To prevent bleach leakage during root canal therapy (RCT), composite is used to repair the defect (Fig.3 (CT coronal section) C) prior to access. The buccal canal is not located probably due its own or iatrogenic (due to composite) obliteration. After thorough debridement of the lingual canal, Calcium Hydroxide paste is placed (*).
Since the two canals fuse near the apex, thorough debridement and obuturation of one of them should be able to prevent recurrent infection.
Fig.4: sagittal section through the buccal canal, the apical portion of which (patent) is pointed by >.
Xin Wei, DDS, PhD, MS 1st edition 11/23/2014, last revision 11/23/2014