Middle Mesial and Middle Distal Canals in Mandibular First Molar.

Background: Root canal anatomy is a complex entity. The main objective of root canal treatment is to get rid of the infection and have a good apical and coronal seal with an appropriate filling. Inability to achieve thorough cleaning and shaping followed by three-dimensional obturation of the root canal system usually causes root canal treatment failure. For this reason, clinicians should be aware of these anatomical variations to achieve successful treatment.

Aim: The aim of this article is to report on the successful treatment and follow-up of mandibular first molar with additional middle mesial (MM) and middle distal (MD) canals.

Case Report: A 29-year-old white male patient reported with a complaint of pain in relation with tooth #19. On clinical examination, diagnosis of symptomatic irreversible pulpitis with symptomatic apical periodontitis and condensing osteitis was made and nonsurgical root canal treatment was planned. Initially, two mesial and two distal canals were located, and the patient was planned for the obturation in the second visit. The complaint of mild persistent symptoms gave a possibility of additional canals. Under the dental operating microscope and selective troughing on the floor of the pulp chamber with ultrasonic tips, additional canals were located as MM and MD canals.

Conclusion: Leaving some area of the root canal system untreated is found to be one of the main reasons for root canal treatment failure. Dentists should take advantage of new tools, such as dental operating microscope and ultrasonic tips to be able to locate and treat the hidden and unusual anatomy.

Clinical Significance: Mandibular first molar with six canals is very rare to encounter. Clinician should have a thorough knowledge of these unusual anatomy to avoid treatment failure due to incomplete disinfection of the root canal system.