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ORIGINAL ARTICLE
Year : 2017  |  Volume : 9  |  Issue : 5  |  Page : 68-72  

Root canal configuration of human permanent mandibular first molars of an indo-dravidian population based in Southern India: An In vitro study


1 Department of Conservative Dentistry, JKK Nataraja Dental College and Hospital, Komarapalayam, Tamil Nadu, India
2 Department of Conservative Dentistry, Malabar Dental College and Research Institute, Malappuram, Kerala, India

Date of Web Publication27-Nov-2017

Correspondence Address:
J V Karunakaran
Department of Conservative Dentistry, JKK Nataraja Dental College and Hospital, Komarapalayam - 638 183, Tamil Nadu
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/jpbs.JPBS_163_17

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   Abstract 


Aim: This study aims to analyze root canal configuration of human permanent mandibular first molars of an indo-Dravidian population based in southern India. Materials and Methods: A total of 1147 mandibular first permanent molars were collected, cleansed, and stored. The number of roots was recorded, access preparations made, pattern of orifices recorded after pulpal floor debridement, dye injected into the canals using apical negative pressure and subjected to a clearing technique. They were then analyzed using a stereo microscope and the canal configurations recorded (Vertucci). The number of roots, the pattern of orifices and canal configuration were recorded. Results: The pattern of orifices was triangular (87.9%), rectangular (8.5%), C-shaped (3.0%), and two orifice pattern (0.6%). About 95.6% of teeth had two roots, and 4.4% had three roots. The most common canal system configuration in mesial root was Vertucci type IV (52.3%), followed by type II (35%). Root canal configuration of the distal root revealed type I configuration in 62.7%, followed by types II (14.5%) and IV (12.4%). The distolingual root had a type I configuration. Conclusion: Awareness of canal configuration, adequate clinical skills, use of specialized techniques of diagnosis, debridement and obturation will pave the way for successful treatment outcomes.

Keywords: Distolingual root, indo-Dravidian population, pattern of orifices, root canal configuration


How to cite this article:
Karunakaran J V, Samuel LS, Rishal Y, Joseph M D, Suresh K R, Varghese ST. Root canal configuration of human permanent mandibular first molars of an indo-dravidian population based in Southern India: An In vitro study. J Pharm Bioall Sci 2017;9, Suppl S1:68-72

How to cite this URL:
Karunakaran J V, Samuel LS, Rishal Y, Joseph M D, Suresh K R, Varghese ST. Root canal configuration of human permanent mandibular first molars of an indo-dravidian population based in Southern India: An In vitro study. J Pharm Bioall Sci [serial online] 2017 [cited 2020 Apr 6];9, Suppl S1:68-72. Available from: http://www.jpbsonline.org/text.asp?2017/9/5/68/219293




   Introduction Top


As how a thorough knowledge of anatomy paves the way for a brilliant surgeon, so does the knowledge of root canal anatomy for a successful endodontist. Although endodontics achieved special recognition as a branch of dentistry only in 1963, its importance was well understood well before, and it was merely a culmination of efforts of various pioneers who were responsible for its development as a science. Cruse and Bellizzi[1],[2] in their historic review of endodontics say, though the practice of this science has been cited by authors since ancient times, it is difficult to view these in the light of the science of endodontics we know and practice today. The clinician needs a precise knowledge of root form and canal morphology. It has been the constant endeavor of various researchers to understand the complexities of root canal anatomy. The shape and curvature of roots, number of canals they contain, and their relationship to each other fully go a long way for successful endodontic therapy. Formerly, the concept of principal and secondary root canals was prevalent. This has now been modified for a more dynamic principle of a root canal system which comprises of a network of small canals that reach the periodontium through apical foramen or other areas of the root. This view is more applicable or more apt in posterior teeth. The difficulty in removing all pulpal tissue from the root canal and problems faced while obturation of the root canal with the aim of achieving a hermetic seal are better appreciated. The outcome of therapy is directly related to the elimination of microorganisms from the canal system and prevention of reinfections.[3] John Ingle in 1976, reported that 58.66% of failures of root canal therapy could be attributed to the incomplete obturation of the root canal space, and 9.68% to root perforations.[4] Failure to recognize the ramifications of the root canal space can lead to incomplete obturation. Often the principal root canal is considered the easiest pathway of inserting endodontic instruments to the apical foramen, but the operator must be aware and always look out for extra canals.

