RCT Of A First Lower Molar with Five Canals And An Additional Distal Root

Fig. 1

A 35-year-old patient comes to the office with severe pain when drinking cold drinks and while chewing. 

In the preoperative X-ray we can suspect an additional distal root. Due to the complexity of the anatomy, we decided to take a CBCT to analyse the position and curvature of the canals.

The diagnosis was irreversible pulpitis without periodontal tissue involvement.

Fig. 2

Axial view showing the crowded shape of the distal canal and the presence of at least 3 canals in the distal root.

Fig. 3

We can see how in the apical zone they separate into two roots.

Fig. 4

Double curvature of the mesial root.

Fig. 5

We can see the complexity of the distal root and the bifurcation in the apical third.

Fig. 6

Initial condition of the patient's tooth, which had deep caries in contact with the pulp chamber.

Fig. 7

Preflaring of the coronal third of the canal with SlimShaper Pro ZS1 (15/02).

We shape the coronal third of the canal up to the first resistance. 

Fig. 8

Before reaching the apical third with the rotary files, we perform a minimal glidepath with K06, 08 and 10 files. When we have managed to get the K10 file completely loose in the canal, we start working in thirds of each of the canals, using a minimally invasive instrumentation system (SlimShaper Pro).

Fig. 9

To help us locate additional distal root anatomy, we use a Micro-opener, which allows us to remove the coronal dentine from the distocentral canal and clean the isthmus by indirect ultrasonic vibration.

Fig. 10

After the canals have been located, we proceed to instrument each of them in thirds, using in this case ZS1 (15/02).

Patency was performed after each rotary file and irrigation with Z-Rinse during mechanical shaping.

Fig. 11

Once we have instrumented the five canals with ZS1 and ZS2, we observe that the 20/04 file is working in the apical third and given that we are dealing with a vital tooth, we decide to finish the mechanical preparation at this point.

Fig. 12

One of the main problems we find in complex anatomies and minimally invasive preparations is the depth of the irrigation needle.

In this case, during treatment we use a 30G metal needle (A) and for the final irrigation protocol we use an Irriflex needle (B).

This combination allows us to irrigate safely during treatment and allows the NaOCl and EDTA 17% to reach the apical third, creating a constant renewal of irrigant in the critical area of the canal.

Fig. 13

We can see how in minimally invasive preparations the irrigant will reach the apical third with the Irriflex needle (B), while in the case of the metal needle, the irrigant will remain in the middle third (A).

Although both needles have the same diameter at the tip, the flexibility of Irriflex (B) allows it to adapt better to the original anatomy of the canal, and to carry the irrigant to the apical third.

Fig. 14

View of the three distal canals after 20/04 preparation with SlimShaper Pro ZS2.

Fig. 15

Intracanal heating of NaOCl 5.25% was performed with the 30/04 plugger of the Elements Free system. 

We placed the plugger at - 3mm from the WL and heated the irrigant at 180º for 4 seconds. After heating, we sonically activate the irrigant.

Repeat this step on all canals.

After washing and drying the canals, we irrigate the five canals with EDTA 17% for 60’, activating the irrigant manually with a calibrated 2% gutta percha tip.

Finally, NaOCl 5.25% is used again in the 5 canals, this time without activation.

In the final irrigation protocol, we used Irriflex instead of Z-Rinse.

Fig. 16

After rinsing the canals and drying them by keeping some moisture, we used NeoSealer Flo in all five canals.

During the injection of the sealer, we observed how it spreads throughout the anatomy of the distal root.

Fig. 17

We repeat the procedure on the mesial canals, also observing that there is a connection between them.

After injection of the bioceramic sealer, we calibrate 2% gutta percha cones and perform vertical compaction with the 30/04 plugger of the Elements Free system.

Fig. 18

Photo of the pulp chamber after obturation of the five canals.

Fig. 19

Orthorradial angulation. We can observe the minimally invasive shaping of the canals.

Fig. 20

Mesiorradial angulation showing the complexity of the apical third of the mesial root

Fig. 21

In the distorradial angulation we can see the isthmus in the middle third and the conection between the main canal and the others in the apical third.