Fig. 1

Initial situation of lower left 3rd Molar with a large carious lesion presented with spontaneous pain, tender to percussion and sensitivity with cold and heat stimulation  

Fig. 2

Pre-op X-Ray showed single, large conical root. 

In this type of configuration, the floor of the chamber wide, larger and lower than normal

Fig. 3

Starting of the procedure with Rubber dam isolation and Liquid dam in order to get maximum seal to isolate the tooth from oral fluid

Fig. 4

This figure shows large amount of soft caries presented in the tooth and the Caries excavation process; Nothing leaking to the mouth 

Fig. 5

Caries extend to the Pulp with large amount of degradation 

Pathological exposure of the pulp

Fig. 6

Profuse bleeding form the inflamed pulp tissue, very difficult to see the canal orifices

Fig. 7

Removal of coronal pulp tissue with Orifice opener file in order to reduce blood flow

Fig. 8

The vision now clear and easy to read pulp map 

Fig. 9

Pulp tissue removed 

We can see large coronal part and decrease in size toward the apical part

Fig. 10

C-shaped canal configuration

With three main canal orifices and we can see the isthmus between them clearly

In this video, I redefined the canal using ultrasonic tip to clean the isthmus area 

Fig. 11

All the canals are connected in a "horseshoe" type ring

Fig. 12

This X-Ray shows Working length determination and (getting 0.00 reading at the apex locator)

Fig. 13

All canals was instrumented individually. However, removing all the tissue from the fins is problematic. A good tip is to keep your chamber full of irrigation agent and then place an ultrasonic tip into it. Ultrasonic k-file for cleaning.

Fig. 14

Cone fit to check gutta percha tag back and to take X-Ray to confirm it 

Fig. 15

the canals will end short of the apex by 2-3 mm and then branch out. If the root canal system cleaned properly , the obturation will fill not only the canals, but also the fins and branches

Fig. 16

This picture shows the mesial and distal canals are interconnected 

the gutta percha cone inserted through the mesial canal and can see it from the distal canal 

Fig. 17

Starting Irrigation protocol 

5.25% NaOCL 

17% EDTA 

2% CHx 

With different time for irrigation 

This video shows the Activation of irrigant solution by using Sonic agitation to Insure maximum cleaning of the canal (Chemical cleaning highly recommend in this case rather than mechanical, because of the presence of large area untouched by the file to clean it)

Fig. 18

Sodium hypochlorite in action after activation 

Whitish appearance and air bubbles formation 

Fig. 19

dryness of the canal multi times to make sure complete dryness of the canal 

Fig. 20

Clean, Clear and ready for obturation

Fig. 21

Obturation by continuous wave technique, down pack the main two canals and then back fill the whole canal

Fig. 22

clean chamber ( c-shape )

Fig. 23

flowable composite to cover the coronal part of the canal to insure maximum sealed and prevent coronal leakage 

Fig. 24

Starting the build up, using Circumferential matrix in order to restore the missing walls

Fig. 25

Final restoration after finishing and polishing 

Fig. 26

Post-op X-Ray

Fig. 27

The Author:

Dr. Abdulwahab Al-Qaraghuli

Baghdad - Iraq

2018: B.D.S (Baghdad University)

2021: M.Sc. student (Mustansiriyah University)

2020: Best case of the year at StyleItaliano Endodontics Facebook group


The C-shaped anatomy represents an important and challenging anatomical variation during negotiation, debridement and obturation, Understanding the anatomical presentations of this variation will enable the clinician to manage these cases effectively.


1- Sidow SJ, West LA, Liewehr FR, Loushine RJ. Root canal morphology of human maxillary and mandibular third molars. J Endod 2000; 26: 675678.

2- Fernandes M, Ataide ID, Wagle R. C-shaped root canal configuration: A review of literature. Journal of Cons Dent 2014; 14: 312-319

3- Melton DC, Krell KV, Fuller MW. Anatomical and histolog- ical features of C-shaped canals in mandibular second molars. J Endod 1991, 17:384–8.

4- Raisingani D, Gupta S, Mital P, Khullar P. Anatomic and Diagnostic Challenges of C-Shaped Root Canal System. Int J Clin Pediatr Dent 2014;7(1):35-39.