Variations in root canal systems in different racial populations have been reported. The three rooted molar is one such variation. Surveys of populations of Mongoloid origin indicate a high prevalence of three-rooted mandibular molars. The frequency of this trait ranges from 6 to 43.6%. Being familiar with these patterns is important for the endodontist, though of rare occurrence. A number of methodologies have been advocated for analyzing the canal configuration of the mandibular first permanent molar.[5] Taurodontism dentinal dysplasia, dens in dente, thalassemia and irradiation during odontogenesis have been found to cause alternations in the normal development of roots. This altered development has a direct influence on the canal anatomy.[6]

The canal configuration has been classified by Wiene, Pineda and Kuttler, and Vertucci.[7] The vertucci classification has been further modified by Kartal and Cimili in 1997[8], Gulabivala et al. in 2001[9], Sert and Bayirli in 2004[10], Peiris et al. in 2007[11] and Al-Qudah and Awawdeh in 2009.[12] This study aimed to determine the root canal configuration of mandibular first permanent molars in an indo-Dravidian population based in southern India.


   Materials and Methods Top


A total of 1147 extracted mandibular molar teeth were collected from various dental hospitals. All attached soft tissue and calculus were removed using ultrasonics, and the teeth were soaked in 5% sodium hypochlorite for 72 h, and the solution changes every 12 h. Access cavities were prepared and the coronal pulp tissue removed and placed in 5% sodium hypochlorite for 48 h before placement in an ultrasonic bath. The teeth were then rinsed under running tap water for 1 h and dried. The teeth were examined visually under magnification loupe and incidence of number of roots recorded. The pulp chambers were analyzed for the pattern of orifices and data recorded. An endodontic irrigating syringe with gauge 28 needle (Hindustan syringes and devices, Faridabad, India) was used to inject Indian ink (Camlin India Pvt ltd) into the root canal systems. Ink penetration was assisted by a specially designed high vacuum suction applied to the apical third of the root. The teeth were dried by an and immersed in 10% nitric acid (Nice Chemicals Pvt ltd, India) to decalcify for five days with the solution being changed on a daily basis. The teeth were rinsed under running tap water, dried and dehydrated using ascending concentrations of ethanol (70%, 80%, 90%, and 100%) for 3 days. Finally, the teeth were rendered transparent by immersion in liquid casting resin (Araldite) for 2 days. The cleared teeth were examined using a stereo microscope. The root canal configurations were observed (Vertucci classification) and recorded for each root [Figure 1].
Figure 1: (a) Type I. (b) Type II. (c) Type III. (d) Type IV. (e) Type V. (f) Type VI. (g) Type VII. (h) Type VIII

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   Results Top


The human permanent mandibular first molars examined presented with two roots in 95.6% and three roots in 4.4% of the samples [Chart 1]. Four types of a pattern of orifices, namely, triangular (87.9%), rectangular (8.5%), twin orifice pattern (0.6%), and C-shaped pattern (3.0%) were observed [Figure 2] and [Table 1]. The most common canal system configuration in mesial root was Vertucci type IV (52.3%), followed by type II (35%) [Chart 2]. Root canal configuration of the distal root revealed type I configuration in 62.7%, followed by types II (14.5%) and IV (12.4%). The distolingual root had a type I configuration [Figure 3], [Figure 4].

Figure 2: (a) Triangular pattern (b) Rectangular pattern (c) Twin orifice pattern (d) ‘C’ shaped pattern

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Table 1: Incidence-pattern of orifices

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Figure 3: (a) Type I. (b) Type II. (c) Type III. (d) Type IV

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Figure 4: (a) Type V. (b) Type VIII. (c) Transverse anastamoses. (d) Apical deltas

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   Discussion Top


The root form and morphology of human permanent mandibular first molar teeth has been reported by a number of researchers. The human permanent mandibular first molar is one of the earliest teeth to erupt and hence more prone to caries than any other permanent tooth. Being the largest tooth in the lower jaw the roots are sufficiently large to provide adequate anchorage and to help in effective distribution of occlusal forces. It is also the tooth which is most frequently treated endodontically. Normally, the two roots of the mandibular first permanent molar presents with three root canals, i.e., two in mesial root and one in distal root. Variations are possible from the normal by branching and intercommunications. The normal as well as the variations in root form and canal anatomy of human permanent mandibular first molar have also been reported from different racial populations. This particular aspect is quite important as knowledge of variations in a given populations is an asset. In the present study, 95.6% of the teeth were found to have two roots, and 4.4% had three roots [Chart 1].

