and BR5 respectively. Pre- and post-operative canal images were taken and superimposed in order to identify aberrations, transportation, and to take measurements of the canal width. In addition, the preparation time and instrument fractures were recorded. The data were analyzed using Student's t test. Results: There is no difference (p&gt;.05) comparing the systems regarding preparation time, canal aberration, and instrument fracture rates. The progressive tapered instruments of ProTaper prepared significantly larger canal widths in the apical third (p&lt;.05). Conclusion: Overall, both systems provided safe canal preparation, associated with few canal aberrations and instrument fractures.

A Comparative Study of ProTaper Universal and ProTaper Next Used by Undergraduate Students to Prepare Root Canals

IntroductionThe purpose of this study was to determine whether final-year undergraduate dental students achieved better shaping outcomes using the new ProTaper Next (PTN; Dentsply Sirona, Ballaigues, Switzerland) system to prepare root canals for the first time compared with the existing ProTaper Universal (PTU, Dentsply Sirona) system on which they had trained. A secondary aim was to explore the attitudes and preferences of the students toward both systems. MethodsForty students prepared 1 simulated S-shaped canal using PTN and another with PTU. Images of the canals were saved before and after preparation, and the outcomes assessed included the formation of aberrations and the amount of resin removed at specific points along the canal length. Student opinions relating to PTN and PTU were collected via a questionnaire completed immediately after using the systems. For statistical analysis, the McNemar test was used to compare the incidence of aberrations, and a paired t test was used to analyze the width measurements. Responses to the questionnaire were analyzed using frequencies. Thus, the McNemar test was used for paired binary data and the marginal homogeneity test for categoric data when more than 2 categories were used. Finally, the overall preferences (either PTN or PTU) were analyzed using the sign/binomial test, which is a standard statistical test that allows us to determine if the proportion preferring one or the other is equal or not. ResultsCanal ledges were formed in 30% of the canals prepared with PTU, whereas no ledges were formed with PTN (P < .001). A middle constriction, a form of canal aberration, was created by both systems although it occurred significantly (P = .006) more often with PTN. The “number of files” was judged by students to be significantly higher (P < .001) for PTU compared with PTN. Even though using PTN for the first time, students were more likely to recommend the system to other students for preparing S-shaped canals than PTU (P = .018) and preferred to use PTN in the future (P < .001). ConclusionsThe students who had previous experience with the use of PTU were able to produce comparable shaping outcomes when they used PTN for the first time. For the preparation of S-shaped canals, the students preferred PTN over PTU in terms of the number of files and would prefer to use it in the future.

Shaping Ability of Reciproc, WaveOne GOLD, and HyFlex EDM Single-file Systems in Simulated S-shaped Canals

IntroductionThe aim of the present study was to compare the shaping ability of Reciproc (RPC; VDW, Munich, Germany), HyFlex EDM (HEDM; Coltene/Whaledent AG, Altstätten, Switzerland), and WaveOne GOLD (WOG; Dentsply Maillefer, Ballaigues, Switzerland) nickel-titanium (NiTi) files made of different NiTi alloys in S-shaped simulated canals. MethodsSixty S-shaped canals in resin blocks were prepared to an apical size of 0.25 mm using RPC R25, WOG Primary, and HEDM OneFile (n = 20 canal/per group) systems. Composite images were made from the superimposition of pre- and postinstrumentation images. The amount of resin removed by each system was measured using a digital template and image analysis software in 22 different points. Canal aberrations were also recorded. Data were statistically analyzed using the Kruskal-Wallis and post hoc Dunn tests at the 5% level. ResultsNiTi file fracture was not observed during shaping of the simulated canals although a danger zone formation in 1 sample and a ledge in 1 sample were observed in the RPC group. There was no statistically significant difference between the WOG and HEDM groups' apical, medial, and coronal regions (P > .05). However, it was determined that the RPC group removed a statistically significantly higher amount of resin from all the canal regions when compared with the WOG and HEDM groups (P < .05). ConclusionsWithin the limitation of the present study, it was determined that all of the tested NiTi files caused various levels of resin removal. However, WOG and HEDM NiTi files were found to cause a lower level of resin removal than RPC NiTi files.

Comparison of the Shaping Ability of WaveOne Reciprocating Files with or without Glide Path in Simulated Curved S-shaped Root Canals.

