Case 36 Lateral canals can be important.

Preoperative x-ray #4

Tooth is symptomatic.

Immediate post operative x-ray #4

Obturation with 2 lateral canals.

2 month post operative check #4

Tooth is asymptomatic.

6 year post operative x-ray #4

Note: resorption of lateral canal filling material.  Probably just sealer only, gutta percha does not dissolve. Lateral lesions have healed.
Please note: Apical lesion on #5.

7 year post operative xray

All lesions have healed around #4 and no evidence of lateral canals being filled.  Root canal was completed on #5.

If lateral canals are not filled i.e. cleaned, there is a good chance that a tooth's apical area will never heal. 

In most cases, it is impossible to mechanically cleanse an lateral canal system. However, sodium hyperchloride may chemically clean a lateral canal. In most of my cases, if a lateral canal is filled it is with softened gutta percha and sealer.  This is speculation on my part, however.