Home | About Us | Editorial Board | Current Issue | Archives | Search | Instructions | Subscription | Feedback | e-Alerts | Login 
Journal of Indian Society of Pedodontics and Preventive Dentistry Official publication of Indian Society of Pedodontics and Preventive Dentistry
 Users Online: 1763  
 
  Print this page Email this page   Small font sizeDefault font sizeIncrease font size


 
ORIGINAL ARTICLE
Year : 2006  |  Volume : 24  |  Issue : 4  |  Page : 186-191
 

In vitro comparison of NiTi rotary instruments and stainless steel hand instruments in root canal preparations of primary and permanent molar


Department of Pedodontics and Preventive Dentistry, College of Dental Sciences, Davangere, India

Correspondence Address:
N D Shashikiran
Department of Pedodontics and Preventive Dentistry, College of Dental Sciences, Davangere
India
Login to access the Email id

Source of Support: None, Conflict of Interest: None


DOI: 10.4103/0970-4388.28075

Rights and Permissions

 

   Abstract 

This study is an attempt to compare the NiTi rotary and K-files hand instrumentation on root canal preparation of primary and permanent molars for their efficiency in preparation time, instrument failure and shaping the canals. About 20 primary mandibular second molar (I) and 20 permanent mandibular first molar (II) were selected. Each was further divided into 10 for K-files (a) and 10 for NiTi (b) groups, respectively. Results showed that preparation time Ib<Ia and IIab<IIa, which was highly significant. In instrument failure, Ia (40%), IIa (30%) showed more deformation but not fracture and Ib (10%), IIb (20%) showed fracture, but not deformation. Profiles showed good canal taper and smoothness compared to the K-files. To conclude profile 0.04 taper 29 series, prepared canal rapidly than conventional K-file with good taper, smoothness though the flow was not satisfactory. Instrument failure with K-files was less. In primary teeth preparation time, instrument failure with profile was less compared to the permanent. To conclude it's encouraging to use the profiles in primary teeth.


Keywords: Canal preparation, K-files, NiTi rotary, permanent teeth, primary teeth


How to cite this article:
Nagaratna P J, Shashikiran N D, Subbareddy V V. In vitro comparison of NiTi rotary instruments and stainless steel hand instruments in root canal preparations of primary and permanent molar. J Indian Soc Pedod Prev Dent 2006;24:186-91

How to cite this URL:
Nagaratna P J, Shashikiran N D, Subbareddy V V. In vitro comparison of NiTi rotary instruments and stainless steel hand instruments in root canal preparations of primary and permanent molar. J Indian Soc Pedod Prev Dent [serial online] 2006 [cited 2019 Nov 12];24:186-91. Available from: http://www.jisppd.com/text.asp?2006/24/4/186/28075



   Introduction Top


Until 1960, root canal instruments were produced of carbon steel, which is now replaced by stainless steel alloys. Manufactures have developed new stainless steel alloys characterized by higher flexibility in bending compared with conventional stainless steel instruments to avoid undesirable shaping effects and removing excessive amount of tooth materials from inner aspect of curved canals. Up to now, even flexible stainless steel instruments with noncutting tips have not produced entirely enlargements of severely curved canals. In order to overcome this problem, modifications of stainless steel instruments, characterized by lower (E) module have been developed and which were highly flexible instruments made of new alloy nickel-titanium (NiTi). NiTi was developed by W. F. Buehler in early 1960, which is non-magnetic, salt resisting and water-proof alloy. This new combination alloy had unique properties of shape memory and super elasticity, which makes engine-driven instruments feasible. With this new technique, there was significant reduction in preparation time and better-cleaned and shaped root canals.

