In fact, this lateral component may represent a relatively large volume, which challenges the cleaning phase of the instrumentation procedure in that tissue remnants of the vital or necrotic pulp as well as infectious elements are not easily removed in these areas.

The space inside the root canals is filled with a highly vascularized, loose connective tissue, called dental pulp.

Recent studies have shown that use of cone-down CT scans can detect accessory canals that would have been missed in 23% of cases, which can in turn lead to apical periodontitis.

When rotary nickel titanium (NiTi) files are used in canals with flat-oval or tear-shaped cross sections, a circular bore is created due to the rotational action of the metal.

Also, small cavities within the canal such as the buccal or lingual recesses may not be instrumented within the tooth, potentially leaving residual disease during disinfection.

Tissue or biofilm remnants along such un-instrumented recesses may lead to failure due to both inadequate disinfection and the inability to properly obturate the root-canal space.