RESEARCH ARTICLEOpen Access
Cross-sectional evaluation of the periapical status
as related to quality of root canal fillings and
coronal restorations in a rural adult male
population of Turkey
Kaan Gündüz1†, Hakan Avsever2*†, Kaan Orhan3and Kadriye Demirkaya4
Background: To determine the prevalence of periapical lesions in root canal-treated teeth in a rural, male adult,
Turkish population and to investigate the influence of the quality of root canal fillings on prevalence of periapical
Methods: The sample for this cross-sectional study consisted of 552 adult male patients, 18-32 years of age,
presenting consecutively as new patients seeking routine dental care at the Dental Sciences of Gulhane Military
Medicine, Ankara. The radiographs of the 1014 root canal-treated teeth were evaluated. The teeth were grouped
according to the radiographic quality of the root canal filling and the coronal restoration. The criteria used for the
examination were slightly modified from those described by De Moor. Periapical status was assessed by the
Periapical Index scores (PAI) proposed by Orstavik.
Results: The overall success rate of root canal treatment was 32.1%. The success rates of adequately root canal
treatment were significantly higher than inadequately root canal treatment, regardless of the quality or presence of
the coronal restoration (P < .001). In addition, the success rate of inadequate root canal treatment was also
significantly affected by the quality of coronal restorations.
Conclusions: Our results revealed a high prevalence of periapical lesions in root canal treatment, which is
comparable to that reported in other methodologically compatible studies from diverse geographical locations. In
addition, the results from the present study confirm the findings of other studies that found the quality of the root
canal treatment to be a key factor for prognosis with or without adequate coronal restoration.
Keywords: Periapical status, rural, root canal treatment
There are plenty of longitudinal studies investigating the
outcome of root canal treatment performed in educa-
tional hospitals (e.g., dental faculties), which have
demonstrated that the reality for the overall population
might be somewhat different, with only 35%-96% of the
root canal treated teeth exhibiting no disease[1-5]. How-
ever, for the most part, epidemiological studies
evaluating the outcomes of root canal treatments per-
formed by general practitioners show much lower suc-
cess rates. Frequencies of periapical lesions in root canal
treatment have been reported in Belgium (40%), Den-
mark (52%) Lithuania (39%), Canada (44% and 51%),
Germany (61%), Scotland (51%), Spain (64.5%), and The
United States (39%)[6-9]. This discrepancy in success
rates may reflect a difference in the quality of the root
canal treatment performed despite improvements in
instruments and materials and advances in the under-
standing of the disease process.
In cross-sectional studies, there is a consistent associa-
tion between periapical radiolucency and inadequate
* Correspondence: firstname.lastname@example.org
† Contributed equally
2Department of Oral, Teeth and Jaw Radiology, Gulhane Military Medical
Academy, Ankara, Turkey
Full list of author information is available at the end of the article
Gündüz et al. BMC Oral Health 2011, 11:20
© 2011 Gündüz et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons
Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in
any medium, provided the original work is properly cited.
root fillings [10,11]. Ray&Trope reported that the
quality of the coronal restoration had a greater impact
on the periapical status of root canal treated teeth. In
contrast to the findings of Ray&Trope, other studies
have revealed that adequate root canal treatment had a
greater influence than coronal restoration. Tronstad et
al. showed that the quality of a well-sealed coronal
restoration only significantly influenced the outcome
when combined with adequate endodontic treatment.
The high rates of success reported in these studies were
obtained with well-trained practitioners under strict
operating condition that may not reflect the situation
found within the average dental clinic .
Such studies demonstrate the potential outcome of
root canal treatment rather than its realistic outcome in
general practice .
In Turkey, 25% of the national population lives in a
rural area. This study is the first to determine the preva-
lence of periapical lesions in root canal-treated teeth in
a rural, adult, Turkish population and to investigate the
influence of the quality of root canal fillings and coronal
restorations on prevalence of periapical lesions.
The sample for this cross-sectional study consisted of
552 adult male patients, 18-32 years of age, presenting
consecutively as new patients seeking routine dental
care at the Dental Sciences of Gulhane Military Medi-
cine, Ankara. All these individuals were army recruits,
who lived in different rural regions of Turkey. Any
patient who lived in a city of Turkey was excluded from
the study. An area with less than 10,000 inhabitants was
classified as towns and villages (rural); and a population
of more than 10,000 defined a location as a city.
Another part of the inclusion criteria was that the
patient had to be visiting the clinic for the first time.