Objectives:The aim was to compare the shaping ability of WaveOne reciprocating files with or without glide path in simulated curved S-shaped root canals.Materials and Methods:Forty ISO #15, 0.02 taper, clear resin Endo Training Bloc-S blocks were studied. The simulated curved S-shaped canals were dyed using ink, preinstrumentation images were scanned, and resin blocks were prepared and divided into Group A: PathFile and WaveOne and Group B: WaveOne. All canals were postoperatively scanned. Pre- and postoperative images were superimposed and evaluated at 12 defined measuring points. The efficacy of the systems was compared based on the amount and direction of canal transportation, centering ability, amount of material removed, and presence of canal aberrations. Mann–Whitney U-test and independent t-test were used for statistical comparison.Results:Both systems produced transportation at all levels and straightened the curved S-shaped canals. No significant differences in the amount and direction of transportation and amount of material removed were observed between the groups at each level (P > 0.05). However, Group A had significantly greater centering ability at the coronal straight zone (P = 0.018) and apical curvature (P = 0.014) levels than did Group B. Moreover, Group B showed more canal aberrations than did Group A.Conclusion:Within the limitations of the present study, the creation of a glide path with the PathFile system improved the centering ability of the WaveOne reciprocating file in the apical and straight coronal portions of the simulated curved S-shaped root canals and reduced the incidence of canal aberrations.

Influence of Operator's Experience on the Shaping Ability of Protaper Universal and Waveone Systems: A Comparative Study on Simulated Root Canals.

Objective:To assess the influence of operator experience on: shaping and centering ability, mean preparation time and presence of canal aberrations of ProTaper Universal and WaveOne systems on simulated root canals.Materials and Methods:Sixty S-shaped canals in resin blocks were assigned to four groups (n=15 for each group). Group1 (Experienced operator, ProTaper), Group2 (Experienced operator, WaveOne), Group3 (Inexperienced operator, ProTaper), Group4 (Inexperienced operator, WaveOne). Photographic method was used to record pre- and post-instrumentations images. After superimposition, it has been evaluated presence of canal aberrations and differences in shaping and centering ability between groups.Results:WaveOne system produced a lower amount of canal aberrations both in the hand of expert than inexpert operators. However, a WaveOne instrument breakage occurred in the hands of an inexperienced operator. No differences have been found in the evaluation of shaping ability with both systematics. Operator’s experience doesn't influence the shaping ability of ProTaper and WaveOne systems.Conclusion:Experience factor could influence the centering ability in the use of both the systematics. However, WaveOne Primary reduce the mean preparation time and the presence of canal aberrations.

Shaping ability of different endodontic single-file systems using simulated resin blocks

Objectives: The aim of this study was to compare the shaping ability of four different single-file systems; WaveOne (Dentsply Maillefer, Ballaigues, Switzerland), Reciproc (VDW), OneShape (Micro Mega), and F360 (Komet Brasseler, Lemgo, Germany). Stainless steel K-file (KSS) (Dentsply Maillefer, Ballaigues, Switzerland) was used as a control during the preparation of simulated root canals. Materials and Methods: Eighty L-shaped canals in resin blocks were prepared to an apical size of 25 using one of the five groups (each group = 16). A series of pre- and post-operative images were taken by a digital camera (EOS 650D. Canon) and superimposed on two different layers. The amount of resin removed from both the inner and the outer sides of the canal were measured at five different points: orifice, half way of the orifice, beginning of the curvature, apex of the curve, and the apical end. The amount of resin removed by each system was measured using image analysis software. Canal aberrations and the preparation time were also recorded. The data were statistically analyzed by using analysis of variance, Tukey's post hoc, and Chi-square tests. Results: There are significant differences between all single files and KSS in time for preparation (P Conclusion: Within the limitation of this study, NiTi instruments are superior to stainless steel K-files in their shaping ability. All single-file systems maintained root canal curvature well and were safe to use. Canals prepared with the F360 and OneShape systems were better centered compared with the Reciproc and WaveOne systems.

Single-rooted pyramidal molars: A rare case report

Anatomical variations of the first primary molars are very rare. Anatomic variation in root canal configuration, especially in multi-rooted teeth such as primary molars, makes the diagnosis and successful root canal therapy challenging. Thorough knowledge of root canal morphology and anatomical variations of primary teeth can help a pediatric dentist in successful root canal treatment. These deviations are also one of the major causes for endodontic treatment failure owing to inadequate cleaning, shaping, and sealing of root canal system. In addition, periodontally, fused roots are more prone to tooth destruction. The main purpose of the article is to present a very rare case of primary first molars with an unusual morphology as a single root called pyramidal molar. Various etiological factors are discussed briefly, and emphasis is placed on endodontic and periodontal aspects of these root canal aberrations.

