~ 19 ~ 

International Journal of Applied Dental Sciences 2016; 2(2): 19-23  ISSN Print: 2394-7489 ISSN Online: 2394-7497 IJADS 2016; 2(2): 19-23 © 2016 IJADS www.oraljournal.com Received: 05-02-2016 Accepted: 05-03-2016

Dr. Vamshi Krishna V Post Graduate Student, Department of Conservative Dentistry and Endodontics, Krishnadevaraya College of Dental Sciences and Hospital, Bangalore, India. Dr. Sujatha I MDS Professor, Department of Conservative Dentistry and Endodontics, Krishnadevaraya College of Dental Sciences and Hospital, Bangalore, India. Dr. Jayalakshmi KB MDS Professor, Department of Conservative Dentistry and Endodontics, Krishnadevaraya College of Dental Sciences and Hospital, Bangalore, India. Dr. Prasanna Latha Nadig MDS Professor Department of Conservative Dentistry and Endodontics, Krishnadevaraya College of Dental Sciences and Hospital, Bangalore, India. Dr. Sharath Chandra SM MDS Professor Department of Conservative Dentistry and Endodontics, Krishnadevaraya College of Dental Sciences and Hospital, Bangalore, India. Dr. Mayur GN BDS Department of Conservative Dentistry and Endodontics, Krishnadevaraya College of Dental Sciences and Hospital, Bangalore, India. Dr. Sivaji K Post Graduate Student, Department of Conservative Dentistry and Endodontics, Krishnadevaraya College of Dental Sciences and Hospital, Bangalore, India. Dr. Gyanendra Pratap Singh Post Graduate Student, Department of Conservative Dentistry and Endodontics, Krishnadevaraya College of Dental Sciences and Hospital, Bangalore, India. Correspondence Dr. Vamshi Krishna V Post Graduate Student, Department of Conservative Dentistry and Endodontics, Krishnadevaraya College of Dental Sciences and Hospital, Bangalore, India.

Comparison of the cleaning effectiveness of Mtwo & protaper next rotary systems in permanent molar root

canals: An in vitro study

Dr. Vamshi Krishna V, Dr. Sujatha I, Dr. Jayalakshmi KB, Dr. Prasanna Latha Nadig, Dr. Sharath Chandra SM, Dr. Mayur GN, Dr. Sivaji K, Dr. Gyanendra Pratap Singh Abstract Aim: The aim of this in vitro study was to evaluate the presence of debris on the dentinal wall of palatal root of maxillary molars and distal root of mandibular molars after instrumentation with rotary Mtwo and Protaper Next files under stereomicroscope. Materials and Methods: Forty freshly extracted human maxillary /mandibular molar teeth were selected for this study. Teeth were divided into two groups of 20 teeth each (group A and B).Teeth were decoronated at the CEJ, palatal and distal roots were taken. In group A, all the 20 canals were subjected to cleaning and shaping with rotary Mtwo files and rotary Protaper Next files in group B. After splitting the roots longitudinally, the dentinal debris of each root canal was evaluated at three areas (coronal, middle and apical thirds of the root) by means of numerical evaluation scale, under a stereomicroscope. The data obtained were analysed statistically using Mann-Whitney Test. Results: There was no significant difference in the debris scores between the Mtwo group and Protaper Next group in the total canal area. Conclusions: Under the condition of the present study, both the instruments Mtwo and Protaper Next rotary systems can be used to complete the preparation of canals. The use of Protaper Next instruments resulted in better canal cleanliness in the middle part compared with Mtwo. Keywords: Dentinal debris; rotary Mtwo; rotary Protaper Next; and Stereomicroscope Introduction The elimination of intracanal microorganisms is the major goal of root canal treatment. This can be achieved with a proper chemo-mechanical preparation and is thus essential for successful endodontic treatment [1, 2]. However, currently no instrument can predictably clean the entire root canal system, especially in the apical portion of the root canals [3, 4]. Canals prepared with stainless steel instruments were only superficially cleaned and much of the pulp tissue was not removed. Stainless steel files have also been shown to create canal aberrations, such as ledges, perforations, zips and elbows [5, 6]. To eliminate some of the short comings of these traditional endodontic instruments, nickel-titanium (Ni-Ti) instruments have been developed. Most of the new systems incorporate instruments with a taper greater than ISO standard.02 design [6, 7]. Besides variation in taper, nickel-titanium instruments are characterized by different cross-sections and blade design [6] Studies have shown that Ni-Ti instruments can effectively produce a well-tapered root canal form sufficient for obturation, with minimal risk of transporting the original canal [7-11]. Moreover, these investigations have shown that the different Ni-Ti instruments produce inconsistent results and this variation in the debri removal efficiency of these instruments may be due to variation in flute designs. Mtwo (VDW, Munich, Germany) instruments have an S-shaped cross sectional design with a non-cutting tip. The two cutting edges have positive rake angle to cut dentine effectively. Moreover, the pitch length increases from the tip to the shaft. This design is claimed to eliminate threading and binding in continuous rotation, and to reduce transportation of debris towards the apex. The manufacturers claim that crown down instrumentation sequence is no longer required, since each instrument creates a glide path to the apex for the following instrument, and is used to the full working length to shape the entire length of the canal [12].

