ORIGINAL RESEARCH
Technical quality of root canal treatment of posterior teeth after rotary or manual
preparation by university students.
Ibrahim Abu-Tahuna, Mohammad A. Al-Rabab’aha, Mohammad Hammada, Ameen
Khraisatb
a Assistant
Professor Department of Conservative Dentistry and Fixed Prosthodontics, Faculty of
Dentistry, The University of Jordan, Amman, Jordan.
b Professor,
Department of Conservative Dentistry and Fixed Prosthodontics, Faculty of
Dentistry, The University of Jordan, Amman, Jordan.
Type of Article: In-vivo study
Running Short Title: Satisfaction and Technical Quality of RCT
Corresponding author’s address
Dr Ibrahim Abu-Tahun
Department of Conservative Dentistry and Fixed Prosthodontics
The University of Jordan, Queen Rania Street, 11942 Amman, Jordan.
Tel: (+962) 79 5607189
e-mail: ihtahun@yahoo.com
1
Abstract
The Aim of this study is to investigate the technical quality of root canal treatment (RCT)
reached by the undergraduate students as their first experience in molar endodontics using
nickel-titanium (NiTi) files in a crown down approach compared to stainless steel (SS) standard
technique. This study was carried out by the 5th year undergraduate students attending peer
review sessions as a part of their training program , using two different questionnaires to assess
the overall technical quality and potential problems regarding endodontic complications after
root canal preparation with these two systems.The overall results indicated statistically
significant difference in the performance of the two instrument systems in difficult cases
showing better performance of the NiTi system and mean rotary preparation time (P < 0.001).
Under the conditions of this study, novice dental students, using NiTi ProTaper rotary files,
were able to prepare root canals, faster with more preparation accuracy , compared to canals of
same teeth prepared with hand instruments.
Key words: NiTi files , SS files , mishaps .
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Introduction
A plethora of investigations on manual and automated root canal preparation has been published
over recent decades. Experimental and clinical evidence from these studies suggests that the use
of Ni-Ti instruments results in improved preparation quality, accuracy and lower incidence of
post-operative pain and discomfort (1).
Recent prospective studies even with untrained operators and inexperienced undergraduate
dental students demonstrated that improved , technical quality of root canal treatments obtained
with NiTi instruments leads to better obturation results compared to stainless steel K-files ( 2, 3,
4), and advances in using NiTi technology and tapered files are seeing more universities adopt
and incorporate rotary instrumentation as part of the endodontic curriculum ( 5, 6).
Despite the results in vitro, randomized, clinical trials are required to evaluate the performance
outcomes when using NiTi and SS instruments. Only one study (7) evaluated the performance
and the incidence of complications of RCT performed by undergraduate dental students in
Jordan using SS instruments and step-back technique.
The objective of this study was to investigate, in vivo, the influence of instrument type for canal
enlargement on the results obtained after using rotary and manual instrumentation techniques to
assess the efficacy of the instrument as well as the technique and its clinical suitability.
Assessment of students’ performance, opinions and views regarding the use of NiTi and SS files
will provide insights into their technical clinical abilities and knowledge, and valuable feedback
on teaching effectiveness.
Materials and Methods
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Two questionnaires, comprising multiple-choice questions , one dealing with rotary nickeltitanium preparation results , while the other questionnaire dealing with stainless steel (SS)
preparation were first developed.
The final series of questions covered demographics, issues related to the technical results after
using both systems, patterns of training in NiTi use , as well as students’ opinions on their
satisfaction and which system to integrate in their future practices.
Each questionnaire consisting of 2 parts was delivered to the undergraduates of the 5th grade of
the Faculty of Dentistry, The University of Jordan at the 1st visit. The 1st part of the questionnaire
was answered by the undergraduates during the various stages of treatment, and the 2nd part
completed and signed by the senior supervisor at the end of treatment, and personally returned. A
letter explaining the objectives of the survey to the students was attached to every questionnaire.
