Cone Beam Computed Tomography Evaluation of Canal ...

Remedy Publications LLC.

Journal of Dentistry and Oral Biology

2022 | Volume 7 | Issue 1 | Article 11871

IntroductionRoot canal shaping is an essential step of endodontic treatment. The objectives of the root

canal preparation are to remove remaining pulp tissues and eliminate microorganisms and their by-products through a chemomechanical preparation combining a mechanical instrumentation and antibacterial irrigation. Nickel-Titanium (NiTi) rotary instruments are commonly used for shaping due to their capacity to create well-tapered canal preparations. Compared with manual instrumentation, they are able to reduce the shaping time and the risk of procedural accidents such as canal transportation [1]. The NiTi alloys are known to be super-elastic. This property has yet been improved with the innovative heat treatment that transforms the molecular structure of the alloy. Indeed, the thermal treatment increases the flexibility and cyclic fatigue resistance of the instruments [2,3]. However, in spite of these advantages, the complexity of endodontic anatomy and particularly canal curvatures is considered to be the major risk of instrument fracture caused by bending cyclic fatigue and torsional stresses [4]. This risk can be reduced by creating a glide path before using NiTi rotary instrumentation in order to prevent torque failure and cyclic fatigue [5]. Moreover, several studies have demonstrated that mechanical glide path improves the preservation of the canal anatomy [6,7]. Initially, this step was performed with hand files. Thereafter, NiTi rotary files were introduced for creating a mechanical glide path. Among them, Proglider (PG) (Dentsply

Cone Beam Computed Tomography Evaluation of Canal Transportation and Centering Ability of Several Glide Path Techniques, after Root Canal Preparation with WaveOne

Gold System

OPEN ACCESS

*Correspondence:Jean-Christophe Maurin, Department of Odontology, Univ Lyon, University

Claude Bernard Lyon 1, 11 rue Guillaume Paradin 69372, LYON Cedex 08, France, Tel: +33 - (0)4.78.77.87.58;

Fax: +33 – (0)6.84.98.93.36,E-mail: jean-christophe.maurin@univ-

lyon1.frReceived Date: 14 Dec 2021Accepted Date: 18 Jan 2022

Published Date: 10 Feb 2022

Citation: Richard E, Villat C, Farges J-C,

Maurin J-C. Cone Beam Computed Tomography Evaluation of Canal

Transportation and Centering Ability of Several Glide Path Techniques, after

Root Canal Preparation with WaveOne Gold System. J Dent Oral Biol. 2022;

7(1): 1187.ISSN: 2475-5680

Copyright © 2022 Jean-Christophe Maurin. This is an open access

article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution,

and reproduction in any medium, provided the original work is properly

cited.

Research ArticlePublished: 10 Feb, 2022

AbstractPurpose: To evaluate the canal transportation and centering ability of the WaveOne Gold® (WOG) system with a mechanical glide path carried out in continuous rotation and with a reciprocating motion using Cone Beam Computed Tomography (CBCT).

Methods: 54 extracted mandibular incisors with canal curvature <35° were divided into 3 groups (n= 18). Each group was randomly assigned to manual K and H-files (MF/WOG), Proglider (PG/WOG) of WaveOne Gold Glider® (WOGG/WOG) for glide path preparation. Each canal was then shaped with WOG to working length. The teeth were scanned before and after instrumentation and CBCT images were superimposed by using the Romexis software. Canal transportation and centering ratio were then calculated at 3 levels (4 mm, 7 mm and 11 mm from the apical end). Data were analyzed using 2 tests: Kruskal-Wallis test and Mann-Whitney test (P<0.05).

Results: At 7 mm (middle section) the groups PG/WOG and WOGG/WOG showed significantly less transportation and better centering ratio compared to the group (MF/WOG).

Conclusion: The mechanical glide path improved shaping ability of WaveOne Gold® and led to less canal transportation. Although no difference was observed between continuous rotation and reciprocating motion glide path, the reciprocating motion represents a reliable approach for glide path preparation.

