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 Table of Contents  
ORIGINAL ARTICLE
Year : 2021  |  Volume : 33  |  Issue : 3  |  Page : 158-164

Evaluation of root canal anatomy of maxillary premolars in a North Indian subpopulation using cone-beam computed tomography


1 Department of Conservative Dentistry and Endodontics, JCD Dental College, Sirsa, Haryana, India
2 Department of Restorative Dental Sciences, College of Dentistry, King Khalid University, Abha, Saudi Arabia

Date of Submission01-Jul-2021
Date of Decision16-Jul-2021
Date of Acceptance03-Sep-2021
Date of Web Publication30-Sep-2021

Correspondence Address:
Dr. Gurdeep Singh Gill
Department of Conservative Dentistry and Endoodntics, JCD Dental College, Sirsa, Haryana
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/endo.endo_128_21

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  Abstract 


Aim: The aim of the present study was to investigate the root canal anatomy of maxillary premolars in a North Indian subpopulation using cone-beam computed tomography (CBCT).
Materials and Methods: CBCT images of 101 extracted maxillary first and second premolars were analyzed, and data were recorded to determine length of the tooth, number of roots, bifurcation level in double rooted teeth, number of apical foramina, and anatomy of the root canal system.
Results: Most maxillary first premolars were double rooted (57.7%), while maxillary second premolars were predominantly single rooted (83.6%). The average length of the maxillary first premolar was 21.6 mm and second premolar was 21.3 mm. All double-rooted maxillary premolars had two canals. Single canal (at apex) was more prevalent in single-rooted maxillary premolars (86% in first premolar and 73% in second premolar). In double-rooted maxillary first premolar, the most prevalent canal type was Type IV (34.6%), followed by Type I (23.1%) and Type V (17.3%), and in maxillary second premolars, the dominant canal morphology was Type II (32.6%), followed by Type IV (22.4%) and Type I (20.4%).
Conclusion: In North Indian subpopulation, most maxillary first premolars have double roots with two root canals, while second premolars are predominantly single rooted with single canals. Maxillary premolars can show all types of Vertucci's root canal anatomy with most prevalent being Type IV in double-rooted maxillary first premolars, Type I in single rooted maxillary first premolars, and Type II in maxillary second premolars.

Keywords: Cone-beam computed tomography, maxillary first premolar, maxillary second premolar, root canal anatomy


How to cite this article:
Malik SK, Singla R, Gill GS, Jain N, Kumar T, Arora S. Evaluation of root canal anatomy of maxillary premolars in a North Indian subpopulation using cone-beam computed tomography. Endodontology 2021;33:158-64

How to cite this URL:
Malik SK, Singla R, Gill GS, Jain N, Kumar T, Arora S. Evaluation of root canal anatomy of maxillary premolars in a North Indian subpopulation using cone-beam computed tomography. Endodontology [serial online] 2021 [cited 2021 Dec 7];33:158-64. Available from: https://www.endodontologyonweb.org/text.asp?2021/33/3/158/327269




  Introduction Top


Knowledge of root canal anatomy and morphology is the cornerstone of contemporary successful endodontic treatment, other factors being diagnosis and treatment planning, debridement, thorough disinfection, obturation, coronal restoration, and three-dimensional imaging of healing of teeth with preexisting pathosis.[1] The importance of root canal anatomy and its variations cannot be understated in endodontic treatment. Most of the failures of endodontic treatment are attributed to inability of clinician to locate, prepare, or obturate one or more of the root canals.[2] The understanding of anatomic configuration of root canals in each tooth is also helpful in anticipating potential complications during treatment.

The maxillary premolars are one of the common candidates for root canal treatment and account for 15.8%–21.5% of all treated teeth.[3] Their less mesiodistal dimensions than molars and more number of canals than anterior teeth leave clinician with less margin of error. All types of Vertucci's root canal configurations have been reported in maxillary premolars.[4] Other anatomical variations such as three roots, longitudinal depressions/concavity, apical foramen not terminating at the root tip (66.6%), lateral canals (38%), apical deltas (12.3%), and isthmi (16%) have been found to be common in maxillary premolars.[5]