The incidence of three roots in mandibular first permanent molars has been first reported in England by A. E. Taylor in 1899 and is found to vary in different racial populations. It is more common in the mongoloid races with incidence ranging from 15% to 43.6%. The instrumentation of the third root requires a different access and small, flexible instruments, given the curvature that is usually present buccally in the apical third.[5],[13] The prevalence of this condition is highest in Aleut Eskimos and incidence is 43.6%.[14] The percentage of incidence of this condition ranges from 0 to 3.4% in Caucasoid population. In the present study, on an indo-Dravidian population based in southern India, the incidence is 4.4%. Walkers hypothesises that distolingual root adds to the stability of first molars by providing an increased surface area of attachment to the alveolus. This added retention may have been needed in cultures where at one time heavy demands were placed on dentition. The continued presence of this trait seems to indicate it is a genetically determined trait. In the present study, all the three roots were present in the distolingual position [Figure 5]. The division of the epithelial diaphragm during the development of the roots possibly divides into three resulting in the formation of three roots. Although walkers hypothesis justifies the presence of three roots, it does not explain as to why the occurrence of the third root is only in the distolingual position. The number of roots on the mandibular first molar is directly related to ethnicity. It is more frequently encountered in the Eskimo, native American, Mongoloid, and Chinese populations.[15]
Figure 5: Distolingual root

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Locating canal orifices in mandibular first molar can be sometimes difficult. Triangular pattern of access preparation has been used traditionally for ease of canal identification. In the present study, 87.9% of the specimens had an arrangement of orifices in a triangular pattern [Table 1] [Figure 2]. Wilcox L. R. and Walton have opined that the traditional access is too far lingually and mesially located which may result in undermining of tooth structure or perforation.[16] Only in cases of extreme root curvature or patient inability to open the mouth access should be extended mesially. However, the outline of access is dictated by the shape of the pulp chamber and we cannot have a standard access cavity for every tooth. The arrangement of orifices in a rectangular pattern is seen invariably in cases with a second canal or a distolingual root which presents a separate canal orifice. Skidmore and Bjorndal suggested that if the triangular shape of the access is changed to a rectangular, it would permit better visualization and identification of the second canal in the distal root.[17] Instead of widening the pulp chamber with the anticipation of the second canal it is better to be guided by the shape of the pulp chamber and when rectangular a second distal canal should always be searched for. This prevents unnecessary weakening of the tooth structure. The use of magnification would also lead to more conservative access preparations. C-shaped orifices and twin orifice pattern are less frequent in the permanent mandibular first molar. The incidence of C-shaped canals of mandibular first molar has been reported.[18] In the present study, the incidence was 3.0% and 0.6%, respectively. When “C-” shaped orifice is seen the possibility of the presence of a ribbon-shaped canal should be considered. The twin orifice pattern is due to a single mesial orifice instead of two. Although only one orifice is present, it later divides into two distinct canals which can be identifies by a proper angulation of the instrument. For achieving successful treatment outcomes, it is necessary for the clinician to search for extra canals even though initial appearance does not suggest an abnormal canal configuration. The fact such cases do exist justifies a complete examination of the pulpal floor even after the expected number of canals have been identified. Access modifications, acquisition of sufficient clinical skills and use of new diagnostic techniques are required to find extra roots or canals.[19],[20]{Figure 2}

Taurodontism, dens in dente, irradiation during odontogenesis, thalassemia, and dentinal dysplasia have been reported cause alteration of normal morphology of the root which in turn affects the canal configuration. The etiology of taurodont tooth is unclear. A morphological anomaly of the root where there is apical extension of the pulp chamber with a proportionately shortened root. The constriction at the cementoenamel junction is absent. The failure of Hertwig's epithelial sheath to invaginate at the proper horizontal level, resulting in a tooth with elongated body, shortened roots, an enlarged pulp, and normal dentin.[21] Previously, taurodontism was related to syndromes such as Down's, Mohr, Trichodentoosseous and Klinefelter's. Today, it is considered as an anatomic variance that could occur in a normal population.[22]

Failure to completely negotiate and obturate a canal has been demonstrated to be a causative factor for unsuccessful endodontic therapy. Prior knowledge of the internal anatomy of the root helps in avoiding ledge formation and perforation. The results of this study on the configuration of the root canals of mandibular first permanent molars are shown [Chart 2]. Type IV canal configuration was most common in the mesial root with an incidence of 77%. Type I was most common in the distal and the distolingual root with an incidence of 74.4% and 100%, respectively. The mesial root has small slit like communications which exist between the two canals and have been termed as transverse anastamoses [Figure 4], which have been shown to contain tissue in varying amounts.{Figure 4}