A pilot testing with a random sample of 20 undergraduate students was conducted by filling out
the two questionnaires and evaluated protocols modified accordingly into a final revision to
assure reliability and credibility of the results.
Staff members involved in data collection were instructed on the nature of the study to ensure
adequate use of data and avoid misleading results and conclusions. Cross - assessment to check
and confirm the results was completed directly either by the supervisors or staff members
undertaking the research.
Data collection and statistical analysis
The data collection period extended from December 2010 to May 2011. Questionnaires were
numerically coded to ease the procedure and each response was allocated its own column. The
study was performed by analyzing the responses to the 2 questionnaires. The data collected from
the responses was entered manually into a Microsoft Excel spreadsheet (Microsoft Corporation
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WA,USA) that was imported into SPSS TM ( SPSS Inc Chicago , IL,USA) statistical software
version 17.0 , presented as tables for comparison of proportion and submitted to percentage
analysis.
Statistical software analysis was carried out using the Chi-square test to determine statistically
significant differences between the technical quality of root fillings and instrument system in
different groups of teeth , and in relation to the degree of difficulty of the case.
Tooth Selection
Inclusion and Exclusion Criteria
One hundred eighty nine teeth included in this study , comprising maxillary and mandibular
molars requiring primary non-surgical endodontic treatment were selected according to the
criteria used by the undergraduate student clinic, Department of Conservative Dentistry, The
University of Jordan. Wisdom teeth were excluded. All RCTs were carried out in the clinic
session by 5th year undergraduate students under the supervision of senior staff members with an
average staff to student ratio of 1: 9 .
The " inexperienced " dental students were asked to shape two molar teeth, one molar with a
sequence of manual SS files using conventional step back technique and the other molar was
prepared with rotary Ni-Ti files in a crown-down manner.
Instruments and Instrumentation Techniques
Access cavity preparations were done. Apical patency was determined by inserting an ISO # 08 # 10 file and the working lengths were determined using working radiographs and / or apex
locator (Root ZX ‘J. Morita USA. Inc.). Irrigation was not a parameter in this study. Selected
teeth were divided into 2 groups and prepared with either NiTi files or SS K-files.
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Group 1: Hand file instrumentation technique
The endodontic treatments performed in the hand technique, comprising 327 root canals were
prepared by conventional SS K-Flexofile hand files (Dentsply-Maillefer, Ballaigues,
Switzerland) and Gates Glidden burs (Dentsply-Maillefer, Ballaigues, Switzerland) , using the
traditional serial step-back preparation technique (8).
To achieve adequate preparation of the root canal system, in routine cases, a minimum apical
preparation size 35 has been suggested for mesial canals and # 45 in palatal and distal canals in
the SS group. Gates Glidden drills number 2-4 were used in the cervical part of the canal. In
difficult cases a minimum apical size of no. 30 for mesial canals has been suggested (9).
Group 2: Rotary instrumentation technique
Prior to instrumentation, the 5th year students involved in our study were given a 2 days
workshop including a hands on training course to the use of rotary instrumentation with
ProTaper files. After establishing of a smooth glide path using SS KFs #15 or 20, the canals were
prepared using ProTaper rotary instruments (Dentsply-Maillefer, Ballaigues, Switzerland),
connected to an x smart low torque motor (Dentsply). A special kit of ProTaper, NiTi rotary
endodontic shaping files, each working pack contains six files (S1,S2,F1,F2,F3&SX)
featuring a variable taper was selected and distributed to each student.
All canals were prepared using S1, S2, F1, and F2. The SX and F3 ProTaper files are occasional
files according to the manufacturer recommendations. Manufacturer recommendations and
instrument sequence should be taken into account for the actual speed used. Root canals of all
groups were obturated with gutta-percha points and AH26 sealer using a cold lateral
condensation technique.
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Evaluation Criteria
Every canal needs to be evaluated on its own merits. For the evaluation of the postoperative
quality of root canal preparation , a detailed list of safety issues were reported and analyzed
including parameters- problems of special interest created by instruments and techniques.
