Root canal morphology of premolar teeth in the population of Maharashtra (Pune) compared to the other Indian population

Kulwinder Singh Banga; Ajinkya Mansing Pawar; Deepak Nagpal; Jayant Landge; Bhagyashree Thakur; Sweta Rastogi

doi:10.4103/endo.endo_46_18

ORIGINAL ARTICLE

Year : 2018 | Volume : 30 | Issue : 1 | Page : 15-20

Root canal morphology of premolar teeth in the population of Maharashtra (Pune) compared to the other Indian population

Kulwinder Singh Banga¹, Ajinkya Mansing Pawar¹, Deepak Nagpal², Jayant Landge³, Bhagyashree Thakur⁴, Sweta Rastogi⁵
¹ Department of Conservative Dentistry and Endodontics, Nair Hospital Dental College, Mumbai, India
² Department of Oral Pathology and Microbiology, D. Y. Patil Dental School, Pune, Maharashtra, India
³ Department of Oral and Maxillofacial Surgery, Government Dental College and Hospital, Mumbai, India
⁴ Department of Dentistry, Sir H. N. Reliance Foundation Hospital, Mumbai, India
⁵ Department of Conservative Dentistry and Endodontics, ESIC Dental College, New Delhi, India

Date of Web Publication

4-Jun-2018

Correspondence Address:
Dr. Ajinkya Mansing Pawar
Department of Conservative Dentistry and Endodontics, Nair Hospital Dental College, Dr. A. L. Nair Road, Mumbai Central, Mumbai - 400 008, Maharashtra
India

Source of Support: None, Conflict of Interest: None

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DOI: 10.4103/endo.endo_46_18

Abstract

Aim: The current study aimed to investigate the root canal anatomy and their variations associated with premolar teeth in a defined population using tooth-clearing technique.
Materials and Methods: Three hundred extracted premolar teeth (maxillary and mandibular) were collected from western Maharashtra (Pune). Access cavities were prepared and samples were placed in 2.5% sodium hypochlorite for 48 h. They were then decalcified with 5% nitric acid, dehydrated, and rendered clear by immersion in methyl salicylate, and methylene blue dye was injected. After staining, cleared teeth were evaluated for (i) number of roots and root canals, (ii) number of apical foramina, (iii) shape of root, (iv) type of root canal based on Vertucci's classification, (v) presence of lateral canals and their locations, and (vi) presence of root curvatures.
Results: Vertucci Type I canal configuration represented the highest percentage (72.66%) followed by Type II (11.66%), Type III (6.33%), Type IV (4.66%), Type VI (2.66%), Type V (1.66%), Type VIII (0.66%), and C shaped (2.33%). Accessory canals were detected in 22.8% and intercanal connections were observed in 24.8% while 54% showed apical delta.
Conclusion: Such knowledge is clinically useful for localization, negotiation, and subsequent management of premolar teeth in the studied population.

Keywords: Decalcification and staining, mandibular first premolar, mandibular second premolar, maxillary first premolar, maxillary second premolar, root canal anatomy, Vertucci's classification

How to cite this article:
Banga KS, Pawar AM, Nagpal D, Landge J, Thakur B, Rastogi S. Root canal morphology of premolar teeth in the population of Maharashtra (Pune) compared to the other Indian population. Endodontology 2018;30:15-20

How to cite this URL:
Banga KS, Pawar AM, Nagpal D, Landge J, Thakur B, Rastogi S. Root canal morphology of premolar teeth in the population of Maharashtra (Pune) compared to the other Indian population. Endodontology [serial online] 2018 [cited 2022 Aug 12];30:15-20. Available from: https://www.endodontologyonweb.org/text.asp?2018/30/1/15/233737

Introduction

It has been well documented that thorough knowledge of root canal configuration is essential and responsible for the success of an endodontic therapy. Knowledge of root canal configuration, before endodontic procedures such as cleaning and shaping, influences more on the changes that occurred during preparation than the instrumentation technique itself, emphasizing the importance of root canal anatomy.^[1] Root canal is a complex system demonstrating numerous branching, divisions, and reunions in its path to the apical termination. Initially, Weine categorized the root canal systems into four basic types. Later, Vertucci classified the root canal systems into more complex eight canal configuration types.^[2],[3]

Different racial groups exhibit a characteristic pattern in root canal morphology, and thus, studying a defined ethnic population can aid in understanding the nature of root canal system, which would help to negotiate the root canals and the subsequent management.^[4] Premolars are considered as teeth frequently requiring root canal treatment and having a wide variety of root canal configurations caused by genetic and environmental influences and can be extremely complex.^{[5],[6],[7],[8],[9]}

To study canal morphology, different techniques have been used such as tooth sectioning, radiographs, posttreatment clinical observation, direct observation with microscope, tooth clearing, three-dimensional (3D) reconstruction, and computed tomography. Of these techniques, it has been reported that in vitro staining and tooth-clearing method is considered to be the simplest and most convenient, with the most detailed information obtained.^[10],[11]

Thus, this study was designed to evaluate the variations in the root canal morphologies of premolar teeth (maxillary and mandibular) exhibited by western Maharashtra (Pune) population using clearing technique.

