Medical

Communication

Biosci. Biotech. Res. Comm. 10(4): 689-696 (2017)

Prevalence of the root canal treatment errors and its

related factors in patients treated by undergraduate

dental students

Dadresanfar B

, Mohammadzadeh Akhlaghi N

and Z. Khodabakhsh

1,2

Assistant Professor of Endodontic Department, Islamic Azad University, Dental Branch, Tehran, Iran

Postgraduate Student of Operative Department, Islamic Azad University, Dental Branch, Tehran, Iran

ABSTRACT

Since errors of root canal treatment can result in tooth loss, it is important to study effective factors on incident

of these errors. In recent years, aiming at reducing errors of root canal treatments and improving performance of

dentaldepartment in Islamic Azad University, Tehran, facilities were provided which included apex locator, teaching

Passive-step back in pre-clinic period and presence of professional assistants and professors who helped students.

Studying and investigating errors during treatment by students and providing proper preventative solutions increases

the chance of successful treatment of patients. According to the changes in methods of teaching root canal prepara-

tion and considering bene t that annual and biennale assessment of prevalence of errors during the treatment has

for studying educational performance and future planning, in this study we studied prevalence of errors during root

treatment by dental students in general dentistry major and its effective factors, in order to study whether these

applied changes reduced errors or not? Firstly, it is hypothesized that effective factors on this errors include qual-

ity of radiography, numbers of radiographies, patients’ age, type of tooth, type of jaw, canal curvature, periapical

lesion, student’s semester of the study, student’s gender, and numbers of treatment sessions,  rst treatment of root

and second treatment of root. In this research 840 record of patients who had received root canal treatment in public

Endodontics sector were evaluated from 2010/9/23 to 2012/09/23. Firstly, two endodontists were calibrated in order

to make sure that kappa coef cientis positive and they both agreed on that, and then endodontists, separately, com-

pleted data forms pertinent to errors during root treatment and related factors. Prevalence of errors was identi ed in

the samples and then role of associated factors was evaluated by logistic regression as statistical test. And after  rst

evaluation of records, sample of study consists of 613 teeth (1131 canals) which out of them 567 teeth received RTC

and 46 teeth received re treatment (Redo). Results indicated that there is statistical difference in frequency of errors

689

ARTICLE INFORMATION:

*Corresponding Author: Khodabakhsh_narges@yahoo.com

Received 27

June, 2017

Accepted after revision 27

Sep, 2017

BBRC Print ISSN: 0974-6455

Online ISSN: 2321-4007 CODEN: USA BBRCBA

Thomson Reuters ISI ESC and Crossref Indexed Journal

NAAS Journal Score 2017: 4.31 Cosmos IF: 4.006

reserved.

Online Contents Available at:

http//www.bbrc.in/

DOI: 10.21786/bbrc/10.4/12

690 PREVALENCE OF THE ROOT CANAL TREATMENT ERRORS AND ITS RELATED FACTORS IN PATIENTS BIOSCIENCE BIOTECHNOLOGY RESEARCH COMMUNICATIONS

Dadresanfar B et al.

INTRODUCTION

Root treatment, aiming at preventing periapical perio-

dontitis and improving periapical lesion, has been recog-

nized as a complicated treatment in dentistry treatments.

This treatment is conducted by removing necrosis pulp,

infectious pulp and batteries and via irrigation and pre-

paring canal, mechanical cleaning and also high qual-

ity obturation. Epidemiologic studies introduced errors

in mentioned procedure as the main reason of treat-

ment failures and imposing higher costs (Lynch 2006;

Mozayeni 2006; Yousuf, 2015). It has been indicated that

acceptable RCT refers to treatments in which root  ll-

ings terminate within 2mm of the radiographic apex and

that are of adequate homogene density and without void

from crown to apical area (Bramanten 1987; Kulic 2011).

