Apical Root Canal Transportation and Remaining Dentin Thickness Associated with ProTaper Universal with and without PathFile

Introduction

This study aimed to compare, using digital subtraction radiography, apical transportation in mesiobuccal root canals of extracted human maxillary molars instrumented with ProTaper Universal F3 and F4 files (Dentsply Maillefer, Ballaigues, Switzerland) with and without the prior creation of glide paths using the PathFile system and to compare, using cone-beam computed tomographic imaging, remaining dentin thickness (RDT) after complete preparation.

Methods

Forty mesiobuccal roots with curvatures of 20°–35° were used. In group A, glide paths were created with PathFile #1, #2, and #3 to the working length; in group B, no glide paths were used. All canals were instrumented up to F4 to the working length. Digital subtraction radiographic images were obtained in buccolingual and mesiodistal directions. Apical transportation associated with F3 or F4 was calculated based on the difference between the tip of the first and the last instrument analyzed in each group. RDT was calculated based on cone-beam computed tomographic images.

Results

Apical transportation was higher after F4 regardless of the use of the PathFile system. No statistically significant differences between groups A and B were observed in apical transportation after instrumentation with F3 or F4 (P > .05). Group A showed greater RDT values at 2 (buccal and mesial walls, P < .05) and 3 mm (buccal and distal walls, P < .05) from the apex but not at 1 mm.

Conclusions

The use of the PathFile system before root canal preparation with ProTaper Universal F3 and F4 did not influence apical transportation but was associated with greater RDTs at 2 and 3 mm from the apex.     

Evaluation of the Amount of Root Canal Dentin Removed and Apical Transportation Occurrence after Instrumentation with ProTaper Next,OneShape, and EdgeFile Rotary Systems

IntroductionThe aim of this study was to evaluate the amount of root canal dentin removed and apical transportation occurrence after instrumentation of mesiobuccal canals of maxillary molars with ProTaper Next (PTN [Dentsply Maillefer, Ballaigues, Switzerland]), OneShape (OS [MicroMega, Besançon, France]), and EdgeFile (EF [Edge Endo, Albuquerque, NM]) rotary systems.MethodsTwenty-seven mesiobuccal canals of maxillary molars were used. Canals were randomly divided into 3 groups for canal preparation: PTN, EF X3, or OS (n = 9 for each group). Micro–computed tomographic imaging was used to measure apical transportation (mm) and the volume of dentin removed (mm³). The amount of dentin removed was measured for the coronal portion and for the whole canal length. Superposition of pre- and postoperative cross-sectional apical slices were used to measure apical transportation at 1 mm from the apex; the differences were evaluated using the Kruskal-Wallis test and Wilcoxon analysis. The Spearman correlation coefficient was used to display the relationship between variables for each group. The significance level was set at P < .05.ResultsThe percentages of the amount of dentin removed on the coronal portion and the amount removed for the whole canal length were statistically similar between groups (P > .05). The average amount of apical transportation for the PTN, OS, and EF X3 were 0.197, 0.263, and 0.218 mm, respectively. Statistically, there were no significant differences between the 3 rotary instruments for apical transportation.ConclusionsThe amount of dentin removed for the coronal third portion and the whole canal length was similar for the PTN, OS, and EF X3 rotary instruments. Although there were differences in the sizes of apical enlargement, no apical transportation was observed in any of the instrumentation systems.     

Evaluation of Root Canal Transportation,Centering Ratio,and Remaining Dentin Thickness Associated with ProTaper Next Instruments with and without Glide Path

IntroductionThe purpose of this study was to evaluate and compare the volume of removed dentin, transportation, and centering ability of ProTaper Next (PTN) system with and without glide path preparation by using cone-beam computed tomography (CBCT) imaging.MethodsSixty mesiobuccal canals of mandibular first molars with curvatures of 25°−35° were divided into 3 experimental groups (n = 20) according to the instrumentation technique as follows: group PG/PTN (glide path was created with ProGlider [PG]) and canals were shaped with PTN system), group PF/PTN (glide path was created with PathFile [PF]) and canals were shaped with PTN system), and group PTN (glide path was not performed and canals were shaped with PTN system only). Canals were scanned before and after instrumentation by using CBCT scanner to evaluate root canal transportation and centering ratio at 3, 5, and 7 mm from the apex and volumetric changes. Data were statistically analyzed, and the significance level was set at P < .05.ResultsThere was no significant difference among the tested groups regarding the volume of removed dentin and centering ratio (P > .05). At 3-mm and 5-mm levels, the PG/PTN group showed a significantly lower mean transportation value among the groups (P < .05). However, at 7-mm level, there was no significant difference in canal transportation among the groups (P > .05).ConclusionsPG/PTN instrumentation method revealed better performance with fewer canal aberrations when compared with instrumentation performed with PF/PTN or PTN only.     