One of the purposes of this project was to observe and obtain sufficient data on the amount of
changes in endodontic anatomy produced by hand and/or rotary instruments to draw definite
conclusions on their usefulness. Pre-, intra- and post-obturation periapical radiographs including
angulated radiographs of each tooth taken by the means of Endo-ray® were carried out for each
treated tooth under standardized conditions, so that these radiographs, taken may be compared to
quantify and measure root canal differences and deviations between pre- and post-preparationobturation root canal anatomy. By nalyzing the pre and post-obturation radiographs, senior
supervisors evaluated every endodontic case performed by the same student. Because of a certain
observer bias that may occur under the conditions of this study a double and triple check by 2
researchers ‘ staff members‘ was employed. To ensure reproducibility and allow a comparison of
the results, canal dimensional were studied and evaluated under a 10- x magnifying lens and xray viewer.
The technical quality of root canal shaping and obturation on films was examined based on
traditional evaluating parameters for the assessment of root canal preparation according to
criteria employed in other similar studies, aiming to reflect radiographic appearance of the
obturation according to length of the “ white line“ in relation to the radiographic apex as well as
density and taper (10, 11). The tooth was considered as a unit and the overall technical quality of
root obturation was scored according to the grading system used in the Department of
Conservative Dentistry, The University of Jordan , where :
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(A), equals Excellent
(B), equals Good
(C), equals Average
(D), equals Failed
Total treatment “working " time for each endodontic case performed, recorded as " working visits
", was also calculated by the same student for each system.
Results
The total sample material used in this investigation consisted of the periapical radiographs of
patients who had received root canal treatment at the Faculty of Dentistry, The University of
Jordan. The descriptive statistic analysis was employed. Of the (220 ) questionnaires distributed,
(31 ) were not completed or dropped as being incomplete, giving a total of ( 86 %) completion,
expressing a high return index of the questionnaires (Table 1).
A final total of 189 molars were treated . The high return index of the questionnaires (86%)
expresses a positive acceptance of the undergraduate students of the advantages and impact of
this study on their teaching discipline and also the intensive follow up of the study by the
research team.
All 189 distributed and answered questionnaires in this study were analyzed . Of the (189)
treated teeth , 96 (50.8%) were treated by rotary NiTi instruments , and 93 ( 49.2 %) were
treated by stainless steel hand files. The prevalence of tooth type and location receiving root
canal treatment are shown in (Table 2).
The overall root fillings graded as 'excellent' in this study was 51 (28.5%) (Table 2). More
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specifically , root fillings graded as 'excellent' in difficult cases were 34 (40.1% ) all in the NiTi
group as opposed to none (0) in the SS hand files group. When cases rated ' good ' were
considered, the overall 'excellent plus good' frequency of root canal fillings out of the (83)
difficult cases included in this study for ProTaper files and SS hand files was 57 (68.7%) and 7
(8.4%) respectively indicating statistically significant difference (P < 0.001) in the performance
of the two instrument systems in difficult cases (Figure 1).
The total number of cases graded as 'failed' in this study was 20 (10.5%). Of these failed cases
19 (95%) belong to the SS hand file group, while only 1 failed case (5%) was treated with NiTi
files (Table 2).
The overall better root preparation quality results produced by NiTi files is indicated clearly by
( table 2&3) showing an overall increased incidence of procedural mishaps and a higher failure
rate of teeth treated with SS hand files compared to ProTaper files (P< 0.001).
Ledge formation occupied the highest incidence 17 (37.7%) among all the procedural mishaps
recorded in this study (Figure 2). The incidence of ledging for ProTaper files and SS hand files
was 1 ( 5.9%) and 16 (94.1%) respectively indicating statistically significant difference between
the two instrument systems (P = 0.001).
Mesiobuccal, mesiolingual and distobuccal root canals in the maxillary and mandibular 1st
molars shared the higher incidence 42 (93.3%) of overall procedural mishaps . These teeth were
also the most frequently ledged teeth 16 (94.1%) compared to one ledge (5.9%) in the 2 nd
molar teeth ( Table 3 ).