Applied method for studying quality of root treatment

is assessing PA Radiographs that are provided before

and after root treatments, radiographically (Kelbauskas

2009; Mosby Co. 2009). Literature review indicated that

errors rate varies from 10 to 58% in different centers

while prevalence of these errors rate in academic centers

(25-45%) is signi cantly higher than professional cent-

ers (10-16%) (Cohen 1998; Er 2006; Estrela, 2017).

Estrela1 et al (2017) performed a research titled as

“Common Operative Procedural Errors and Clinical Fac-

tors Associated with Root Canal Treatment”. They con-

cluded that in each phase of RCT, an operative error can

have adverse implication on prognosis, and these errors

show that risk factors lead to failure.Akbar (2015) per-

formed radiographic study of the endodontic treatment’s

problems and failures. His results illustrated that com-

pare to anterior and premolar teeth, endodontic prob-

lems and failures were most common in molars. The

most frequently canals with endodontic problems and

failures included Mesiobuccal, mesiolingual and dis-

tobuccal root canals. Finally, based on results he con-

cluded that the most common cause of endodontic treat-

ment failure was under  lling followed by poor  lling

and over  lling and  rst molar was the most frequently

involved tooth with endodontic problems and failures.

Yousuf, et al., (2015) studied endodontic procedural

errors and showed that the most frequently treated tooth

was right permanent mandibular  rst molar. The least

commonly treated teeth were the permanent mandibu-

during  rst root treatment and re treatment. In addition, factors including jaw type, tooth type, canal curvature, peri-

apical lesion, and student’s semester of study have signi cant effect on Non homogene-Exact  lling length ‘Trans-

portation ‘Ledge’ Over  lling’s error. However, numbers of treatment sessions was effective with low correlation.

Comparing frequencies of errors during root treatment in this study and paper, it was clari ed that adding tools such

as apex locator, teaching Passive-step back in pre-clinic period and presence of professional assistants and professors

who helped students reduces errors during root treatment.

KEY WORDS: DENTAL STUDENTS, RADIOGRAPHIC ENDODONTIC ERRORS, QUALITY OF ROOT CANAL TREATMENT

lar third molars. Bakhshi and Shahabi (2015) identi ed

the least mistakes compared to obturation phase, with

the most frequent errors including void, over lling and

imperfect cleaning.

A research was carried out by Kulic et al in 2011

in Serbia which indicated that 51.6% treatments were

acceptable with accurate working length and homogeny

density. In Fonseka et al (2015) study, it was reported

that 74.3% treatments were acceptable. In addition, in a

research in 2008 in Islamic Azad University, endodontics

department, Tehran, it was reported that 51.5% errors

happened during root canal treatment while 49.5% were

error-free. Most of the studies illustrated that highest

error incident was occurred in posterior teeth (Braman-

ten CM. 1987; Eleftheriadis GI. 2005; Khabbaz M.G.

2010) and factors including increasing instruction hours

reduces errors (Yousuf, W. 2015). Study and considera-

tion of students’ errors during treatment and providing

appropriate preventive ways increase treatment success

in patients (Bramanten CM. 1987) Recent years, facili-

ties including apex-locator, teaching Passive-step back

method in pre-clinic, presence of professional assistants

and professors who helped students were added into

endodontics department of Islamci Azad University in

order to reduce errors during treatment.

Based on literature review (Estrela, 2017; Lynch 2006;

Yousuf, 2015), popular errors during endodontic treat-

ments are as follow:

Last years equipment including teaching Passive-

step back method in pre clinic and presence of profes-

sional assistants helping students were applied in order

to reduce errors during treatment in endodontic sector.

According to the changes made in methods of teaching

root canal preparation and considering the bene ts that

annual and biennale assessment of prevalence of errors

during the treatment has for studying educational per-

formance and future planning, thus due to lack of infor-

mation about the subject in endodotics sector of Islamic

Azad University, Tehran, and also because of differences

and lacks of previous researches (Er O. 2006 and You-

suf 2015), studying students’ error during treatment and

providing proper methods increase chance of successful

treatment of patients. This study, therefor, investigates

prevalence of errors during root trees and related factors

in patient referring to endodontics sector of Islamic Azad

BIOSCIENCE BIOTECHNOLOGY RESEARCH COMMUNICATIONS PREVALENCE OF THE ROOT CANAL TREATMENT ERRORS AND ITS RELATED FACTORS IN PATIENTS 691

Dadresanfar B et al.