Canal Transportation,Centering Ability,and Cyclic Fatigue Promoted by Twisted File Adaptive and Navigator EVO Instruments at Different Motions

Introduction

This study compared the cyclic fatigue and the canal transportation promoted by Twisted File (TF) Adaptive and Navigator EVO systems when used with 2 different motions.

Root Canal Preparation Does Not Induce Dentinal Microcracks In Vivo

IntroductionThis in vivo study aimed to evaluate the development of dentinal microcracks after root canal preparation of contralateral premolars with rotary or hand instruments using micro–computed tomographic technology.MethodsSixty contralateral intact maxillary and mandibular premolars in which extraction was indicated for orthodontic purposes were selected and distributed into positive (n = 6, teeth with induced root microcracks) and negative (n = 6, intact teeth) control groups as well as 2 experimental groups (n = 24) according to the instrumentation protocol: ProTaper rotary (PTR) or ProTaper hand (PTH) systems (Dentsply Maillefer, Ballaigues, Switzerland). After root canal preparation, teeth were extracted using an atraumatic technique and scanned at a resolution of 17.18 μm. A total of 43,361 cross-sectional images of the roots were screened for the presence of dentinal microcracks. The results were expressed as the percentage and number of root section images with microcracks for each group.ResultsAll roots in the positive control group showed microcracks at the apical third, whereas no cracks were observed in the specimens of the negative control group. In the PTR group, 17,114 cross-sectional images were analyzed, and no microcrack was observed. In the PTH group, dentinal microcracks were observed in 116 of 17,408 cross-sectional slices (0.66%) of only 1 specimen. These incomplete microcracks extended from the external root surface into the inner root dentin at the area of reduced dentin thickness.ConclusionsRoot canal instrumentation with PTR and PTH instruments of contralateral maxillary and mandibular premolars did not result in the formation of dentinal microcracks in vivo.     

Comparative Study of Different Novel Nickel-Titanium Rotary Systems for Root Canal Preparation in Severely Curved Root Canals

Introduction

We compared the effects of 6 different rotary systems on transportation, canal curvature, centering ratio, surface area, and volumetric changes of curved mesial root canals of mandibular molar via cone-beam computed tomographic (CBCT) imaging.

Methods

Mesiobuccal root canals of 120 mandibular first molars with an angle of curvature ranging from 20°–40° were divided into 6 groups of 20 canals. Based on CBCT images taken before instrumentation, the groups were balanced with respect to the angle and radius of canal curvature. Root canals were shaped with the following systems with an apical size of 25: OneShape (OS) (MicroMega, Besancon, France), ProTaper Universal (PU) F2 (Dentsply Maillefer, Ballaigues, Switzerland), ProTaper Next X2 (Dentsply Maillefer), Reciproc (R) R25 (VDW, Munich, Germany), Twisted File Adaptive (TFA) SM2 (SybronEndo, Orange, CA), and WaveOne primary (Dentsply Tulsa Dental Specialties, Tulsa, OK). After root canal preparation, changes were assessed with CBCT imaging. The significance level was set at P = .05.

Results

The R system removed a significantly higher amount of dentin than the OS, PU, and TFA systems (P < .05). There was no significant difference among the 6 groups in transportation, canal curvature, changes of surface area, and centering ratio after instrumentation.

Conclusions

The 6 different file systems straightened root canal curvature similarly and produced similar canal transportation in the preparation of mesial canals of mandibular molars. R instrumentation exhibited superior performance compared with the OS, TFA, and PU systems with respect to volumetric change.     

