From:  Endodontic management of a mandibular first molar with four mesial root canals

 Literature review of four-canal variants in mandibular first molar mesial roots.

Root configurationAgeGenderEthnicityCountryReference
N/A23MaleN/AUSAReeh, 1998 [15]
Mesial root with a Gulavibala Type 11 (4-2)30FemaleN/AIranAminsobhani et al., 2010 [16]
Mesial root with a Gulavibala Type 11 (4-2)37FemaleCaucasianUSAMartins and Anderson, 2015 [17]
N/A37MaleN/AN/AVineet et al., 2018 [18]
N/A30MaleN/AN/AKontakiotis and Tzanetakis, 2007 [20]
4-2-1 pattern37MaleN/AN/ASubbiya et al., 2013 [21]

N/A: not available.