Table 1. popular errors during endodontic treatments are as follow

Error type Description

1 Under  lling Space between canal obturation and radiographic apex is more than 2 mm

2 Over  lling Radiographic beyond apex  lling

3 Non-homogen Lack of homogene density of  lling material from coronal area to apical area

4 Ledge Deviation from main path of canal and creating one step in some cases is cause of under lling

5 Transportation Deviation from main path of canal and  nding new path in root

6 Zipping Perforation of apical area which results in reverse cone and it disrupts apical seal

7 Strip perforation Association of pulp space with periodontal space in root branching region

8 Cervical perforation Association of pulp space with periodontal space in cervical region of tooth

9 Forcation perforation Association of pulp space with periodontal space in forcal region of tooth

10 Broken Instrument Broken instrument that is not extracted from canal

11 Gouging Over

Opening cavity more than required space due to not locating grinder in longitudinal axis of

tooth or futileattempt for accessing to the pulp

University, Tehran, during 2010-2012 in order to  nd out

whether these applied changes reduced error or not?

MATERIALS AND METHODS

All people who received root treatment from 2010/9/23

to 2012/09/23 in public Endodontics sector in Islamic

Azad University; Tehran belonged to the population

of the current study. Then, out of endodontics sector

records’ list that belonged to two years and was gathered

statistically, accurate records were selected and studied.

In this study, research method was performed by exist-

ing data which collected by observation and  ling infor-

mation forms. In addition, samples were selected statis-

tically from all treated patients by dentistry students in

general coarse. Out of 840 selected records, 227 records

(27%) were eliminated due to poor radiography quality

(182 records, 21.6%) and lack of suf cient radiography

(45 records, 5.3%).

Records that lacked  nal radiography, or did not

contain at least both diagnostic and  nal radiography

and also records that, in spite of second recording, their

radiographic quality was poor were eliminated from

the study. Lack of radiography quality happens due to

manual radiography developing and  xing by student

in public sector of endo which results in over developing

the  lms, insuf cient  xing, and lack of PA Radiographs

quality. Assessing quality of student’s performance in

root treatment procedure was conducted in two steps

including preparation and root canal obturation based

on recorded radiographic images in patients’ records.

Nevertheless, there are 2 dimension images instead of

3 dimension structures, this system has been applied in

different studies (Cohen 1998; Guttman 1997).

Assessing images of all records was conducted by two

experts from university endodontic sector, separately,

by microscope with at times enlargements and desktop

negatoscope. Before study, observers agreed on similar

interpretation for radiographic PA Radiograph after per-

forming an experiment. Evaluators were calibrated and

Kappa coef cient was reported as 0.88 which proved

there is perfect coef cient of agreement among evalu-

ators. Due to perfect coef cient of agreement among

evaluators, mentioned samples were assessed again in

cases with no agreement among observers. This method

was utilized by Khabbaz et al. (2010).

For PA Radiograph homogenization by observers, ray

radiation direction considered mesial in all radiogra-

phies. Poor radiographies were  xed again and reevalu-

ated. Records which lacked 2 diagnostic and  nal radi-

ographies were eliminated. Two endodontists conducted

diagnostic and  nal radiographies and used microscope

at  ve times enlargement and one negatoscope. In addi-

tion, some rare errors mentioned in the record and they

were not observable in radiography but they were men-

tioned in the record were studied. Firstly, errors’ evalu-

ators explained errors, thencoef cientof concordance

(Kappa) were identi ed and then records’ assessment

was started. Evaluators were calibrated in order to make

sure that Kappa coef cient is positive and they are com-

patible. For preventing errors of answers, each endo-

dontist  lled data forms separately and then errors that

endodontist were agreed upon considered as real error.