Planned Apical Preparation Using Cone-Beam Computed Tomographic Measures: A Micro-Computed Tomographic Proof of Concept in Human Cadavers

IntroductionThis study assessed the amount of unprepared surface areas at the apical 4-mm segment of the root canal after a planned preparation based on cone-beam computed tomography (CBCT) measurements.MethodsEighteen posterior mandible segments were obtained from cadavers and scanned using CBCT and micro-computed tomographic (micro-CT) imaging. CBCT images were used to measure the largest initial canal diameter from 29 root canals of premolars at 1, 2, 3, and 4 mm short of the apical foramen. Each measurement was used to select a master apical instrument with size/taper that was 1 diameter larger to prepare the apical 4 mm of each particular root canal. A post-preparation micro-CT scan was obtained, and the unprepared canal areas were calculated.ResultsA very high amount of surface areas over the apical 4 mm of the root canal was included in the final preparation (mean >90%). The unprepared areas ranged from as low as 3.7% to a maximum of 14.6% (mean and median, 9.2% and 9.1%, respectively).ConclusionsThe proposed planned apical root canal preparation resulted in optimized root canal shaping with a substantial amount of prepared surface areas. The protocol used also resulted in a conservative canal enlargement using final instruments that were 1 size larger than the initial largest canal diameter.     

Effects of ProTaper Universal,ProTaper Next,and HyFlex Instruments on Crack Formation in Dentin

Introduction

The aim of the present study was to investigate the incidence of cracks in root dentin after root canal preparation with ProTaper Next (Dentsply Maillefer, Ballaigues, Switzerland), HyFlex (Coltene-Whaledent, Allstetten, Switzerland), and ProTaper Universal (Dentsply Maillefer) rotary instruments.

Methods

One-hundred mandibular premolars were selected. Twenty-five teeth were left unprepared and served as a negative control; another 25 teeth were instrumented with the ProTaper Universal system up to size F4 as a positive control, and the remaining 50 teeth were shaped with the following experimental groups with an apical size 40 file: ProTaper Next X4 and HyFlex 40/0.4. After root canal preparation, all of the roots were sectioned perpendicular to the long axis at 2, 4, 6, and 8 mm from the apex, and the sections were then observed under a stereomicroscope. The absence/presence of cracks was recorded, and the data were analyzed with a chi-square test. The significance level was set at P = .05.

Results

No cracks were observed in the negative control group. Vertical root fractures were not observed in any of the groups. The ProTaper Next and HyFlex instruments caused fewer cracks (28%) than the ProTaper Universal instrument (56%) (P < .05). However, there were no significant differences in crack formation between the ProTaper Next and HyFlex groups (P > .05).

Conclusions

Within the limitations of this in vitro study, all of the instrumentation systems used in this study created cracks in the root dentin. The ProTaper Next and HyFlex instruments tended to cause fewer dentinal cracks compared with the ProTaper Universal instrument.     

Changes in Geometry and Transportation of Root Canals with Severe Curvature Prepared by Different Heat-treated Nickel-titanium Instruments: A Micro–computed Tomographic Study

IntroductionThe aim of this study was to compare the shaping ability of 4 different nickel-titanium systems, considering their variation in alloy treatment, kinematics, and design, used to prepare canals with severe curvature using micro–computed tomographic analysis.MethodsThirty-two mesial roots of mandibular molars with severe curvature were matched based on similar morphologic dimensions and assigned to 4 experimental groups (n = 8) according to the canal preparation: ProTaper Next (PTN; Dentsply Maillefer, Ballaigues, Switzerland), Reciproc (RC; VDW GmbH, Munich, Germany), Reciproc Blue (RCB, VDW GmbH), and TRUShape (TRU; Dentsply Tulsa Dental Specialties, Tulsa, OK) systems. Changes in 2-dimensional (area and perimeter) and 3-dimensional (volume, surface area, and structure model index) morphologic parameters as well as canal transportation were compared among groups using the analysis of variance post hoc Tukey tests with the significance level set at 5%.ResultsPreparation significantly increased all analyzed parameters. No statistically significant differences (P > .05) were observed between RC and RCB or between PTN and TRS in any of the analyzed parameters. In the cervical third, RC and RCB presented higher mean increases than PTN and TRU. In the apical third, there were no statistically significant differences (P > .05) among the systems.ConclusionsThe instruments of greater taper may promote greater morphologic changes. However, regardless of the number of instruments (multiple or single), the type of movement (rotation or reciprocating), the type of heat treatment of alloys, and the particular characteristics of each instrument (taper and design), the evaluated systems did not result in different dimensional changes and canal transportation in the critical apical area.     

Use of Cone-beam Computed Tomography to Evaluate Root Canal Morphology and Locate Root Canal Orifices of Maxillary Second Premolars in a Chinese Subpopulation

Introduction

The aim of this study was to investigate root canal morphology and locate root canal orifices of maxillary second premolars in a Chinese subpopulation using cone-beam computed tomographic imaging.

