Do lateral canals matter?

Fig. 1

The first thing we have to understand is that nature does not create lateral canals. It simply creates root canal systems with portals of exit. This becomes obvious if we take a look at Walter Hess work. This is what we encounter in everyday practice!

Fig. 2

From clinical point of view it is important to understand two facts:

1. Lesions of endodontic origin form in the bone next to the portal of exit, regardless of location along the root surface
2. Every portal of exit is potentially significant because it can be the cause of treatment failure

So let's take a look at clinical cases that support those facts. 

Fig. 3

This patient was presented with a buccal swelling in the region of lower left second premolar. On preoperative radiograph it was obvious that primary treatment was failing. It was interesting that lesion was located on the lateral side of the root.

Fig. 4

Non surgical retreatment was performed and two canals, which were joining in the common apical foramen, were filled to their full apical and lateral extent. Notice the previously untreated lateral canal which was related to lateral lesion.

Fig. 5

Six month follow up radiograph showing the lesion completely healed. So, does it matter that we filled lateral canal? For this patient it did!

Fig. 6

Case of upper central incisor (Courtesy, Dr. Clifford J. Ruddle). The lesion was on the lateral side of the root. Notice the absence of lesion in the apical part. What was the reason of failure?

Fig. 7

After raising a flap it was obvious that treatment was failing because of untreated lateral canal.

Fig. 8

In this case lateral canal was treated with surgical approach.

Fig. 9

Lateral canal filled with amalgam.

Fig. 10

Follow up radiograph shows complete healing.

Fig. 11

Pre operative radiograph of upper first molar with large lesion on palatal root. 

Fig. 12

Post operative x ray demonstrates four portals of exit in palatal canal. Which one is important and which ones are not if the laterals do not matter? It is rational, from clinical and scientific point of view, that we want them all! Study by West found that all the failures (100 percent) demonstrated at least one underfilled portal of exit. 

Fig. 13

Complete healing after one year.