In cases that observers did not agree on, due to perfect

coef cient of agreement between evaluators, mentioned

samples were reassessed and evaluators agreed on that.

In epidemiologic studies, there are different standards

for categorizing root treatment quality. The most preva-

lent parameters of acceptable treatment categorization

Dadresanfar B et al.

692 PREVALENCE OF THE ROOT CANAL TREATMENT ERRORS AND ITS RELATED FACTORS IN PATIENTS BIOSCIENCE BIOTECHNOLOGY RESEARCH COMMUNICATIONS

are length of root canal  lling,  lling homogenization

without void, and absence of iatrogenic errors (Cohen

2006; Haji-Hassani, 2015; Mozayeni 2006). In this study,

standards of determining radiographic categorization of

root treatment were based on length and density of  ll-

ing in the absence of iatrogenic errors and they were

categorized into two acceptable and unacceptable treat-

ments.

The  lling material ends 0-2 mm shorter than radio-

graphic apex with no visible voids within the material

or between the material and root canal walls. 2) Unac-

ceptable treatments: A) the  lling material ends more

than 2mm from radiographic apex or beyond the radio-

graphic apex. B) Visible voids within or between  lling

material and root canal walls

1. Acceptable treatment: under  lling is 0-2 mm and

density of  lling material is homogene with no

visible void within the material or between crown

and apical area. Besides no observable iatrogen-

icerror is in patient’s record and in canals.

2. Unacceptable treatment

a. The  lling material ends more than 2mm from ra-

diographic apex or beyond the radiographic apex

b. Density of  lling material in not homogene and

there is void between crown to apical area.

c. Iatrogenic error is observed in canals and it is also

reported in pateint’s record.

In addition, in this study we assessed demographic

information of students (gender, and the semester) and

factors pertinent to patient and tooth including patient

gender, age, tooth location, tooth root numbers, canal

numbers, periapical radiolucencies, canal curvature and

treatment sessions numbers.

RESULTS AND DISCUSSION

Results indicated that 61%  rst treatments (RCT) were

acceptable and 39% had errors during root treatment.

Acceptable treatment which consists of exact length of

 lling and proper density of  lling and no incidence of

iatrogenic errors, in anterior teeth was 75.6%, in pre-

molar was 72% and in molars was 38.4%. Redo were

acceptable for 100% cases and the most prevalent redo

tooth was Mandibular second premolar. Previous short

 lling was identi ed as the most common cause of redo.

In table 2, there is information about frequency of

errors during root treatment in patients who received

treatment by dental students in general coarse in endo-

dontics sector of Islamic Azad University, dentistry

department, during 2010-2012. In addition, table 2 indi-

cates frequency of errors during root treatment associ-

ated to relevant factors.

Based on table 2 and table 3 and results of logistic

regression, it is concluded that:

1. 55% studied canals had curvature which it was

more in molar teeth. 24.2% canals with curva-

ture had errors during root treatment. 14.5% tooth

that received RCT had periapical lesion which was

more in mandibular  rst molar. 47% canals had

periapical error during treatment.

Table 2. Prevalence of errors during root treatment

total Molar premolar anterior

Error type

Tooth type

Percentage Frequency Percentage Frequency Percentage Frequency Percentage Frequency

100 7 42.8 3 28.6 2 28.6 2 Broken instrument

100 40 67.5 27 20 8 12.5 5 Homogen Over  lling

Root canal

100 22 59 13 32 7 9 2 Nonhomogen

100 35 45.7 16 25.7 9 28.6 10 Homogen Under

Filling

Root canal

100 28 67.8 19 21.4 6 10.8 3 Nonhomogen

100 102 60.8 62 23.5 24 15.7 16 Nonhomogen- Exact  lling

length Root canal

0 0 0 0 0 0 0 0 Forcal Perforation

0 0 0 0 0 0 0 0 Cervical Perforation

100 5 100 5 0 0 0 0 Strip Perforation

100 9 100 9 0 0 0 0 Strip preparation

100 25 52 13 16 4 24 6 Ledge

100 54 72.2 39 18.5 10 9.3 5 Transportation

100 4 75 3 25 1 0 0 Zipping

100 6 0 0 33.3 2 66.7 4 Gouging

100 567 35.8 203 35.9 204 28.2 160

Dadresanfar B et al.