Methods

A total of 392 cone-beam computed tomographic images of maxillary second premolars were obtained from 238 patients who required a preoperative assessment for implant surgery or orthodontic treatment. The number of roots and root canals and root canal configuration were investigated and categorized using Vertucci's criteria. The distance between the root canal orifice and the anatomic apex and the distance between root canal orifices in those teeth with 2 root canals were measured and evaluated. The Fisher exact test was used to analyze the correlation between the number of roots and sex.

Results

Among the 392 teeth, 86.5% (n = 339) had 1 root; 45.4% (n = 178) of the teeth had 1 root canal, and 54.3% (n = 213) had 2 root canals that ranged from type II–type V. The majority of teeth with 2 root canals showed a type IV canal configuration (n = 79, 20.2%) followed by type II (n = 64, 16.3%), type III (n = 45, 11.4%), and type V (n = 25, 6.4%). Only 1 tooth had 3 root canals. No significant difference was found between the number of roots and sex (P > .05). Among the 213 teeth with 2 root canals, the most frequent distribution of the distance between the root canal orifice and the anatomic apex was 5–10 mm (n = 157). The distance between the 2 orifices of 189 teeth was 1–4 mm.

Conclusions

The frequency of teeth with 2 root canals was high in maxillary second premolars. The internal morphology of teeth with 2 root canals was variable. This study provided useful information about the root canal morphology of maxillary second premolars in a Chinese subpopulation.     

Cone-beam Computed Tomographic Scans in Comparison with Periapical Radiographs for Root Canal Length Measurement: An In Situ Study

Introduction

The primary aim of this study was to compare the precision of root canal length determination on cone-beam computed tomographic (CBCT) scans and periapical radiographs (PAs) with the actual root canal length. The secondary aim was to examine the influence of tooth type on root canal length measurements as assessed on CBCT scans and PAs.

Methods

In total, 40 root canals of 33 teeth (molars, premolars, canines, and incisors) out of 5 dentate maxillas of human cadavers were included. Root canal length measurement was performed by a consensus panel (2 examiners) on CBCT scans (3D Accuitomo 170; J Morita, Kyoto, Japan) and digital PAs. After straight-line access opening, a #15 file was fixated in every root canal at the length measured on CBCT scans. All teeth were extracted, and the root canal containing the file was uncovered. Measurements made on images taken with a digital camera (AxioCam; Carl Zeiss, Sliedrecht, The Netherlands) linked to a stereozoom microscope (Stemi SV6, Carl Zeiss) were used as the actual root canal length.

Results

When all roots were examined together, it was not clear which method is better for all types of teeth. For root canals of anterior teeth, there was no significant difference between the 2 methods. For root canals of posterior teeth, CBCT images gave results significantly closer to the actual root canal length in comparison with PAs (t value = −1.96; critical value is 1.74 with a significance level of 0.05).

Conclusions

Root canal length measurements of posterior maxillary teeth were more accurate when assessed by CBCT images than PAs.     

Micro-Computed Tomographic Evaluation of Canal Transportation and Centering Ability of 4 Heat-Treated Nickel-Titanium Systems

IntroductionThis study aimed to evaluate and compare canal transportation and centering ability of 4 different root canal preparation systems produced with thermal treatments by means of micro–computed tomographic imaging.MethodsEighty mesial canals of human extracted mandibular molars were selected based on similar morphologic parameters and were randomly assigned to 4 experimental groups (n = 20) according to the canal instrumentation technique: HyFlex CM (HCM [Coltène-Whaledent, Allstätten, Switzerland]), HyFlex EDM (HEDM [Coltène-Whaledent]), WaveOne Gold (WOG [Dentsply Sirona, Ballaigues, Switzerland]), and OneCurve (OC [Micro-Mega, Besancon, France]). The specimens were scanned before and after root canal preparation using X-ray micro-computed tomographic imaging at a resolution of 19.9 μm. Apical transportation and centering ability were then analyzed at 3 different levels: 3 mm, 5 mm, and 7 mm from the apex, representing the apical, midroot, and coronal thirds of the root, respectively. One-way analysis of variance and Kruskal-Wallis tests were used to statistically compare the groups. The significance level was set at 5%.ResultsHCM caused less canal transportation than WOG at the 3-mm level in both the buccal and lingual canals (P < .05). Also, HCM resulted in less canal transportation than WOG and OC at the 7-mm level regarding lingual canals. No statistically significant differences were recorded between the groups when the mean centering ratios were compared.ConclusionsThe 4 evaluated systems safely prepared root canals causing minimal canal transportation and producing relatively centered preparations. In terms of canal transportation, HCM performed better than WOG at the apical level and better than WOG and OC at the coronal level.     

