Prevalence Of Canal Variations In Mandibular 1st Molar In South Indian Population And Association With Age And Gender
Vaishnavi Devi. B1, S. Delphine Priscilla Antony2*
1 Saveetha Dental College and Hospital, Saveetha Institute of Medical and Technical Science, Saveetha University, India.
2 Senior Lecturer, Department of Conservative Dentistry and Endodontics, Saveetha Dental College and Hospital, Saveetha Institute Of Medical and Technical Science, Saveetha University, India.
*Corresponding Author
S. Delphine Priscilla Antony,
Senior Lecturer, Department of Conservative Dentistry and Endodontics, Saveetha Dental College and Hospital, Saveetha Institute Of Medical and Technical Science, Saveetha
University, India.
E-mail: delphine.sdc@saveetha.com
Received: November 09, 2020 Accepted: November 22, 2020; Published: November 30, 2020
Citation:Vaishnavi Devi. B, S. Delphine Priscilla Antony. Prevalence Of Canal Variations In Mandibular 1st Molar In South Indian Population And Association With Age And Gender. Int J Dentistry Oral Sci. 2020;S10:02:0023:125-130. doi: dx.doi.org/10.19070/2377-8075-SI02-0100023
Copyright: S. Delphine Priscilla Antony© 2020. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution and reproduction in any medium, provided the original author and source are credited.
Abstract
Background: Mandibular first molars are amongst the most common teeth requiring endodontic treatment due to their early
emergence in the oral cavity and subsequent caries. Proper knowledge and understanding of the root canal morphology and
anatomy of mandibular first molars, will help the clinician in developing a proper and standard treatment protocol by predicting
possible variations that potentially challenge the treatment outcome.
Aim: The main objective of the present study was to know the prevalence of canal variations in mandibular 1st molar among the
South Indian population and its association with age and gender. Materials and method - All the patients who reported during June
2019 to March 2020 for mandibular 1st molar endodontic therapy were chosen for the study. Information was collected from the
dental hospital record system and the resulting data was tabulated in excel and imported to SPSS for correlation and association.
Results: Within the limits of the study the results obtained are: prevalence of canal variations is 7.6% and 2.2% in single and multi
visit root canal treatment respectively with an higher incidence among the male patients and it is primarily seen in the age group
of 21 to 40 years.
Conclusion: This knowledge about the canal variations in the South Indian population will be helpful to the clinician to look for
any unusual anatomy while performing endodontic therapy which will prevent any unwanted procedural errors. It necessitates the
careful negotiation and cleaning of all accessible canal spaces.
2.Introduction
3.Materials and Methods
4.Results and Discussion
5.Conclusion
6.Author Contribution
7.Acknowledgements
8.References
Keywords
Mandibular Molars; Canal Variation; C Shaped Canal; Anatomy; Endodontic Therapy; Morphology.
Introduction
Success of an endodontic therapy depends mainly on adequate
debridement and removal of the necrotic pulpal tissue followed
by obturation of the root canal [26]. Knowledge of root canal
anatomy, its configurations and possible variations is important
for success of the treatment [17, 1]. Complex root canal morphology
and the presence of an untreated canal is always a clinical
challenge which can often compromise the outcome of the treatment
[23, 18]. The efficiency of the diagnostic aids also plays an
important role in the success of the treatment [14]. It is important
for the clinicians to use all the required armamentarium to locate
and treat the entire root canal system [34, 23]. Methods used to
study complex root canal morphology include intraoral radiographs,
tooth sectioning, clinical observation, direct microscope
and computed tomography [43]. All of these methods help us to
observe and understand the presence of root canal morphology
and its abnormal configurations.