Many factors can influence the variations found in the root canal morphology such as gender, ethnic background, sample size, data collection methods, study design, and techniques used for analyzing the root canal system.[6],[7],[8],[9],[10],[11] Many traits and differences in root canal anatomy of the maxillary premolars are specific to races and populations making the study of root canal anatomy of specific populations essential for better endodontic management.[12]

Different methodologies have been used in the past to understand the anatomical complexities of the root canal systems in human teeth, most common being tooth clearing and staining,[9],[13],[14] modified canal clearing and staining,[10] radiographic techniques[15] and more recently, computed tomography (CT) techniques, i.e. microcomputed[16] and cone-beam CT (CBCT).[17],[18],[19],[20],[21],[22],[23],[24] Clearing technique provides three-dimensional view of pulp cavity in relation to external surface, but it cannot be used in in vivo studies. Periapical radiographs provide only two-dimensional image of teeth and surrounding structures. CBCT is a noninvasive technique for the three-dimensional assessment of the root canal system and can be used in clinical settings as well. It is as accurate as clearing and staining technique in identifying the root canal anatomy[25] and better than conventional radiography as the area of interest can be visualized in any plane and eliminates superimposition of anatomic structures.[26]

Very few studies have been conducted on maxillary premolars using clearing and staining in North Indian population.[8],[16] To the best of our knowledge, no study has employed CBCT to determine root canal anatomy of maxillary premolars in North Indian population. In order to fill the lacunae, the aim of the present study was to investigate the root canal anatomy of maxillary premolars in a North Indian population using CBCT.


  Materials and Methods Top


The study was approved by Ethical research and Review Board of the dental college (JCDV/DC/18/2153). One hundred and ten extracted intact human maxillary first and second premolars were collected from the Department of Oral and Maxillofacial Surgery of the college. Staff in oral surgery department was familiarized with purpose of the study and requirements. It was ensured that all collected teeth belonged to indigenous North Indians. Teeth with large carious lesions, cracked teeth, broken roots, having resorption, incompletely formed root apices, and with root canal fillings were discarded. The surfaces of teeth were cleared of external debris, calculus, and soft tissue using ultrasonic scaler (woodpecker, UDS-E) and then examined under an illuminated magnifying lens with illumination (×2) for intact occlusal and root morphology. The selected samples were divided into two groups, namely, maxillary first premolars and maxillary second premolars which were further subdivided into single and double rooted teeth.

Tooth length of individual teeth was measured using digital Vernier Caliper as distance between the buccal cusp tip and the root apex. In teeth with two apices, the buccal root apex was used for the measurements. They were then rinsed with normal saline and then stored in distilled water in separate bottles and labeled. The teeth were mounted group wise on to wax rims made of modeling wax. The samples with rims were then coded and numbered separately for easy identification and stored in separate sealed pouches for further analysis.

CBCT imaging

CBCT images were obtained using CS9300 (Carestream Dental LLC, Atlanta, Georgia) CBCT extraoral imaging system. The scan parameters were set with 85 kv, 2.5 mA, and exposure time of 8.01 s (For one rim with 10 teeth). The fixed field of view was 5 cm × 10 cm across the whole rim with voxel size 180 μm3. All images were taken following the manufacturer's instructions by an experienced radiologist in the department of oral medicine and radiology. In a single imaging scan, two rims containing ten teeth each were included. The rims were kept with occlusal surfaces facing upward. Cellophane tape was used to wrap around these two rims for additional stabilization and for mounting on the CBCT machine. After the imaging procedure, the scanned images were named according to the sample block numbers. The individual CBCT images were analyzed by Dental imaging 6.14.7 software. The consecutive slice images on axial, coronal, and sagittal planes were set by 0.20 mm thickness for accurate evaluation.

Assessment of canal configuration

The canal configuration was assessed using the Vertucci's classification.[4] Additional patterns were classified according to Sert and Bayirli's[7] classification.