The study aims to compare the engine-driven method with Profile 0.04 taper 29 series technique and conventional manual methods with stainless steel K-files in primary and permanent teeth for their efficiency in

  1. Shaping the canals
  2. Time consumed
  3. Instrument failure.



   Materials and Methods Top


The present study was conducted in the Department of Pedodontics and Preventive Dentistry. Materials used were K-files (15-40) (Mani), Profile 0.04 taper 29 series NiTi rotary files (size2-7) (Dentsply Tulsa Dental), Stopwatch, Reduction gear Handpiece, Rubber based putty impression material (3M Express STD), Light bodied hydrophilic vinyl polysilioxane impression material (Reprosil, Dentsply caulk), Stereomicroscope.

Sample selection

40 freshly extracted molar teeth were collected. Among which were 20 primary mandibular second molar teeth of minimum 8 mm root length (Group I) and 20 were permanent mandibular first molar with complete root formation (Group II). Group I and II were further divided into subgroups into 10 each, respectively. 10 teeth of each group were prepared by Conventional methods with Stainless steel K files (a) and rotary method with NiTi files (b), respectively.

Sample preparations

Access opening was done for all samples. Canal length was determined by placing no: 10 files into each until the file was just visible at apical foramen and then canal shaping and cleaning was done.In conventional canal stainless steel K-files using quarter turn-pull technique. Instrumentation started with no 15 file then enlarged to no 25. In NiTi rotary methods, teeth were instrumented with profile 0.04 taper 29 series rotary instruments starting from size 2 to 7 in reduction gear hand piece. Files were advanced slowly towards the apex, which was withdrawn as soon as working length was reached. If the instruments failed before that time, information was recorded and new file was substituted. Time taken for preparation of the canal was recorded. Copious irrigation with saline was done after each filing. Approximate 10 ml saline was used per tooth. Canal preparation was done by step down technique of instruments.

Intracanal impressions

Internal 3D shapes of the canals was determined by intracanal impressions made using light bodied and heavy bodied vinyl poly silioxane impression materials. Light bodied materials were filled over the floor of the pulp chamber over which the putty material kneaded with hand to facilitate the product of light bodied material into the root canal. The heavy bodied also acts as support for the coronal part of the impression and for easy removal. The impression was viewed within 24 h under stereomicroscope to assess the following.

Flow

Good flow, when continuous flow of the materials from the orifice to apical stop. Poor flow, when abrupt change in direction and flow of the material is half way.

Taper

Good taper, when the canal has conical shape throughout the length. Poor taper, when the canal has an hourglass/cylindrical shape.

Smoothness of the walls

Good, if roughness/ledge formation is absent, poor, roughness/ledge formation is present data was recorded directly on coding sheets and analyzed statistically using, unpaired t -test and Fischer's exact test.


   Results Top


Comparison between the methods in primary teeth in terms of preparation time showed mean of 13.39±2.09 for conventional method and 8.51±1.45 for NiTi rotary method with P <0.01, which was highly significant [Table - 1]. In terms of instrument failure in primary teeth 4(40%) teeth showed deformation for conventional method and 1(10%) teeth showed fractured instrument for NiTi rotary method. For deformation P =0.04 Sig (significant) and fractured instruments P =0.05 NS (not significant) [Table - 1]. In terms of canal shaping in primary teeth, the flow showed in mesiobuccal canal, mesiolingual canal and distal canal was 6 (60%), 6 (60%) and 3 (30%) for the conventional method and 9 (90%), 9 (90%), 8 (80%) for NiTi method with P =0.14 NS, 0.14 NS and 0.03 Sig, respectively. Taper showed in mesiobuccal, mesiolingual and distal canal was 4 (40%), 3 (30%) and 2 (20%) for conventional and 8 (80%), 7 (70%) and 8 (80%) for NiTi method with P =0.08 NS, 0.07 NS and 0.01 Sig, respectively. Smoothness in mesiobuccal, mesiolingual and distal canal was 5 (50%), for conventional was 10 (100%) for NiTi with P =0.02 Sig [Table - 1].

