|Year : 2022 | Volume
| Issue : 1 | Page : 38-44
Pulp chamber floor anatomy of the maxillary first and second molars in an Indian population: A descriptive cross-sectional study using a new classification
Ajinkya M Pawar1, Shishir H Singh2
1 Department of Conservative Dentistry and Endodontics, Nair Hospital Dental College; Department of Conservative Dentistry and Endodontics, TPCT's Dental College and Hospital, Navi Mumbai, Maharashtra, India
2 Department of Conservative Dentistry and Endodontics, TPCT's Dental College and Hospital, Navi Mumbai, Maharashtra, India
|Date of Submission||01-Aug-2021|
|Date of Decision||19-Dec-2021|
|Date of Acceptance||24-Dec-2021|
|Date of Web Publication||25-Mar-2022|
Dr. Ajinkya M Pawar
Department of Conservative Dentistry and Endodontics, Nair Hospital Dental College, Mumbai - 400 034, Maharashtra
Source of Support: None, Conflict of Interest: None
Aim: The purpose of the present descriptive study was to evaluate and depict the form of the coronal pulp chamber floor in the permanent maxillary first (pMFM) and second (pMSM) molars in an Indian population.
Subjects and Methods: Five hundred freshly extracted pMFM (n = 250) and pMSM (n = 250) were acquired from a pool of freshly extracted teeth unrelated to the current study. The crowns were flattened occlusally till the pulpal anatomy was seen and were photographed using a stereomicroscope at ×4.5 magnification. The number of orifices, shapes of the orifices, incidence of mesiobuccal 2 (MB-2), incidence of discobuccal 2 (DB-2), incidence of palatal 2 (P-2), shape of the access cavity, incidence and shape of isthmus, location of extra orifice, and the shape of the pulp chamber floor according to the Pawar and Singh classification© (K, Y, I, and others) were observed.
Statistical Analysis: The level of significance for descriptive and frequency statistics was determined at 5%, with 95% confidence intervals.
Results: Three root canal orifices occurred predominantly in 50.4% pMFM and 69.2% pMSM. The root canal orifices in the MB and distobuccal roots were round, whereas palatal orifices were oval. The access cavities were triangular in 51.6% pMFM, 51.2% pMSM, rhomboid shaped in 34.8% pMFM, 20.4% pMSM, and others in 13.6% pMFM and 28.4% pMSM. The extra orifices in pMFM were in MB in 20.8%, distobuccal in 14%, and palatal in 8% roots. For the pMSM, extra orifices were in MB (7.2%), distobuccal (6.4%), and palatal (2.4%) roots. The K, Y, I, and other classification were seen in 18.4%, 55.2%, 12.8%, and 13.6%, respectively, for pMFM and in 3.6%, 61.6%, 23.6%, and 11.6%, respectively, for pMSM.
Conclusion: Our study investigated and described the various anatomical patterns of the coronal pulp chamber floor in maxillary molars. The classification applied to the patterns of the pulp chamber floor architecture can help clinicians determine the total number of canals as well as their unique orifice position and better communication.
Keywords: Anatomical configurations, canal orifices, maxillary molars, Pawar and Singh pulp chamber floor classification, pulp chamber floor
|How to cite this article:|
Pawar AM, Singh SH. Pulp chamber floor anatomy of the maxillary first and second molars in an Indian population: A descriptive cross-sectional study using a new classification. Endodontology 2022;34:38-44
|How to cite this URL:|
Pawar AM, Singh SH. Pulp chamber floor anatomy of the maxillary first and second molars in an Indian population: A descriptive cross-sectional study using a new classification. Endodontology [serial online] 2022 [cited 2022 May 23];34:38-44. Available from: https://www.endodontologyonweb.org/text.asp?2022/34/1/38/340831
| Introduction|| |
Because the fundamental cornerstone of all surgical operations is a comprehension of anatomy, any attempt to treat endodontic lesions/diseases must be preceded by a complete overview of the morphology of the pulp space. Dental pulp occupies the internal space of the tooth structure.,, The anatomical landmarks of importance are the cementoenamel junction (CEJ), the central groove of central fossa, the roof and floor of the pulp chamber, and the furcation area. Pulp space is conventionally referred as the main passage present at the core of the tooth and the primary debridement area during root canal treatments. It has been known that pulp space lies within the composite root canal system made up of synchronized and fine small tributaries present along the breadth and length of the tooth dentin. Thus, it is mandatory for the clinicians' to completely understand this system.
It is very appropriately mentioned by expert clinicians that what they cannot see and cannot negotiate is what they fail to instrument. With regard to the anatomic complexity of root and root canals, Hess and Zurcher concluded that the root with a tapered canal and the existence of a single apical foramen is considered an exception.
