Final answer:
Accessory canals are most commonly detected during instrumentation procedures. Radiographs might not always reveal them, and their presence may also be indirectly noticed following canal obturation if they are filled with material.
Step-by-step explanation:
Accessory canals, also known as lateral canals, are often challenging to detect because they can be very small and are not always visible on radiographs. The best chance to detect accessory canals is typically B. during instrumentation procedures. While pretreatment radiographs are essential for initial assessment of the tooth anatomy, they may not reveal the presence of accessory canals due to their size and orientation.
However, during the cleaning and shaping phase of root canal therapy, dentists might infer the presence of accessory canals when there are unexpected bleeding points or when debris is noted to extrude from the sides of the canal. Lastly, after the obturation of the main canal, accessory canals may also be noticed if they get filled with obturation material, revealing their presence indirectly.