BIOSCIENCE BIOTECHNOLOGY RESEARCH COMMUNICATIONS PREVALENCE OF THE ROOT CANAL TREATMENT ERRORS AND ITS RELATED FACTORS IN PATIENTS 693

Table 3. related factors to errors during treatment

Related factors Error gender manual endo coarse Numbers of treatment sessions

male Female two three four one two three Four Five

No error 148

61.7

197

60.3

192

71.9

41.1

112

70.4

185

63.8

44.1

28.6

With error 92

38.3

130

39.7

28.1

57.9

31.6

105

36.2

55.9

71.4

Total 240 327 267 160 140 159 290 102 14 2

(A)

Related factors

Error

Canal numbers Tooth type Jaw type

one two three four anterior Premolar molar lower upper

No error 205

75.3

67.6

28.1

121

75.6

147

38.4

125

53.9

221

With error 68

24.7

32.4

71.9

24.4

125

61.6

107

46.1

114

Total 273 92 160 32 160 204 203 232 335

(B)

Related factors

error

Canal curvature lesion PA Patient age

Direct canal Curved

canal

With

error

Under

Between

30-45

Older

than 45

No error 412

84.1

451

75.8

819

81.7

143

60.3

123

57.5

With error 78

15.9

144

183

19.3

39.7

42.5

Total 490 335 83 1002 237 214 116

(C)

2. 39.7% treatments conducted by female students

and 38.3% performed by male students had errors

during the treatment. But there was no signi cant

difference between students’ gender and errors

during treatment (p>0.05).

3. 71.4% four sessions treatment and 29.1% one ses-

sion treatment had errors during the treatment. It

means that there was signi cant difference be-

tween errors rate during treatment and treatment

sessions number (p<0.001). However, considering

correlation coef cient (= 0.21), this relationship

was poor.

4. Considering root treatment error, there was sig-

ni cant difference between two jaws (p=0.004).

Regarding that its incidence in mandibular teeth

was signi cantly more than maxillary teeth (34%).

Considering correlation coef cient, = -0.12, this

error was more prevalent in mandibular than up-

per jaw.

5. Error incidence rate by students in manual endo

coarse 2 was identi ed 28.1%, by manual endo

coarse 3 was 40%, and by manual endo coarse

4 was 57.1%, which indicated that there is sig-

ni cant relationship between errors during treat-

ment and students study in manual endo coarse

(p<0.001) and considering correlation coef cient,

= 0.52, this relationship was average.

In addition, results obtained from prevalence of errors

during treatment indicated that:

a. Non homogen-Exact  llng length was identi ed

in 13.4% canals (145 canal) as the most prevalent

error in root  lling procedure ( lling with in ade-

quate quality in exact length of function). This er-

ror was signi cantly more prevalent in molar teeth

canal (60.8%) than premolar and anterior teeth

(p<0.001) but considering correlation coef cient,

= 0.25, this relationship was poor. This error was

35.3% in mandibular molars and 25.5% in maxil-

lary molars. Highest prevalence was identi ed in

mandibular molars and mesiobacal canal (18%)

and then it was observed in mesiolingual (17.2%).

b. In  eld of errors during root canal preparation,

the most common error was transportation which

was observed in 9.5% teeth (54 teeth) highest

rate of this error happened among molars which

prevalence rate was 72.3% and highest preva-

lence happened in mesiobacal canal of mandib-

Dadresanfar B et al.