Previous pulp chamber anatomy research has offered not as much detail for accurately predicting the number and location of canal orifices.,, Thus, safely locating the canal orifices is essential also in cases where the tooth structure is heavily restored or destructed or the pulp chamber has been gauged by previous attempt of an access preparation.,
In today's world of evidence-based dentistry, a thorough examination of the morphology of the coronal pulp chamber floor is critical. As a result, the morphological configurations of the pulp chamber floor have been proposed as the deciding component for the endodontic access cavity, which is the first and most significant step in endodontic treatment. Failing to locate all canals existent in complicated teeth is due to a lack of awareness of the coronal pulp chamber architecture of the tooth being treated (molars). As previously indicated, limited studies have been conducted on the importance of pulp chamber floor architecture in root canal treatment effectiveness. As a result, while treating the population, this innovation can assist in recognizing and differentiating the form of an endodontic access cavity. To address certain clinical cases, the Pawar and Singh molar pulp chamber floor classification© was recently proposed. This classification entails describing the shape the position and number of canal orifices present, resulting in a unique alphabetical letter (K, Y, I, and others) [Figure 1].
|Figure 1: Pawar and Singh molar pulp chamber floor classification© of the canal orifices and number of canals present, forming a peculiar alphabetical letter (K, Y, I)|
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The primary intent of the study was to assess number of canals, shapes of the orifices, incidence of extra canals, shape of the access cavity, incidence and shape of isthmus, location of extra canal, and the shape of the pulp chamber floor according to the new classification were observed for maxillary first and second molars.
| Subjects and Methods|| |
The current in vitro descriptive cross-sectional study was conducted after obtaining relevant permissions from the Institutional Ethics board (TDC/IRB-EC/161/2017.) The study was carried out on freshly extracted pMFM and pMSM teeth collected from dental schools from India running postgraduate institutes. The study methodology executed was according to the Checklist for Reporting In vitro Studies (CRIS) guidelines. In this study, a total of 500 extracted teeth (250 pMFM and 250 pMSM) were obtained by stratified random sampling method. Stratified random sampling is a method of sampling that involves the division of a population into smaller sub-groups known as strata. Stratified random sampling allows researchers to obtain a sample population that best represents the entire population being studied.
The eligibility criteria of the samples followed were those permanent maxillary (first and second) molars extracted of patients of indigenous Indian origin of Dravidian, Aaryan, and Mixed ethnicities and with fully formed and developed roots, apices, and intact crowns. Teeth with previous endodontic treatment, those fractured during the extraction, having root caries and root canal calcifications, and grossly carious crowns were not included in the study.
The collected samples were cleaned of any hard and soft tissue debris using an ultrasonic scalar and were stored in phosphate buffered solution until use. The crowns of all the samples were flattened occlusally till the pulpal anatomy was visualized clearly using a diamond disc with continuous water spray. The observation was done and photographed using a stereomicroscope at ×4.5 magnification.
Data were input and organized in Microsoft Excel (2017), and statistical analysis was carried out on a MacBook running version 20 of the (SPSS; IBM Corp., Armonk, NY, USA). The results were derived by performing descriptive and frequency analysis for the number of canals, shapes of the orifices, incidence of mesiobuccal 2 (MB-2), incidence of discobuccal 2 (DB-2), incidence of palatal 2 (P-2), shape of the access cavity, incidence and shape of isthmus, location of extra canal, and the shape of the pulp chamber floor according to the Pawar and Singh classification© in maxillary molars. Chi-square test of proportion was used to determine the significance within each parameter. P < 0.05 was appraised as statistically significant.
| Results|| |
The parameters described in our current descriptive cross-sectional study on extracted pMFM and pMSM were the number of canals, the shape of canal orifices, the shape of the pulp chamber, the location of the extra canal, the anatomy of the isthmus, and the classification of the pulp chamber anatomy of maxillary first and second molars separately.
Number of orifices
Majority of the pMFM had 3 orifices (50.4%) followed by 4 (36%) and only 5 teeth showed 6 orifices. With regard to pMSM, almost 69.2% showed presence of 3 orifices followed by 4 (11.6%) and about 7 teeth showed single orifice. The Chi-square test was used to evaluate the difference in the number of orifices in maxillary first and second molars. A statistically significant difference (P < 0.05) was noted amongst the maxillary first and second molars with respect to the number of root canal orifice openings [Table 1].
|Table 1: Distribution of maxillary first and second molars according to the number of orifices present|
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Shape of the orifice
Depending on the presence of canals, the shape of the canal orifice was observed. The different canals observed in maxillary first and second molars were buccal canal, MB canal, MB2 canal, distobuccal canal, distobuccal-2 canal, palatal, and palatal-2 canal. Each of the canal was assessed for its shape. With reference to MB canal, about 52% and 71.6% showed a round orifice in maxillary first and second molars respectively. MB2 canal where it was present, majority of pMFM (23.2%) showed a round canal orifice and very less (4%) showed an oval canal orifice, whereas majority in pMSM (12%) showed a round orifice and very less (0.8%) showed oval orifice.
