Position of MB2 orifice and upper first and second molars

This is just a short blog post sharing my experience with the MB2 canal in upper molars.

I have found this canal to be extremely challenging to both find and negotiate. I had, once upon a time, thought in theory the MB2 orifice could be located by drawing a line between MB1 and P canal and intersecting it with a perpendicular to the D canal. The MB2 theoretically can be found somewhere along this intersection.

The two yellow perpendicular lines represent the intersection where the MB2 can theoretically be found.

However, after treating many more RCT cases on upper molars, I have found the position of MB2 to be extremely aberrant and using such simple ‘rules’ as described above could no longer help.

I will share some cases:

MB1 and MB2 orifices being very close together, almost confluent. These orifices lead to two seperate canals with two seperate portals of exit.

Position of MB2 orifice in the more traditional position. About 3-4mm palatal to MB2 orifice.

Access cavity in upper second molar. Extremely aberrant position of MB2 orifice, positioned closer to P orifice than MB1 orifice.

Access cavity in upper first molar LHS. Initially only a singular MB orifice could be found along the floor of the pulp chamber. This single orifice split into two separate MB1 and MB2 canals, about 2mm apical to the pulp chamber floor.

Endodontics can be so difficult at times. I think many dentists can relate.