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More transportation and more dentin formation were created with hand files sharing equal
frequency and rate , eight for each mishap (4.2%) vs. (0) compared to the NiTi instrumentation
that achieved more correct preparation length (p = 0. 004).
The overall incidence of instrument fracture in the total sample was 6 (3.2%), of which one
(16.7%) was a NiTi file and 5(83.3%) hand files (p=0.105). With three instrument fractures ( 50
%) in the apical third, two (33.3%) in the middle of the root, and one instrument failure (16.7%)
in the coronal part, Table 3, shows a statistically significant difference between the type of two
instrument systems and their location in the canal (p=0.31).
The incidence of perforation in the total sample was 6 (3.2%) , all in the SS hand file treated
teeth , significantly more frequently compared to NiTi rotary preparation (P = 0.014). Most
perforations were reported in the apical third 4 (66.7% ) compared to two perforations (33.3% )
in the middle third and no perforation occurrence in the coronal third (p= 0.01).
The mean time required for manual preparation (Table 4) was significantly longer than that
required for rotary preparation (P < 0.001). Seventy two teeth in the rotary group (75 %)
required only 1 session to complete obturation compared to 3 sessions or more in all 93 (100%)
of the cases in the hand file group.
Discussion
The shift to a rotary technique led to superior performance and its benefits became firmly
established for a number of reasons not seen with hand instrumentation (12,13). Various studies
rated preparation enlargement with NiTi root canal instruments superior compared with the
Conventional stepback techniques even when used by undergraduate students (14 ).
10
In the present study Protaper and K-files, used by novice dental students ,were compared to
assess radiographically the technical quality of the root filling and the incidence of endodontic
procedural adverse effects on the extent of overall technical quality.
189 molar teeth , a total of (659 ) root canals , comprised of maxillary and mandibular first and
second molars were treated by these senior dental students. At the start of study, patients were
subjected to a clinical and radiographic examination and when indicated cases were chosen for
the study , the medical and dental history of the patient were taken.
Good diagnostics including the exposure and analysis of adequate radiographs to carefully
determine the degree of difficulty of the case regarding root anatomy, the existence, extent, and
position of canal curvatures as it may potentially have an impact on treatment quality outcome
were involved. The procedural tooth was anesthetized and isolated with rubber dam. A direct
straight line of access was optimized with high speed burs and canals carefully explored with
straight, small hand files. Mechanical procedures involved, enlarging the canal wall by
instruments and mechanical flushing action of the irrigant solution. EDTA was used only as a
paste during preparation.
The overall technical quality
Different epidemiological criteria have been used to categorize root fillings and evaluate postoperative root canal shape , using extracted teeth or simulated root canals in resin blocks and
clinical assessment as well (15) resulting in discrepancy in quality scores of treated teeth due to
the different scoring parameters. While the length and homogeneity were used by most studies
as evaluating criteria of the root filling quality (7, 16), the taper of the root filling was included in
some other studies ( 10, 11) according to the guidelines of the European Society of
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Endodontology ( 17). To allow better following of canal profiles and assessment of the overall
technical quality of root canal fillings, three criteria , the length , density (voids) and taper
(width) were used in the present study.
Amongst the 189 root treated teeth, all 34 (40.1%) root fillings graded as 'excellent' in difficult
cases were in the NiTi group as opposed to none (0) in the SS hand files group. Using dense
root fillings rated as “ good” , raised the overall 'excellent plus good' frequency of root canal
fillings in the (83) difficult cases included in this study for ProTaper files and SS hand files to
57 (68.7%) and 7 (8.4%) respectively indicating statistical significance in the performance of
these two systems (P < 005). In addition, the percentages of failed cases indicated clearly that SS
hand instruments did not perform as well as NiTi rotary instruments, results that are supported
by other studies (18).