694 PREVALENCE OF THE ROOT CANAL TREATMENT ERRORS AND ITS RELATED FACTORS IN PATIENTS BIOSCIENCE BIOTECHNOLOGY RESEARCH COMMUNICATIONS

ular  rst molar. There was signi cant relation

between transport and canal curvature (p<0.05).

However, considering correlation coef cient, =

0.1, this relation was weak. There was signi cant

difference in transport incidence among molar

teeth (72.2%) and premolars (18.5%) and anteriors

(9.3%) (p<0.05).

c. Second prevalent error during canal preparation

was ledge which was observed 4.4% of total teeth.

There was signi cant relation between canal ledge

and curvature (p<0.05) however considering cor-

relation coef cient,  = 0.06, this relation was

poor. In molar teeth, error prevalence was 52%

which was more than pre molar and anterior teeth.

In addition, ledge prevalence was signi cantly

higher in mandibular (40%) than maxillary (12%)

(P<0.005). Highest rate of error happened in  rst

mandibular (32%) and mesial root and it is ob-

served equally in mesiobacal canals (25.6%) and

mesiolingual (25.6%).

d. Over  lling has been studied in 6.8% canals and

it was identi ed that 4.2% were over homogene

and 2.6% were over non-homogene. the highest

prevalence rate happened in mesiolingual canals

of mandibular molars. Signi cant difference was

observed in over lling and teeth with priapical

lesion (p<0.05) however considering correlation

coef cient, = 0.08, this relation was very poor.

e. Foracal Perforation and Cervical Perforation were

not observed. 6 Strip Perforation cases, 7 Broken

Instrument cases, 4 zipping cases, 6 Gouging cases

and 9 Strip Preparation cases were identi ed and

there was not signi cant relationship with related

factors.

In this study, maximum error happened in root  ll-

ing step, Non homogen-Exact  lling length ( lling with

inadequate quality in exact length of function) and the

most prevalent error in  eld of errors during root canal

preparation was transportation error. Second prevalent

error during canal preparation was ledge. In this study,

613 teeth including 1131 canal were evaluated which

consists of 567 teeth which received RCT and 46 teeth

received retreatment. Acceptable treatment in ante-

rior teeth was 75.6%, 72% in premolars and 38.2% in

molars. 100% redo were identi ed as acceptable treat-

ment and the most prevalent retreated tooth was man-

dibular second premolar and under- lling was identi ed

as the most prevalent cause of retreat.

In this study, similar to Kulic et al (2011), multi root

teeth which had error during treatment, even in one

canals, was considered as unacceptable treatment. Unal

et al (2011) reported highest prevalence of acceptable

treatment in anterior teeth was 90.1% and the least

prevalence was reported in 46.6% molars. In 71% ante-

rior teeth, 61% premolars and 30% molars were reported

as acceptable treatment prevalence by Khabbaz et al

(2010). In current study, 61% treatments were acceptable

and 39% treatment were unacceptable. Acceptable treat-

ment in anterior teeth was 75.6%, in premolars was 72%

and in molars was 38.2%.

Mozayeni et al (2006) reported that the most preva-

lent error during root canal preparation was transporta-

tion. In addition, Dadresanfar et al (2008) reported that

transport prevalence was 27.5%. Statistical difference

of these  ndings can be due to applying Passive-step

back preparation method in pre clinic coarse, applying

Gates-Gliden drills for coronal preparation of root which

reduces coronal interferences from deviation of  rst

path canal and also due to professional assistance and

their help to students. High prevalence of transportation

in molar teeth its signi cant difference with anterior and

pre molar teeth can be due to complicated anatomy of

these teeth, high numbers of canals and curvature of

canals in these teeth. There was signi cant statistic rela-

tionship between root canal curvature and transporta-

tion which shows there is potential effect of root canal

curvature on canal displacement. Lack of attention to

canal curvature, not providing Pre curve to  les during

preparation of curved canals and lack of removing inter-

ferences of root canal Ori ces can be reasons of high

transportation rate in canals.

