Endodontic Irrigation

There is a famous saying with regard to endodontic treatment "It does not matter what you put in, it is more important what you take out" (from root canals). And irrigation protocols can play a key role in disinfecting and debriding root canal system. Another important aspect is that chemo-mechanical action is needed to optimally clean the canal system. Mechanical part is done by instruments and chemical prep is done by using irrigation.

Irrigation in Endodontic treatment serves the following purposes:

Some of the commonly used irrigants are:

There are so many systems which help you deliver the irrigants safely to the canals, but the safest and best in recent times is Endovac, it absolutely ensures safely of your patient (See this apical extrusion study) and avoids nasty hypochlorite accidents despite cleaning apex to full working length in addition to giving you the cleanest possible apical portion ensuring success in single visit endo. 5.25% hypochlorite is easily used with Endovac which has proved to be most effective but can also cause more tissue damage if goes beyond canal orifice, and hence not adviced to be used with manual syringe methods. High cost of Endovac may be a deterrent where input costs are crucial, but better than paying huge costs after litigation.

Here is another recent paper on hypochlorite accident and how to avoid it, CLICK HERE

One important aspect to note is that irrigant can clean only if it comes in contact with the canal walls, and this can happen only if you have canal size prepared to at aleast a size 35. Other important thing is volume exchange, many sonic/ultrasonic methods fail on this count they can agitate the solution but do not work completely as there is inadequate exchange of solution. Many believe that using patency file or matercone will puch the irrigant to apical third, it does not happen because of airlock. Watch This Video to see airpocket

Most of you who rely on needle irrigation, need to be very careful regarding extrusion beyond apical foramen. Needles may be simple or side vented, but the risk of hypochlorite accident is always there ..See THIS PAPER

It is often asked if one should use ETDA paste or liquid ? It is common sense that paste will mix with debris and is harder to get in and out of canal. Also you are more likely to face other problem with paste, fig below illustrates how EDTA paste has extruded from apex with the use of tapered rotary instrument.

Method of 17% Liquid EDTA Preparation

Liquid EDTA is always easy to use and much more efficient. One can easily prepare 17% ETDA by following the method given below:
Put 50 gms of EDTA salt in 300 ml distilled water, stir it ( it will not fully dissolve), then put 5-10 gm NaOH in this liquid and you will see the liquid quickly becomes totally transparent. Store in a dark bottle.

Some recommend use of warm hypochlorite, but it does not have any merits and literature does not support it. Also if you are using 5% hypochorite you must use Rubber dam, To read on hypochorite accident and its management CLICK HERE

Available Systems:

Passive ultrasonic irrigation (PUI) is after the root canal has been shaped to MAF. Small file (10-20) is placed (without touching the canal walls) and activated by ultrasonic unit. Proponents of this technique claim that this leads to acoustic streaming around the file leading to efficient action. Basically Passive irrigation is initiated by slowly injecting an irrigant into a canal. In this method, irrigant is passively dispensed into a canal through a variety of different gauged and flexible canulas. Compared to this Active irrigation is intended to initiate fluid hydrodynamics to improve cleaning into all aspects of the root canal system.

Hydrodynamic irrigation
When irrigant is energised with different techniues they may call it hydrodynamic. Endo activator uses sonic vibrations, RinsEndo (attached to air tubing of your handpiece) delivers irrigant and air in pulsating fashion with simultaneous suction.

Laser-activated irrigation (LAI)

with an erbium laser has been introduced as a method for activating the irrigant. The effect is based on cavitation; in water, activation of the laser at subablative settings may result in the formation of large elliptical vapor bubbles, which expand and implode. These vapor bubbles may cause a volumetric expansion of 1,600 times the original volume, which increases pressure and drives ?uid out of the canal. When the bubble implodes after 100 to 200 microseconds, an underpressure develops and sucks ?uid back into the canal, inducing secondary cavitation effects. Therefore, the laser works as a fluid pump. FULL PAPER

Photon-initiated photoacoustic streaming (PIP)

The PIPS technique presupposes the use of the Erbium laser (Powerlase AT/HT and LightWalker AT, both Fotona) and its interaction with irrigating solutions (EDTA or distilled water). The technique uses a different mechanism from the preceding LAI. It exploits the photoacoustic and photomechanical phenomena exclusively, which result from the use of subablative energy of 20mJ at 15Hz, with impulses of only 50�s. With an average power of only 0.3W, each impulse interacts with the water molecules at a peak power of 400W, creating expansion and successive �shock waves� and leading to the formation of a powerful stream of fluids inside the canal, without generating the undesirable thermal effects seen with other methodologies. See FULL PAPER
See PIPS company brochure

Recommended protocol for manual irrigation
After gaining access to pulp chamber, fill hypochlorite and vigorously scrape with excavator. Henceforth use EDTA until WL determination with EAL is over. Hypochorite is known to interfere with Apex Locator readings. During canal instrumentation pulp chamber is flooded with EDTA. Between change of instruments flush out the canal with NAOCL.
After instrumentation is complete irrigate the canal with HypoCl, EDTA (removes smear layer and open tubules), and final irrigation with Chlorhexidine (disinfects opened up tubules)