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Video Presentation: How often does the mandibular first molar have three canals in the mesial root?


Cunha Pic EditedDr. Rodrigo Sanches Cunha, from the College of Dentistry at the University of Manitoba, was interviewed by Dr. Suham Alexander, Oasis Clinical Editor, about the prevalence of the third mesial canal or middle mesial canal in mandibular 6’s. 

Anatomy is considered a major challenge in root canal treatment and is documented in Hess’ study in 1925 where the words “root canal system” were coined. The complex system is subdivided into micro-anatomy and macro-anatomy.

Micro-anatomy includes the lateral and accessory canals that often merge and separate in various portions of the root canal and usually exits in the periodontal ligament (PDL).
Macro-anatomy is what is visualized with and without magnification and includes the canals which comprise the communication between the pulp chamber and the foramen.

The mandibular first molar is one of the most common teeth referred to specialists for endodontic therapy. Its anatomy should be carefully examined to avoid missing a canal which can lead to failure. The endodontic treatment of mandibular molars is challenging due to variations in root canal morphology. The mandibular first molar usually has two roots (1 mesial and 1 distal) and 3 (2 mesial and 1 distal) or 4 (2 mesial and 2 distal) canals. However, the clinician must also be aware that there instances where the mandibular first molar may have a third canal in the mesial root.

Listen to the audio interview


Interview Highlights

Dr. Cunha, in your experience and from your knowledge of the literature, what is the prevalence of occurrence of the 3rd mesial canal or middle mesial canal in mandibular 6’s? 


What is the best way to look for this canal?


Do you have any tips for clinicians that would help them locate this middle mesial canal?


Would you please walk us through the video clip you have?


Some clinicians may be afraid to look for it for fear of perforation. Is the orifice of the middle mesial canal found at the same level as the MB and ML canals or is it slightly more apical?


You have an interesting case in which you retreated a tooth that had a 3rd mesial canal. Would you discuss the particulars of this case, please?

Case Study


Can you give us an algorithm or process that the clinician should follow perhaps to decide whether there may be a 3rd mesial canal given the prevalence is fairly low?


Rodrigo Sanches Cunha, DDS, MSc, PhD, FRCD(C)

Dr. Cunha completed his Undergraduate Dental Degree from the Pontificia Universidade Catolica de Campinas (PUCC) in Campinas, SP-Brazil in 1994. His post-graduate studies include a Specialty degree in Endodontics from the State University of Campinas (UNICAMP) in 1997; M.Sc. degree in Clinical Dentistry (Endodontics) in 2002, and a PhD degree in Dental Sciences from Sao Leopoldo Mandic Centre for Dental Research in 2006. 

Dr. Cunha is currently an Assistant Professor at the College of Dentistry, Faculty of Health Sciences at the University of Manitoba and is the Head of the Restorative Department and Head of the Endodontics Division.

Dr. Cunha is a renowned speaker worldwide and has published papers in several peer reviewed journals, three book chapters and is a Reviewer for the International Endodontic Journal and Journal of Endodontics. In 2013, Dr. Cunha became Fellow of the Royal College of Dentists of Canada (Endodontics).

Dr. Cunha has also extensive clinical experience in private practice in the specialty of Endodontics.


1 Comment

  1. dr bedi July 18, 2014

    Excellent information about rc system. One can learn lot from such posts


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