Canal Centering Ability Research Articles

Comparative evaluations on the canal-centering ability of novel heat-treated retreatment file system using nano-computed tomography

Abstract Introduction: The main goal of instrumentation during retreatment is to maintain the original curvature of the canal during retrieval of gutta-percha. The present study evaluates the canal-centering ability of two different retreatment file systems. Materials and Methods: Forty extracted single-rooted teeth were decoronated and obturated at the standardized root length of 16 mm. Samples were divided into two groups of each 20 single root teeth and they were instrumented using Solite RS3 Retreatment and ProTaper Retreatment files, respectively. Both pre- and postoperative nano-computed tomography scans were taken, and three-dimensional reconstruction was done for analysis. Sections of both the pre- and postoperative samples were taken at 7 mm, 5 mm, and 3 mm from the apex to calculate the canal-centering ratio. Independent t-test was used for statistical analysis between the two groups. Results: Solite RS3 retreatment files showed a significant difference at the 3 levels (P < 0.000) compared to ProTaper retreatment files. Conclusion: From the above results, we can conclude that Solite RS3 caused minimal canal transportation and produced a relatively centered preparation in comparison to the ProTaper Retreatment system.

Canal-Centering and Apical Transportation Ability of Similar Cross-Section NiTi Instruments Working with Different Kinematics-Micro-CT-based In Vitro Analysis.

Evaluating the canal-centering and apical transportation ability of endodontic file systems working with different kinematics but of similar cross section. Sixty human maxillary first molar mesiobuccal (MB) roots were assigned to three experimental groups based on instrumentation techniques: Reciproc Blue (RB), Mtwo (M2), and OneShape (OS). Pre- and post-instrumentation micro-computed tomographic analysis was performed. Centering ability and apical transportation were analyzed at 3 mm, 6 mm, and 9 mm short of the apex. Statistical analysis was conducted using Mann-Whitney U test and Kruskal-Wallis test. OS showed better canal-centering ability than RB and M2 at 3 mm, 6 mm, and 9 mm. No significant difference among the tested groups was observed during the assessment of apical transportation (P < 0.05). The systems evaluated safely prepared curved MB canals with minimal canal transportation. OS showed superior canal-centering ability compared to the other two groups.

Transportation and Canal Centering Ability of Reciprocating vs Full Rotating Files after Instrumenting Severely Curved Canals. A Cone Beam Computed Tomography Comparative Study

Transportation and Canal Centering Ability of Reciprocating vs Full Rotating Files after Instrumenting Severely Curved Canals. A Cone Beam Computed Tomography Comparative Study

Effect of preset torque setting on torque/force generation, shaping ability and surface changes of nickel titanium rotary instrument in different root canal curvature locations: An ex vivo study.

The aim of this study was to evaluate how preset torque settings influence the torque, vertical force, and root canal-centering ability of ProGlider and ProTaper NEXT nickel-titanium rotary instruments in canals with different curvature locations. Based on micro-computed tomography, mesial roots of human mandibular molars (25°-40° curvature) were allocated to the apical curvature (apical 1-5 mm) or the middle curvature (apical 5-9 mm) groups, and mandibular incisors (curvature <5°) to the straight canal group. Each group was subjected to automated instrumentation and torque/force measurement with the preset torque of 1, 2.5, or 5 N•cm. Canal-centering ratios were determined with micro-computed tomography. Instrument fracture occurred only in the 2.5 and 5 N•cm groups in curved canals. The preset torque setting and curvature location did not influence canal shaping ability.

Evaluation of Canal-centering Ability and Apical Transportation of Hyflex-EDM, OneShape, WaveOne Gold, and Reciproc Files: An Ex Vivo Study.