Keywords: Centering ratio; Cone-beam computed tomography; Glide path, Proglider®; WaveOne Gold Glider®; Canal transportation

Etienne Richard1,2, Cyril Villat1,2,3, Jean-Christophe Farges1,2,4 and Jean-Christophe Maurin1,2,4*1Department of Odontology, Univ Lyon, University Claude Bernard Lyon 1, Lyon, France

2Odontology Medical Activities Center, Hospices Civils de Lyon, France

3Laboratory of Multimaterials and Interfaces, Univ Lyon, University Claude Bernard Lyon 1, CNRS, France

4Univ Lyon Lab, Tissue Biology and Therapeutic Engineering, UMR5305 CNRS/UCBL, Lyon, France

Etienne Richard, et al., Journal of Dentistry and Oral Biology

Remedy Publications LLC. 2022 | Volume 7 | Issue 1 | Article 11872

Maillefer, Ballaigues, Switzerland) consists of a single instrument manufactured from M-Wire alloy. This file has a variable taper with 0.02 taper and 0.16 mm diameter at tip. More recently other systems using the reciprocating motion were introduced to decrease the impact of cyclic fatigue compared with a rotational motion [8]. Hence, WaveOne Gold Glider® (WOGG) (Dentsply Maillefer, Ballaigues, Switzerland) and R-Pilot (VDM) are two single glide path files, designed to be used with reciprocating motion. WaveOne Gold Glider® files exhibit a variable taper from 0.02 to 0.06 with 0.15 mm diameter at its tip. This file is manufactured from heat treated NiTi M-WireTM alloy and has two different cross-sections: a modified convex triangular cross-section at the tip and a convex triangular cross-section in the middle and coronal portion.

Various methods have been used to evaluate instrumentation of different NiTi rotary systems [9,10], including Cone Beam Computed Tomography (CBCT) [11,12]. CBCT is a modification of the computed tomography providing 3-dimensional images with a high resolution. Image acquisition is rapid and can be performed before and after instrumentation without distortion. Thus, it is possible to use this method for geometric analysis of root canal area [11,12].

The aim of this study was to evaluate the canal transportation and centering ability of the WaveOne Gold system with a mechanical glide path carried out in continuous rotation (PG) and with a reciprocating motion (WOGG) using CBCT. The null hypothesis was that there would be no differences between groups after glide path and shaping.

Materials and MethodsSpecimens selection and groups

The 66 human mandibular incisors extracted for periodontal reasons were used under a protocol approved by the local ethical committee. Only teeth with curvature <35° with a single canal were selected. The canal curvature was evaluated according the method previously described by Schneider [13]. In order to standardize the samples and to remove coronal stresses, crowns were removed at 12 mm of the apical foramen by using a dremel Speed Clic diamond cutting disc (38 mm). The specimens were stored at 4°C in saline solution. Canals were explored by inserting a size 10 K-type file (Dentsply Maillefer, Ballaigues, Switzerland) which was passively advanced into the canals until the tip of the instrument was adjusted to the apical foramen. The root canal length was recorded, and the working length was calculated by subtracting 1 mm from this measurement [11]. Twelve teeth were then discarded because of fractures or absence of apical patency. The samples were then randomly divided into 3 experimental groups (n=18) according to the instrumentation technique used for glide path: group Handfile (HF)/WaveOne Gold® (WOG) (group #1: Glide path was created with HF and canal were prepared with WOG), group Proglider® (PG)/WOG (group #2: Glide path was created with PG and canal were prepared with WOG), group WaveOne Gold Glider® (WOGG)/WOG (group #3: Glide path was created with WOGG and canal were prepared with WOG).

Root canal preparationCanals were instrumented according to manufacturers'

instructions for each system.

In group 1, the glide path was created with a size 10, 15 and 20 K-File (Dentsply Maillefer, Ballaigues, Switzerland) up to the working length [14]. In group 2 the glide path was made with the Proglider® (Dentsply Maillefer, Ballaigues, Switzerland) using a continuous

rotary motion at 300 rpm and 2 Ncm powered by the VDW Gold Reciproc motor (VDM, Munich, Germany). In the group 3, the glide path was established with the WaveOne Gold Glider® system (Dentsply Maillefer, Ballaigues, Switzerland) using a reciprocating motion with the VDW Gold Reciproc motor (VDM, Munich, Germany) set on Reciprocation mode - "Reciproc all".