While Georgelin-Gurgel et al.( 19) found manual instrumentation safer than rotary
instrumentation in the hands of inexperienced students arguing the need for the theoretical and
practical coursework in endodontics teaching in dental schools, taken with the in vitro
experiments, or the very few studies that have assessed their impact when used in primary root
canal treatment , this study suggests that the use of Ni-Ti rotaries does lead to enhanced
technical quality, particularly for clinicians with less expertise (20, 21 ). These findings are in
agreement with the conclusions reached by the vast majority of several earlier studies on postpreparation technical quality and support the hypothesis that, more efficient preparation results
virtually free of gross preparation errors can be obtained with NiTi instruments, even by
untrained operators and inexperienced dental students (22 ).
The higher incidence of overall excellent quality and failed cases in maxillary and mandibular 1st
molars may be explained by the larger number of these teeth in the total sample size 156
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(82.5%) . Mesiobuccal and distobuccal canals of maxillary molars as well as mesiobuccal canals
in these teeth are usually narrow, with great apical curvatures predisposing to a higher fracture
frequency (23).
Safety aspects
Evaluation of universal findings in hand prepared curved root canals, was one of the purposes of
the present study to assess post-operative disruptive changes and distortion of canal
morphology. The highest mishap occurrence recorded was ledge formation indicating
statistically significant difference between the two instrument systems (P = 0.000), with
Mesiobuccal, mesiolingual and distobuccal root canals being the most frequently ledged 39
(88.2%).
Dentin mud formation and transportation were not detected in the NiTi group compared to
significantly more apical dentin plugs and more transportation with hand files sharing equal
frequency and rate, 8 (4.2%) for each. NiTi instrumentation achieved better preparation length
accuracy and better performance and behavior in preparing curved canals (p= 0.0004), results
that were uniformly confirmed by earlier reports (24 ).
One of the most commonly encountered procedural errors, when dental students perform molar
endodontics is straightening of curved canals (25). While changes in the canal shape differed
significantly between the different instruments at all measuring points (24), the NiTi instrument
seemed to be safer because of the reduced amount of transportation towards the danger areas
(26).
The studies described so far indicate that it’s unlikely to prepare a root canal system and prevent
dentin debris build up at the very apical part of the canal produced as a side effect of canal wall
preparation (27). Rotary NiTi systems vary in their debris removal efficiency, possibly because
13
of differing flute designs, but crown down techniques have generally been reported to produce
less apically extruded debris than stepback preparation (28).
Even though irrigation was not a parameter in this study and the potential clinical impact of
these preparation effects remain questionable (29), the findings of this study and other
available studies underline the limited efficiency of hand instruments in cleaning the apical part
of the root canal and indicate the crucial role of sufficient irrigation for disinfection of the canal
system and prevention of procedural mishaps (27).
Instrument fracture is a multifactorial problem (27) but torsional and flexural instrument
fractures during root canal preparation is the major concern , (30). A preliminary canal
enlargement by the students, to secure a smooth glide path in the apical 1/3 was mandatory
before introducing rotary files to reduce cyclic fatigue and allow the instrument to shape canals
to length with little or no procedural errors (31).
Despite the common belief among dental practitioners that NiTi rotary instruments have an
increased frequency of clinical fracture or deformation compared to retained stainless steel hand
files, (32), and despite that Spili et al. (33) , found rotary instruments fractured in a specialist
practice to be slightly more frequently than stainless steel files, current results do not support
this view . On the basis of these results, the respective rate of fracture frequency by the
undergraduate students in their initial therapies was higher and more frequent in hand file cases.
Although higher in the hand files group , the breakage rate obtained in the present study is close
to similar other studies (23, 28 ). A review of literature reveals lower frequency 0.4%– 4.4% of
retained fractured NiTi rotary instrument than that for SS hand files after clinical use (34). The
low incidence of NiTi rotary instrument fracture in this study and other similar early studies
14
supports the continued use of these instruments in root canal treatment although their impact on
clinical outcomes remains uncertain (35).
Reported perforations in clinical treatment as well as in experimental studies (26), agree with the
current findings reporting (3.2% ) incidence of root perforations in the total sample , all in the SS
hand file group. Most perforations resulted in stripped over-prepared curved canals from
straightening along their inner aspect with higher prevalence of perforations in the middle third
of the root canal (p=0.014 ).