Comparison between the methods in permanent teeth in terms of preparation time showed mean of 15.99±2.99 for conventional method and 9.91±1.47 for rotary method with P <0.001, highly significant. In terms of instrument failure in permanent teeth 3(30%) showed deformation for the conventional method and 2(20%) teeth showed fractured instruments for NiTi rotary method. For deformation P =0.11 NS and fractured instruments P =0.24 NS [Table - 2]. In terms of canal shaping , the flow showed in mesiobuccal, mesiolingual and distal canal was 9 (90%), 10 (100%) and 10 (100%) for conventional and 9 (90%), 9 (90%) and 9 (90%) for NiTi method with P =0.53 NS, 0.50 NS and 0.50 NS, respectively. Taper showed mesiobuccal, mesiolingual and distal canal was 6 (60%), 7 (70%) and 6 (60%) for conventional and 9 (90%), 10 (100%) and 9 (90%) for NiTi method with P =0.14 NS, 0.10 NS and 0.11 NS, respectively. Smoothness showed in mesiobuccal, mesiolingual and distal canal was 5 (50%) each for conventional method and 9 (90%), 10 (100%) and 9(90%) for NiTi method with P =0.06 NS, 0.02 Sig and P =0.06 NS [Table - 2].

The preparation time between the two methods compared between primary and permanent peeth showed P <0.05 Sig [Graph 1, [Table - 3]]. The instrument failure compared between primary and permanent teeth, showed P =0.33 NS for deformation and P =1.00 NS for fractured instrument for conventional method. In NiTi rotary method P =1.00 NS for deformation, P =0.39 NS for fractured instrument [Graph 2, [Table - 4]]. The flow in primary and permanent for conventional method was P <0.01 Sig and for NiTi rotary methods was P < 0.34 NS [Graph 3, [Table - 5]]. The taper compared between primary and permanent showed P <0.07 and P <0.15, respectively for methods which was not significant [Graph 4, [Table - 6]]. Smoothness in both the methods in primary and permanent were P <0.34 and P <0.24, respectively, which was not significant [Graph 5, [Table - 7]].


   Discussion Top


With the beginning concepts of root canal therapy, stainless steel hand files were extensively used for the preparation of root canal. All stainless steel files have a propensity to create aberrations as a result of inherent stiffness of metal confounded by the instrument design and canal shape.[1],[2],[3] In most cases, use of stainless steel in narrow curved canals is difficult and limits apical enlargement.So hindering obturation.

To counter the difficulties faced with the use of the stainless steel instrument, NiTi was developed that allows shaping narrow curved canals without causing aberrations. These instrument show an enhanced flexibility and superior resistance to torsion fracture. In present study, profile 0.04 taper 29 series rotary instruments were compared with the stainless steel K-files for the efficacy in terms of preparation time, instrument failure and canal shaping on extracted primary and permanent molar.

During the canal preparation, the time taken for the NiTi files to prepare the canal was shorter than hand stainless steel K-files in primary teeth than permanent teeth that may be due to the shorter root length.[3],[4],[5] NiTi reduces the operator time, patient fatigue, provided proper handling of the instruments in the hand piece than the K files.[3]

Fracture was seen more in NiTi, though K files showed more deformities. This was due to tendency of instruments to bind with the canals, with results that continued rotation of the hand piece resulted in wearing of the cutting blades. This was the main drawback of the NiTi. Yared et al.[6] showed that at 150 r.p.m. NiTi had very low failure with experienced hands. Thus the experience of the operator is one of the main factors.[7],[8],[9],[10],[11] Deformity of the K-files was due to the less modules of elasticity.

Interestingly, larger profiles were associated with more fracture than the smaller instruments whereas the stainless steel K-files showed more deformities in narrow curved canals. This failure of larger instruments were due to the lack of the initial orifice enlargement, a reflection of increased taper of the instruments with results that they bound more at the orifice.[1] But further work should be carried out to the determine the exact cause. The elastomeric impressions were used to check the flow, taper, smoothness of the canal and it was found that the profiles 0.04 taper 29 series produce good tapering when compared with stainless steel K files. This might be due to increased taper of the instruments combined with their planning action during rotation.[3] Overall the profiles showed good smoothness, taper and flow compared to the K files.