For all groups, each canal was shaped with the WaveOne Gold primary file (Dentsply Maillefer, Ballaigues, Switzerland) (25/0.7) using the VDW Gold Reciproc motor (VDM, Munich, Germany) set on Reciprocation mode - "Reciproc all" according to manufacturers' instructions. The canals were irrigated with 2 mL 5% sodium hypochlorite during instrumentation.

Image analysisThe teeth were positioned in a custom-made specimen holder

as previously described [15], in order to place the specimens in the same position before and after instrumentation. The teeth were aligned perpendicularly to the beam. They were scanned before and after instrumentation by using the CBCT scanner ProMax 3D Mid (Planmeca, Helsinki, Finland) in the dental radiology service of the Dental Service of the teaching Hospital, HCL, Lyon, France.

The samples were scanned at a high spatial resolution (150 µm) with the following parameters: 90 kV - 14 mA. The field of view was 10 cm in diameter and 6 cm in height.

CBCT measurementsFollowing instrumentation, the pre and post-operative images

were measured by using the Image J software (NIH, Bethesda, USA). Canal transportation and the centering ratio were calculated at 3 cross-section levels corresponding to 4 mm, 7 mm and 11 mm from the apical end by using the following equations [1].

• Canal centering ratio: (M1-M2)/(D1-D2) in the mesiodistal direction and (B1-B2)/(L1-L2) in the buccolingual direction.

• Degree of canal transportation: (M1-M2)-(D1-D2) for the mesiodistal direction and (B1-B2)-(L1-L2) for the buccolingual direction.

M1 represents the distance between the mesial portion of the root and the uninstrumented canal, M2 is the distance between the mesial portion of the root and the instrumented canal. D1 is distance between the distal portion of the root and the uninstrumented canal, D2 is the distance between the distal portion of the root and the instrumented canal. B1 represents the distance between the buccal portion of the root and the uninstrumented canal and B2 is the distance between the buccal portion of the root and the instrumented canal. L1 is the distance between the lingual portion of the root and the uninstrumented canal whereas L2 is the distance between the lingual portion of the root and the instrumented canal (Figure 1A, 1B).

The pre-and post-instrumentation CBCT images were then superimposed by using the Romexis software (Planmeca, Helsinki, Finland).

Statistical analysisAll statistical analyses were performed using the software

XLSTAT (Addinsoft, Paris? France). Cross-sectional areas were analyzed by using two tests: The Kruskal-Wallis H test and the Mann Whitney test. Statistical significance level was set at P<0.05 (α=0.05).



At first, a Kruskal-Wallis H test was realized to determinate if there was a statistical significance level between each group. If the result was under α, a Mann Whitney test was performed to determinate which group was better than the others.

ResultsCentering ratio

Table 1 and Figure 2 do not show any statistically significant differences in canal transportation among the 3 groups at the coronal level both mesiodistally and buccolingually (P>0.05). The same results were obtained in the apical section.

However, at 7 mm level corresponding to the middle third of the root, the group’s 2 (PG/WOG) and 3 (WOGG/WOG) showed a significantly lower mean transportation value compared to the group 1 (P<0.05) in the mesiodistal direction (Table 1 and Figure 2).

Canal transportationNo statistical difference was observed in the coronal and in the

apical third between the 3 groups (Table 2 and Figure 3). However, a significant difference has been revealed in the middle third between the group 1 (WOG) and the groups 2 and 3 (P<0.05). At 7 mm, the mean canal transportation is lower for the group 2 and 3 compared to the group 1.

DiscussionThe aim of this study was to evaluate the impact of the type of glide

path on shaping ability. The best outcomes are achieved when the root canal shaping maintains the original canal centre while minimizing canal transportation [4]. Canal transportation and centering ratio are commonly used to assess the ability of a shaping technique to preserve the original canal shape [5,11]. In the present study, these 2 parameters were analyzed before and after instrumentation by using CBCT. This method provides the advantages to acquire 3-dimensional images with a high resolution allowing evaluating precisely the root canal geometry. Moreover, unlike other methods previously described for evaluating root canal shaping [5,16], this

approach is non-invasive and shows more details compared with conventional radiography [17].

In this study, natural teeth with intact root apex were chosen to simulate the clinical condition. In order to standardize root canal anatomy and to constitute homogenous groups, human mandibular incisors with curvatures <35° were included. Indeed, these teeth have an oval-shaped root canal with a narrower mesiodistally than buccolingually, providing a clinical situation particularly adapted for a glide path before canal shaping [18]. All the teeth have been instrumented with the WaveOne Gold system® after removing the crown in order to avoid interferences between the file and the walls of the access cavity.

