PDF: Apical Vapour Lock Effect in Endodontics – A Review


The root canal system is complex enough to perplex, challenge and sometimes frustrate even the best of clinicians. There can be no doubt today that microorganisms, either remaining in the root canal space after treatment or re-colonizing the filled canal system, are the main cause of endodontic failure.



The primary endodontic treatment goal must thus be to optimize root canal disinfection and prevent re-infection. A thorough cleaning and shaping is mandatory for optimum disinfection ‘Files shape, irrigants clean’ is the current
concept in endodontics.


The importance of irrigation in endodontics cannot be overemphasized, as an irrigant can touch areas in the root canal that an endodontic instrument cannot. The term ‘excessive irrigation’ does not exist in endodontic parlance.

There is an overall consensus that volume of irrigant is the most important criteria during irrigation. In fact, Schilder in 1974 advocated an average of 39 ml of NaOCl per visit, to clean the root canal space. Schilder’s irrigation protocol became the benchmark of excellent clinical treatment.

Chow (1983) put forth an infallible paradigm for endodontic irrigation: ‘For the solution to be mechanically effective in removing all the particles, it has to a) reach the apex, b) create a current, and c) carry the particles away.’

It is critically important to develop an irrigation protocol wherein the irrigant penetrates into all areas of the root canal, including the apical ramifications, isthmi, fins and deltas. It is easier said than done. Apical vapour lock effect is one such major hindrance in achieving this objective.