Each root canal begins as a channel of the canal orifice and is
generally present apical to the cervical line [38]. Usually the roots
of primary teeth have single large canals, with age there would
be increased deposition of secondary dentine. Eventually resulting
in the formation of seperations, which causes substantial
modification of the root canal system sequelling to development
of separate canals [8]. The modification of a simple root canal
into a complex form occurs mostly in roots which have external
grooves. The mandibular first molar is typically presented with
two roots, a mesial root and straight, more rounded distal root
with three canals [6]. The distal surfaces of these roots have a
parabolic angle which makes the wall very thin. Mostly all the root canals are curved in a labio-lingual direction. These curvatures
create obstacles during biomechanical preparation because they
are not usually visible on a periapical radiograph [42, 29].
The root canal is complex and canals can branch, divide and rejoin
[12]. However due to familial, ethnic and gender differences
in a population, a wide range of anatomic and morphological
variations are encountered [37]. Most of the root canal variations
are seen in mandibular molars due to their divergent root structures
[21]. Sometimes, middle mesial canal can be found in the
groove between the mesiolingual and mesiobuccal canals with its
incidence ranging between 1% to 13.3% [36, 25]. C-shaped canals
in mandibular molars is one of the most common anatomic
variations of the root canal system and is named after its cross
sectional morphology [19]. While most C-shaped canals occur in
the mandibular second molar, they have also been reported in the
mandibular first molar, and the mandibular first premolar. The
occurrence of these variations in mandibular first molars is less
than 3% in African populations, 4.2% in Caucasians, less than
5% in Asian populations and higher than 5% in populations with
Mongolian traits [13]. According to a study of Reuben et.al, the
prevalence of root canal variations in Indian population shows
that there is an incidence of 4.84% with the majority having normal
root canal morphology and no statistical differences among
the female and male patients [31].
The anatomy of the root canal system varies greatly in different
populations and among the different individuals within the
same population, thus it is important to be aware of complexities
in tooth anatomy among racial groups because this understanding
will help clinician in providing better treatment [44]. Bayirli
in his study, concluded that gender and ethnicity plays a role in
determining the root canal anatomy and that both should be considered
during the pre- operative stage of root canal therapy [34].
Clinical determination of root canal anatomy is challenging at best
[11, 39, 35, 22]. All of these factors are important to be known
and considered by dentists to suggest an appropriate measure to
prevent any further complications and long term damage to the
oral tissues [32, 30, 15]. Although the pulpal anatomy of mandibular
molars has been extensively studied, information about
canal variations is limited. The main aim of this study is to know
the prevalence of canal variations in mandibular 1st molar in the
South Indian population and its association with age and gender.
Materials And Methods
Study setting
This retrospective cross sectional study is about knowing the
prevalence of canal variations in mandibular 1st molar endodontic
therapy. A randomised sample of healthy adults who had
undergone root canal therapy in the mandibular 1st molar were
chosen for the study. The study took place in a hospital setting
within the university. The retrospective data was being ethically
approved(ethical approval number: SDC/SIHEC/2020/DIASDATA/
0619-0320) and the number of people involved in the
study includes 3 members - Guide, researcher, reviewing expert.
Sampling
All the cases reported for mandibular 1st molar endodontic therapy
from the month of june 2019 to march 2020 was required
for the study. The records of all patient data were obtained from
the dental hospital record system from initial to last and were arranged
in chronological order. A total of 86000 patient records
were reviewed and analysed for the study. All the data were properly
verified and cross verified by another examiner. Sampling
bias was minimised by simple random sampling. The sample size
includes 1239 multi visit RCT patients and 403 single visit RCT
patients.
Data analysis
The collected data includes both single visit and multi visit, 1st
mandibular molar RCT details. Gross incomplete data was excluded
as it affects the study. Excel tabulation of all the verified
data along with SPSS importing was done. Data was imported to
the SPSS software for the statistical tests.The data was assessed by
being subjected to descriptive analysis with the help of frequencies,
percentage and analysed by running descriptive statistics in
the form of crosstabs. Independent variables in the study include
ethnicity, age and gender whereas dependent variables include canal
variations. Non parametric Chi square statistical test was done
and the results were correlated and associated.
