06/07/2026
Understanding why the filling of lateral canals sometimes is not visible on the radiograph.
First of all, it must be reminded that cleaning and filling lateral canals don’t require any special effort by the operator., and this is for two simple reasons. Sodium hypochlorite, especially today that is ultrasonically activate with simultaneous apical negative pressure, will digest all the debris contained in the lateral canal. Then the obturating material, softened by the heat and vertically compacted, following a low of hydrodynamics (Law of Pascall) will automatically enter in the empty space.
The reasons why sometimes the filling is not detectable on the radiograph are mainly two:
- The obturation has been executed with cold lateral condensation, where no hydraulic forces have been developed
- The thickness of the obturating material is too small and is hidden by the thickness of the cortical bone
My case shows the typical situation. The central incisor has to be extracted for periodontal reasons, but with the permission of the patient it has been treated in the mouth before the extraction.
The post-operative film shows may be just one lateral canal obturated, but when the tooth has been clarified following a precise protocol which doesn’t include the use of xylene (which we know it causes softening and dimensional changes of gutta-percha in root canals causing “artifacts”), now the transparent tooth shows 4 little lateral canals filled.
By the way, the root canal of the central incisor (like any root canal I treat in my office) was cleaned, shaped and obturated at the “electronic apex”, which, according to Dr. Domenico Ricucci, is my “fantastic new terminology”.
What is your answer? Share your reasoning in the comments.
P.S. According to Dr. Domenico Ricucci lateral canals don’t contain bacteria but only represent the “portal of exit” for toxins present in the main canal, therefore it is sufficient to take care of the main canal and forget the existence of the lateral. By the way, in the International Endodontic Journal issue #5 May 2013, Dr. Domenico Ricucci published an article with the following title: “Exuberant biofilm infection in a lateral canal as the cause of short-term endodontic treatment failure: report of a case.” It is evident that with this article Dr. Domenico Ricucci is contradicting himself.
