Maxillary Molar Access Open: Part 1

The following is the process of preparing a root canal access in an maxillary molar using Dental EndoMaster.
MirrorWorks Dental's avatar
Mar 06, 2024
Maxillary Molar Access Open: Part 1

I'm gearing up for root canal treatment on an upper first molar.

After diagnosis, a seasoned dentist would administer anesthesia and isolate the tooth with a rubber dam, promptly moving on to create the root canal access. Choosing a bur based on experience, the dentist navigates towards either the center of the occlusal surface or the palatal side where the largest canal resides, feeling for the moment the bur pierces through the pulp chamber. Expanding the access and locating each canal orifice unfolds seamlessly.


Occasionally, calcification within the canal may present unforeseen challenges. No sensation is transmitted through the bur, no matter how deep it goes, making it difficult to ascertain its exact location, leading to a surge of unease.

Until now, intuition and tactile feedback have been the cornerstones of root canal treatments, but it's time to explore new avenues.

We aim to adopt an approach grounded in numerical and logical data for creating root canal access. Even dentists with a wealth of experience in root canal treatments can find it tricky to precisely predict the location and shape of canal orifices. It can feel as though the tooth's interior is veiled in mist, akin to navigating through a fog-shrouded labyrinth. The MB2 canal in the upper molars is a classic example, showcasing the variability from one tooth to another.

Clearing this fog and basing our treatments on objective facts paves the way for clinical advancements. Recent advancements in MCT and the use of CBCT have allowed us to visualize the MB2 canal and predict the location of canal orifices. Despite the challenges posed by internal calcification and variations, the general anatomy of teeth remains largely unchanged.

Before picking up the handpiece, closely examine the tooth's exterior and envision its internal architecture. Coupling this with radiographic images enriches your understanding of the positioning of the four pulp horns in upper molars, typically aligned in a manner akin to the occlusal surface's contour. Armed with this knowledge, you're better prepared to embark on root canal treatment.

As depicted in the image provided by Dental EndoMaster...

Let's set the reference for the upcoming root canal treatment. In clinical practice, this stage mirrors the removal of the occlusal surface. It is advisable to identify the central pit using the Dental EndoMaster app as a reference point for occlusal reduction. Also, take a moment to reconsider the tooth's size and height, which might have been overlooked.

Next, we should identify the CEJ line, a pivotal external landmark on the tooth that offers depth information about the canal orifice, often neglected in clinical settings.

The CEJ line not only furnishes depth information but also assists in locating the canal orifices. If the orifices are obscured by calcification, navigating along the CEJ line can prove invaluable.

See the CEJ profile for yourself through Dental EndoMaster, and store this image in your mind to wield like a magic wand when faced with challenges.

Now, it's time to earnestly seek out the canal orifices. Relying on tangible information rather than mere feeling necessitates gathering all available data. The CEJ line stands out as a prime visual indicator. As previously mentioned, you can employ the contour of the CEJ as a guide to pinpoint the locations of canal orifices. Another crucial piece of information is the direction of the roots. While the gingiva may conceal them, the shape of the crown can offer clues about the roots' trajectory. Adjusting the transparency of the gingiva in the Dental MirrorMaster app can aid in understanding root direction.

You're now ready to locate the canal orifices. Before proceeding, consider the typical arrangement of these orifices. The illustration below represents the average configuration when overlaying the orifice positions of 50 upper molar canals. Most teeth adhere to this pattern. Ensure you remember the triangular formation created by the canal orifices.

Canal orifice map video clip

Notice how the line connecting the MB and DB canal orifices aligns parallel to the CEJ line. Regularly observing the CEJ line in the Dental EndoMaster app can help cultivate a habit of referencing the CEJ in clinical practice.

When locating canal orifices becomes challenging due to calcification, leveraging the relationship between the identified orifices and the CEJ can be beneficial.

Consider a real patient case where the MB and P canal orifices were located, but finding the DB canal orifice proved difficult. Despite the severe calcification obscuring the orifice, the information discussed above can aid in estimating the canal positions.

The final step involves determining the depth and direction for forming the root canal access. With the increasing prevalence of canal calcification among the aging population, it's not uncommon to miss the sensation of the bur dropping, continuing to shape the access without any sign of the pulp chamber. Verification in such uncertain moments can prevent unwanted mishaps. Clinically, it's prudent to confirm via radiographic imaging. Another reference for the access depth can be gleaned from existing research.

It's now time to review the access we've crafted. Although creating larger access simplifies locating canal orifices and eases instrument manipulation, it can compromise the tooth's structural integrity. As the tooth narrows towards the CEJ from the occlusal surface, forming the access based on the occlusal surface often results in less than 1mm of remaining tooth structure in the pericervical region, further jeopardizing the tooth when preparing for a crown.

This wraps up our discussion on forming root canal access using Dental EndoMaster.

In the next post, we'll delve into analyzing the shaped root canal access.

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