Results And Discussion
The study evaluated the prevalence of canal variations in mandibular
1st molar among the patients visiting Saveetha Dental
College. A total of 1642 patients' mandibular 1st molar root canal
treatment records were included in this study. The statistical software
SPSS was used for the descriptive and inferential analysis.
Results on categorical measurement were presented in percentage(%).
Level of significance was predetermined at the probability
value of P = 0.05 and any value≤ 0.05 was considered to be
statistically significant.
Age prevalence in root canal treated patients infer that below the
age of 20 years 3 (0.74%) in single visit and 9 patients (0.73%)
have reported with the root canal variations. In the age group
of 21 to 40 years 17 patients (4.22%) in single visit RCT and 13
(1.05%) patients in multi visit RCT have been reported. 7 patients
(1.74%) in single visit RCT and 6 patients (0.48%) in multi visit
RCT in the age group of 41 to 60 years have reported. Above the
age group of 60 years, 3 patients (0.74%) in single visit and no
patients in multi visit RCT have reported with canal variations.
The remaining patient population shows normal root canal morphology.
It shows that 21 to 40 years show more prevalence of
canal variations in mandibular 1st molars in both single and multi
visit RCT (Figure 1, 2). P value is =0.001 and hence it is statistically
significant.
Gender prevalence in this study shows that among 403 patients
who had undergone endodontic therapy in a single visit RCT, 19
male patients have been reported with canal variations and 11 female
patients have reported (Figure 3). Similarly, 1239 patients
reported for multi visit RCT, in which 23 male patients have
reported with root canal variations and 5 female patients have
reported with the rest of the patients having normal root canal
(Figure 4). There is an increased prevalence of canal variations in
male patients in both single and multi visit RCT. P value is =0.002
and hence it is statistically significant.
Root canal variation prevalence among the mandibular 1st molar
reported patients shows that 31 patients (7.6%) out of 403 patients
in single visit RCT and 28 patients (2.2%) in multi visit RCT
have canal variations and the remaining have normal root canal
anatomy (Figure 5,6). P value is =0.001 and hence it is statistically
significant. The data shows that there is a higher incidence of
canal variations in single visit when compared to multi visit RCT.
The probability value is =0.001 for the study and hence the study
was statistically significant.
Dental caries is the most common cause for the loss of tooth in
a clinical situation, hence the final option in saving the tooth is
endodontic therapy [27]. Anatomy and morphology knowledge of the root canal has an important role in endodontic treatments
[3]. Gao et.al have reported variations in the root canals along
with the location of the canals. These include the presence of
additional canals or any anatomical variations [5]. If the presence
of any variation is suspected through a variety of preoperative
intraoral radiographs at different angles, then adequate cavity access
will help in the correct localization of root canal orifices.
Sometimes, it may be difficult to visualize the variations radiographically,
hence the use of an electronic apex locator and direct
microscope will be helpful in detection [41].
The pattern of age distribution in the prevalence of canal variations
showed that people of all groups have canal variations however
peak incidence was observed among the age group of 21 to
40 years (Fig 1, 2) (p=0.001, statistically significant). This finding
is in concordance with a study, 32.1% canal variations reported
in 21 to 40 years [24] and similarly in a study held among chinese
population, patients aged 20 to 30 years showed a higher prevalence
of additional root canals [46] and shows that this prevalence
does not vary with gender and tooth position. Younger patients
have a significantly higher incidence of canal variations. Continued
deposition of secondary dentin [20] within the root as the age
progresses will divide it into separate canals producing changes
in the number and size of the root canals, as well as many small
connecting branches between the facial and lingual aspects of the
canals [7].
Morphological variations in root canal anatomy due to gender and
genetic differences have been reported earlier in few studies (10).
In our study, there was a male preponderance in the prevalence
of root canal variations (Fig 3, 4) (p=0.002, statistically significant).
