The Secret to Mandibular Molar Access Cavity Preparation

Unlock the secret to effective mandibular molar access cavity preparation. Follow our expert guide for precise techniques that enhance your endodontic practice.
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Oct 18, 2024
The Secret to Mandibular Molar Access Cavity Preparation

Today, let's look closer at access cavity preparation for mandibular molars. In the image below, you can see the roots and pulp chamber of a tooth, with the crown hidden.

If you were to prepare an access cavity for root canal treatment, which direction would you choose? Most likely, you would align your approach with the direction of the pulp, represented by the green line.

Now, let's remove the hidden part of the tooth. Does the green access path align with the typical approach you're used to?

Surprisingly, the most efficient straight-line access to the pulp is achieved by approaching from the buccal cusp, not the center of the occlusal surface. Many dentists habitually start from the center of the occlusal surface, but this can lead to iatrogenic errors, such as perforating the lingual side when the bur is placed too vertically.

To master access cavity preparation for mandibular molars, it’s essential to understand their anatomy.

The following image shows a view of the mandibular molar from mesial to distal.

The pulp chamber has a rhomboid shape, tilted toward the lingual side.

The pulp chamber has a rhomboid shape, tilted toward the lingual side. Understanding this shape is crucial. To properly access the pulp chamber, you should start cavity preparation not from the center of the occlusal surface but from the buccal side of the central groove.

The next image shows the pulp chamber and canal orifices projected onto the occlusal surface.

Canal orifices(green) and pulp horns(yellow) projected onto the occlusal surface.

All the canal orifices are located buccally from the central groove. Therefore, starting the access cavity preparation on the buccal side of the central groove will increase your chances of easily locating the canal orifices.

Now, let's run a 3D simulation. In the first scenario, the access cavity is created at the center of the occlusal surface. Looking at the bucco-lingual cross-section, you can see that the access is too far toward the lingual side, making it harder to locate the buccal canals.

The access cavity is created at the center of the occlusal surface.

In the second scenario, we prepare the access cavity on the central groove's buccal side. As a result, the canal orifices are much more visible, leading to a more efficient treatment.

The access cavity is created on the buccal side of the central groove.

In conclusion, understanding the anatomical structure of mandibular molars and starting access cavity preparation from the buccal side is key to successful root canal treatment.

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