Endodontic retreatment of a mandibular first molar with missing Mid-Mesial canal

Fig. 1

A 39 years old female came to my attention complaining about pain on the first lower right molar.

The pre-operative x-ray showed an periapical radiolucency, and suggested the presence of apical periodontitis.

On clinical examination, The tooth was tender to percussion.

I decided to retreat the tooth to relief the symptoms referred by the patient. 

Fig. 2

Possible problems in this case may be 

1. Possible missing canal 
2. Short old obturation 
3. Blockage or ledge 
4. Periapical lesion 

Fig. 3

Local anesthesia was administered. 

The tooth was isolated with rubber dam and removal of coronal restoration was done.

Before starting the retreatment procedures, the length of the old root filling was measured on a precise primary radiograph. 

I removed the existing gutta-percha with a rotary Ni-Ti file designed for retreatments 1 mm short of the measured length to remove filling material quickly. 

I don’t like to use solvent because the solvent will make the gutta percha fluid so make our penetration easier but also our instrument will push this flowable gutta percha on the walls to unreachable anatomy so reduce the quality of removal of filling material. 

Fig. 4

Manual files .02 SS (size 10 to 15) was used to penetrate last mm of the material to the length measured on X-ray and then mechanically.

Manual & Mechanical technique because : 

• If the old filling ends near the apex, it will reduce risk of extrusion of debris.
• If the old filling ends away from the apex, it will permit manual scouting of last mm of the material to understand why it stopped there (presence of ledge or blockage)  

Fig. 5

The mesial canals were shaped up to 25.04 and distal canals were shaped up to 30.04

Fig. 6

Master cone radiograph 

Fig. 7

Ultrasonic tip ET 25 was used for isthmus cleaning.

The literature reported that the frequency of post-treatment apical periodontitis in teeth with at least one untreated canal was 98%: missed canal have a significant impact on treatment prognosis.

Proper irrigation dynamics is crucial for effective cleaning and disinfection of the root canal system, as it helps to ensure that the irrigant reaches all areas of the canal and effectively removes debris, bacteria, and necrotic tissue.

Sonic activation was used.

Supplementary use of XP-Endo Finisher R file increases the removal of root canal filling materials from root canal system during retreatment procedures.

Fig. 8

Canals were dried using paper points and ready to be obturated

Fig. 9

Obturation radiograph

Fig. 10

Final restoration radiograph 

Fig. 11

Final restoration

Fig. 12

One year follow up

Fig. 13

Two years follow up