A round distobuccal canal orifice was prominent in about 71.6% and 68.8% of pMFM and pMSM respectively. Palatal canal was having oval orifice (67.6% and 58.8%) predominantly in pMFM and pMSM, followed by a round orifice, whereas only palatal-2 canal showed oval orifice in about 8.8% maxillary first molars and 2.4% second molars. All these differences observed in maxillary first and second molars were significant statistically [Table 2] and [Table 3].
|Table 2: Distribution of maxillary first molars according to the shape of canal orifices present|
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|Table 3: Distribution of maxillary second molars according to the shape of canal orifices present|
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Shape of the access
In our study, the shape of the pulp chamber was evaluated. About 34.8% and 51.2% of the maxillary first and second molars respectively, showed a triangular shape, followed by rhomboidal shape. This difference was significant for first as well as second molars (P = 0.001). When the location of extra orifice was assessed, a mesial extra orifice was seen in 19.2% of first molars and 5.6% of second molars followed by distal and palatal respectively. A peculiar isthmus anatomy was observed between extra orifices. It was straight in 38.8% and 12% of the maxillary first and second molars respectively. This difference was statistically significant among first and second molars (P = 0.000) [Table 4].
|Table 4: Distribution of maxillary first and second molars according to the shape of the pulp chamber, location of extra canal and isthmus anatomy between extra canal|
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Incidence of extra canals
Our study evaluated the incidence of extra orifices in mesial, distal and palatal roots in pMFM and pMSM. In pMFM, in mesial root 20.8%, distal root 14%, and palatal root 8% extra orifices were seen. In pMSM, in mesial root 7.2%, distal root 6.4%, and palatal root 2.4% extra orifices were seen. This difference was significant in cases of first as well as second molars (P = 0.000) [Table 4].
Incidence and shape of Isthmus
In our study, the shape of isthmus was evaluated in the maxillary first and second molars. It was noted that about 38.8% of the maxillary first molars showed straight isthmus whereas about 12% maxillary second molars showed straight isthmus. This difference was statistically significant amongst both first and second molars (P = 0.000) [Table 4].
Application of Pawar and Singh classification©
Using Pawar and Singh classification for the pulp chamber floor anatomy, the overall shape of the pulp chamber floor was assessed. Maxillary molars showed Y shaped in majority (55.2%), followed by the K shaped (18.4%). Similar findings were reported in maxillary second molars, wherein majority showed Y shaped (61.6%) floor, followed by I shaped (23.2%). These differences in the shape of pulp chamber floor were statistically significant for maxillary first and second molars (P = 0.000) [Table 5] and [Figure 2].
|Figure 2: Representative images of the pulp chamber floor of maxillary teeth on application of the Pawar and Singh classification© K, Y, I, and others: (a and b) K type, (c) Y type, (d) I type, and (e) others|
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|Table 5: Distribution of maxillary first and second molars according to the classification of orifice in pulp chamber|
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| Discussion|| |
Our study described the pulp chamber floor anatomy of pMFM and pMSM using Pawar and Singh molar classification. Furthermore, the shape of each canal orifice along with the presence and location of an extra canal was assessed in our study. Beyond the common perception of root canal anatomy lies the intricate complex coronal pulp anatomy. The research on the anatomical configurations of the pulp has primarily revealed that before reaching apex of the tooth, dental pulp has many delicate configurations and shapes. Depending on an accurate confirmatory diagnosis, followed by locating, cleaning, and shaping and obturating the root canals, the prospect of endodontic treatment is determined. An expert clinician must understand the disparity of the absolute root canal system, to avoid complications and offer best possible treatment to the patients with higher success rate.
Numerous research on the radicular canal architecture of maxillary permanent molars have been published in the literature.,,,, These teeth frequently have numerous canals. If they are presumed to have numerous canals, comprehending the coronal pulp chamber floor of these teeth is critical with respect to the root canal orifices. If the practitioner is unfamiliar with the coronal pulp chamber floor, there is a significant risk of missing root canals. Several factors contribute to the variation in the pulp morphology found in maxillary molar teeth. Variations and complexity in the pulp morphology may result may be because of ethnic background, age, and gender of the population studied.,
For almost a century, researchers all around the world have been researching root canal anatomy. Many techniques have been utilized to explore the anatomy of root canals. The most commonly used methods in analyzing, are canal staining and tooth clearing, conventional radiographs, digital and contrast medium–enhanced radiographic techniques, radiographic assessment enhanced with contrast media, and, more recently, computed tomographic techniques. In these investigations, canal staining, and tooth clearance is often regarded as the gold standard. Singh and Pawar emphasized the benefits of this approach. They suggested, since the original form of the root is left intact and the association between internal root surfaces and the external contour of the tooth is maintained, the form of the canal and even minute structures could be seen clearly. Thus, failure in specimen preparation is resisted. Furthermore, the specimen may be conserved for an extended period of time, with less equipment and space necessary, and the chemicals employed are less harmful and economical.
