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Int Poster J Dent Oral Med 14 (2012), No. 1     15. Mar. 2012

Int Poster J Dent Oral Med 2012, Vol 14 No 1, Poster 570

Clinical management of a mandibular first molar with multiple mesial canals

Language: English
 

Authors:
Reader Dr. Puneet Ajwani,
Department of Conservative Dentistry and Endodontics, Kalka Dental College and Hospital, Meerut, U.P., India
Senior Lecturer Dr. Nalini Saini Ajwani,
Department of Periodontology, Kalka Dental College and Hospital, Meerut, U.P., India
Reader Dr. Manoj Kumar Hans,
Department of Conservative Dentistry and Endodontics, K.D. Dental College and Hospital, Mathura, U.P., India

Date/Event/Venue:
22nd to 24th December, 2006
21st FODI & 14th IES National Conference
Nehru Centre, Mumbai, India
 

Introduction

The main objective of root canal treatment is the thorough mechanical and chemical cleansing of the entire pulp space followed by complete obturation with an inert filling material.1 Therefore it is imperative that aberrant root canal anatomy is identified prior to and during root canal treatment of such teeth. Mandibular first molar is the earliest permanent posterior tooth to erupt and most often requires root canal treatment. Usually it has two roots with two canals in mesial root and one in distal root, but sometimes additional mesial or distal canals may be present. Unusual canal anatomy associated with the mandibular first molar has been reported in several studies.2-11 In 1981, Pomeranz et al became the first to address treatment considerations for the middle mesial canal of the mandibular first and second molars. They reported on 100 first and second mandibular molars consecutively treated in private practice. Twelve separate middle mesial canals were identified and treated (12%). They classified three separate morphological possibilities in the mesial root:

  1. Fin - when an instrument could pass freely between the mesiobuccal or mesiolingual canal and the middle mesial canal;
  2. Confluent - when the prepared canal originated as a separate orifice but apically joined the mesiobuccal or mesiolingual canal; and
  3. Independent - when the prepared canal originated as a separate orifice and terminated as separate foramen.6

In a radiographic study of extracted teeth, Goel et al reported mandibular first molars had three mesial canals in 13.3% of specimens, four mesial canals in 3.3% of specimens, and three distal canals in 1.7% of specimens. Furthermore their study showed one apical foramen was present in 30%, two in 60%, three in 6.7%, and four in 3.3% of the cases.9
 

Clinical Case

A 21 year old female patient presented to the department of Conservative Dentistry and Endodontics with a chief complaint of spontaneous pain in lower left back tooth since two days. There was also a history of periodic discomfort to biting on the tooth. Medical history revealed that the patient had bronchial asthma since last six years. Clinical examination revealed carious mandibular left first molar which gave delayed response to electric pulp test when compared to adjacent as well as contra-lateral teeth. Radiographic examination revealed radiolucency in the crown of mandibular left first molar approximating the pulp. (Figure 1) Based on the subjective and objective findings, a diagnosis of irreversible pulpitis was made.

 
Fig. 1: Preoperative Radiograph
 
 

Material and Methods

After administering local anaesthesia and adequate isolation, caries was excavated and access gained to the pulp chamber. The coronal necrotic pulp tissue was removed and the chamber irrigated with 5.25% sodium hypochlorite solution. Four root canal orifices were detected, two mesial and two distal. Exploring the fissure between the main mesial canals, with a sharp endodontic explorer, a "stick" was encountered. A middle mesial canal orifice was found which was closer to the mesiobuccal canal orifice. (Figure 2) A small precurved size 08 K-file (Dentsply Mailleffer) was inserted into the middle mesial canal orifice. With clockwise and counter-clockwise rotational movements, the instrument was advanced till the predetermined working length (as per preoperative radiograph). The working length was then confirmed with another radiograph. The radiograph confirmed three separate mesial root canals with separate apical foramina. (Figure 3) Cleaning and shaping was completed using K-files under constant irrigation with 5.25% sodium hypochlorite and all the canals were obturated with gutta-percha and zinc-oxide eugenol based sealer at the next appointment. (Figure 4 and 5)

Fig. 2: Intraoral photograph showing three separate mesial canal orifices Fig. 3: Working Length Radiograph
Fig. 4: Master Cone Radiograph Fig. 5: Radiograph after Obturation
 

