This fact is from Access Cavity & Pulp Anatomy in Conservative & Endodontics. It is a commonly tested concept in NEET MDS examinations. Understanding this fact is crucial for answering MCQs correctly.
Mandibular molar = trapezoidal access outline
Most common extra canal = MB2 mesiobuccal second canal maxillary molars
Lower incisors often have 2 canals
Maxillary premolar = 2 canals common
C-shaped canal = mandibular second molar
Isthmus between canals.