To be enrolled in the study, the patient’s chart had to
contain a panoramic radiograph with supplemental peri-
apical radiographs. Periapical radiographs were only
used when panoramic radiographs showed poor image
quality particularly in the upper and lower anterior
region. All periapical radiographs were taken using the
paralleling technique. All radiographs were taken and
processed at the same radiology center in 2008. The
Bluex Pantos 16 XP (Assago, Italy) panoramic roentgen
unit and Trophy Trex X-ray (Croissy, Beaubourg,
France) periapical radiography unit were used to take
This study was based on retrospectively evaluation of
radiographs. Thus, no ethical approval was obtained
from the local ethical committee since only the achieve
data were used for the study. However, before taking
any radiograph or intra/extra-oral examination, patients
gave their informed consent prior to radiography and
examinations according to the principles of the Helsinki
Declaration, including all amendments and revisions.
Collected data was only accessible to the researchers.
Moreover, all examiners in the study only examined the
radiographs and were blinded to any other patient data
in the radiographic examination procedure.
In total, the radiographs of 1014 root-filled teeth were
evaluated. The teeth were grouped according to the
radiographic quality of the root canal filling and the cor-
onal restoration. The criteria used for the examination
were slightly modified from those described by De Moor
et al.  as follows:
Quality of root filling
Adequate: All canals were obturated. There were no
voids present. The end of the root canal fillings was 0-2
mm short of the radiographic apex.
Inadequate: The end of the root canal fillings were
more than 2 mm short of the radiographic apex or
grossly overfilled. Root canal fillings had voids, inade-
quate density, unfilled canals, and/or were poor
Adequate: Intact restoration with good margin adapta-
tion and no signs of recurrent caries
Inadequate Restoration with overhangs, open margins,
recurrent caries; or no restoration at all.
Apical status was assessed by the Periapical Index (PAI)
proposed by Ørstavik et al. who scored the apical
area of the radiographic images as follows:
1. Normal periapical structures
2. Small changes in bone structure
3. Changes in the bone structure with little mineral
4. Periodontitis with a well-defined radiolucent area
5. Severe periodontitis with exacerbating features
A score of PAI 1 was defined as a healthy periapical
region, indicating a normal width of the permanent liga-
ment space and normal appearance of the surrounding
bone. All other PAI scores were evaluated as apical peri-
odontitis. All radiographs were evaluated independently
by an endodontic consultant and a dental radiologist
who both had over 10 years of clinical experience. Both
examiners were calibrated. As a part of the calibration
phase, study methodology was explained to the exami-
ners. To minimize discrepant results they also familiar-
ized themselves with the scores they should attribute to
the radiographic images and the established evaluation
method for the study. Two hundred teeth were assessed
Gündüz et al. BMC Oral Health 2011, 11:20
Page 2 of 6
to calibrate the 2 examiners, and inter-examiner agree-
ment was detected by Cohen’s kappa (kappa = 0.86).
The radiographs were observed using an x-ray viewer
with 2 times magnification. To get optimal image qual-
ity, the room was darkened to control the surrounding
light for the best radiographic contrast. When disagree-
ment occurred, a third observer, a dental radiologist
with 15 years of clinical experience, asked to make a
SPSS software was used for statistical analysis (SPSS
Inc., Chicago, IL). Differences between the groups were
examined using the chi-square test. The significance
level was established at 5%.
Of the 1014 root canal treatment investigated in this
study from 552 male patients, maxillary central incisors
were the most frequently treated teeth, followed by
mandibular premolars, maxillary lateral incisors, and
maxillary premolars (Table 1). Mandibular incisors were
the teeth with the lowest frequency of endodontic
On the basis of the PAI scoring system, 326 (32.1%)
teeth were classified as healthy and 688 (67.9%) teeth as
apical periodontitis. The root canal filling was rated as
adequate in 425 teeth (41.9%). In this group, the success
rate was 59.8%. The group with inadequate root canal
treatment corresponded to 58.1% of the examined cases
and had a success rate of 12.2% (Table 2). In general,
the success rates of adequately root canal treatment
were significantly higher than inadequately root canal-
treatment, regardless of the quality or presence of the
coronal restoration (P < .001).
