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Jayde Balderston
Henry Schein Content Strategist
Jayde Balderston
Henry Schein Content Strategist

This article explores why root canal treatments in molars are more complex, and how to overcome common challenges such as curved canals, limited access, and higher failure rates, outlining practical solutions to help improve clinical outcomes, with insights from Adrian Stewart BDS, PGDip Endo(UCL), MSc(RestDent), MEndo, F(Endo)RCS Edinburgh.

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Key Takeaways:

  • Molar root canal treatment is more complex because of posterior access, curved canals and anatomical variation.
  • MB2 canals are commonly missed in maxillary molars and may affect long-term prognosis.
  • CBCT, magnification, apex locators, and flexible NiTi files can support diagnosis and navigation.
  • Irrigation activation can help disinfect complex canal anatomy.
  • A strong coronal seal and final restoration are essential to protect the treated molar.

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"Molar teeth present several challenges during Endodontic treatment. These include, but are not limited to:

  • Variable and unpredictable canal anatomy – think MB2, mid-mesial canals, isthmuses between canals, and apical bifurcations.
  • Canals are already narrow, but can become much more so over years of bruxism and restoration.
  • Roots are very often curved, in three dimensions.
  • Access can be difficult at the best of times, but can be much worse in a patient with reduced or limited opening."

Adrian Stewart BDS, PGDip Endo(UCL), MSc(RestDent), MEndo, F(Endo)RCS Edinburgh

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Ultimate Endo Guide

Jayde Balderston

Ensure your endodontic treatments are well rounded and reliable with our complete step-by-step guide of the endodontic workflow, created to help you achieve the best outcomes for your patients.

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3D Imaging

A CBCT scanner is a state-of-the-art scanning machine that is used to produce precise, high resolution 3D images of a patient’s mouth including the teeth, jaws, soft tissue and bones – all with high levels of detail.

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"When you use a CBCT scanner, you’re not just seeing a 2D image: you're getting a 360° view of the anatomy. You can clearly visualise the space from multiple angles for a more accurate diagnosis of what's going on inside your patient’s mouth."

Read Laura’s full CBCT Q&A here.

Laura Cooper, Henry Schein Equipment Sales Specialist

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Edge Endo

Find out how Edge Endo files can save your practice money and perform as well as your current files

What Do Endodontic Experts Recommend For Complex Molar Cases?

Adrian Stewart (BDS, PGDip Endo(UCL), MSc(RestDent), MEndo, F(Endo)RCS Edinburgh) has an expansive industry knowledge and is familiar with the challenges molars can present, and how to overcome them.

"One of the biggest game changers for management of molar teeth has been the advent of ‘Shape Memory’ files. These files, which are more martensitic than the traditional NiTi alloys, are capable of being pre-curved, to aid insertion to the canal orifice in cases where access is limited.

Martensitic files are also more conservative of canal architecture, as they tend to follow the natural curves of the molar canals, rather than try to impose a shape upon them.

Another advantage is their tendency to ‘unwind’ before fracture. Careful inspection of the flutes between uses in a very tight canal can often reveal a file that is under stress, allowing the dentist to dispose of and replace it. With more austenitic alloys, very often, the first sign that the file is over-stressed is when it emerges from the canal 2mm shorter than it went in.

Currently, my file of choice is EdgeEndo X7 Utopia. In the 4% taper, it has a shorter working portion than many files, with a maximum diameter of 1mm. This is very conservative of the pericervical dentine, which is so important for prolonging the life of the tooth after RCT."

Adrian Stewart (BDS, PGDip Endo(UCL), MSc(RestDent), MEndo, F(Endo)RCS Edinburgh) 

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FAQs

Molars are more difficult to treat because they often have multiple canals that can be deep, narrow or heavily curved. Their position at the back of the mouth can also make access and visibility more challenging, increasing the need for careful planning and appropriate endodontic tools.
A variety of tools are available that can support molar root canal treatment, including loupes or microscopes for improved visibility, electronic apex locators for working length measurement, CBCT imaging for 3D assessment, flexible NiTi files, irrigation solutions, EndoActivators, and appropriate sealers.
Dentists can help to reduce risk by assessing each case individually, improving visibility, selecting files suited to the canal anatomy, using effective irrigation techniques, achieving a reliable seal, and planning a strong final restoration.
Visibility is important because molars are positioned at the back of the mouth and can have narrow, hidden or unexpectedly curved canals. Magnification, illumination, and imaging tools can help dentists assess the tooth more clearly and navigate canal anatomy with greater confidence.
Using appropriate irrigating solutions, such as sodium hypochlorite alongside EDTA where suitable, and considering an EndoActivator to help circulate irrigants within complex canal anatomy, including deeper areas, curves and isthmuses, can help improve irrigation in deep or curved molar canals.
Yes – NiTi files offer greater flexibility than stainless steel files, which can make them useful when treating curved molar canals. Establishing a glide path with a small stainless steel hand file before following with a NiTi file is recommended.
Bioceramic sealers are typically used with cold techniques, but they may be used with warm vertical condensation if the clinical challenges are carefully considered. Heat control is important because prolonged overheating can affect the sealer’s properties, and the canal should not be over-dried because bioceramic sealers require residual moisture to set.