A recent study to evaluate the ability of a group of third-year dental students without any
endodontic clinical experience who received a brief structured training session to use the
ProTaper Instruments in curved canals on human molar teeth concluded that rotary instruments
performed adequately with inexperienced operators (36). However, for less experience
clinicians, adequate clinical handling needs to be emphasized (37).
Working time
In the present study, time for treatment was recorded aiming to evaluate the total working time
for each instrument and technique and draw conclusions on their efficacy and clinical
suitability in the hands of inexperienced operators.
Decisive in many cases, data on working time show large differences for identical instruments
and techniques, due to methodological problems as well as to individual factors (26, 38) and
should be interpreted with caution as it might not exactly mirror the clinical situation (22).
Although the total working time calculated in this study does not represent the significantly
shorter actual “ real “ working time by using the NiTi instruments, the mean time required for
manual preparation was significantly longer than that required for rotary preparation time
(P<0.001). The findings of this study indicate that prior acquired experience with a hand
15
preparation technique was not reflected in an improved working time and that ProTaper NiTi
shaping instruments were superior in preparing curved canals more rapidly.
While some comparative studies (28), have shown no difference in working times when
compared rotary NiTi preparations with manual instrumentation, the majority of comparative
studies present some evidence for shorter working times for rotary NiTi preparation when
compared with manual instrumentation.
CONCLUSIONS
Under the conditions of this study, the quality of root canal fillings in posterior molar teeth
performed by undergraduate dental students in the University of Jordan , using NiTi rotary files
as their first experience was safer, faster and better. In light of the undergraduate students
performance using NiTi instruments and techniques , systematic incorporation of these systems
into the preclinical and clinical curriculum and education about newer techniques and
instruments seems promising and advocated to improve the success with molar teeth.
Acknowledgement
This study was supported by grants from the Deanship of Academic Research, The University of
Jordan . The authors express their sincere gratitude to all the undergraduate students (2010-2011)
and assistant staff for completing the data collection forms meticulously. Special thanks also to
Prof Faleh El Sawaeer for his valuable contribution in conducting the statistical analysis of the
results.
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References
1. Wei X, Lin Z, Peng S. The effect of root canal preparation with nickel-titanium rotary
instruments in reducing post-operative pain. Odontostomatol Trop 2008;31:5-11.
2. Gluskin A, Brown D, Buchanan L. A reconstructed computerized tomographic comparison of
NiTi rotary GT files versus traditional instruments in canals shaped by novice operators. Int
Endod J 2001;34: 476–484.
3. Lynch CD, Burke FM. Quality of root canal fillings performed by undergraduate dental
students on single-rooted teeth. Eur J Dent Educ 2006;10:67–72.
4. Pettigrew LK, Jauhar S, Lynch CD, Savarrio L, Carrotte P, Hannigan. A An audit of the
quality of root canal treatments performed by undergraduate dental students on single-rooted
teeth in Glasgow dental hospital and school. The European Journal Of Prosthodontics And
Restorative Dentistry 2007;15: 72-76.
5. Hänni S, Schönenberger K, Peters OA, Barbakow F. Teaching an engine-driven preparation
technique to undergraduates: initial observations. Int Endod J 2003;36:476–82.
6. Peru M, Peru C, Mannocci F, Sherriff M, Buchanan LS, Ford TRP. Hand and nickel-titanium
root canal instrumentation performed by dental students: a micro-computed tomographic study.
Eur J Dent Educ 2006;10:52–9.
7. Barrieshi-Nusair KM, Al-Omari MA, Al-Hiyasat AS. RadiograpAhic technical quality of root
canal treatment performed by dental students at the Dental Teaching Center in Jordan. J Dent.
2004; 32:301–307.
8. Torabinejad M. Passive stepback technique. Oral Surg Oral Med Oral Pathol 1994;77: 398–
401.