Preparation of simulated root canals using the Macfile, Canal Master U and K-Flexofile

The efficacy of three different root canal instruments in maintaining the original shape of curved canals was evaluated. Acrylic blocks were prepared to simulate canals with 40° and 60° curvature. K-Flexofiles and Macfiles were used with a step-back technique utilizing an 'in/out' filing motion. The balanced-force technique was used with Canal Master 'U' instruments. Ten 40° and 10 60° canals were prepared with each instrument. The results were evaluated using superimposed photographic slides at ×20 magnification to show the canals before and after the instrumentation. The width of the prepared canals was measured at their convex/concave point to determine the divergence of the instrumented canal shape from the original canal shape. The measurements were taken at the level of the apical foramen and 3 and 6 mm coronal to it. In this way it was possible to recognize all the defects created during the preparation of a canal. Among the tested instruments, the Macfile provoked minimal canal deviation ( P = 0.05). The Canal Master 'U' was similarly effective ( P = 0.05), but had the highest incidence of instrument fracture. The K-Flexofile demonstrated the most defects in canal preparation and canal deviation, particularly at the level of the apical foramen ( P < 0.01).     

The Apical Root Canal System of Teeth with Posttreatment Apical Periodontitis: Correlating Microbiologic,Tomographic, and Histopathologic Findings

IntroductionThis study evaluated the microbiological conditions of the apical root canal system of teeth with posttreatment apical periodontitis and correlated them with observations from cone-beam computed tomographic (CBCT) imaging, micro–computed tomographic (micro-CT) imaging, and histopathology.MethodsRoot apices were obtained from 36 root canal–treated teeth subjected to periradicular surgery. CBCT examination was available before surgery. The apical root specimens were scanned in a micro-CT device and then cryopulverized. The powder was subjected to DNA extraction for real-time polymerase chain reaction quantification of total bacteria, Streptococcus species, members of the phylum Actinobacteria, and Enterococcus faecalis. Microbiological findings were evaluated for associations with CBCT, micro-CT, and histopathologic data. An association between lesion size and the proportion of unfilled apical canal system volume was also assessed.ResultsAll cryopulverized specimens were positive for total bacteria. Actinobacteria and streptococci occurred in 35 and 33 specimens, respectively, and were usually dominant in the community. Actinobacteria counts were 2.23 times higher in granulomas than in cysts. Streptococci were significantly more present in small lesion cases. E. faecalis was detected in only 7 samples, always as a dominant community member. The association of total bacteria, streptococci, and Actinobacteria counts with the unfilled canal volume was significant in the univariate analyses but not confirmed in the adjusted analyses. Large lesions were significantly associated with a higher volume of unfilled apical canals.ConclusionsBacterial infection occurred in all root apices, with high prevalence and dominance of Actinobacteria and streptococci. The volume of the unfilled apical canal system was significantly associated with the lesion size and possibly with bacterial counts. Findings illustrate the need to thoroughly disinfect and fill the apical root canal of infected teeth during endodontic therapy.     

Lack of Causal Relationship between Dentinal Microcracks and Root Canal Preparation with Reciprocation Systems

Introduction

This study aimed to evaluate the frequency of dentinal microcracks observed after root canal preparation with 2 reciprocating and a conventional full-sequence rotary system using micro–computed tomographic analysis.

Methods

Thirty mesial roots of mandibular molars presenting a type II Vertucci canal configuration were scanned at an isotropic resolution of 14.16 μm. The sample was randomly assigned to 3 experimental groups (n = 10) according to the system used for the root canal preparation: group A—Reciproc (VDW, Munich, Germany), group B—WaveOne (Dentsply Maillefer, Baillagues, Switzerland), and group C—BioRaCe (FKG Dentaire, La-Chaux-de-Fonds, Switzerland). Second and third scans were taken after the root canals were prepared with instruments sizes 25 and 40, respectively. Then, pre- and postoperative cross-section images of the roots (N = 65,340) were screened to identify the presence of dentinal defects.