 

~ 20 ~ 

International Journal of Applied Dental Sciences

The ProTaper Next (Dentsply Maillefer, Ballaigues, Switzerland) is the successor of the Pro Taper Universal system (Dentsply Maillefer). It has an innovative off-centred rectangular cross section that gives the file a snake-like swaggering movement as it advances into the root canal. The manufacturer claims that the rotation of this cross section generates enlarged space for debris removal. These instruments are manufactured from M-wire alloy that is claimed to improve file flexibility and resistance to cyclic fatigue whilst retaining cutting efficiency [13, 14]. The ability of rotary NiTi instruments to remove dentine and pulpal debris during shaping is related to design features of the instrument, particularly the cross-sectional profile and the flutes [15]. The purpose of this study was to compare the cleaning effectiveness of the Mtwo and ProTaper Next systems, in the palatal canal of maxillary molar and distal canal of mandibular molars in human permanent molar teeth. Materials and Methods: A total of 40 extracted human mandibular and maxillary molar teeth with single distal and palatal root canal were used. Teeth were decoronated at CEJ and the canals were assessed for apical patency using an ISO 15 file. Teeth with intact root apices and root canal width of ISO 15 size in the apical third region were used [Fig 1]. The selected teeth were then divided randomly into two experimental groups of 20 each. In group A, the Mtwo system was used in the selected distal/palatal canal, according to the manufacturer's instructions. The instrumentation sequence employed five files, as follows: 0.04 taper ISO 10, 0.05 taper ISO 15, 0.06 taper ISO 20, 0.06 taper ISO 25, 0.06 taper ISO 30. All five instruments were used to the full working length of the canals, employing a cyclical in-out motion. Irrigation was performed after each instrument change, with 2 ml of 2.5% NaOCl and finally at the end of instrumentation with 5 ml of Nacl using syringe. Each instrument was used to prepare only four root canals in group B, the selected distal/palatal root canal was instrumented using the ProTaper Next system to the full length of the canals in the following sequence: X1 instrument. Taper 0.04, Size 17; X2 instrument. Taper 0.06, Size 25; X3 instrument. Taper 0.07, Size 30. The same cyclical in-out motion and irrigation protocol was used as with Mtwo instruments. Each instrument was used to prepare only four root canals. After preparation, all the root canals were flushed with 5ml Nacl and dried with absorbent paper points and roots were split longitudinally [Fig 2] with water-cooled double-faced diamond disk operated at low speed and then examined under a stereomicroscope with 20x magnification. [Fig 3] Presence of debris was evaluated with the 5-score index [16]. The cleanliness of each root canal was evaluated at three different areas {apical, middle, coronal third of root}. [Table 1] Score 1: clean canal wall, only very few debris particles. [Fig 4] Score 2: few small conglomerations. [Fig 5] Score 3: many conglomerations; less debris than 50 % of the canal wall covered. [Fig 6] Score 4: more than 50% of the canal wall covered. [Fig 7] Score 5: complete or nearly complete covering of the canal wall by debris [Fig 8] The data were recorded and analysed statistically using Mann-Whitney Test for comparison of the two groups. The level of statistical significance was set at P<0.05.

Results There was no significant difference in the scores between the coronal third and apical third between group A and group B. However there was statistical difference in the scores at the middle third level between the groups [Table 2]. There was no significant difference in scores between Mtwo group and the Protaper Next group in the total canal area [Table 3].