To evaluate and compare canal-centering ability (CCA), canal transportation (CT), and dentinal crack formation by using Hyflex-electrical discharge machining (EDM), OneShape, WaveOne Gold, and Reciproc single file system in the mesiobuccal root of maxillary first molar at coronal, middle, and apical third using cone-beam computed tomography (CBCT) and scanning electron microscopy (SEM). Mesiobuccal roots of 120 freshly extracted maxillary molar teeth were divided into four experimental groups; Hyflex-EDM, OneShape, WaveOne Gold, and Reciproc (n = 30/group). Preinstrumentation scanning was done using CBCT for all samples at coronal one-third (4 mm), middle one-third (8 mm), and apical one-third (12 mm). After cleaning and shaping with standard irrigation protocol, the specimens were again scanned. Canal-centering ability and CT were calculated using pre- and postinstrumentation CBCT values. A scanning electron microscope was used to identify dentinal crack formation. No significant difference was found for CCA by any of the systems at coronal, middle, and apical third, respectively. However, OneShape was found to have better CCA at the coronal third and WaveOne Gold at the middle and apical third. There was a significant difference in canal transportation at the apical third (p = 0.004) with WaveOne Gold having the least CT followed by Reciproc at the apical third. OneShape resulted in more dentinal cracks in the coronal and middle thirds. Also, Hyflex-EDM was better in the apical third. No difference in CCA was observed between the groups. The lowest values for CT were obtained for WaveOne Gold (similar to Reciproc) whereas both rotary files showed higher values for CT. Also, OneShape showed the most dentinal at all levels. Furthermore, Hyflex-EDM and WaveOne Gold produced the least dentinal cracks at all levels. Given that the Reciprocating file system had the least CT and least dentinal cracks, the clinical success rate of root canal treatment (RCT) with the Reciprocating file system can be a better choice to improve the longevity of root canal-treated teeth.

Comparative Evaluation of Root Canal Centering Ability of Two Heat-treated Single-shaping NiTi Rotary Instruments in Simulated Curved Canals: An In Vitro Study

Comparative Evaluation of Root Canal Centering Ability of Two Heat-treated Single-shaping NiTi Rotary Instruments in Simulated Curved Canals: An In Vitro Study

A cone-beam computed tomographic analysis of total dentin removed, canal transportation, and canal-centering ability following instrumentation with three different file systems: An in vitro study.

The aim of this study was to evaluate the shaping ability following instrumentation with XP-endo Shaper (XPS), TruNatomy (TRN), and HyFlex CM (HCM) file system. Fifty-four mesiobuccal canals of mandibular molars were selected and allocated into three groups randomly: XPS, TRN system, and HCM file system. Pre- and postinstrumentation scans were taken using a cone-beam computed tomography scanner to determine the amount of root dentin removed, mesiodistal and buccolingual transportation, and canal-centering ratio at 2, 5, and 8 mm from the root end. Data were statistically analyzed using Kruskal-Wallis test and the significance level was set at P = 0.05. TRN file system removed the least amount of root dentin. XPS showed statistically higher M-D canal transportation at 5 mm level from the apex. TRN file system showed better dentin preservation as compared to XPS and HCM. XPS showed the highest canal transportation at 5 mm. All three file systems performed similarly in terms of canal-centering ability.

Canal centering ability of various file systems during endodontic treatment and re-treatment: A systematic review

Introduction: The canal-centering ability of an endodontic file is the ability of a file to maintain its path centered through the root canal without causing transportation. Various researchers have attempted to compare the canal-centering ability of the different file systems used routinely in endodontic practice. The present systematic review aimed to comparatively analyze the canal-centering ability of the various endodontic file systems. Methods: A systematic search was performed using the keywords ‘Canal centering ability’ and ‘Endodontics’ across the databases Medline, PubMed, PubMed Central, Web of Science Citation Index Expanded, and Google Scholar to identify studies related to canal-centering ability of various file systems in endodontic treatment or re-treatment in English language without any restriction for the date of publication. Results: A total of 22 studies were identified, most of which utilized human extracted teeth for analyzing the canal-centering ability. The mesial root of the mandibular first molars was most commonly used, with the mesiobuccal canal being commonly chosen to compare the canal centering ability. No significant difference was found between the canal-centering ability of reciprocating and continuous rotary file systems. The individual conclusions regarding comparisons made between respective file systems in each study have been summarized in the text. Conclusion: The canal-centering ability of various endodontic file systems does not depend on the speed or motion of the file but is a derivative of multiple factors including geometry, composition, size, and shape of the files. Findings from the present systematic review would serve as a guide for an appropriate selection of the files to be used in cases with challenging canal morphology requiring endodontic treatment.

