IRRIGATION IN ENDO

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The necessity to achieve thorough disinfection of diseased pulpal systems is well understood and documented.1 Our relentless aspiration to eliminate all irritants within a diseased pulpal system remains a committed objective. Unfortunately, our ultimate goal to completely disinfect every root canal system has not yet been practical. Hence the terminology of disinfection opposed to sterilization. The challenge of dissolving tissue and killing or eliminating all bacteria from deep complexities that exist within the randomness that is pulpal anatomy has been a difficult challenge to overcome. Figures 1a to 1d reveal original anatomy of premolars reconstructed from a microcomputed tomography technique.2 Adding to the challenge of pulpal anatomy is the porosity of the dentin and the ability of bacteria to penetrate and flourish within the root structure. However, our pursuit for complete disinfection through root canal treatment has gained significant advancement with the help of recent technological improvements. In addition to improving debridement, these innovative advances have greatly increased our potential to safely and actively disinfect even the most anatomically complex spaces.
SHAPE DICTATES DISINFECTION
Pioneering clinicians who have come before us have blazed the trail that guides our current principles and techniques. Likewise, carving the trail during shaping of the root canal system guides successful disinfection. Shape sets the stage for effective disinfection because the space that is established allows for disinfectants to reach full potential. Although “Cleaning and Shaping” are done concurrently, there is value that comes when considering disinfection as beginning after the desired shape has been accomplished.3 Said differently, there is greater potential to fulfill 3-D disinfection of the entire root canal system after the instrumentable aspect of the root canal system has been addressed. Traditional endodontic techniques are based on the theory that files shape and irrigants clean.4 This statement highlights the knowledge that there are uninstrumentable areas of pulpal anatomy. This complicated mandibular molar contains branches that communicate among the main systems, fins, and multiple portals of exit. Although this type of anatomy is difficult, we are empowered to more effectively engage such complexities with our irrigants through modern irrigation techniques after the main systems have been opened. is an annotative model of a similar tooth, which assists in visualizing these complexities.5
When establishing the desired shape of the root canal system, it is logical to respect a balance between the shape needed to accomplish sufficient disinfection and the need to conserve tooth structure. Individual practitioners have preferences in this regard; however, one proponent that seems to be widely accepted is the need for a deep apical shape. This need for a deep shape stems from physical and biologic standpoints. Anatomical studies have shown that there are an increased frequency of lateral ramifications present at the apical region of canals.6 Microbiology studies have documented that diseased pulpal systems are more advanced and virulent at this critically important apical zone.7 demonstrates a safely produced deep apical shape, which aided in the treatment of this common apical branching. gives example of the reproducible healing potential that occurs when these apical lateral systems are disinfected.
The amount and time of use of an irrigant also holds great value in disinfection. illustrates a good reservoir of irrigant that promotes high levels of disinfection. In this modern era of efficient shaping techniques it is beneficial to remember that a shaped system does not equal a cleaned system. Many clinicians have routinely accounted for this by utilizing a postshaping soak time. This passive soak time has evolved into a time for a more active form of 3-D disinfection