Materials and Methods

A total of 300 human premolars were acquired from the department of oral and maxillofacial surgery of the parent institute and from private clinics in western Maharashtra (Pune). The age and gender of the patients were not recorded during the time of tooth collection. The exclusion criteria for the tooth were as follows:^[1]

Carious tooth
Presence of cracks
Tooth with restorations
Incomplete root formation or root resorption
History of previous root canal treatment.

Standard oval access cavities were prepared for the selected teeth using Endo Access Kit (Dentsply Tulsa Dental Specialties, Tulsa, Oklahoma). The samples were then immersed in 2.5% sodium hypochlorite (Organo Biotech laboratories Pvt., Ltd., New Delhi, India) for 48 h aiding in the removal of the organic debris. The samples were further cleaned with an ultrasonic scalar to remove calculus, soft-tissue remnants, or any bony fragments and then stored in 10% neutral buffered formaldehyde until further use.

The samples were then flushed under running tap water and then decalcified using nitric acid 10% for initial 3 days then by nitric acid 5% for 2 days. The solution was changed each day, and the teeth were examined physically for the consistency. The decalcified teeth were then kept under running tap water for 24 h and then dehydrated in ascending grades of ethyl alcohol (70%, 80%, 90%, and 100%) for 10 h each. Complete decalcification was assessed by insertion of paper pin in the crown and by radiographs for random samples to check for a uniform decalcification of the tooth. After dehydration, the teeth were allowed to dry.

To clear the teeth, they were immersed in methyl salicylate solution (98%) and observed. At the end of 3 days, complete transparency was achieved. Methylene blue dye was then injected in the tooth through the access cavity into the coronal pulp chamber and the root canal system using an insulin syringe until the ink was seen out through the apical foramen. Excess ink was wiped out with gauze soaked in absolute alcohol. Standardized images were then taken, and the following features were evaluated (i) number of roots and root canals, (ii) number and location of apical foramens, (iii) shape of root, (iv) type of root canal based on Vertucci's classification, (v) presence of lateral canals and their locations, and (vi) presence of root curvatures.

Results

A total of 300 premolars were selected of which 150 were maxillary premolars (75 first premolar and 75 second premolar) and 150 mandibular premolars (75 first premolar and 75 second premolar). With reference to number of roots, it was observed that 12% of maxillary first premolars were single rooted and 22.66% of mandibular second premolars showed two roots.

Regarding the number of canals, Vertucci Type I canal configuration represented the highest percentage (72.66%) followed by Type II (11.66%), Type III (6.33%), Type IV (4.66%), Type VI (2.66%), Type V (1.66%), Type VIII (0.66%), and C shaped (2.33%). Accessory canals were detected in 22.8% and intercanal connections were observed in 24.8% while 54% showed apical delta [Figure 1].

Figure 1: Root canal anatomies according to Vertucci seen in maxillary and mandibular premolar teeth after clearing and injection of methylene blue dye. (a) Type I, (b) Type II, (c) Type III, (d) Type IV, (e) Type V, (f) Type VI, (g) Type VIII, and (i) Category C

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Discussion

Knowledge of root canal anatomy and its variations are an integral part of endodontic treatment. Numerous techniques have been approached to study canal morphology including tooth sectioning, radiographs, posttreatment clinical observation, direct observation with microscope, tooth clearing, 3D reconstruction, and computed tomography.^[1],[3],[10]

It has been discussed by Alhadainy ^[1] that to study the morphology of teeth, the most detailed information can be obtained by tooth clearing and in vitro staining as it gives a 3D view of the pulp cavity in relation to the exterior of the tooth. This method also allows visualization of root canal forms and the anastomoses among them. The original form and relation of canals are maintained because canal negotiation with instruments is avoided.^[12] However, the limitation of this method is the difficulty to detect C-shaped canal, which is better seen with cross-sectioning method.^[1],[13]

Premolars are frequently observed to undergo root canal treatment, and these groups of teeth exhibit numerous variations as reported in literature. Various studies have shown that ethnicity also has a definite influence on the morphology and anatomy of these teeth.^[1],[14] The current study was an attempt to evaluate the anatomy of premolars in the population of western Maharashtra particularly from the district of Pune, using clearing technique, and compare the findings with other studies on Indian population.

It was found in literature search that most of the studies in Indian population were carried out on one particular group such as mandibular premolars or more frequently mandibular second premolars, maxillary second premolars, and maxillary first premolars. This study was thus designed to analyze anatomy and morphology of all the premolars, and for statistical purpose, an equal number of teeth were selected in each group of premolars.

