Where the **** is MB2?

MB2 is hard to find. It becomes even harder to find in amalgam stained teeth, calcified pulp chambers, senior patients, previously endo treated and rotated teeth.

I am always looking for the MB2 in all upper first molars. Here is how I do it as a GP with 6.0x magnification and light.

After finding the main 3 canals, MB1, DB, and P. Do NOT trough the developmental groove from MB1 to Palatal because that goes through the mesial furcation and you might see red when you don’t want to (i.e. perforation).

Instead, trough from the MB1 directly towards palatal side of the tooth, and not towards the palatal canal. See the CBCT cross section below.

CBCT axial cross section of upper right first premolar to second molar

Upper right first molar directional troughing for MB2

Imagine the MB root as oriented buccal-palatal, between the buccal and palatal plate, that’s the direction to trough (dotted white line). The palatal canal is located distal-palatal to the MB root.

A few other tips to find it the MB2. Use CBCT, use the bisecting lines from MB to P, and DB to MB2.

Try it out!