Results

Dentinal microcracks were observed in 8.72% (n = 5697), 11.01% (n = 7197), and 7.91% (n = 5169) of the cross-sections from groups A (Reciproc), B (WaveOne), and C (BioRaCe), respectively. All dentinal defects identified in the postoperative cross-sections were also observed in the corresponding preoperative images.

Conclusions

No causal relationship between dentinal microcrack formation and canal preparation procedures with Reciproc, WaveOne, and BioRaCe systems was observed.     

Marginal Gaps between 2 Calcium Silicate and Glass Ionomer Cements and Apical Root Dentin

Introduction

The outcome of periapical surgery has been directly improved with the introduction of novel material formulations. The aim of the study was to compare the retrograde obturation quality of the following materials: calcium silicate (Biodentine; Septodont, Saint-Maur-des-Fosses, France), mineral trioxide aggregate (MTA+; Cerkamed Company, Stalowa Wola, Poland), and glass ionomer cement (Fuji IX; GC Corporation, Tokyo, Japan).

The Impact of TruNatomy and ProTaper Gold Instruments on the Preservation of the Periradicular Dentin and on the Enlargement of the Apical Canal of Mandibular Molars

IntroductionThis study aimed to evaluate the preservation of periradicular dentin and the enlargement of the apical canal of mandibular molars with TruNatomy (Dentsply Sirona, Ballaigues, Switzerland) and ProTaper Gold (Dentsply Sirona) instruments.MethodsTwenty mandibular molars were scanned in a micro–computed tomographic device, anatomically paired, and distributed into 2 groups (n = 10). In the ProTaper Gold group, mesial and distal canals were prepared up to F2 (25/.08v) and F3 (30/.09v) instruments, whereas in the TruNatomy group, mesial and distal canals were enlarged up to the prime (26/.04v) and medium (36/.03v) instruments, respectively. After a new scan, the surface area, volume, unprepared areas, transportation, percentage of dentin removal, and dentin thickness parameters were calculated. Data were compared between groups using the Mann-Whitney test, the Student t test, and the nonmetric multidimensional scaling test with alpha set at 5%.ResultsNo difference was found between groups regarding unprepared canal areas and the reduction of dentin thickness (P > .05). Transportation was lower than 0.1 mm in all groups, and statistical differences were observed only at the apical third of the mesiobuccal canal with lower values in the TruNatomy group. ProTaper Gold removed more dentin than TruNatomy at the coronal level of mesial roots (1.8% and 1.0%, respectively) (P < .05).ConclusionsTruNatomy and ProTaper Gold were efficient for performing canal preparation in mandibular molars. The tested systems were similar in terms of untouched canal walls and remaining dentin thickness and slightly different in the apical transportation of mesial canals and the percentage of dentin removal at the coronal third but without clinically significant errors.     

Root Canal Preparation and Enlargement Using Thermally Treated Nickel-Titanium Rotary Systems in Curved Canals

IntroductionThe purpose of this study was to evaluate root canal preparation and apical enlargement of curved canals using rotary heat-treated and heat/surface-treated systems by micro–computed tomographic imaging.MethodsCurved mesial root canals (n = 48) of mandibular molars (20°–40°) were prepared using ProDesign Logic (PDL; Easy Equipamentos Odontológicos, Belo Horizonte, MG, Brazil) 25/.01 and 25/.06 or HyFlex EDM (HFEDM) 10/.05, HyFlex CM 20/.04, and HFEDM 25/.08. Apical enlargement was performed using PDL 40/.05 or HFEDM 40/.04. Scanning (9 μm) was performed before and after preparation and after apical enlargement using micro–computed tomographic imaging. Volume, percentage of volume increase, debris, untouched root canal surface, and centering ability were analyzed. Statistical analysis was performed using Mann-Whitney, Wilcoxon, and unpaired t tests (α = .05).ResultsHFEDM promoted a higher volume increase of the root canals than PDL after preparation and after apical enlargement (P < .05). The apical enlargement promoted a significant decrease in debris and untouched surface in both groups (P < .05). The percentage of debris and untouched surface were similar between HFEDM and PDL after preparation and after apical enlargement (P > .05). Both systems promoted centered canals (P > .05).ConclusionsHFEDM instruments promoted greater volume of the root canal than PDL. However, the cleaning ability of the instruments was similar. The apical increase up to size 40 with both instruments provided less debris and untouched surfaces and allowed centralization of the curved root canals.