A review of literature reveals that the anatomy of maxillary central incisors is single-rooted teeth with a single canal in 100% of cases. The prevalence of maxillary central incisors with 2 roots is extremely rare and has never been investigated; only a few clinical case reports have been published (Levin et al. 2015).
Below there is a similar case report from Levin et al. published in the Journal of Endodontics
This article can be read in full HERE