Fig. 1

The Pre-OP Radiograph shows :

Open margin Crown

Severe unnecessary cutting toward the Mesial. 

Short Filling on DB canal.

Shadow of missing MB2

Fig. 2

Axial cut of CBCT scanning shows a clearly missed MB2 canal

Fig. 3

The coronal cut shows the MB system: MB1 & MB2 are confluent.

Fig. 4

The sagittal cut shows the presence of apical periodontitis around the MB system with the foramen being in a lateral position.

Fig. 5

Access Opening through the crown.

The use of ultrasonic tips helps to remove obstacles and redefine the access cavity.

The removal of the filling materials done with a rotary file in the presence of irrigant solution.

MB2 Detection using Sharp DG16 Probe.

Fig. 6

After gutta-percha removal and access refinement

Fig. 7

Master Cone Fitting for DB & MB1

Fig. 8

MB1 and MB2 after shaping and dryness.

Fig. 9

Confluence shown with the down-packing

Fig. 10

Post-op radiograph with DB Delta in the apical third & MB2 filled.

Fig. 11

Post-OP Obturation


It is very important to assess the cause of the treatment failure before starting a new treatment and also be aware with every step in the treatment, including the armamentarium for a better treatment outcome and for apical periodontitis prevention.


Baruwa AO, Martins JNR, Meirinhos J, Pereira B, Gouveia J, Quaresma SA, Monroe A, Ginjeira A. The Influence of Missed Canals on the Prevalence of Periapical Lesions in Endodontically Treated Teeth: A Cross-sectional Study. J Endod. 2020 Jan;46(1):34-39.e1. doi: 10.1016/j.joen.2019.10.007. Epub 2019 Nov 14. Erratum in: J Endod. 2020 Jun;46(6):881. PMID: 31733814.

Karabucak B, Bunes A, Chehoud C, Kohli MR, Setzer F. Prevalence of Apical Periodontitis in Endodontically Treated Premolars and Molars with Untreated Canal: A Cone-beam Computed Tomography Study. J Endod. 2016 Apr;42(4):538-41. doi: 10.1016/j.joen.2015.12.026. Epub 2016 Feb 10. PMID: 26873567.