Radiologic evaluation

Three experienced endodontists (observers) jointly determined the characteristics of root and canal anatomies of maxillary premolars by analyzing CBCT images. They were calibrated by showing the 50 sample images (not related to present study) to each examiner and recording their analysis to evaluate the reliability of the assessment. Wilcoxon's matched-pairs signed rank test was used for intraobserver, whereas interobserver reliability was assessed by the intraclass correlation coefficient (ICC) and the coefficient of variation. CBCT evaluations revealed no intraobserver variance for the observers (P > 0.05). Overall measurement consistency for endodontist 1, 2, and 3 was rated at 92.1%, 90.3%, and 91.2%, respectively. ICCs between the three observers were ranged from 0.858 to 0.987 (high interobserver agreement). Every examiner performed the evaluation of CBCT images twice with a 2-week interval between assessments. Senior oral radiologist participated in decision-making when a consensus could not be reached.

The CBCT images were evaluated for length of the tooth, number of roots, number of root canals in each root, root canal configuration, and bifurcation level in double-rooted teeth. The data were expressed as numbers with percentages for categorical variables. Descriptive analyses of the data were performed in the IBM SPSS Statistics software (version 22) (IBM Corp., NY, USA).


  Results Top


In the present study, 101 extracted maxillary premolars (52 maxillary first premolar and 49 maxillary second premolars) met the inclusion criteria and were evaluated [Table 1], [Table 2], [Table 3] and [Figure 1].
Table 1: Number of roots and root canals

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Table 2: Prevalence of root canal configuration

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Table 3: Bifurcation level of double rooted maxillary first and second premolar

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Figure 1: Cone beam computed tomography images of root canal configurations

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Maxillary first premolar

The average length of the maxillary first premolar was 21.6 mm. Double-rooted teeth were 57.7% and single rooted teeth were 42.3%. In single rooted maxillary first premolar, 86.3% showed one canal, 13.6% contained two canals, and Type I configuration was most common. All double-rooted premolars had two canals and most prevalent root canal configuration was Type IV (56.7%), followed by Type V. Overall most prevalent root canal configuration in maxillary first premolars was Type IV (34.6%), followed by Type I (23%). Three rooted maxillary premolars and three canals were not seen were not found in this study. Most of the double-rooted maxillary first premolars showed bifurcation at middle third (43.3%), followed by apical third (36.7%) and cervical third (20%).

Maxillary second premolar

Average length of maxillary second premolar was 21.3 mm. Single-rooted premolars predominated with 83.6%, only 16.3% were double rooted. In single-rooted second premolars, 73.2% had one canal and 26.8% had two canals, Type II canal configuration was most prevalent (39.6%). Additional type XIX configuration was found in one single rooted second premolar. All double rooted maxillary second premolars showed the presence of two canals and type IV configuration was found in 62.5% of cases. Overall most common configuration in maxillary second premolars Type II (32.6%) followed by Type IV (22.4%). All the double-rooted maxillary second premolars showed bifurcation at apical third of the root.


  Discussion Top


The crux of successful endodontics revolves around sound knowledge of root canal morphology and its anatomic variations and meticulously performed cleaning and shaping procedures. In the present study, root canal anatomy of maxillary first and second premolars was analyzed using CBCT for the first time in an North Indian subpopulation. Vertucci's classification[4] was used as reference as it is most widely used classification in the contemporary literature and can help in better comparison with the previous studies. We have compared the results of our study with previous studies using CBCT or clearing technique and excluded radiographic studies as they do not provide three dimensional assessment of root canal anatomy [Table 4] and [Table 5].
Table 4: Comparison of root forms in maxillary first premolars in previous studies and those in this study

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Table 5: Comparison of root forms in maxillary second premolars in previous studies and those in this study

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Maxillary first premolar

Average length of tooth length provides an idea about the working length, which is one of the most important steps in endodontic therapy. Average length of maxillary first premolar in the present study (21.6 mm) was which is comparable to that reported by Wheeler's (22.5 mm).[27] In the present study, double-rooted teeth predominated (58%) as in studies by Banga et al.[14] and Neelakantan et al.[28] Same pattern was also observed in studies on Brazilian,[18],[23] Egyptian,[22] Saudi,[19],[29] Spanish,[6],[30] and Turkish[9],[21] population though frequency varies between 49% and 88%. These findings were different from Indian studies by Gupta et al.[8] and Dinakar et al.[13] and studies on Chinese population[17],[20] where single-rooted teeth predominate. This difference can be explained based on difference in population groups and sampling area. Three rooted premolars were not found in the present study although incidence of three-rooted maxillary first premolars has been reported to be 0.4%, to 9% in previous studies.[6],[15],[22]