Pinneda and Kuttler, on the other hand, proposed using radiography to examine the root canal architecture of teeth. Weine et al. were the first to use sectioning and radiography methods to categorize root canal configurations inside a single root into three kinds based on the pattern of division of the primary root canal along its length from the pulp chamber to the apex. Following it, Vertucci et al. developed a classification system evaluated on the basis of 200 cleared maxillary second premolars with dye-stained pulp cavities; they discovered canal systems which were more complex than those described by Weine et al. and defined a total of eight configurations. Weine then added an extra type to his original proposal. Vertucci found, using both staining and radiographic techniques, that utilizing an entire root of a specimen rendered transparent by decalcification and radiographic inspection allows the investigator to see all of the ramifications of the root canal system more precisely. Several researchers have correctly indicated that maxillary molars commonly have a second canal in the MB root, although clinically locating it is challenging.,, There is no question that unless radiographic and clinical studies indicate otherwise, this second canal, labeled “MB2,” should be expected.
Singh and Pawar discovered that the prevalence of MB2 canals in maxillary molars is higher in Indian teeth than in other ethnicities. This may be true but contrasting in the current study, where in the incidence of MB2 orifice was found to be less than reported. This could be due to the fact that, the current preliminary study was focused on the anatomy of the coronal pulp chamber floor. The samples were sectioned restricting the anatomical landmark of CEJ. It's not always that the MB2 is located at the level of CEJ and most of the times its below that suggesting clinicians to trough below the level of the main MB canal.
This might be a racial trait, as it is more common among Caucasian, European, Far Eastern Thai, and Japanese ethnicities. Their findings indicate that the root canal architecture of Indian molar teeth is analogous to that of Mexicans, Brazilians, African Ugandans, and Kuwaitis, which may be regarded a racial feature.
Until now, the endodontic literature has mostly focused on the anatomy of root canals in diverse teeth, with just a few studies pertaining to the pulp chamber floor. Clinicians begin access cavity preparation with preconceived notions about the location of pulp chambers and root canal orifices based on appealing images of maiden teeth. However, a dependance on this perception lead to undesirable results, like perforation of the pulp chamber. The number of root canal orifices in a specific tooth can never be predicted before treatment begins. Although radiographs can occasionally show the number of roots, they cannot identify the number or position of the root canal orifices.,
This study presented findings on the pulp chamber floor, which were sparingly detailed. The relationships that are reported occurred with very high frequency. In our study, the pulp chamber floor, and canals of maxillary first and second molars have been studied and described intricately. The change in their anatomical shapes have been noted and then the classification of orifice in the pulp chamber has been considered accordingly. To avoid the possible complications during an endodontic treatment like dentinal gouging, loss of sound tooth structure, accidental pulp exposure, perforation and missed canals, the most probable outcome of the shape of the pulp chamber has been assessed in our study, Hence, the appropriate procurement of the knowledge about the canals, orifices and their shapes has been emphasized upon in our study. This will also guide the clinicians in controlled and selective access opening during the endodontic procedure. Moreover, when the pulp chamber is calcified it causes reduction in the tactile sensation and thus, such anatomical measurements of floor of the pulp chamber would be great help to the clinician, while performing endodontic therapy. All these contribute to the strengths of our study. A few study limitations that can be thought of are the racial predisposition and changes in the root and root canal configurations was not compared and separately analyzed in our study. Moreover, only the indigenous Indian population was studied in the present study. Therefore, the generalizability of our study to other ethnic populations will be limited.
| Conclusion|| |
Our study results conclude that the most common type of classification of orifice in the pulp chamber was the Y type in cases of pMFM and pMSM. There has been extensive literature regarding the morphological variations of the root canal system. Hypothesizing the average number of root canals in a tooth has little practical use for the individual tooth being treated. If one or more root canals go undetected, the risk of failure raises. As a result, this study investigated and characterized the different anatomical patterns of both the chamber and the pulp chamber floor in maxillary molars. These categorization and patterns can be utilized to assist practitioners in determining the overall number of canals in a tooth as well as the particular orifice position on the pulp chamber floor. Future research studies might compare the structural patterns of root canal systems based on ethnic differences.
This research is a part of PhD dissertation being carried out in the Department of Conservative Dentistry and Endodontics at Terna Dental College and Hospital, Navi Mumbai affiliated to the Maharashtra University of Health Sciences, Nashik.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]