Importance of accurate working length determination:
· Confine the instrumentation to the canal system (within dentin).
· Create and maintain an apical stop or seat at the minor constriction.
· Prevent under- instrumentation that could leave tissue and debris in the apical segment.
· Prevent over- instrumentation which could cause patient discomfort, damage periapical
tissue, or potentially cause an infection or cyst development from the placement of
irritating materials beyond the apex.