Discussion The removal of vital and/or necrotic pulp tissue, infected dentine and dentine debris to eliminate most of the micro-organisms from the root canal system is still one of the most important objectives during root canal instrumentation [17]. Debris have been used as criteria in this study to assess the cleaning efficiency of the different instruments, because debris comprises dentine chips, residual vital or necrotic pulp tissue attached to the root canal wall that is considered to be infected in many cases [18]. Considering the major objective of the present study (to compare the cleaning effectiveness of the different instruments), a simple irrigation protocol with only NaOCl was used, avoiding any influence of different irrigation solutions, as justified in detail in several previous studies [19, 20,

21]. Thus, it should be accentuated that the cleaning efficiency of the instruments evaluated in the present investigation might be enhanced using a combination of NaOCl and EDTA as a chelating agent. In the present study, the cleaning efficiency was examined on the basis of a numerical evaluation scheme for debris, by means of an Stereomicroscope -evaluation of the coronal, the middle and the apical parts of the canals [22]. The present results confirm previous observations that cleanliness decreased from the coronal to the apical part of the root canal. [23-25] Therefore, sufficient disinfection and copious irrigation are essential to improve root canal cleanliness [23, 25]. In the coronal third and middle third of the canals, instrumentation with Protaper Next resulted in significantly less remaining debris compared with Mtwo. A possible reason for this could be their cross sectional design. ProTaper Next files have a unique swaggering motion which is attributed to unique patented off-centred rectangular cross section. This swaggering motion means that at all times the file is only contacting with the canal in two places which allows a greater space for removal of debris, optimises canal tracking and reduces binding [26]. In the apical third of the canals, Mtwo resulted in less remaining debris compared with Protaper Next but there is no significant difference. The greater taper of ProTaper next (size 30, taper.07) compared with Mtwo (size 30, taper.06) might be reason for the increased amounts of residual debris especially in the apical portion of the canals because it might be assumed that ProTaper Next instruments are less flexible at their tip region compared to the less tapered Mtwo files [27, 28]. A comparison of the results obtained in previous studies under similar experimental conditions with those of the present study reveals that all instruments used displayed a relatively good cleaning ability. The mean overall score for debris was in the range from 2.03 for protaper next to 2.36 for Mtwo. Thus, according to the average score for debris obtained in the present study, it can be concluded that both the instruments can be used to complete the preparation of canals.

Conclusion Under the condition of the present study, both the instruments Mtwo and Protaper Next rotary systems can be used to complete the preparation of canals. The use of Protaper Next instruments resulted in better canal cleanliness in the middle part compared with Mtwo.

 

~ 21 ~ 

International Journal of Applied Dental Sciences

Fig 1: Armamentarium

Fig 2: Sectioned samples after preparation

Fig 3: Stereomicroscope with mounted sample

Fig 4: Score 1

Fig 5: SCORE 2

Fig 6: SCORE 3

Fig 7: SCORE 4

Fig 8: SCORE 5

Table 1: Summary of scores for debris

 

~ 22 ~ 

International Journal of Applied Dental Sciences

Table 2: Mean and Std. Deviation values

N Minimum Maximum Mean Std. Deviation p-value Coronal [Group A] 20 1 3 1.75 .716

0.422 Coronal [Group B] 20 1 2 1.55 .510 Middle [Group A] 20 1 4 2.65 1.089

0.010 Middle [Group B] 20 1 3 1.80 .616 Apical [Group A] 20 1 5 2.70 1.218

0.742 Apical [Group B] 20 1 5 2.75 1.020

P<0.05

Table 3: Over all mean value

Instrument N Mean value p-value Mtwo 60 2.36

0.09 Protaper Next 60 2.03

P<0.05 References 1. Hu¨lsmann M, Peters OA, Dummer PMH. Mechanical

preparation of root canals: shaping goals, techniques and means. Endodontic Topics 2005; 10:30-76.

2. Averbach RE, Kleier DJ. Clinical update on root canal disinfection. Compendium of Continuous Education in Dentistry 2006; 27:284, 286-9.

3. Usman N, Baumgartner JC, Marshall JG. Influence of instrument size on root canal debridement. Journal of Endodontics. 2004; 30:110-2.

4. Wu MK, Wesselink PR. Efficacy of three techniques in cleaning the apical portion of curved root canals. Oral SurgeryOral Medicine Oral Pathology Oral Radiology & Endodontology 1995, 79:492-6.

5. Schafer E, Tepel J, Hoppe W. Properties of endodontic hand instruments used in rotary motion: Part 2- Instrumentation of curved canals. J Endod. 1995; 21:493-7.

6. Bergmans E, Van Clenynenbreugel J, Wevers M, Lambrechts P. Mechanical root canal preparation with NiTi rotary instruments: rationale, performance and safety- Status report for the American journal of Dentistry. Am J Dent. 2001; 14:324-33.

7. Thompson SA, Dummer PM. Shaping ability of NT engine and McXim rotary nickel-titanium instruments in stimulated root canals: Part 1. Int Endod J. 1997; 30:262-9.