Effect of Rotational Modes on Torque/Force Generation and Canal Centering Ability during Rotary Root Canal Instrumentation with Differently Heat-Treated Nickel-Titanium Instruments.

This study aimed to evaluate how various rotational modes influence the torque/force production and shaping ability of ProTaper Universal (PTU; non-heat-treated) and ProTaper Gold (PTG; heat-treated) nickel–titanium instruments. J-shaped resin canals were instrumented with PTU or PTG using an automated instrumentation device operated with reciprocating rotation [150° clockwise and 30° counterclockwise (R150/30) or 240° clockwise and 120° counterclockwise (R240/120)], optimum torque reverse motion (OTR), or continuous rotation (CR) (n = 10 each). Maximum force and torque were recorded, and canal centering ratios were calculated. Statistical analysis was performed with two-way ANOVA and a Bonferroni test (α = 0.05). The results were considered with reference to previous studies on the microstructure of the instruments. The upward force generated by R240/120 and OTR was smaller than that generated by R150/30 and CR in PTG (p < 0.05). The clockwise torque produced by OTR was lower than that produced by R150/30 in PTU and R240/120 and CR in PTG (p < 0.05). R240/120 and OTR induced less canal deviation compared to CR in PTU at 0 mm from the apex (p < 0.05). In conclusion, R240/120 and OTR reduced the screw-in force in PTG and improved the canal centering ability in PTU, which may be associated with the heat treatment-induced microstructural difference of the two instruments.

Comparative Evaluation of Root Canal Centering Ability of ProTaper, Mtwo, WaveOne, and Reciproc Using Cone-beam Computed Tomography: In Vitro Study

To compare the centering ability of rotating (ProTaper and Mtwo) and reciprocating (WaveOne and Reciproc) file systems using cone-beam computed tomography (CBCT). Eighty extracted human mandibular molars with curvature within 15-45° were selected and randomly divided into four groups (n = 20): group I (ProTaper), group II (Mtwo), group III (WaveOne), and group IV (Reciproc). The selected teeth were arranged in a template, and pre-instrumentation and post-instrumentation CBCT scans were taken using Kodak Carestream CS 9300 machine. The centering ability was measured in four planes namely, at furcation, 3 mm apical to furcation (coronal), 6 mm apical to furcation (middle), and 3 mm coronal to the apex (apical), wherein dentin thickness was measured from pre- and post-instrumentation CBCT scans and recorded for each canal (mesiobuccal and mesiolingual) separately and statistically analyzed. Mtwo and Reciproc remained better centered followed by WaveOne and least by ProTaper in different-level comparisons. In the mesiodistal dimension (MD) at the 3 mm, 6 mm, and 3 mm apical level, Mtwo and Reciproc showed better centering, meanwhile, in the buccolingual dimension, only in the 3 mm apical level, Mtwo and Reciproc remain better centered. A significant difference was seen between the group and type of canal. Mtwo and Reciproc showed better centered preparation than ProTaper and WaveOne. Significant differences were seen between the groups and types of canal. Root canal instrumentation should maintain the original canal anatomy. The proper enlargement keeping in mind the remaining strength in the tooth structure is essentially decided by how the selected instrument is centered. The alloy used for instrument manufacture and its design (taper, cross-section, and tip) will influence the centered preparation. The type of instrument and the instrumentation techniques should be chosen based on root canal anatomy.

Comparative Evaluation of Canal-shaping Abilities of RaceEvo, R-Motion, Reciproc Blue, and ProTaper Gold NiTi Rotary File Systems: A CBCT Study