17
9. Weiger R, Elayouti A, Löst C. Efficiency of Hand and Rotary Instruments in Shaping Oval
Root Canal . Journal of Endodontics 2002; 28: 580–3.
10. Er O, Sagsen B, Maden M, Cinar S, Kahraman Y. Radiographic technical quality of root
fillings performed by dental students in Turkey. Int Endod J 2006;39:867–872.
11. Balto H, Al Khalifah Sh, Al Mugairin S, Al Deeb M, Al-Madi E.Technical quality of root
fillings performed by undergraduate students in Saudi Arabia. Int Endod J 2010;43:292-300.
12. Boucher Y, Matossian L, Rilliard F, Machtou P.Radiographic evaluation of the prevalence
and technical quality of root canal treatment in a French subpopulation . Int Endod J 2002;
35:229-38.
13. Chen JL, Messer HH.A.Comparison of stainless steel hand and rotary nickel-titanium
instrumentation using a silicone impression technique. Int Endod J 2003; 36:199-207.
14. Sadeghi S.Shaping. Ability of NiTi rotary versus stainless steel hand instruments in simulated
curved canals. Med Oral Patol Oral Cir Bucal 2011;16:e454-8.
15. Pettiette MT, Metzger Z, Phillips C, Trope M. Endodontic complications of root canal
therapy performed by dental students with stainless-steel K-files and nickel–titanium hand files.
J Endod 1999;25: 230–234.
16. Gencoglu N, Pekiner FN, Gumru B, Helvacioglu D. Periapical status and quality of root
fillings and coronal restorations in an adult Turkish subpopulation. Eur J Dent 2010;4:17–22.
17. European Society of Endodontology. Quality guidelines for endodontic treatment consensus
report of the Euoropean Society of Endodontology. International Endodontic Journal
2006;39:921-30.
18
18. Leonardi PD , Filho FB, Haragushiku GA, Tomazinho FSF, Lopes MGK, Moro A.
Undergraduates' opinion after 5-year experience with rotary endodontic instruments. RSBO
(Online) 2011;8 :68-74.
19. Georgelin-Gurgel M, Devillard R, Lauret ME, Diemer F, Calas P, Hennequin M. Root canal
shaping using rotary nickel-titanium files in preclinical teaching. Odontostomatol Trop 2008;
31:5-11.
20. Guelzow A, Stamm O, Martus P, Kielbassa AM. Comparative study of six rotary nickel-
titanium systems and hand instrumentation for root canal preparation. Oral Surg Oral Med Oral
Pathol Oral Radiol Endod 2011;111:659-67.
21. Schäfer E, Bürklein S. Impact of nickel-titanium instrumentation of the root canal on clinical
outcomes: a focused review. Dent Today 2012;31:80, 82, 84-7.
22. Paque F, Musch U, Hu¨lsmann M. Comparison of root canal preparation using RaCe and
ProTaper rotary Ni–Ti instruments. Int Endod J 2005;38: 8–16.
23. Tzanetakis GN, Kontakiotis EG, Maurikou DV, Marzelou MP. Prevalence and management
of instrument fracture in the postgraduate endodontic program at the Dental School of Athens: a
five-year retrospective clinical study. Int Endod J 2001;34:476-84.
24. Schäfer E, Lau R. Comparison of cutting efficiency and instrumentation of curved canals
with nickel-titanium and stainless-steel instruments. Int Endod J 2011;44:357-61.
25. Schäfer E, Schulz-Bongert U, Tulus G (2002) Comparison of hand stainless steel and nickel
titanium rotary instrumentation: a clinical study. Int Endod J 35,505-13.
26. Hu¨ lsmann M, Peters OA & Dummer PMH. Mechanical preparation of root canals: shaping
goals, techniques and means. Endodontic Topics 2005;10: 30–76.
19
27. Prati C, Foschi F, Nucci C, Montebugnoli L, Marchionni S. Appearance of root canal walls
after preparation with NiTi rotary instruments: a comparative SEM investigation. Clin Oral
Invest 2004;8:102–110.