Mandibular premolars with unusual root canal configuration: A report of two cases

Knowledge of the normal root canal morphology and its variation is essential to ensure a successful root canal therapy. The aim of this report is to describe the endodontic treatment of two mandibular premolars with aberrant root canal morphology with the aid of dental operating microscope. A 29-year-old Saudi male with three mandibular left premolars was referred by the Prosthodontic Department for endodontic evaluation prior to placement of final coronal restorations. The first premolar was diagnosed as having necrotic pulp while the third premolar was previously treated. Root canal treatment and nonsurgical root canal retreatment were performed for the first and third premolars, respectively. The first premolar had a C-shaped configuration and Vertucci's Type V (1-2) canal system while the third premolar had Type III configuration (1-2-1). One year later, the teeth were asymptomatic with normal periapical tissues radiographically. Root canal aberrations may occur in any tooth type, and the clinicians should always assume the presence of these aberrations and use all the available tools to detect and manage them.

A Central Incisor with 4 Independent Root Canals: A Case Report

The maxillary central incisor is the tooth with the least anatomic variations. Despite the fact that several studies have reported a prevalence of 100% for the presence of a single canal, root canal aberrations of maxillary central incisors with up to 3 canals have also been reported. Such cases represent both a diagnostic and technical challenge to the clinician. The present case describes root canal treatment performed in a maxillary central incisor with 4 canals. The detection of all canals was achieved by examination of the pulp chamber floor with the help of the dental operating microscope as well as careful examination of intraoral radiographs. The canals were prepared with hand and rotary instruments and obturated with a warm gutta-percha technique. The present report is the first to describe a maxillary central incisor with 4 canals in a tooth with no developmental abnormalities. It stresses the importance of using a dental operating microscope during endodontic treatment as well as questioning the routine use of cone-beam computed tomographic imaging for similar cases.

Accessory roots and root canals in human anterior teeth: a review and clinical considerations.

Anterior teeth may have aberrant anatomical variations in the number of roots and root canals. A review of the literature was conducted using appropriate key words in major endodontic journals to identify the available reported cases as well as experimental and clinical investigations on accessory roots and root canals in anterior teeth. After retrieving the full text of related articles, cross-citations were identified, and the pooled data were then discussed. Results revealed a higher prevalence in accessory root/root canal variations in mandibular anterior teeth than in maxillary counterparts. However, maxillary incisor teeth revealed the highest tendency for accessory root/root canal aberrations caused by anomalies such as dens invaginatus and palato-gingival groove. Primary anterior teeth may also exhibit external and internal anatomical variations in the root, especially maxillary canines. Therefore, dental practitioners should thoroughly assess all teeth scheduled for root canal treatment to prevent the undesirable consequences caused by inadequate debridement of accessory configurations of the root canal system.

Shaping Ability of 4 Different Single-file Systems in Simulated S-shaped Canals

IntroductionThe aim of this study was to compare the shaping ability of 4 different single-file systems in simulated S-shaped canals. MethodsSixty-four S-shaped canals in resin blocks were prepared to an apical size of 25 using Reciproc (VDW, Munich, Germany), WaveOne (Dentsply Maillefer, Ballaigues, Switzerland), OneShape (Micro Méga, Besançon, France), and F360 (Komet Brasseler, Lemgo, Germany) (n = 16 canals/group) systems. Composite images were made from the superimposition of pre- and postinstrumentation images. The amount of resin removed by each system was measured by using a digital template and image analysis software. Canal aberrations and the preparation time were also recorded. The data were statistically analyzed by using analysis of variance, Tukey, and chi-square tests. ResultsCanals prepared with the F360 and OneShape systems were better centered compared with the Reciproc and WaveOne systems. Reciproc and WaveOne files removed significantly greater amounts of resin from the inner side of both curvatures (P < .05). Instrumentation with OneShape and Reciproc files was significantly faster compared with WaveOne and F360 files (P < .05). No instrument fractured during canal preparation. ConclusionsUnder the conditions of this study, all single-file instruments were safe to use and were able to prepare the canals efficiently. However, single-file systems that are less tapered seem to be more favorable when preparing S-shaped canals.