8. Bertrand MF, Lupi-Pegurier L, Medioni E, Mullar M, Bolla M. Curved molar root canal preparations using Hero 642 rotary nickel-titanium instruments. Int Endod J. 2001; 34:631-6.

9. Hulsmann M, Schade M, Schafers F. A comparative study of root canal preparation with HERO 642 and Quantac SC rotary Ni-Ti instruments. Int Endod J. 2001; 34:538-66.

10. 10. Hulsmann M, Gressmann G, Schafers F. A comparative study of root canal preparation using Flexmaster and HERO 642 rotary Ni-Ti instruments. Int Endod J. 2003; 36:358-66.

11. Schafer E, Lohmann D. Efficiency of rotary nickel-titanium Flexmaster instruments compared with stainless steel hand K-flexofile: Part 2- Cleaning effectiveness and instrumentation results in severely curved root canals of extracted teeth. Int Endod J. 2002; 35:514-21.

12. Kuzekanani M, Walsh LJ, Yousefi MA. Cleaning and shaping curved root canals: Mtwo® vs ProTaper®

instruments, a lab comparison. Indian J Dent Res. 2009; 20:268-70.

13. Alapati SB, Brantley WA, Iijma M. Metallurgical characterization of a new nickel-titanium wire for rotary

endodontic instruments. Journal of Endodontics 2009; 35:1589-93.

14. Zhou H, Peng B, Zheng YF. An overview of the mechanical properties of nickel-titanium endodontic instruments. Endodontic Topics 2013; 29:42-54.

15. Gambarini G, Lasakiewics J. A scanning electron microscopic study of debris and smear layer remaining following GT rotary instruments. Int Endod J. 2002; 35:422-7.

16. Hulsmann M, Rummelin C, Schafers F. Root canal cleanliness after preparation with different endodontic handpieces and hand instruments: a comparative SEM investigation. J Endod. 1997; 33:150.

17. European Society of Endodontology. Quality guidelines for endodontic treatment: consensus report of the European Society of Endodontology. International Endodontic Journal 2006; 39:921-30.

18. Hu¨lsmann M, Ru¨mmelin C, Scha¨fers F. Root canal cleanliness after preparation with different endodontic handpieces and hand instruments: a comparative SEM investigation. Journal of Endodontics. 1997; 23:301-6.

19. Scha¨fer E, Vlassis M. Comparative investigation of two rotary nickel-titanium instruments: ProTaper versus RaCe. Part 2. Cleaning effectiveness and instrumentation results in severely curved root canals of extracted teeth. International Endodontic Journal. 2004; 37:239-48.

20. Bu¨ rklein S, Scha¨fer E. The influence of various automated devices on the shaping ability of Mtwo rotary nickel-titanium instruments. International Endodontic Journal 2006; 39:945-51.

21. Bu¨ rklein S, Hiller C, Huda M, Scha¨fer E. Shaping ability and cleaning effectiveness of Mtwo versus coated and uncoated EasyShape instruments in severely curved root canals of extracted teeth. International Endodontic Journal. 2011; 44:447-57.

22. Singh S, Nigam N. Comparative evaluation of surface characteristics of dentinal walls with and without using plastic finishing file. J Conserv Dent. 2010; 13:89-93.

23. Hu¨lsmann M, Gressmann G, Scha¨fers F. A comparative study of root canal preparation using Flex Master and HERO 642 rotary Ni-Ti instruments. International Endodontic Journal. 2003; 36:358-66.

24. Haapasalo M, Endal U, Zandi H, Coil JM. Eradication of endodontic infection by instrumentation and irrigation solutions. Endodontic 2005; 10:77-102.

25. Paque´ F, Musch U, Hu¨lsmann M. Comparison of root canal preparation using RaCe and ProTaper rotary Ni-Ti instruments. International Endodontic Journal. 2005; 38:8-16.

26. Macmillan publishers limited: An endodontic file with swagger. British dental journal. 2013; 214:11.

27. Dobo´-Nagy C, Serba´n T, Szabo´ J. A comparison of the shaping characteristics of two nickel-titanium endodontic hand instruments. International Endodontic Journal. 2002; 35:283-8.

 

~ 23 ~ 

International Journal of Applied Dental Sciences

28. Scha¨fer E, Erler M, Dammaschke T. Comparative study on the shaping ability and cleaning efficiency of rotary Mtwo instruments. Part 2. Cleaning effectiveness and shaping ability in severely curved root canals of extracted teeth. International Endodontic Journal. 2006; 39:203-12.