   Conclusion Top


The profile 0.04 taper series 29 rotary instruments prepared canal rapidly with good taper and smoothness but fracture was noted more, which may be due to the unwinding, reverse winding with tightening of the spirals. Hence these instruments should be checked with each use. Canal preparation with K-files is time consuming with poor taper, smoothness but instrument fracture is less and it is more economic. In the primary teeth, preparation time, instrument failure with the profile 0.04 taper 29 series was less when compared to permanent teeth.

In general, the results of NiTi rotary were encouraging but operator had to weigh advantageous of the both groups of instruments. Better results can be obtained with NiTi, which depends on the efficiency of the operator and experience. Irrespective of the cost factors, there were good results with NiTi in primary teeth.

According to this study, NiTi rotary showed to be more advantageous in the child patient as the chair side time is significantly reduced. To establish the use of NiTi rotary in primary teeth more studies are yet to be done.

 
   References Top

1.al-Omari MA, Dummer PM, Newcombe RG, Doller R. Comparison of six files to prepare simulated root canals: Part 2. Int Endod J 1992;25:67-81.  Back to cited text no. 1  [PUBMED]  
2.Eldeeb ME, Boraas JC. The effect of different files on the preparation shape of severely curved canals. Int Endod J 1985;18:1-7.  Back to cited text no. 2  [PUBMED]  
3.Thompson SA, Dummer PM. Shaping ability of ProFile.04 Taper Series 29 rotary nickel-titanium instruments in simulated root canals. Part 1. Int Endod J 1997;30:1-7.  Back to cited text no. 3    
4.Glosson CR, Haller RH, Dove SB, del Rio CE. A comparison of root canal preparation using Ni-Ti hand, Ni-Ti engine driven and K flex endodontic instruments. J Endod 1995;21:146-51.  Back to cited text no. 4    
5.Esposito PT, Cunningham CJ. A comparison of canal preparation with niti and stainless steel instruments. J Endod 1995;21:173-6.  Back to cited text no. 5  [PUBMED]  
6.Yared GM, Bou Dagher FE, Machtou P. Influence of rotational speed, torque and operators efficiency on profile failures. Int Endod J 2000;34:47-53.  Back to cited text no. 6    
7.Bryant ST, Thompson SA, al-Omari MA, Dummer PM. Shaping ability of Profile rotary nickel-titanium instruments with ISO sized tips in simulated root canals: Part 1. Int Endod J 1998;31:275-81.  Back to cited text no. 7  [PUBMED]  [FULLTEXT]
8.Jungmann CL, Uchin RA, Bucher JF. Effect of instrumentation on the shape of root canals. J Endod 1975;1:66-9.  Back to cited text no. 8  [PUBMED]  
9.Dederich DN, Zakariasen KL. The effects of cyclical axial motion on rotatory endodontic instrument fatigue. Oral Surg Oral Med Oral Pathol 1986;61:192-6.  Back to cited text no. 9  [PUBMED]  
10.Barr ES, Kleier DJ, Barr NV. Use of nickel titanium rotary files for root canal preparation in primary teeth. Pediatr Dent 2000;22:77-8.  Back to cited text no. 10  [PUBMED]  
11.Thompson SA. An overview of nickel-titanium alloys used in dentistry. Int Endod J 2000;33:297-310.  Back to cited text no. 11  [PUBMED]  [FULLTEXT]


    Figures

[Figure - 1], [Figure - 2], [Figure - 3], [Figure - 4], [Figure - 5], [Figure - 6], [Figure - 7], [Figure - 8], [Figure - 9]

    Tables

[Table - 1], [Table - 2], [Table - 3], [Table - 4], [Table - 5], [Table - 6], [Table - 7]