Second prevalent error during anal preparation was

ledge. Al-Kahtani et al reported that ledge prevalence

was 7.5% which is compatible with current study.

Eleftheriadis et al reported that ledge prevalence in

molars were 34.9% which is caused by step-back technic

and curvature of molar canals. Less prevalent of ledge

in this study can be due to using other canal preparation

technics including Passive-step back and applying  les

with higher  exibility such as Flexo File by dentistry

students.The most prevalent error during root  lling was

Non homogen-Exact  llng length. More errors in molars

can be because of lack of adequate access of students

to these teeth and in adequate canal  aring which is

caused by their stress for bad incidents. Because inad-

equate canal  aring prevents suitable penetration of

spreader, especially stainless spreaders, which will cause

bad  lling density.

Er et al (2006) reported that 48.8%  lling had inad-

equate density. In addition, Khabbaz et al (2010) stated

that 33.5%  lling had inadequate density and Kulic L

et al (2011) in 25% and Dadresanfar et al reported that

29.2%  lling had inadequate density. Statistical dif-

ference of these results with mentioned studies can be

stemmed from increase of assistants and professors’

Dadresanfar B et al.

BIOSCIENCE BIOTECHNOLOGY RESEARCH COMMUNICATIONS PREVALENCE OF THE ROOT CANAL TREATMENT ERRORS AND ITS RELATED FACTORS IN PATIENTS 695

numbers and continuous study of patients during treat-

ment by professors via providing constancy control

radiographies during obscuration which reduces preva-

lence of errors during canal  lling.

Maximum error prevalence of over  lling was  nd

out in mesiolingual canal of mandibular molars and

there was signi cant statistical difference between over-

 lling and teeth with periapical lesion, because periapi-

cal lesion root top resorption so students cannot deal

with length control easily then it ends to over lling. Kel-

bauskas et al (2009) reported that 5.42% had over lling

which was compatible with this study. Kulic et al (2011)

reported3.3% over lling which this low prevalence can

be due to less numbers of their samples (306 canal). Er

et al (2006) reported 13% over lling cases and Khabbaz

et al reported 22.6% over lling. Statistical difference of

current studies with those can be due to studying more

canals in samples (1109 canals).

Highest rate of under lling error happened in Mesio-

bacal canal of mandibular molars. It can be due to

higher rate of transportation and ledge in molars which

results in diversion from main canal path and interfer-

ence in  lling steps. In addition in Step-back technic

there is possibility of debris and dentin debris packag-

ing in apex top so there is no way for  lling with exact

length. Kelbauskas et al (2009) reported that in 10.5%

cases, underi lling happened. They also reported that

the main reason is ledge and debris packaging.

CONCLUSION

It seems that using tools such as apex locator, presence

of professional assistants and attention of professors of

the related sector and also applying Passive-Step back

in curved canals by some students reduces preparation

error rate and errors of root canal  ling. However utiliz-

ing more  exible  les, emphasizing on before-during-

and after treatment radiographies, meticulous super-

vision of professors during treatment and presence of

lower semester students with higher semester students

and professional assistants in third and second year of

experience could be considered as a guide for increasing

quality of root treatments and reducing errors.

REFERENCES

Barriesh-Nusair KM, Al-omari MA, Al-Hiyasat AS. (2004).

Radiographic technical quality of root canal treatment per-

formed by dental student at the Dental Teaching Center In Jor-

dan. J Dent 3:301-7

Bramanten CM, Berbert A, Barges RP. (1987). A Methodology

for Evaluation of Root Canal Instrumentation. Endod J 13:

243.

Cohen S, Burns RC. (1998). Pathways of the pulp,7 th

ed,Missouri, Mosby. ch8:209.

Cohen S, Burns RC. (2006). Pathways of the pulp. 9th ed. St.