Conclusions

Many dental clinicians have the perception that a given tooth will contain a predetermined number of roots and/or canals. Careful evaluation of research material has, however, shown that deviation from the norms in root canal morphology are not uncommon. Among these anatomic variances, multiple canals in the mesial root of mandibular molars have been reported in the literature as having an incidence of 2.07% up to 13.3% of the examined cases.5,9 Although many authors have agreed on the presence of three foramina in the mesial root, only a few have reported the presence of three independent canals, which presents itself as a rare anatomic variant.12
Dental clinicians should keep this possibility in mind whenever they perform root canal treatment. The detection of additional root canals requires a careful clinical and radiographic inspection. Diagnostic tools such as multiple radiographs from different horizontal angulations, careful examination of the pulpal floor with a sharp endodontic explorer, and better visualization using devices such as loupes or dental operating microscope are all important aids in the detection of additional root canals. Recently, various attempts have been made to use CT imaging for the confirmatory diagnosis of morphologic aberrations in the endodontic field. Cone-Beam CT has been successfully used in endodontics for better understanding of the root canal anatomy, evaluation of root canal preparation/obturation, detection of bone lesions, and vertical root fractures.13-15
Although such root canal variations occur infrequently, these canal systems do exist and alert the clinician to proceed with thorough examination of the pulp chamber floor even after the expected number of canals have been identified. Over the past 20 years, numerous articles have appeared in endodontic literature, suggesting that the middle mesial canal is an anomalous condition. Recent articles, however, have demonstrated that the "middle mesial canal is a reality rather than an anomaly". By removing this additional tissue from the root canal system, the clinician may be able to increase the success rate of endodontic therapy.
There is an old saying: "What the mind doesn't know, eyes cannot see". So, a good knowledge of root canal anatomy and its variations, and expecting the unexpected can spell the difference between success and failure.
 

Literature

  1. Vertucci FJ. Root canal anatomy of the human permanent teeth. Oral Surg Oral Med Oral Pathol 1984;58:589-99.
  2. Vertucci FJ, Williams RG. Root canal anatomy of the mandibular first molar. JNJ Dent Assoc 1974;48:27-8.
  3. Weine FS. Case report: three canals in the mesial root of a mandibular first molar (?). J Endod 1981;8:517-20.
  4. Bond JL, Hartwell GR, Donnelly JC, et al. Clinical management of middle mesial root canals in mandibular molars. J Endod 1988;14:312-4.
  5. Fabra-Campos H. Unusual root anatomy of mandibular first molars. J Endod 1985;11:568-72.
  6. Pomeranz HH, Eidelman DL, Goldberg MG. Treatment considerations of the middle mesial canal of mandibular first and second molars. J Endod 1981;7:565-8.
  7. Min KS. Clinical management of a mandibular first molar with multiple mesial canals: a case report. J Contemp Dent Pract 2004;3:142-9.
  8. Ricucci D. Three independent canals in the mesial root of a mandibular first molar. Endod Dent Traumatol 1997;13:47-9.
  9. Goel NK, Gill KS, Taneja JR. Study of root canals configuration in mandibular first permanent molar. J Indian Soc Pedod Prev Dent 1991;8:12-4.
  10. Beatty RG, Krell K. Mandibular molars with five canals: report of two cases. J Am Dent Assoc 1987;114:802-4.
  11. Jacobson EL, Dick K, Bodell R. Mandibular first molars with multiple mesial canals. J Endod. 1994;20:610-3.
  12. Holtzmann L. Root canal treatment of a mandibular first molar with three mesial root canals. Int Endod J 1997;30:422-3.
  13. Matherne RP, Angelopoulos C, Kulild JC, et al. Use of cone-beam computed tomography to identify root canal systems in vitro. J Endod 2008;34:87-9.
  14. Estrela C, Bueno MR, Leles CR, et al. Accuracy of cone beam computed tomography and panoramic and periapical radiography for detection of apical periodontitis. J Endod 2008;34:273-9.
  15. Hassan B, Metska ME, Ozok AR, et al. Detection of vertical root fractures in endodontically treated teeth by a cone beam computed tomography scan. J Endod 2009;35:719-22.
     

This Poster was submitted by Dr. Puneet Ajwani.
 

Correspondence address:
Dr. Puneet Ajwani
Kalka Dental College and Hospital
Department of Conservative Dentistry and Endodontics
B - 71, Sector - 27, Near Jain Mandir
Noida - 201301
U.P., India.