In our study, with reference to number of roots, the maximum variations seen were in mandibular second premolars having 22.66% two roots, followed by maxillary first premolar with single root found in 12% of the teeth, mandibular first premolar with two roots in 8%, and maxillary second premolars with two roots in 2% of the teeth studied [Table 1]. Our findings are greater than the findings of Jain and Bahuguna ^[15] for mandibular first premolars, where they found two-rooted teeth in 2.89%. Gupta et al.^[16] had found 53.6% of maxillary first premolars to be single rooted, but in our study, we found 12%. In the previous studies, the prevalence of one root in these teeth varied from 15.5% to 60%; two roots, 40%–80.9%; and three roots, 0%–9.2%.^{[4],[17],[18],[19]}

Table 1: Number and percentage of the first and second premolars root numbers

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The canal configurations of the samples were classified according to Vertucci ^[8] since it is the most accepted method. [Table 2] illustrates the frequency of root canal configuration showing Vertucci Type I as the most frequent type found in our study (75%) followed by Type II (13.33%), Type III (6.33%), Type IV (4.66%), and Type VIII (0.66%) [Table 2].

Table 2: Frequency of root canal classification of premolars in the population of western Maharashtra (Pune) using tooth-clearing technique

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For mandibular first premolars, the Indian literature showed Type I in a range from 50% by Parekh et al.^[20] to 80% by Singh and Pawar ^[21] and our finding confined within these limits (70%). Type II was the next most frequently seen, and the highest percentage being 11.36% in our study and the lowest being 5% by Parekh et al.^[20] We found the frequency of Type III configuration greater in mandibular first premolars (9.33%) as compared to the other Indian studies reported in literature, where they found Type IV to be more frequent with maximum of 25% by Parekh et al.^[20] and lowest 2% by Sandhya et al.^[22] In their study, Jain et al. saw Type V in a range of 17.39% and 2% by Singh and Pawar.^[21] We found Type V configuration in 1.66% of the samples. The next types of configuration showed very minimal percentages such as Type VI 2.5% by Parekh et al. to 0.72% by Jain et al., Type VIII 0.4% by Iyer et al.,^[23] and Type IX 2% by Singh and Pawar.^[21] In the current study, we found the frequency of Type VI to be 2.66%. A complex category type was also shown by Sandhya et al.^[22] to be 2% of the mandibular first premolars, and in our study, we found it to be 2.33% [Table 3]a.

Table 3:

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In mandibular second premolars, also the literature showed that Type I was the most frequent ranging from 80% by Parekh et al.^[20] to 66% by Singh and Pawar.^[21] Our study showed 66.68% of second premolars having Type I configuration. This was followed by Type II 30% by Singh and Pawar ^[21] to 1% by Iyer et al.^[23] We found that 20% of mandibular second premolars had Type II configuration. Type V configuration was the next commonly seen variant in mandibular second premolars with 17.5% by Parekh et al.^[20] to 2.4% by Iyer et al.^[23] We found Type III in 6.66% in the studied samples, and till date no other Indian studied showed this configuration in mandibular second premolar. The frequency of Type IV ranged from 20.8% by Iyer et al. to 2.5% by Parekh et al. In our study, we found the frequency to be 6.66%. The next variation seen in mandibular second premolars was Type VIII seen in range of 0.4%–2.66% [Table 3]b.

Very few studies were found in literature search for maxillary premolars among Indian population as compared to the mandibular premolars probably, due to the known fact that a number of variations in root canal architecture are more frequently seen in the mandibular premolars as compared to maxillary premolars.

In maxillary first premolar, Gupta et al.^[16] found Type IV to be the most common 33.2% followed by Type I 23.2%, Type II 14.8%, Type III 13.6%, Type V 6.4%, Type VII 4%, Type VI 2%, and Type VIII 0.4%. In contrast to this study, we found the following frequency of root canal configuration in maxillary first premolar Type I 80%, Type II 8%, Type IV 6.66, Type III 5.33%, and Type VIII 0.66%. No other variations were seen our study sample of maxillary first premolars [Table 3]c.

Similarly, in maxillary second premolars, Raj and Mylswamy ^[24] found Type II to be the most common 33.6% followed by Type IV 31.1%, Type I 29.2%, Type V 2.1%, Type III 1.3%, Type VI 1.2%, and Type VII 1%. In our study samples, we found Type I 84%, Type II 9.33%, Type III 4%, Type IV 2%, and Type VI 0.66% [Table 3]c.

Lateral canals were observed in 27% of the samples [Table 4] with maximum being in the apical third and least in the cervical third [Figure 2]. Horizontal interconnection was noted in 1.33% of the studied samples, and these findings are in accordance with the literature. Among the root curvatures observed, most of them had straight roots followed by distal curvature [Table 5].

Table 4: Frequency of lateral canals presents in premolars in the specified population studied using tooth-clearing technique

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Figure 2: Presence of lateral canals and complex communications

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Table 5: Frequency of curvatures

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Conclusion

This study has observed that there are numerous variations seen in premolars and such knowledge is clinically useful for localization and negotiation of canals as well as their subsequent management in the studied population. Similar studies with large sample size are needed among different groups of the Indian population, which would help to develop a standardized baseline point for root canal anatomy comparison making endodontic therapy to be more predictive and effective.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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