C

Multiple CBCT studies report that a second canal is present in roughly one-quarter to two-fifths of mandibular incisors—e.g., 40.5 % of central and 37.9 % of lateral incisors in an Israeli cohort [Shemesh, 2018, PMID 29033082] and 39 % of central incisors in a Chinese series [Zhang, 2014, PMID 25543607]. This places the typical incidence within the 20–41 % range.