Fig. 1

Initial situation of referred lower first premolar with temporary filling

Fig. 2

Pre-op xray showing the abnormal anatomy

Fig. 3

After temporary filling removal and rubber dam isolation

Fig. 4

gates glidden was used to enlarge the coronal third of the canal

Fig. 5

Files in the canals

Fig. 6

Working length determination to the four canals

( distal , mesial , buccal , lingual )

Fig. 7

Rotary file was separated during the instrumentation of distal canal

Separated instrument removal by loop technique

Fig. 8

Separated file was successfully retrieved by BTR pen

Fig. 9

Files reached the full working length in all canals

Fig. 10

Sodium hypochlorite in action

Fig. 11

The stars refer to the canals orifices (Distal , Mesial , Buccal , Lingual)

Fig. 12

Cone fit X-rays


Fig. 13

Obturation in process

Fig. 14

Clean chamber

Fig. 15

Final restoration

Fig. 16

Post-op X-ray

Fig. 17

2 years follow up


This case report presents the successful endodontic treatment of a mandibular first premolar with Four Canals. It is essential to always consider variations in pulp anatomy and morphology before the beginning of root canal treatment. Utilizing magnification tools, e.g. a microscope, to magnify the internal anatomy of a root canal increases the probability of finding additional canals. Furthermore, radiographic examination is imperative when endodontic treatment is to be successful. If canals are identified and negotiated correctly, complex premolars’ anatomy can be treated predictably


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