Regarding to the centering ratio, our results showed no significant difference among the groups in the coronal third. The same results were obtained in the apical third, where a lower transportation of the centering ratio has been observed for the 3 tested groups. Similarly, regarding the canal transportation, no difference was noticed between the 3 groups in the same zones. However, in the middle third, the results demonstrated a significant difference between the manual and the mechanical glide path. This could be explained by the anatomy of the endodontic system of the mandibular incisors displaying a narrower canal in this area [18]. Thus, endodontic instruments could undergo a greater stress in this zone. This hypothesis is strengthened by the fact that the stainless-steel K-files are known to their stiffness and their tendency to straighten the canal [14]. However, the higher flexibility of NiTi alloy minimizes the canal transportation and maintains the original canal centre [19]. Moreover, these results are consistent with those obtained in a previous study, showing that Proglider® instrument can create a preliminary enlargement of the root canal in the middle portion, due to its progressive taper [20]. Even if our results have not demonstrated any significant differences between Proglider® and WaveOne Gold Glider®, it seems that these latter may present the better values as previously described [21]. This might be attributed to the innovative M-Wire technology associated with the heat "gold treatment" improving the mechanical properties

Figure 1: Illustration of pre-instrumentation (A) and post-instrumentation (B) CBCT images with markings showing points of measurements used for determination of canal transportation and centering ratio.

Section Direction LM/WOG PG/WOG WOGG/WOG P value

CoronalMesiodistal 1.062 ± 0.388 2.698 ± 4.945 0.943 ± 0.571 0.282

Buccolingual 1.955 ± 1.850 0.979 ± 1.142 1.841 ± 2.706 0.299

MiddleMesiodistal 0.788 ± 0.341 1.304 ± 0.658 1.118 ± 0.469 0.010

Buccolingual 3.658 ± 7.131 1.656 ± 2.101 2.385 ± 3.566 0.299

ApicalMesiodistal 1.288 ± 1.974 1.131 ± 1.218 1.554 ± 1.833 0.321

Buccolingual 3.331 ± 5.804 2.477 ± 3.137 1.100 ± 1.372 0.076

Table 1: Mean ± Standard deviation of centering ratio for tested groups and statistical analysis with LM: Manual files, PG: Proglider®; WOD: Wave One Gold® and WOGG: Wave One Gold Glider®.



[22].

The preliminary glide path is a fundamental step before root canal shaping because it facilitates file progress in the apical direction. Indeed, by creating a smooth canal shape, the intensity of torsional stresses affecting shaping instrument can be reduced [5] and their use is safer. Compared with manual glide path, mechanical procedures improve the preservation of the canal; reduce time required for

shaping and the incidence of postoperative pain [6,23]. In this study, WaveOne Gold® system has been chosen for root canal shaping. All the teeth were instrumented with this system in order to analyze only the influence the preflaring system used. Previous studies have demonstrated the ability of this system to maintain the root canal anatomy and to respect the biological and the mechanical objectives of endodontic treatment [24-26]. By using this system, the operative procedure is simplified because one single file is required for root

Figure 2: Graphical representation of mean difference in centric ability.

Figure 3: Graphical representation of mean difference in canal transportation.

Section Direction LM/WOG PG/WOG WOGG/WOG P value

CoronalMesiodistal -0.003 ± 0.081 0.039 ± 0.086 0.031 ± 0.100 0.486

Buccolingual 0.008 ± 0.163 -0.031 ± 0.096 0.004 ± 0.051 0.386

MiddleMesiodistal -0.044 ± 0.070 0.027 ± 0.074 0.003 ± 0.056 0.008

Buccolingual -0.003 ± 0.196 0.002 ± 0.057 0.004 ± 0.072 0.479

ApicalMesiodistal -0.008 ± 0.109 -0.013 ± 0.048 0.002 ± 0.015 0.354

Buccolingual 0.024 ± 0.097 0.012 ± 0.061 -0.012 ± 0.049 0.400

Table 2: Mean ± Standard deviation of canal transportation for tested groups and statistical analysis with LM: Manual files, PG: Proglider®; WOD: Wave One Gold® and WOGG: Wave One Gold Glider®.