Louis: Mosby, Elsevier. ch26:1025-1026, ch9:327

Dadresanfar B, Mohammadzadeh Akhlaghi N, Vatanpour M,

Atef Yekta H. (2008). Technical quality of root canal treatment

performed by undergraduate dental students. Iranian Endo-

dontic J 3:73-78

Eleftheriadis GI, Lambrianidis TP. (2005). Technical quality of

root canal treatment and detection of iatrogenic errors in an

undergraduate dental clinic. Int Endod J 38:725-34.

Er O, Sagsen B, Maden M, Cinar S, Kahraman Y. (2006). Radio-

graphic technical quality of root canal  lling performed by

dental students in Turkey. Int Endod J, 39, 867-72

Estrela, C., Pécora, J. D., Estrela, C. R., Guedes, O. A., Silva, B.

S., Soares, C. J., & Sousa-Neto, M. D. (2017). Common Opera-

tive Procedural Errors and Clinical Factors Associated with

Root Canal Treatment. Brazilian Dental Journal, 28(2), 179-

190.

Farzaneh M, Abitbol S, Friedman Sh. (2004). Treatmen Out-

come in Endodontic: The Toronto study. Phases 1 and 2:

Orthograde Retreatment. Endod J 30:627-33

Friedman Sh, Abitbol S, Lawrence H. (2003). Treatment Out-

come in Endodontics: The Toronto Study. Phase 1: Initial

Treatment. Endod J 29:787-93

Guttman J, Dumsha T, Lovdahl P, Hovland E. (1997). Problem

solving in endodontics 3th ed mosby U.S.A, 5-6

Haji-Hassani, N., Bakhshi, M., & Shahabi, S. (2015). Frequency

of Iatrogenic Errors through Root Canal Treatment Procedure

in 1335 Charts of Dental Patients. Journal of international oral

health: JIOH, 7(Suppl 1), 14.

Ingle J, Bakland L (2008). Endodontics. 6th Ed. Ch27:921

Javidi M, Shoja Razavi A, Esmaieli H. (2006). A Comparision

between conventional and digital radiography in estimating

the working length of root canal. J Dent, 30:30-44

Kelbauskas E, Andriukaitien L, Irena N. (2009). Quality of root

canal  lling performed by undergraduate students of odontol-

ogy at Kaunas University of Medicine in Lithuania. Stomato-

logic, Baltic. Dental and Maxillofacial J 1:92-96

Khabbaz M.G, protogerou E., douka E. (2010). Radiographic

quality of root  llings performed by undergraduate students.

Int Endod J 43:499-508

Kulic L, Nogo-Zivanovic D, Krunic J, Vujaskovic M, Stojanovic

N. (2011). Radiological Assessment of the Quality of Root Canal

Filling in Teeth Endodontically Treated at Students’ Practical

session. Serbian Dent J; 3:139-143

Lynch CD, Burke FM. (2006). Quality of root canal  lling per-

formed by under graduate dental students on single rooted

teeth.Eur J Den;10:67-22

Mozayeni MA, Asnaashari M, Modaresi J. (2006). Clinical and

radiographic evaluation of procedural accidents and errors

during root canal therapy. Iranian Endodontic J 97-100

Dadresanfar B et al.

696 PREVALENCE OF THE ROOT CANAL TREATMENT ERRORS AND ITS RELATED FACTORS IN PATIENTS BIOSCIENCE BIOTECHNOLOGY RESEARCH COMMUNICATIONS

Pratten DH, McDonald NJ. (1996). Comparison of radiographic

and electronic working lenghts. J Endod; 22:173.

CV Mosby Co. (2009) Toronto; Ch18:322

Unal GC, Kececi AD, Kaya BU, Tac AG. (2011). Quality of root

canal  llings performed by undergraduate dental student. Eur

J Dent 3:324-30

Yousuf, W., Khan, M., & Mehdi, H. (2015). Endodontic proce-

dural errors: frequency, type of error, and the most frequently

treated tooth. International journal of dentistry, 2015.

Zinman EJ. (2002). Records and legal responsibilities. In: Cohen

S, Burns RC, editors. Pathways of the pulp. 8th ed. St.Louise:

Mosby; P. 400.