28. Schäfer E, Schlingemann R. Efficiency of rotary nickel-titanium K3 instruments compared
with stainless steel hand K-Flexofile. Part 2. Cleaning effectiveness and shaping ability in
severely curved root canals of extracted teeth. Int Endod J 2009 ;42:22-33.
29. Peters OA, Paqué F. Current developments in rotary root canal instrument technology and
clinical use: A review. Quintessence International 2010;41:479-488.
30. Fife D, Gambarini G, Britto L. Cyclic fatigue testing of ProTaper NiTi rotary instruments
after clinical use. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2004;97: 251–256.
31. Pasqualini D, Mollo L, Scotti N, Cantatore G, Castellucci A, Migliaretti G, Berutti E.
Postoperative pain after manual and mechanical glide path: a randomized clinical trial. J Endod
2012;38:32-6.
32. Parashos P, Messer HH. Rotary NiTi instrument fracture and its consequences. J Endod
2006; 32:1031-1043.
33. Spili P, Parashos P, Messer HH. The impact of instrument fracture on outcome of endodontic
treatment. J Endod 2005;31:845-50.
34. Kohli M, Kim J, Iqbal M, Kim S. A retrospective clinical study of incidence of root canal
instrument separation in an endodontic graduate program. J Endod 2005;31:223.
35. Murad M, Murray C. Impact of retained separated endodontic instruments during root canal
treatment on clinical outcomes remains uncertain. J Evid Based Dent Pract 2011;11:87-8.
36. Ünal GÇ, Maden M, Orhan EO, Sarıtekin E, Teke A. Root canal shaping using rotary nickeltitanium files in preclinical dental education in Turkey. J Dent Educ 2012;76:509-13.
20
37. Vaudt J, Bitter K, Neumann K, Kielbassa AM. Ex vivo study on root canal instrumentation
of two rotary nickel-titanium systems in comparison to stainless steel hand instruments. Int
Endod J 2009 ;42:22-33.
38. Rhodes SC, Hülsmann M, McNeal SF, Beck P, Eleazer PD. Comparison of root canal
preparation using reciprocating Safesiders stainless steel and Vortex nickel-titanium instruments.
Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2011;111:659-67.
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Table 1. Number of questionnaires distributed and responded per system and Prevalence of
tooth type receiving root canal treatment per system.
System used
Delivered Questionnaires
System used
Responded Questionnaires
Type of Tooth
Total
U6
L6
U7
L7
Rotary NiTi files
110 (100%)
Rotary NiTi files
96 (87 %)
33
44
8
11
96(50.8%)
Manual files
110 (100%)
Manual SS
93 (85 %)
31
48
1
13
93(49.2%)
Total
220 (100%)
Total
189 (86%)
64
92
9
24
189(86%)
22
Table 2 Quality outcomes of overall results
System
Quality of work
Degree of Difficulty
Easy
Difficult
Excellent
Good
Failed
Excellent
Good
Failed
Excellent
Good
Failed
NiTi
43
47
1
9
24
0
34
23
7
Hand
8
32
19
8
25
6
0
7
13
23
24
Figure 1 Overall quality of teeth obturation per system
50
45
40
35
30
25
20
15
10
5
0
System NiTi
System Hand
Excellent
Good
Average
Failed
25
Table 3 Distribution of procedural errors per system, tooth and canal location
System
NiTi
Hand
Ledge
Transportation
Dentine Mud
Type of teeth
U6
L6
U7
L7
1
0
0
16
8
8
7
3
5
9
4
3
1
0
0
0
1
0
0
0
1
1
2
2
3
2
0
1
separation
Coronal
Middle
Apical
Coronal
Middle
Apical
0
0
0
0
2
4
3
3
0
0
Perforation
26
Figure 2 The incidence of mishaps per instrument system
18
16
14
12
10
8
6
4
2
0
System NiTi
System Hand
27
Table 4 Total working time per system
Working time
System
NiTi
Hand
1 session
72
0
2 sessions
24
0
3 sessions
0
29
More than 3 sessions
0
64
28