To evaluate the canal transportation, canal-centering ability, and touched and untouched surfaces of the root canal dentin after instrumentation with various newer file systems in continuous rotation and reciprocating motion using cone-beam computed tomography (CBCT) imaging. This in vitro study was conducted on one hundred recently extracted human mandibular molars, which were selected and instrumented using the following rotary NiTi file systems: RaceEvo, R-Motion, Reciproc Blue, and ProTaper Gold. The canal preparations for all four (04) experimental groups were done according to the manufacturer's instructions; the CBCT imaging was done for all the teeth compared at different levels of 2 mm, 5 mm, 8 mm from the apex, before and after the canal preparations. The data thus collected were evaluated for variation where p <0.05 was calibrated as significant using "ANOVA and Mann-Whitney" statistical tests. When the file systems were compared at different levels of the canal i.e. 2 mm, 5 mm, 8 mm from the apex, we observed a statistically significant difference for all the experimental groups (p = 0.021, 0.023, 0.032) respectively for the canal transportation (CT), (p = 0.045, 0.040, 0.037) respectively for the canal centering ability (CCA), (p <0.001) respectively for the touched (TS) and untouched (US) surfaces. R-Motion showed the least CT, greater CCA, with maximum TS, and the least US dentinal surfaces in the root canal preparations followed by RaceEvo, Reciproc Blue, and ProTaper Gold. R-Motion exhibited better canal centering ability, lower canal transportation due to its improved cutting efficiency down to the apex while preserving the dentin of the root canal walls and also exhibits lesser stress on dentin. The newer rotary file systems of R-Motion and RaceEvo described in this study could be recommended for clinical use during endodontic treatment. The newly introduced R-Motion and RaceEvo showed better preparations of the root canal compared to other file systems and could be used as a reliable alternative to the ProTaper file systems which is considered as the gold standard in rotary endodontics.

Effect of Different Downward Loads on Canal Centering Ability, Vertical Force, and Torque Generation during Nickel-Titanium Rotary Instrumentation.

This study aimed to examine how downward loads influence the torque/force and shaping outcome of ProTaper NEXT (PTN) rotary instrumentation. PTN X1, X2, and X3 were used to prepare J-shaped resin canals employing a load-controlled automated instrumentation and torque/force measuring device. Depending on the torque values, the handpiece was programmed to move as follows: up and down; downward at a preset downward load of 1 N, 2 N or 3 N (Group 1N, 2N, and 3N, respectively; each n = 10); or upward. The torque/force values and instrumentation time were recorded, and the canal centering ratio was calculated. The results were analyzed using a two-way or one-way analysis of variance and the Tukey test (α = 0.05). At the apex level, Group 3N exhibited the least canal deviation among the three groups (p < 0.05). The downward force was Group 3N > Group 2N > Group 1N (p < 0.05). The upward force, representing the screw-in force, was Group 3N > Group 1N (p < 0.05). The total instrumentation time was Group 1N > Group 3N (p < 0.05). In conclusion, increasing the downward load during PTN rotary instrumentation improved the canal centering ability, reduced the instrumentation time, and increased the upward force.

Shaping ability of WaveOne Gold reciprocating instruments compared to two analogous counterparts

The aim of this study was to evaluate and compare canalcentering ability and transportation of three analogous reciprocating shaping instruments after glide path preparation. Radiographs were used to select sixty untreated mesiobuccal canals with curvatures of 25° to 35° from extracted, human, mandibular molars. The canals were randomly divided into three groups for glide path preparation and shaping (n = 20): Group TWOG (WaveOne Gold Glider + Primary WaveOne Gold); Group TEF (Edge GlidePath + Primary EdgeOne Fire); and Group TOFG (One File G Reciprocating Glide Path File + Primary Shaping file). Pre- and post-preparation micro-CT scans were compared at levels 7 mm (coronal), 5 mm (midroot), and 3 mm (apical) from the apex to evaluate transportation and centering ratios. There were no significant differences in centering ratios at the coronal and midroot levels (P &gt; 0.05). Transportation values were similar at the coronal level and for the combined mean values (P &gt; 0.05). Transportation values for TEF and TWOG were similar (P = 0.98) at the midroot level but significantly lower than TOFG (P = 0.04). Apically, TEF remained significantly more centered with significantly lower transportation values than TWOG and TOFG (P &lt; 0.05). Combined results showed that TEF was significantly more centered than TWOG but similar to TOFG (P = 0.017). Centering ratios and transportation values were more favorable in the apical region after use of TEF. All three groups evaluated in this study proved to be safe for the preparation of moderately curved root canals.