This finding is in concordance with the previous study held
among the Iran population, shows that the male patients show
more deviation in the root canal anatomy [4, 10].
In our study the prevalence of canal variation in single and multi
visit RCT is 7.6% and 2.2% respectively (Fig 5,6) (p=0.001, statistically
significant). Additional canals were found in 34.39% of the
mesiobuccal roots, 0.30% of the mid buccal roots, 0.30% of the
distobuccal roots, and 1.82% of the palatal roots. There is an increased
tendency to locate the middle mesial canal in second molars
(60%) versus first molars (37.5%) [33]. According to a study
on Chinese population using CBCT on permanent mandibular
first molars concluded that most mesial roots had more complex
canal morphologies when compared to the distal roots [45]. A
recent study evaluating root anatomy of permanent mandibular
molars shows that there was high prevalence of C-shaped root
canals in the Korean population [16]. It occurs due to the failure
of the Hertwig's epithelial root sheath to fuse to the facial and lingual
side. All these above studies show that the configuration of
the root canal system varies with different frequencies in different
populations. Several possible reasons may account for these differences,
such as ethnicity of the populations, sample size, and the
method used to study the canal variations.
Cohenhca reported that these canal variations pave way for the infectious
microorganisms to enter into the root canal system even
if the main canals were well obturated [2]. These canal variations
cannot be obturated using gutta-percha instead can be made patent
using root canal irrigants as it prevents any reinfection of the
root canal system through periodontal ligament space and also
reduces the postoperative pain [28, 40, 9].
There is a geographic limitation to the study as it predominantly
covers the South Indian population and it is also an unicentered
study. This can be modified by performing longitudinal and periodic
studies to evaluate the prevalence of canal variations. In the
future, a larger population with different ethnicity can be included to provide better results. This study gives valuable information to
dental practitioners in proposing strategies for the management
of canal variations. It will be helpful in creating awareness by
knowing the prevalence among different gender and age groups.
Figure 1. Bar graph showing the prevalence of canal variations in single visit RCT among different age groups of patients. x axis represents age group and y axis represents the number of patients. There is a significant higher incidence in the age group of 21 to 40 years among these patients. (p)= 0.001 statistically significant.
Figure 2. Bar graph showing the prevalence of canal variations in multi visit RCT among different age groups. x axis represents age group and y axis represents the number of patients. There is a significant higher incidence in the age group of 21 to 40 years among these patients. (p)= 0.001 statistically significant.
Figure 3. Bar graph showing the association between canal variations in single visit RCT and gender. x axis represents gender of the patient and y axis represents the number of patients. There is a significant higher incidence of male patients reported with canal variations than the female patients. (p)= 0.004 statistically significant.
Figure 4. Bar graph showing the association between canal variations in multi visit RCT and gender. x axis represents gender of the patient and y axis represents the number of patients. There is a significant higher incidence of male patients reported with canal variations than the female patients. (p)= 0.002 statistically significant.
Figure 5. Bar graph showing the prevalence of canal variations in single visit RCT. x axis represents the prevalence of canal variations and y axis represents the number of patients. There is a significant incidence of canal variations among the patients reported. (p)= 0.001 statistically significant.
Figure 6. Bar graph showing the prevalence of canal variations in multi visit RCT. x represents the prevalence of canal variations and y axis represents the number of patients. There is a significant incidence of canal variations among the patients reported. (p)= 0.001 statistically significant.
Conclusion
Within the limits of the current study the prevalence of canal
variations in both single and multi visit RCT of the mandibular
1st molar is known and it was more common in the male population
among the age group of 21 to 40 years. Thorough knowledge
of root morphology and its associated root canal anatomy with
possible variations forms the prime basis for the success of any
endodontic therapy. The importance of accurately determining
the presence of variations in root canals is reflected in the increased
failure rate that occurs when additional canals are missed
during root canal therapy.
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