canal preparation. When this latter is associated with a preliminary glide path, time dedicated to the shaping is yet reduced [27]. The originality of this study was to analyze the impact of a mechanical glide path system working with a reciprocating motion on a large number on samples. Indeed, our study is one of the first to analyze the impact of the WaveOne Gold Glider® on final root canal preparation. The reciprocal motion was created in order to reduce the torsional stress and to decrease the cyclic fatigue [28]. Thus, it seemed interesting to compare the input of this motion with a rotational motion through WOGG and PG. Contrary to a previous study [21]; our study has not showed any differences between PG and WOGG. Nevertheless, different elements could explain these results. First, the canal curvatures of the selected teeth were not very strong. Previous studies have selected teeth with canal curvature ranging within 20° to 35° [11,20,29]. Thus, curved canals could be more discriminative to evaluate the shaping performance of the tested groups. Furthermore, the crown removal could also minimize the stresses applied on the files and could facilitate path file and root canal preparation. Then, PG and WOGG have different designs. It is so difficult to evaluate the part dedicated to the motion with those concerning the intrinsic properties of the files. A study analyzing a same system working both with a reciprocal and with a rotational motion could be performed. However, each system is designed to be used with a specific motion. Finally, a microcomputed tomographic evaluation of the root canal morphology could be also an interesting approach because it allows a 3D analysis of canal volume and surface area with a better resolution than CBCT [20,21,30]. However, both the cost and the acquisition time make the Micro CT not very accessible.

ConclusionIn conclusion, under the conditions of the current study, Wave

Gold Glider® single NiTi reciprocating file appears suitable for glide path management and has similar results than Proglider® single NiTi rotary file regarding canal transportation and centering ability.

AcknowledgmentThe authors thank Mrs. Marie-Thérèse Crozet-Boisson and Mr.

Bernard Guironnet for his technical help.

References1. Gambill JM, Alder M, del Rio CE. Comparison of nickel-titanium and

stainless steel hand-file instrumentation using computed tomography. J Endod. 1996;22(7):369-75.

2. Di Nardo D, Galli M, Morese A, Seracchiani M, Ferri V, Miccoli G, et al. A comparative study of mechanical resistance of two reciprocating files. J Clin Exp Dent. 2019;11(3):e231-5.

3. Fangli T, Maki K, Kimura S, Nishijo M, Tokita D, Ebihara A, et al. Assessment of mechanical properties of WaveOne Gold Primary reciprocating instruments. Dent Mater J. 2019;38(3):490-5.

4. Peters OA. Current challenges and concepts in the preparation of root canal systems: A review. J Endod. 2004;30(8):559-67.

5. Berutti E, Negro AR, Lendini M, Pasqualini D. Influence of manual preflaring and torque on the failure rate of ProTaper rotary instruments. J Endod. 2004;30(4):228-30.

6. Berutti E, Paolino DS, Chiandussi G, Alovisi M, Cantatore G, Castellucci A, et al. Root canal anatomy preservation of WaveOne reciprocating files with or without glide path. J Endod. 2012;38(1):101-4.

7. Lim YJ, Park SJ, Kim HC, Min KS. Comparison of the centering ability of Wave•One and Reciproc nickel-titanium instruments in simulated curved

canals. Restor Dent Endod. 2013;38(1):21-5.

8. De-Deus G, Moreira EJ, Lopes HP, Elias CN. Extended cyclic fatigue life of F2 ProTaper instruments used in reciprocating movement. Int Endod J. 2010;43(12):1063-8.

9. El Batouty KM, Elmallah WE. Comparison of canal transportation and changes in canal curvature of two nickel-titanium rotary instruments. J Endod. 2011;37(9):1290-2.

10. Hashem AA, Ghoneim AG, Lutfy RA, Foda MY, Omar GA. Geometric analysis of root canals prepared by four rotary NiTi shaping systems. J Endod. 2012;38(7):996-1000.

11. Elnaghy AM, Elsaka SE. Evaluation of root canal transportation, centering ratio, and remaining dentin thickness associated with ProTaper Next instruments with and without glide path. J Endod. 2014;40(12):2053-6.

12. Jonker CH, Van der Vyver PJ, De Wet FA. The influence of glide path preparation on the failure rate of WaveOne reciprocating instruments. SADJ. 2014;69(6):266-9.