This article has been cited by
1 Evaluation of the efficacy of rotary vs. hand files in root canal preparation of primary teeth in vitro using CBCT
P. K. Musale,S. A. V. Mujawar
European Archives of Paediatric Dentistry. 2013;
[Pubmed] | [DOI]
2 Anatomical challenges, electronic working length determination and current developments in root canal preparation of primary molar teeth
H. M. A. Ahmed
International Endodontic Journal. 2013; : n/a
[Pubmed] | [DOI]
3 Evaluation of canal cleanliness and tubular penetration of root canal sealers in extracted primary second molars: A SEM study
Guler, C. and Gurbuz, T. and Yilmaz, Y. and Guler, M.S.
Cumhuriyet Dental Journal. 2013; 16(2): 116-124
[Pubmed]
4 In vitro evaluation of mesial molars canals preparation with manual Ni-Ti instruments and rotatory Protaper Universal [EvaluaciĆ³n in vitro de la preparaciĆ³n de conductos mesiales de molares con instrumentos manuales Ni-Ti y Protaper Universal rotatorio]
Aracena Rojas, D. and Borie, E. and Fuentes, R. and Boldt, F. and Aracena, A. and Valenzuela, R.
Avances en Odontoestomatologia. 2013; 29(2): 73-79
[Pubmed]
5 The clinical success of different root canal treatments in primary molars
Guler, C. and Gurbuz, T. and Yilmaz, Y.
Cumhuriyet Dental Journal. 2013; 16(1): 31-39
[Pubmed]
6 Evaluation of cleaning capacity and instrumentation time of manual, hybrid and rotary instrumentation techniques in primary molars
Pinheiro, S.L. and Araujo, G. and Bincelli, I. and Cunha, R. and Bueno, C.
International Endodontic Journal. 2012; 45(4): 379-385
[Pubmed]
7 Comparison between rotary and manual techniques on duration of instrumentation and obturation times in primary teeth
Ochoa-Romero, T. and Mendez-Gonzalez, V. and Flores-Reyes, H. and Pozos-Guillen, A.
Journal of Clinical Pediatric Dentistry. 2011; 35(4): 359-364
[Pubmed]
8 Rotary Mtwo system versus manual K-file instruments: Efficacy in preparing primary and permanent molar root canals
Azar, M.-R. and Mokhtare, M.
Indian Journal of Dental Research. 2011; 22(2): 363
[Pubmed]
9 Evaluation of cleaning capacity and instrumentation time of manual, hybrid and rotary instrumentation techniques in primary molars : Primary teeth instrumentation
S. L. Pinheiro, G. Araujo, I. Bincelli, R. Cunha, C. Bueno
International Endodontic Journal. 2011; : no
[VIEW] | [DOI]
10 Comparison between rotary and manual instrumentation in primary teeth
Crespo Jimenez, S., Cortes, O., Garcia, C., Perez, L.
Journal of Clinical Pediatric Dentistry. 2008; 32(4): 295-298
[Pubmed]



 

Top
Print this article  Email this article
Previous article Next article

    

 
  Search
 
   Next article
   Previous article 
   Table of Contents
  
 
    Similar in PUBMED
   Search Pubmed for
   Search in Google Scholar for
 Related articles
    Article in PDF (202 KB)
    Citation Manager
    Access Statistics
    Reader Comments
    Email Alert *
    Add to My List *
* Registration required (free)  


    Abstract
    Introduction
    Materials and Me...
    Results
    Discussion
    Conclusion
    References
    Article Figures
    Article Tables

 Article Access Statistics
    Viewed10548    
    Printed270    
    Emailed10    
    PDF Downloaded1346    
    Comments [Add]    
    Cited by others 10    

Recommend this journal


Contact us | Sitemap | Advertise | What's New | Copyright and Disclaimer 
 © 2005 - Journal of Indian Society of Pedodontics and Preventive Dentistry | Published by Wolters Kluwer - Medknow 
Online since 1st May '05