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 Table of Contents  
ORIGINAL ARTICLE
Year : 2018  |  Volume : 30  |  Issue : 1  |  Page : 21-24

Comparative evaluation of buckling resistance of Proglider and One-G file: An in vitro study


Department of Conservative Dentistry and Endodontics, M.G.V's K.B.H. Dental College and Hospital, Nashik, Maharashtra, India

Date of Web Publication4-Jun-2018

Correspondence Address:
Dr. Swapnil Janardan Kolhe
Audumbar, Mangalmurti Nagar, Next to RTO Colony, Nashik-Pune Road, Nashik - 422 011, Maharashtra
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/endo.endo_121_17

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  Abstract 

Aim: Comparative evaluation of buckling resistance of Proglider and One-G file, An In vitro Study.
Materials and Methods: The test instruments – Proglider and One-G files were subjected to a devised buckling resistance test, which consisted of the application of an increasing load in the axial direction of the instrument by using a universal testing machine. The maximum load required to generate a lateral elastic displacement of 1 mm was recorded for each instrument. Data were analyzed using the one-way ANOVA test.
Results: The results indicated that the buckling resistance of One-G files is significantly better than Proglider files (P < 0.05).
Conclusion: One-G rotary files manufactured with conventional nickel-titanium alloy showed higher buckling resistance compared to Proglider files manufactured with M-wire alloy.

Keywords: Buckling resistance, One-G, Proglider


How to cite this article:
Patil PH, Gulve MN, Kolhe SJ. Comparative evaluation of buckling resistance of Proglider and One-G file: An in vitro study. Endodontology 2018;30:21-4

How to cite this URL:
Patil PH, Gulve MN, Kolhe SJ. Comparative evaluation of buckling resistance of Proglider and One-G file: An in vitro study. Endodontology [serial online] 2018 [cited 2018 Oct 21];30:21-4. Available from: http://www.endodontologyonweb.org/text.asp?2018/30/1/21/233736


  Introduction Top


A successful outcome of endodontic treatment depends on instrumentation and mechanical debridement, which in turn allows delivery of irrigants, medicaments, and obturation.[1] Initial scouting of the root canal system is a crucial step during biomechanical preparation because it allows assessment of the root canal anatomy, which cannot be appreciated with routine radiographic examination. It also helps the clinician to verify the configuration and number of canals.[2] Negotiation of this complex system allows access to the apical region of the canal creating a path for subsequent instruments to follow.[3] Establishment of a glide path is accomplished by enlargement of this initial path to allow unimpeded access to apical region and can be complicated further in canals with calcification/constrictions or severe curvatures.

During negotiation of constricted or calcified canals, the exploring instruments should ideally exhibit adequate resistance to torsion and buckling so as to endure the loads imposed on them during apical progression.[4] The instrument is slowly pushed apically with watch winding or a quarter-turn pull movement. Repetition of these steps lead to the advancement of the instrument within a constricted canal.[5] Several manufacturers have designed the instruments to manage thin, constricted, curved canals; by altering tip and taper configuration to achieve balance between small size, increased rigidity, and minimal deformation.[6],[7]

Buckling can be defined as “the lateral deformation of an endodontic instrument when subjected to a compressive load applied in the direction of its long axis.”[8] Buckling resistance of instruments is very important during scouting of canal to prevent elastic or plastic deformation that hampers their apical advancement in the canal. This deformation along with continuous rotational movement in the canal leads to separation of the instrument. This behavioral property should not be correlated with flexibility of instrument because the latter is related to the application of force perpendicular (and not parallel) to the axis of the instrument.[9]

Studies have shown that stainless steel hand file has better buckling resistance than nickel-titanium (NiTi) instruments.[10] Recently, single NiTi file systems such as Proglider and One-G have been introduced in endodontics to negotiate the narrow, curved canals within less time, instead of multiple file systems such as Path files and G-files, respectively. Till date, literature has failed to show any study comparing buckling resistance of these single file systems. Hence, the aim of this study was to evaluate and compare the buckling resistance of two single file systems, namely Proglider and One-G.


  Materials and Methods Top


The following pathfinding instruments were evaluated in this study. Each group contains 10 files (n = 10).

  • Group I: Control: In this group, C + files (Maileffer/Dentsply, Switzerland) were used
  • Group II: Proglider files (Maileffer/Dentsply, UK)
  • Group III: One-G files (Micro Mega, France).


All the tested instruments were of 25 mm in length. The instrument handle was fixed to the head of the universal testing machine, and the instrument tip was placed in a small punch cavity prepared on the stainless steel plate. A small punch hole (1 mm depth and 0.5 mm width) was placed in the center of stainless steel plate using small round bur. This punch hole was prepared to prevent slippage of a file laterally during force application, as shown in [Figure 1]. For the buckling test, an increasing load was applied in the axial direction of each instrument from its head to the tip by a universal testing machine (DL 10.000; Emic, Sao Josdos Pinhais, PR, Brazil), using a speed of 1 mm/min. A load cell of 20 N was used. Maximum load needed to induce the lateral elastic displacement of 1 mm was recorded as the buckling resistance of the respective instrument as shown in [Figure 2].
Figure 1: Photograph of Proglider file fitted into universal testing machine for the buckling resistance test

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Figure 2: Photograph showing lateral bending of file after application of force

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Statistical analysis

Statistical analysis was done by using one-way ANOVA test using a commercially available software program SPSS version 16 (SPSS Inc. Chicago, IL, USA).


