The tooth happens to be a very small organ (if you think about it one). It contains a pulp that is barely a few millimeters in diameter if you see it in cross-sections. passage treatment (RCT) involves manipulation and removal of this fine piece of tissue. So if through with the eye there's an opportunity (albeit small chance) that some parts of the pulp are going to be left behind during removal. These residual pulp tissues are present in accessory canals, which are sometimes missed when working without a microscope.

When an equivalent procedure is completed with a microscope, the probability of leaving any tissue or canal is way lesser because the dentist can view the tooth in magnifications of up to 10 times that seen with the eye (10x).

So the chances of failure of RCT are lesser.

Another reason microscope-assisted RCT is supposedly better is that if an instrument breaks inside a passage , it's far easier to retrieve it when a microscope is employed. within the case of conventional RCT, repeatedly the broken instrument may have to be left behind inside the canal. Broken instruments with improperly instrumented canals could also cause the failure of RCT.

Having said that, despite the simplest of instrumentation with the simplest of technology, sometimes a little percentage of RCTs will fail to reply to any treatment .