IRRIGATION Sodium hypochlorite
The importance of effective irrigation in root canal preparation cannot be overemphasised. A maxim in endodontics states that it is what you take out of a root canal that is important, not what you put in. Sodium hypochlorite is considered the most effective irrigant, as it is bactericidal, dissolves organic debris and is only a mild irritant. It must be clearly understood that almost any irrigant solution will cause an inflammatory reaction in the periapical tissues if it is expressed under pressure.Great care must be taken to follow the irrigation regime described below. There is considerable debate about the recommended or optimum concentration of sodium hypochlorite. Ordinary domestic bleach, such as that purchased from any supermarket, has approximately 5% available chlorine. This may be used neat, or may be diluted with purified water BP up to 5 times. Greater dilutions do not affect the antibacterial properties, but diminish the tissue dissolution property. Diluted solutions must therefore remain in the root canal for longer. Warming the irrigant makes it even more effective.
The importance of effective irrigation in root canal preparation cannot be overemphasised. A maxim in endodontics states that it is what you take out of a root canal that is important, not what you put in. Sodium hypochlorite is considered the most effective irrigant, as it is bactericidal, dissolves organic debris and is only a mild irritant. It must be clearly understood that almost any irrigant solution will cause an inflammatory reaction in the periapical tissues if it is expressed under pressure.Great care must be taken to follow the irrigation regime described below. There is considerable debate about the recommended or optimum concentration of sodium hypochlorite. Ordinary domestic bleach, such as that purchased from any supermarket, has approximately 5% available chlorine. This may be used neat, or may be diluted with purified water BP up to 5 times. Greater dilutions do not affect the antibacterial properties, but diminish the tissue dissolution property. Diluted solutions must therefore remain in the root canal for longer. Warming the irrigant makes it even more effective.
There are other commercially available sodium hypochlorite products, but it must be emphasised that there should be no other additives, particularly sodium chloride.
During preparation, the root canal should be kept wet, with copious irrigation used after each instrument. The irrigant in the canal is only replaced to the depth of insertion of the needle. The needle must remain loose in the canal while the irrigant is being injected, to prevent the solution being expelled under pressure into the periapical tissues. To obtain total replacement of irrigant solution in the root canal, the smallest needle available (30-gauge) should be placed at the apical foramen. Obviously, this is a most hazardous procedure and it is suggested that the irrigation needle is only inserted to a maximum depth of 2.0 mm short of the working length. A file may then be worked in the apical 2.0 mm, to stir and withdraw the dentine debris further into the canal, so that it can be flushed away. There are several differently designed irrigation needle tips, but in the author s opinion these are of little importance compared with the diameter of the needle. Whatever the tip design, unless the needle can penetrate loosely to the correct depth in the root canal, irrigation, however copious, will not remove dentinal debris.