Impact of Radial Lands on the Reduction of Torque/Force Generation of a Heat-Treated Nickel-Titanium Rotary Instrument

This study investigated the impact of a one-sided radial-landed cross-sectional design of a heat-treated nickel-titanium rotary instrument (JIZAI, MANI, Japan; JZ) on torque/force generation and canal-shaping ability, using an experimental non-landed instrument (non-landed JZ) for comparison. Both instruments had tip sizes of 25 and 0.04 or 0.06 taper and were similar in metallurgy and geometry, except for the presence/absence of a radial land. Twenty J-shaped simulated resin canals were instrumented in a two-instrument single-length sequence using an automated root canal instrumentation device with a torque/force analyzing unit. Pre- and post-instrumentation images of the resin canals were analyzed for canal-centering ability at 0–3 mm from the apex. The mean centering ratio was not significantly different between JZ and non-landed JZ (p &gt; 0.05). In the 2nd instrumentation, JZ showed a significantly smaller torque compared with the non-landed JZ (p &lt; 0.05). Regardless of instrumentation sequence, JZ showed a significantly smaller maximum upward force, representing screw-in force (p &lt; 0.05), and a larger maximum downward force (p &lt; 0.05) than the non-landed JZ. JZ generated smaller screw-in forces and had similar canal-centering ability compared with the non-landed JZ.

Comparison of Canal Transportation and Centering Ability of One-G, EdgeGlidePath, and Neolix: A MicroComputed Tomography Study of Curved Root Canals

Aims A glide path is created prior to root canal instrumentation by nickel-titanium (NiTi) rotary files to increase the efficiency and safety of cleaning and shaping. This study aimed to assess root canal transportation in use of different glide path files in curved canals. Materials and Methods 30 sound mesiobuccal root canals of mandibular molars with 20° to 40° curvature were selected and randomly assigned to 3 groups of EdgeGlidePath (EGP, EdgeEndo), One-G (Micro-Mega), and Neolix (Neoniti). The specimens were scanned before and after glide path creation by microcomputed tomography (micro-CT). The pre- and postoperative micro-CT scans were superimposed, and the degree of canal transportation and centering ratio were measured at 1, 3, 5, and 7 mm distances from the apical foramen. Statistical Analysis. The data were analyzed by two-way and one-way ANOVA. Results The effects of distance from the apical foramen and instrument type and the interaction effect of the two were not significant on the centering ability of the files or canal transportation. Conclusion EdgeGlidePath, One-G, and Neolix files fabricated from the conventional NiTi alloy or heat-treated M-Wire alloy showed similar performance regarding centering ability and canal transportation in glide path preparation in curved canals.

Cone-Beam Computed Tomography Assessment of Canal-Centering Ability for Traditionally Used Nickel Titanium and Nickel Titanium Files with Reciprocating Hand Piece and Wave-One Files.

Aim of the Study:Need for our study was to evaluate a comparison between canal preparation ability of nickel–titanium (NiTi) hand files with step-back manual technique, of NiTi files installed on a reciprocating hand piece and of Wave-One files utilizing noninvasive cone-beam computed tomography (CBCT) technique.Materials and Methods:Thirty extracted intact single-rooted human mandibular premolars were used in the study, segregated in three sets of 10 specimens each, where canal instrumentation was done by different methods using NiTi in step-back technique, using reciprocating hand piece with NiTi files and using primary file with the use of Wave-One reciprocating system. Later, evaluation of centering ability was conducted using the references through CBCT images.Results:Hand NiTi files showed even less canal centering ability as compared to other two sets. Mesiodistal diameter at 9 mm length of the prepared canal was 1.06 and later was 0.98, which shows excessive preparation in case of Set I versus Set II. In case of comparison between Set III and Set I, mesiodistal diameter at 9 mm length of the prepared canal was 0.99, and later was 1.06, depicting better canal shaping ability with Wave-One file.Conclusion:The use of hand NiTi files installed on a reciprocating hand piece would be economically beneficial producing the similar results as that of wave one without any deviation from the original canal anatomy.