Two canals were found in majority of first premolars (63.5%) in the present study, a trait common throughout the world populations though incidence was on the lower side than reported in previous studies (61%–96%). Vertucci's type IV canal configuration was most prevalent (34.6%) in the present study another finding observed consistently in all populations with reported frequency of 33%–83%.[6],[9],[10],[13],[16],[17],[18],[19],[20],[21],[22] Three canals were not found in this study though they have a prevalence of 0%–4%.[6],[22]

Bifurcation level is critical for locating missed canals and preventing perforations. In the present study, the furcation level in maxillary first premolars was mostly at middle third (43.3%) similar to Egyptian population[22] though frequency (79%) was comparatively less. It is different from Spanish[6] (apical third 57%), SriLankan[31] (apical third mostly), and Japanese[31] (coronal/middle third) populations.

Maxillary second premolar

The average length of maxillary second premolar (21.3 mm) was comparable to a previous study[32] done on Indian population and Wheeler's[27] (22.5 mm). Majority of maxillary first premolars are single rooted as reported in various populations with frequency of 66%–98%, in our study single rooted teeth were 83.65%. No three rooted premolars were observed in the present study which is consistent with low frequency (0.3%–1.7%) observed in other studies.[9],[11],[18],[21],[22]

Number of root canals shows a wide variation even between similar populations throughout the world. Single root canals were predominantly (61.2%) found in this study which is similar with findings in studies by Abella et al.,[6] Yang et al.,[11] de Lima et al.,[18] Banga et al.,[14] and in Turkish population.[9],[21] These findings are contrary to studies of Li et al.,[17] Alqedairi et al.,[19] Saber et al.,[22] Estrela et al.,[23] and Raj and Mylswamy.[32] Root canal configuration in second premolars also shows high variability with Type II (32.6%) being most common in our study. Same was reported by Raj and Mylswamy[32] in Indian population and Alqedairi et al.[19] in Saudi population. Meanwhile in Spanish,[6] Turkish,[9],[21] Chinese,[11],[17] and Brazilian[18],[23] population Type I configuration is predominant (39%–78%). Saber et al.[22] and Elnour et al.[24] reported Type IV configuration as predominant, while Banga et al.[14] reported Type I as the most common configuration in maxillary second premolar.

All the double-rooted maxillary second premolars showed bifurcation at apical third level. No study on North Indian population has mentioned the bifurcation level. It is difficult to identify bifurcation level with radiographs and CBCT should be performed when necessary.

In the present study, the root and canal morphology of North Indian maxillary first and second premolars showed high variability. The differences from other studies can be explained on the basis of variation in population, gender, ethnic background, sample size, data collection methods, study design, and techniques used in analyzing the root canal system.[6],[7],[8],[9],[10],[11] In this investigation, presence of three rooted maxillary premolar though was rare, but possibility should always be contemplated as it has been consistently reported in Asian populations as well.

In the current study, CBCT provided us a clear three-dimensional visualization of the canal trajectory in maxillary premolars, which contributed to an accurate identification of their canal morphologies. Many previous studies[6],[17],[18],[19],[20],[21],[22],[23],[24] also proved the reliability of CBCT in endodontic treatment. Furthermore, CBCT is noninvasive, provides three-dimensional image assessments without superimposition of structures, and can be used in clinical settings, if indicated. CBCT is a better choice for evaluating the characteristics of root canal system though radiation dose to the patient remains a concern. Sample size collected for the present study was small, and we did not take into account age and gender of the patients.


  Conclusion Top


Within the limitation of the present study, it can be concluded that maxillary first and second premolar in north Indian population has average length of 21.6 mm and 21.3 mm, respectively. The most prevalent root canal configuration found is Type IV followed by Type I in maxillary first premolar and Type II canal configuration followed by Type IV canal configuration in maxillary second premolar. The finding of additional canal configurations in this study is low but should be kept in mind when performing endodontic therapy for these teeth. In vivo CBCT analysis is a noninvasive and clinically effective tool for examining root and canal morphology that may help improve the outcome of endodontic treatment.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
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    Tables

  [Table 1], [Table 2], [Table 3], [Table 4], [Table 5]



 

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