  Results Top


Mean values of buckling resistance for tested three groups were given in [Table 1]. Statistical analysis showed a significant difference in the maximum load necessary to buckle the 3 instruments tested (P< 0.05). The results for the buckling test are depicted in [Table 2].
Table 1: Buckling resistance of pathfinding endodontic instruments (in Newton)

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Table 2: Statistical analysis was done by using one-way ANOVA test

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Control group I (C + files) showed greater resistance to buckling force than Group II (Proglider files) and Group III (One-G files). Difference of buckling resistance among the files is statistically significant.


  Discussion Top


During biomechanical preparation of severely curved root canals, establishment of glide path, maintaining the original shape of the canal, and avoiding canal aberrations such as ledge formation and zip configuration are challenging tasks.[11] Initially, manual stainless steel files were used to prepare glide path of the canals but these files produced a more marked straightening of the canal curves.[12]

Since the introduction of NiTi glide path files in the market, the manufacturers claimed to shape root canals more effectively than stainless steel instruments because they have 2–3 times greater flexibility.[11] During the crown-down technique, rotary glide path preparation removes the pulp tissue and debris from the canal and maintains the working length and patency of root canals. This eventually facilitates better flow of irrigation solutions to the apical root canal. Less hand fatigue for the clinician as well as less chair time for the patient are the other advantages of using NiTi rotary instruments.[13],[14],[15]

Allen et al. tested the deflection of pathfinding instruments by applying the load perpendicular to the long axis of instrument.[16] In another study, Lopes et al.[10] and Kwak et al.[17] compared the buckling resistance of C + file with other pathfinding instruments. They applied load along the long axis of an instrument. Resistance to buckling is an important property of the pathfinding instrument to pass it beyond the constrictions and other anatomic impediments. In our study, the same method was used as that of Lopes et al. and Kwak et al. used. The reason behind this is during exploration of canal, forces are always exerted along the long axis of an instrument.[10],[17]

Recently, manufacturers have introduced single file systems such as Proglider and One-G to improve mechanical properties and reduce the preparation time and cost of multiple files. Literature has shown that C + stainless steel files showed better buckling resistance than other tested files.[10],[17] It will be inappropriate to compare rigid C + stainless steel hand file with flexible NiTi rotary files. Hence, in this study, C + file was used as a control.

The results obtained can be explained by the different sizes, tapers, and mechanical behavior of the metallic alloys used for manufacturing. The higher buckling resistance of the control group may be related to its metallurgy. Owing to higher modulus of elasticity, stainless steel files are less flexible than NiTi files.[17]

Results of this study showed buckling resistance of Proglider files is significantly lesser than One-G files. This may be due to the design and taper of the file. Proglider file is manufactured with a tip diameter of 0.16 mm with a progressive taper ranging from 2% to 8% along the entire shaft.[17],[18] One-G file is manufactured with a tip diameter of 0.14 mm and constant 3% taper along the entire shaft. This design provides stable, larger core diameter of file which can resist to buckle during axial force.

Another justification of the result is the type of alloy used to manufacture the file. According to manufacturer, Proglider is prepared using M-Wire NiTi alloy to enhance flexibility and cyclic fatigue resistance. Whereas One-G file is manufactured using regular superelastic NiTi wire. A lower buckling resistance value of Proglider file could be related to the lower modulus of elasticity of the M-Wire alloy as compared to the conventional NiTi alloy.[18] Low modulus of elasticity of alloy leads to greater flexibility and superelastic behavior of Proglider file.[19],[20] The M-Wire alloy provides the NiTi instruments with greater flexibility than those made of regular superelastic wire.[18],[21],[22],[23]


  Conclusion Top


Within the experimental conditions of the study, we may conclude as:

  • One-G file showed better resistance to buckling than Proglider file due to its design and type of alloy used
  • Files manufactured with M-wire alloy did not show higher buckling resistance compared to conventional NiTi rotary files.


Acknowledgment

Special thanks to Dr. Hyeon-Cheol Kim (Department of Conservative Dentistry, School of Dentistry, Dental Research Institute, Pusan National University, Yangsan, Korea) for his continuous guidance & support during research work).

