|Year : 2014 | Volume
| Issue : 5 | Page : 43-46
Mandibular second molar with five canals
Hari Kumar Vemisetty1, Venkata Ravichandra Polavarapu1, Kavitha Anantula2, Ramkiran Dandolu1
1 Department of Conservative Dentistry and Endodontics, Kamineni Institute of Dental Sciences, Narketpally, Nalgonda, Andhra Pradesh, India
2 Department of Conservative Dentistry and Endodontics, Dr. B.R. Ambedkar Institute of Dental Sciences and Hospital, Patna, Bihar, India
|Date of Web Publication||10-Mar-2014|
Hari Kumar Vemisetty
Department of Conservative Dentistry and Endodontics, Kamineni Institute of Dental Sciences, Sreepuram, Narketpally, Nalgonda, Andhra Pradesh
Source of Support: None, Conflict of Interest: None
A unique case of a mandibular second molar with five canals is described. Recent literature pertaining to an unusual root canal morphological structure is reviewed and a recommendation is made for a complete and thorough examination of the chamber floor for even seemingly straight forward and simple non-surgical endodontic cases for a successful endodontic treatment.
Keywords: Five canals, mandibular second molar, middle mesial canal
|How to cite this article:|
Vemisetty HK, Polavarapu VR, Anantula K, Dandolu R. Mandibular second molar with five canals. J NTR Univ Health Sci 2014;3, Suppl S1:43-6
|How to cite this URL:|
Vemisetty HK, Polavarapu VR, Anantula K, Dandolu R. Mandibular second molar with five canals. J NTR Univ Health Sci [serial online] 2014 [cited 2020 Mar 31];3, Suppl S1:43-6. Available from: http://www.jdrntruhs.org/text.asp?2014/3/5/43/128489
| Introduction|| |
The main objective of root canal therapy is thorough cleaning and shaping of all pulp spaces and its complete obturation with an inert filling material. The presence of an untreated canal may be a reason for failure. A canal may be left untreated because the dentist fails to recognize its presence. To obtain a better visualization of the morphology present, it has been suggested that several radiographs from different angulations can be obtained. It is extremely important that clinicians use all the armamentaria at their disposal to locate and treat the entire root canal system. 
The root canal anatomy of mandibular second molars has been described by a number of investigators.  Beatty and Krell documented a mandibular first molar and a mandibular second molar with five canals.  Both of these cases had three canals in the mesial root and two canals in the distal root. As per literature, incidence of five canals with three mesial canals in the mandibular second molar is very rare in comparison to first mandibular molar and the present case is unique with five canals in second molar. Many of the studies have been done and conflicting results have been obtained, which may be due to differing methods of study or the variation in the population from which the teeth were taken with regard to racial group, age, sex and the side of the mouth from which the tooth originated.
Since Vertucci and Williams first reported the presence of a middle mesial (MM) canal in a mandibular molar, there have been multiple case reports of aberrant canal morphology in the mesial root.  In a clinical evaluation of 100 mandibular molars, Pomeranz et al.  found that 12 molars had MM canals in their mesial roots and classified them into three separate morphologic categories as follows: (1) Fin - when an instrument could pass freely between the mesiobuccal (MB) or mesiolingual (ML) canal and the MM canal; (2) confluent - When the prepared canal originated as a separate orifice, but apically joined the MB or ML canal; and (3) independent - when the prepared canal originated as a separate orifice and terminated as a separate foramen.
This case report presents a mandibular second molar with five root canals and discusses the significance of treating such cases.
| Case Report|| |
A 25-year-old male patient presented to the dental clinic with a spontaneous pain in the lower right second molar area. A radiograph revealed caries associated with mandibular second right molar [Figure 1]. His medical history was noncontributory. Periodontal probing was within the normal limits. The mandibular right second molar was hypersensitive to cold and tender on vertical percussion. The involved tooth gave exaggerated response to electric pulp tester in comparison to the contralateral tooth. Palpation was unremarkable for all teeth. A diagnosis of an acute irreversible pulpitis was made for the mandibular right second molar.