   Conclusion Top


The complex interlinking channels present in root canals which have not been biomechanically prepared, cleansed and debrided could be the cause of failures of therapy. Awareness that different possible canal configurations can occur, cultivation of adequate clinical skills, use of specialized techniques of diagnosis, debridement, and obturation will pave the way for successful treatment outcomes.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
   References Top

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Cruse WP, Bellizzi R. A historic review of endodontics, 1689-1963, part 1. J Endod 1980;6:495-9.  Back to cited text no. 1
    
2.
Cruse WP, Bellizzi R. A historic review of endodontics, 1689-1963, part 2. J Endod 1980;6:532-5.  Back to cited text no. 2
    
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Fabra-Campos H. Three canals in the mesial root of mandibular first permanent molars: A clinical study. Int Endod J 1989;22:39-43.  Back to cited text no. 3
    
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Ingle J Endodontics: 2nd ed. Philadelphia: Lea and Febriger; 1976, p. 160.  Back to cited text no. 4
    
5.
Walker RT. Root form and canal anatomy of mandibular first molars in a Southern Chinese population. Endod Dent Traumatol 1988;4:19-22.  Back to cited text no. 5
    
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Cichon JC, Pack RS. Taurodontism: Review of literature and report of case. J Am Dent Assoc 1985;111:453-5.  Back to cited text no. 6
    
7.
Vertucci FJ. Root canal anatomy of the human permanent teeth. Oral Surg Oral Med Oral Pathol 1984;58:589-99.  Back to cited text no. 7
    
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Kartal N, Cimilli HK. The degrees and configurations of mesial canal curvatures of mandibular first molars. J Endod 1997;23:358-62.  Back to cited text no. 8
    
9.
Gulabivala K, Aung TH, Alavi A, Ng YL. Root and canal morphology of Burmese mandibular molars. Int Endod J 2001;34:359-70.  Back to cited text no. 9
    
10.
Sert S, Bayirli GS. Evaluation of the root canal configurations of the mandibular and maxillary permanent teeth by gender in the Turkish population. J Endod 2004;30:391-8.  Back to cited text no. 10
    
11.
Peiris R, Takahashi M, Sasaki K, Kanazawa E. Root and canal morphology of permanent mandibular molars in a Sri Lankan population. Odontology 2007;95:16-23.  Back to cited text no. 11
    
12.
Al-Qudah AA, Awawdeh LA. Root and canal morphology of mandibular first and second molar teeth in a Jordanian population. Int Endod J 2009;42:775-84.  Back to cited text no. 12
    
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Drusini AG, Swindler DR. Frequency and variation of three-rooted lower first permanent molars in precontact Easter Islanders and in Pre-Conquest Peruvians. Dent Anthropol 2009;22:1-6.  Back to cited text no. 13
    
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Turner CG 2nd. Three-rooted mandibular first permanent molars and the question of American Indian origins. Am J Phys Anthropol 1971;34:229-41.  Back to cited text no. 14
    
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de Pablo OV, Estevez R, Péix Sánchez M, Heilborn C, Cohenca N. Root anatomy and canal configuration of the permanent mandibular first molar: A systematic review. J Endod 2010;36:1919-31.  Back to cited text no. 15
    
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Wilcox LR, Walton RE, Case WB. Molar access: Shape and outline according to orifice locations. J Endod 1989;15:315-8.  Back to cited text no. 16
    
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de Pablo OV, Estevez R, Heilborn C, Cohenca N. Root anatomy and canal configuration of the permanent mandibular first molar: Clinical implications and recommendations. Quintessence Int 2012;43:15-27.  Back to cited text no. 17
    
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Barnett F. Mandibular molar with C-shaped canal. Endod Dent Traumatol 1986;2:79-81.  Back to cited text no. 18
    
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Skidmore AE, Bjorndal AM. Root canal morphology of the human mandibular first molar. Oral Surg Oral Med Oral Pathol 1971;32:778-84.  Back to cited text no. 19
    
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Ballullaya SV, Vemuri S, Kumar PR. Variable permanent mandibular first molar: Review of literature. J Conserv Dent 2013;16:99-110.  Back to cited text no. 20
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21.
Mena CA. Taurodontism. Oral Surg Oral Med Oral Pathol 1971;32:812-23.  Back to cited text no. 21
    
22.
Saini T, Wilson CA. Taurodont molars: Review of literature and radiological features. Saudi Dent J 1990;2:68-70.  Back to cited text no. 22
    


    Figures

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