For the 310 (30.6%) teeth with adequate coronal
restorations, the success rate was 59%. The group with
inadequate restorations consisted of 704 teeth (69.4%),
and the success rate in this group was 20.3%. The differ-
ence between the 2 groups was statistically significant(P
The healthy rate was 76.2% (231/303) for cases with
adequate root canal treatment and adequate restora-
tions. In cases of adequate root canal treatment and
inadequate restoration, the success rate was 45% (55/
122) (Table 3). The difference between the 2 groups was
statistically significant, indicating that the outcome of
adequately treated root canals was affected by the qual-
ity of the coronal restoration (P = .04).
Teeth with inadequate treatment and adequate
restoration showed a success rate of 10.8% (25/231).
Teeth with inadequate treatment and inadequate
restoration yielded the lowest healthy rate of this study,
i.e., 3.7% (15/358). Statistical analysis revealed that the
healthy rate of inadequate root canal treatment was also
significantly affected by the quality of coronal restora-
tions. When compared to teeth with inadequate root
canal treatment and adequate restoration, the difference
was statistically significant (P = .02).
This study is a cross-sectional study. The main disad-
vantages of a cross-sectional study are that the data ana-
lyzed are restricted to the information available and
thereby vulnerable to biases of interpretation . For
instance, radiographs were examined at a given point in
time, and it was impossible to determine whether a peri-
apical lesion was healing or not. On the other hand,
misinterpretations and misdiagnoses in cross-sectional
studies are known to be fairly equally distributed, so the
results are still meaningful . Additionally, a large
sample size and random selection are the most impor-
tant advantages of this method.
In intraoral radiography, the 3-dimensional object is
compressed into a 2-dimensional image from which the
Table 1 The distribution of ROOT-FILLED treated teeth
according to the type of tooth (n = 1014)
Tooth Maxillary Mandibular
Table 2 An overview of the relationship between the
quality of root filling, coronal restorations and periapical
status (n = 1014)
Table 3 The periapical status for combinations of
different qualities of coronal restoration and root canal
fillings (n = 1014)
coronal restorationroot fillingn healthy (pai 1)%
Gündüz et al. BMC Oral Health 2011, 11:20
Page 3 of 6
observer has to mentally recreate the 3 dimensions .
This can be difficult even when more than a single
radiograph is used. The use of more than 1 radiograph
is of course inestimable when there is a need to display
the roots of a tooth with as little superimposition onto
each other as possible and when root fractures are sus-
pected . Best possible periapical radiographs are
obtained when the paralleling technique is used .
This is, however, not always possible, e.g., in the upper
molar regions where, owing to anatomic conditions,
there is the greatest need for 3-dimensional information.
Therefore, periapical intraoral radiographs may be quite
sufficient in many areas and less so in others, depending
on the diagnostic problems and the anatomic conditions
Another limitation of this and other studies with a
similar methodology is the fact that radiographic eva-
luation without clinical data does not always provide
reliable information. For example, leaky occlusal mar-
gins and cracks in restorations could not be observed
in radiographs. Likewise, apical periodontitis lesions
limited to the cancellous bone might pass unnoticed in
a radiographic examination . Moreover, the micro-
biologic conditions of the root canal system, which
influence the treatment outcome, cannot be inferred
on the basis of the radiographic examination . The
accuracy of panoramic radiographs in the detection of
apical periodontitis has been also questioned although
Ahlqwist et al  supported their use in epidemiolo-
gical studies. This was also supported by Muhammed
and Manson-Hing  who showed no statistically sig-
nificant difference between the panoramic and periapi-
cal surveys in the detection of periapical changes.
However, they also suggested that a complete radio-
graphic examination should include periapical, panora-
mic and bite-wing radiographs. In this study, periapical
radiographs were only used when panoramic radio-
graphs with poor image quality particularly in the
upper and lower anterior region. In addition, only
teeth scored as PAI 1 were accepted as healthy.
Further studies with more sensitive techniques, such as
cone beam computed tomography, have the potential
to minimize this limitation.
This study of Turkish patients living in rural areas has
similar results for the prevalence of periapical lesions to
that of other epidemiological studies in Turkey and
other countries [6,8-10,12,24-32]. In relation to these
results, it is evident that a need for betterment of the
quality of root canal treatment in general dental prac-
tice. In fact, these studies have been performed on peo-
ple who live in cities and have high incomes and more
treatment opportunities. Studies from controlled envir-
onments are usually carried out by specialists or super-
vised operators and reveal the potential outcome of root
canal treatment rather than its realistic outcome in the
general population. In Turkey, almost 17.1 million peo-
ple are living in rural areas. Prevalence of perapical
lesions in root-filled teeth in Turkey are conducted on
people who live in cities and obtain medical treatment
in private and public university hospitals [30,32] This
research is the first in terms of targeting a population
from a rural area. Kayahan et al. , an example of a
study done in Turkey, detected 1268 teeth that received
root canal treatment among 280 patients. In 754 (59.5%)
of these teeth, there were no pathological findings. In
another study by different researchers, the panoramic
radiographs of 375 patients were investigated, and root
canal treatment was applied to 449 teeth . In 209
(46.5%) teeth, there were no pathological findings. In
our study, 688 (67.9%) of 1014 teeth underwent root
canal treatment, and apical periodontitis was detected.