After administering local anesthesia with 2% lignocaine containing 1:100,000 epinephrine (Lignox 2%; Warren, India), rubber dam isolation was done and all carious tissue was removed and an adequate endodontic access was made. After pulp extirpation and copious irrigation of the pulp chamber, upon careful examination with endodontic explorer, the pulp chamber floor showed five orifices corresponding to 5 root canals: MB, MM, ML, DB and DL [Figure 2]. Working lengths were estimated by using an electronic apex locator (Root ZX; Morita, Tokyo, Japan) and then confirmed with radiographs taken in mesial and distal angulations [Figure 3] and [Figure 4]. The angled radiograph confirmed the presence of an additional canal in the mesial root and the MM canal is of confluent type (fusing with ML canal).
|Figure 2: Pulpal chamber showing five canal orifices-mesiobuccal, middle mesial, mesiolingual, distobuccal and distolingual|
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All canals were cleaned and shaped with ProTaper rotary instruments (Dentsply-Maillefer, Ballaigues, Switzerland) under copious irrigation with 5% sodium hypochlorite and saline. Canals were dried with sterile paper points and Ca(OH) 2 intracanal medicament placed and temporized with IRM (Caulk/Dentsply Milford, DE).
At the second appointment, all the canals were recapitulated, irrigated, dried and an angled radiograph was taken with master cones in all canals [Figure 5] and [Figure 6]. Upon verification of master cone length, the canals were obturated by using gutta-percha and sealer (AH-plus, Dentsply-Maillefer). A post-obturation angled radiograph was taken [Figure 7] and the coronal restoration was done with amalgam. Patient experienced no post-treatment discomfort and subsequently porcelain fused to metal crown was placed. At 1-year post-treatment radiograph [Figure 8] revealed favorable results.
| Discussion|| |
Studies of the morphologic structure of root canal systems have demonstrated the complexity, numbers and distributions of canals in mandibular first molars. There appears to be a great disparity between studies in number of canals, orifices and anatomy. The differences may be due to dissimilarities of examination methods, classification systems and ethnic background of tooth sources. In Pineda and Kuttler's study,  the method used was a radiographic technique that may not be able to detect extremely calcified canals or canals that are superimposed on each other.
The main areas of dispute are the number of roots possessed by mandibular second molars and the type and shape of canals. The most commonly found configurations in the second mandibular molar with two roots are represented in [Table 1].
Root canal anatomy and root morphology may have definitive racial influences, thereby necessitating the identification of root canal morphologies of different races.  Studies on the root canal anatomy of mandibular first and second molars have been performed on several populations. ,,,
A higher number of mandibular second molars with single roots have been found in Mongoloid populations and C-shaped canals have also been found more frequently in the same populations.  The Indian race is typically considered to be a hybrid of several races with a characteristics of Caucasian, Mongoloid and Negroid races, which is generally referred to as the Dravidian race. 
Study by Neelakantan et al.  characterized the root morphology and number of roots and root canals in mandibular second molars in an indian population [Table 2].
|Table 2: Root morphology and number of roots and root canals in mandiblar second molars in indian population|
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Most morphologic studies have examined only a limited number of teeth for any tooth type. The small sample size and relative infrequent occurrence of various morphologic canal patterns may result in a pre-operative bias of the frequency of additional canals. The clinician may fail to explore the possibility of additional canals that may lead to potential failure. This case and others reported earlier have described variable morphologic canal patterns. The MM canal can terminate as its own apical foramen, join the MB canal or join the ML canal. The research concerning the occurrence of a third mesial canal and its apical termination is insufficient at this time. Fabra-Campos  has described this extra canal as an intermediate canal. Bond et al. and Pomeranz et al.  described this canal as the MM canal. Although these cases occur infrequently, these canal systems do exist and alert the dentist to proceed with a thorough examination of the pulp chamber floor even after the expected number of canals have been identified.
| References|| |
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8]
[Table 1], [Table 2]