13. Schneider SW. A comparison of canal preparations in straight and curved root canals. Oral Surg Oral Med Oral Pathol. 1971;32(2):271-5.

14. Berutti E, Cantatore G, Castellucci A, Chiandussi G, Pera F, Migliaretti G, et al. Use of nickel-titanium rotary PathFile to create the glide path: comparison with manual preflaring in simulated root canals. J Endod. 2009;35(3):408-12.

15. Özer SY. Comparison of root canal transportation induced by three rotary systems with noncutting tips using computed tomography. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2011;111(2):244-50.

16. Bürklein S, Flüch S, Schäfer E. Shaping ability of reciprocating single-file systems in severely curved canals: WaveOne and Reciproc versus WaveOne Gold and Reciproc blue. Odontology. 2019;107(1):96-102.

17. Patel S, Brown J, Pimentel T, Kelly RD, Abella F, Durack C. Cone beam computed tomography in Endodontics - A review of the literature. Int Endod J. 2019;52(8):1138-52.

18. Leoni GB, Versiani MA, Pécora JD, Damião de Sousa-Neto M. Micro-computed tomographic analysis of the root canal morphology of mandibular incisors. J Endod. 2014;40(5):710-6.

19. Song YL, Bian Z, Fan B, Fan MW, Gutmann JL, Peng B. A comparison of instrument-centering ability within the root canal for three contemporary instrumentation techniques. Int Endod J. 2004;37(4):265-71.

20. Alovisi M, Cemenasco A, Mancini L, Paolino D, Scotti N, Bianchi CC, et al. Micro-CT evaluation of several glide path techniques and ProTaper Next shaping outcomes in maxillary first molar curved canals. J Endod. 2019;45(6):791-6.

21. Aydyn ZU, Keskin NB, Özyürek T, Geneci F, Ocak M, Çelik HH. Microcomputed assessment of transportation, centering ratio, canal area, and volume increase after single-file rotary and reciprocating glide path instrumentation in curved root canals: A laboratory study. J Endod. 2019;45(6):791-6.

22. Keles A, Eymirli A, Uyanık O, Nagas E. Influence of static and dynamic cyclic fatigue tests on the lifespan of four reciprocating systems at different temperatures. Int Endod J. 2019;52(6):880-6.

23. Pasqualini D, Mollo L, Scotti N, Cantatore G, Castellucci A, Migliaretti G, et al. Postoperative pain after manual and mechanical glide path: A randomized clinical trial. J Endod. 2012;38(1):32-6.

24. Keskin C, Demiral M, Sarıyılmaz E. Comparison of the shaping ability of novel thermally treated reciprocating instruments. Restor Dent Endod. 2018;43(2):e15.

25. van der Vyver PJ, Paleker F, Vorster M, de Wet FA. Root canal shaping using nickel titanium, M-Wire, and Gold Wire: A micro-computed tomographic comparative study of one shape, ProTaper next, and WaveOne gold

https://pubmed.ncbi.nlm.nih.gov/8935064/



https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6461731/












































































instruments in maxillary first molars. J Endod. 2019;45(1):62-7.

26. Özyürek T, Yılmaz K, Uslu G. Shaping ability of reciproc, WaveOne GOLD, and HyFlex EDM single-file systems in simulated S-shaped canals. J Endod. 2017;43(5):805-9.

27. Vorster M, van der Vyver PJ, Paleker F. Influence of glide path preparation on the canal shaping times of WaveOne gold in curved mandibular molar canals. J Endod. 2018;44(5):853-5.

28. Giuliani V, Di Nasso L, Pace R, Pagavino G. Shaping ability of waveone primary reciprocating files and ProTaper system used in continuous and reciprocating motion. J Endod. 2014;40(9):1468-71.

29. Dhingra A, Nagar N, Sapra V. Influence of the glide path on various parameters of root canal prepared with WaveOne reciprocating file using cone beam computed tomography. Dent Res J (Isfahan). 2015;12(6):534-40.

30. Silva EJNL, Pacheco PT, Pires F, Belladonna FG, De-Deus G. Microcomputed tomographic evaluation of canal transportation and centering ability of ProTaper next and twisted file adaptive systems. Int Endod J. 2017;50(7):694-9.



















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