The income and treatment opportunities for patients,
especially those living in rural areas of Turkey, are lim-
ited. Perhaps this explains the high apical periodontitis
rate found in our study.
Consequently, it was found that the prognosis of
inadequate root canal treatment was not affected by cor-
onal restoration. When root canal treatment was inade-
quate, there was only a 7.4% difference between the
inadequate and adequate crown restoration groups. This
shows that the quality of the root canal treatment is the
most important factor affecting the health of peri-radi-
The results from the present study confirm the find-
ings of other studies that found the quality of the root
canal treatment to be a key factor for prognosis with or
without adequate coronal restoration. Siqueira et al.
reported that if the root canal filling was inadequate, it
did not matter whether the coronal restoration was ade-
quate, inadequate, or absent; the tooth would still have
a poor prognosis when compared to an adequately filled
tooth. Tronstad et al. suggested that a correlation
exists between the quality of the restoration and peri-
radicular health but concluded that the quality of the
restoration was significantly less important than the
quality of the root canal filling. Additionally, Kayahan et
al. reported that, in an urban Turkish subpopulation,
healthy periapex rates were significantly higher in teeth
with good root canal filling regardless of the type of
In the literature, there are different studies that dis-
cuss the quality of root canal treatment and the effects
of coronal restorations on peri-radicular tissues. More-
over, they have different results.
Kirkevang et al. stated that the combination of
inadequate root canal treatment and inadequate coronal
restoration was associated with an increased incidence
of apical periodontitis. This result was also supported by
Gündüz et al. BMC Oral Health 2011, 11:20
Page 4 of 6
Hommez et al. who demonstrated that an adequate
coronal restoration and adequate root canal treatment
were both important to the overall success of the root
canal treatment. Ray and Trope  suggested that the
quality of the restoration had a greater impact on peria-
pical health than the quality of the root canal filling.
Tavares et al. reported that higher success rates for
teeth with adequate or inadequate root canal treatment
were always observed in teeth with adequate coronal
restorations. Ricucci et al. reported that exposure of
root fillings to the oral microbiota was not significantly
correlated with peri-radicular status. In our study, when
a coronal restoration was inadequate, the success rate of
adequately treated canals was reduced. Laboratory stu-
dies have suggested that the direct exposure of a root
canal filling to microorganisms and their products may
facilitate reinfection of the root canal system in a rela-
tively short time [35-37].
Our results revealed a high prevalence of periapical
lesions in root canal treatment teeth. The results from
the present study confirm the findings of other studies
that found the quality of the root canal treatment to be
a key factor for prognosis with or without adequate cor-
We would like to thank to Dr. Tuncer OZEN, professor and chairman of the
department of Oral, Teeth and Jaw Radiology, Gulhane Military Medical
Academy, Ankara, TURKEY, for the great help they rendered to us during the
process of data collection.
1Department of Oral, Teeth and Jaw Radiology, Faculty of Dentistry,
Ondokuz Mayis University, Samsun, Turkey.2Department of Oral, Teeth and
Jaw Radiology, Gulhane Military Medical Academy, Ankara, Turkey.
3Department of Oral, Teeth and Jaw Radiology, Faculty of Dentistry, Ankara
University, Turkey.4Department of Endodontics, Gulhane Military Medical
Academy, Ankara, Turkey.
KG and HA made substantial contributions to the conception and design of
this study, participated in data collection, statistical analysis and
interpretation of results, drafted and revised the final manuscript, and read
and approved the final manuscript. KO and KD participated in the design
and data analysis. All authors read and approved the final manuscript
The authors declare that they have no competing interests.
Received: 8 November 2010 Accepted: 20 June 2011
Published: 20 June 2011
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The pre-publication history for this paper can be accessed here:
Cite this article as: Gündüz et al.: Cross-sectional evaluation of the
periapical status as related to quality of root canal fillings and coronal
restorations in a rural adult male population of Turkey. BMC Oral Health
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