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
  References Top

1.
Peters OA. Current challenges and concepts in the preparation of root canal systems: A review. J Endod 2004;30:559-67.  Back to cited text no. 1
[PUBMED]    
2.
Peters OA, Peters CI. Cleaning and shaping of the root canal system. In: Hargreaves KM, Cohen S, (editor) Cohen's Pathways of the Pulp. 10th ed. Mosby/Elsevier Publication, Missouri USA, 2010. p. 283-348.  Back to cited text no. 2
    
3.
Siqueira JF Jr., Lopes HP. Chemomechanical preparation. In: Siqueira JF Jr., editor. Treatment of Endodontic Infections. London: Quintessence Publishing; 2011. p. 236-84.  Back to cited text no. 3
    
4.
Lopes HP, Elias CN, Amaral G, Vieira VT, Moreira EJ, Mangelli M, et al. Torsional properties of pathfinding instruments. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2011;112:667-70.  Back to cited text no. 4
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5.
Jafarzadeh H, Abbott PV. Ledge formation: Review of a great challenge in endodontics. J Endod 2007;33:1155-62.  Back to cited text no. 5
    
6.
Koch K, Brave D. Real world Endo: Design features of rotary files and how they affect clinical performance. Oral Health 2002;2:39-49.  Back to cited text no. 6
    
7.
Dearing GJ, Kazemi RB, Stevens RH. An objective evaluation comparing the physical properties of two brands of stainless steel endodontic hand files. J Endod 2005;31:827-30.  Back to cited text no. 7
    
8.
Beer FP, Johnston ER. Mechanics of Materials. 3rd ed. New York: McGraw-Hill; 1992.  Back to cited text no. 8
    
9.
Serene TP, Adams JD, Saxena A. Nickel-titanium Instruments Applications in Endodontics. St. Louis: Ishiyaku Euroamerica Inc.; 1995.  Back to cited text no. 9
    
10.
Lopes HP, Elias CN, Mangelli M, Lopes WS, Amaral G, Souza LC, et al. Buckling resistance of pathfinding endodontic instruments. J Endod 2012;38:402-4.  Back to cited text no. 10
    
11.
Bürklein S, Poschmann T, Schäfer E. Shaping ability of different nickel-titanium systems in simulated S-shaped canals with and without glide path. J Endod 2014;40:1231-4.  Back to cited text no. 11
    
12.
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;35:408-12.  Back to cited text no. 12
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13.
Sung SY, Ha JH, Kwak SW, Abed RE, Byeon K, Kim HC, et al. Torsional and cyclic fatigue resistances of glide path preparation instruments: G-file and PathFile. Scanning 2014;36:500-6.  Back to cited text no. 13
    
14.
Uroz-Torres D, González-Rodríguez MP, Ferrer-Luque CM. Effectiveness of a manual glide path on the preparation of curved root canals by using Mtwo rotary instruments. J Endod 2009;35:699-702.  Back to cited text no. 14
    
15.
Capar ID, Kaval ME, Ertas H, Sen BH. Comparison of the cyclic fatigue resistance of 5 different rotary pathfinding instruments made of conventional nickel-titanium wire, M-wire, and controlled memory wire. J Endod 2015;41:535-8.  Back to cited text no. 15
    
16.
Allen MJ, Glickman GN, Griggs JA. Comparative analysis of endodontic pathfinders. J Endod 2007;33:723-6.  Back to cited text no. 16
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17.
Kwak SW, Ha JH, Lee W, Kim SK, Kim HC. Buckling resistance, bending stiffness, and torsional resistance of various instruments for canal exploration and glide path preparation. Restor Dent Endod 2014;39:270-5.  Back to cited text no. 17
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18.
Pereira ES, Peixoto IF, Viana AC, Oliveira II, Gonzalez BM, Buono VT, et al. Physical and mechanical properties of a thermomechanically treated NiTi wire used in the manufacture of rotary endodontic instruments. Int Endod J 2012;45:469-74.  Back to cited text no. 18
    
19.
Walia HM, Brantley WA, Gerstein H. An initial investigation of the bending and torsional properties of Nitinol root canal files. J Endod 1988;14:346-51.  Back to cited text no. 19
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20.
Nakagawa RK, Alves JL, Buono VT, Bahia MG. Flexibility and torsional behaviour of rotary nickel-titanium PathFile, RaCe ISO 10, Scout RaCe and stainless steel K-file hand instruments. Int Endod J 2014;47:290-7.  Back to cited text no. 20
    
21.
Gao Y, Shotton V, Wilkinson K, Phillips G, Johnson WB. Effects of raw material and rotational speed on the cyclic fatigue of ProFile Vortex rotary instruments. J Endod 2010;36:1205-9.  Back to cited text no. 21
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22.
Aoun CM, Nehme WB, Naaman AS, Khalil IT. Review and classification of heat treatment procedures and their impact on mechanical behavior of endodontic files. Int J Curr Res 2017;9:51300-6.  Back to cited text no. 22
    
23.
Wagle S, Azeez MU. Endodontic glide path: A review. Res Rev J Dent Sci 2017;5:13-6.  Back to cited text no. 23
    


    Figures

  [Figure 1], [Figure 2]
 
 
    Tables

  [Table 1], [Table 2]



 

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