Comparative Evaluation Of Apical Transportation and Canal Centering Ability Of Various NickelTitanium Rotary Systems In Curved Canals Using Cone-Beam Computed Tomography: An In Vitro Study

Comparative Evaluation Of Apical Transportation and Canal Centering Ability Of Various NickelTitanium Rotary Systems In Curved Canals Using Cone-Beam Computed Tomography: An In Vitro Study

Canal transportation and centering ability of root canals prepared using rotary and reciprocating systems with and without PathFiles in cone-beam computed tomography-based three-dimensional molar prototypes

Background:It is important to use instruments that cause minimal changes in the canal path for root canal preparation. There is inadequate literature comparing rotary and reciprocating systems and hand files. No study used three-dimensional printed models to compare rotary, reciprocating, and hand files.Aims:We aimed to assess the canal transportation and centering ability of WaveOne Gold, ProTaper Gold, and NiTi Flex K-file systems with and without glide path preparation.Material and Methods:Forty-nine resin models were randomly divided into Group I A – WaveOne Gold with WaveOne Gold Glider and Group I B – WaveOne Gold without glide path; Group II A – ProTaper Gold with ProGlider and Group II B – ProTaper Gold without glide path; and Group III A – NiTi Flex K-files with no. 10 stainless steel K-file and Group III B – NiTi Flex K-files without glide path. Pre- and postinstrumentation cross-sectional images at levels 3, 5, 7, 9, and 11 mm were compared.Results:WaveOne Gold caused the least canal transportation and improved centering ability (P < 0.05). NiTi Flex K-files transported the canal more than others in the apical levels (3, 5 mm). Glide path creation reduced canal transportation and improved canal-centering ability.Conclusions:WaveOne Gold system has better centering ability and lesser canal transportation than ProTaper Gold and NiTi Flex K-file. Glide path creation reduced canal transportation and improved canal-centering ability.

Enhanced root canal-centering ability and reduced screw-in force generation of reciprocating nickel-titanium instruments with a post-machining thermal treatment.

This study aimed to evaluate the influence of a post-machining thermal treatment on canal-centering ability and torque/force generation of reciprocating nickel-titanium instruments. Simulated J-shaped resin canals were prepared with reciprocating instruments sharing identical geometric architecture and with/without post-machining thermal treatment (Reciproc Blue/Reciproc, VDW, Munich, Germany). Using an original automated root canal instrumentation and torque/force analyzing device, files were operated in a combination of reciprocation and up-and-down motion, and torque/force values were monitored. Canal-centering ratios were measured after superimposition of pre- and post-instrumentation images. Compared with Reciproc, Reciproc Blue showed a significantly lower canal-centering ratio (i.e., less deviation; p<0.05) at 0-1 mm from the apex and generated a significantly smaller upward maximum vertical force (p<0.05). Under standardized conditions using the automated device, Reciproc Blue showed better canal-centering ability and reduced screw-in forces than Reciproc, indicating that the post-machining thermal treatment confers superior performance to reciprocating nickel-titanium instruments.

Comparative evaluation of the shaping ability of rotary systems of varying metallurgy in curved canals and its analysis using cone-beam computed tomography: An in vitro study

Background: This study compared the shaping ability of four nickel-titanium rotary file systems of varying metallurgy along curved canals. Aim: The aim of the present study is to compare the shaping ability of rotary systems of varying metallurgy in curved canals and its analysis using cone-beam computed tomography (CBCT). Materials and Methods: Forty mesiobuccal canals of mandibular first molars with an angle of curvature ranging from 20° to 40° were divided according to the instrument used in canal preparation into four groups of 10 samples each: Hyflex CM (Group I), Vortex Blue (Group II), Flexicon (Group III), and K3XF (Group IV). All samples were instrumented according to the manufacturer's guidelines and prepared to size 30, 0.06-taper master apical file. Canals were scanned and evaluated using an NNT CBCT unit before and after preparation at different levels from the apex. The data were subjected to statistical analysis. Statistical Analysis: The intergroup comparison in terms of canal transportation and the time taken for canal preparation was done by the one-way analysis of variance (ANOVA) test with Bonferroni post hoc test. The intragroup comparison in terms of canal transportation was done by the repeated measures ANOVA test with the post hoc Bonferroni test. For the canal-centering ability, the Kruskal–Wallis test with Mann–Whitney U-test was used for the intergroup comparison and the intragroup comparison was done by Friedman's test with Wilcoxon signed-rank test. Results: Hyflex CM and Vortex Blue files showed significantly least canal transportation and highest canal-centering ability values as compared to Flexicon and K3XF file systems. Conclusion: The metallurgy and file design of Hyflex CM and Vortex Blue file systems resulted in superior shaping ability, with the instruments remaining more centered in the canal than Flexicon and K3XF.