If you are interested in an endodontic refresher lecture, come and join me next Thursday at the Pacific Dental Conference (PDC 2019). Two and a half hours lecture filled with pictures and videos demonstrating the initial endodontic treatment.
Irrigating the canals…probably the easiest part of providing root canal treatment, yes?
I think I graduated from dental school years and years ago with a deeply instilled fear of perforation, a reluctance to tackle calcified teeth, and anxiety whenever I waited for my obturation film to emerge from the processor. Irrigating the root canal was the breeziest part of treatment, to my memory. I placed an irrigating tip into the canal, made sure it didn’t bind in any place, it was probably hanging around the coronal or mid-root part of the canal, and I pressed the plunger a few times. Presto! Irrigation done. Right. Right?
Reading up on the irrigation literature these past few years has changed my thinking about the importance of irrigation, and it is a procedure that I spend a lot of time on now, probably equalling instrumentation! Many advocate viewing shaping of the canal with rotary instruments as a means to allow irrigants to effectively reach the most apical portion of the root canal. Many would be surprised to see that if our irrigation needle tips are not placed in the apical third of the root canal, we may not be achieving effective irrigation. The easiest way to show this is through a little home made video here, which shows me irrigating in a plastic canal, with a 30 gauge needle, using a fair amount of pressure, equal to about 5 ml/min. The needle tip is held about 3 or 4 millimeters from the “end” of the root canal. Notice how the exchange of irrigant only extends a small distance beyond the end of the needle tip:
Based on some of the literature to date, here are a few suggestions for achieving effective irrigation using a conventional irrigation method:
1. Use a flexible, small gauge irrigation needle, for example, a 30 gauge needle or smaller, that is designed with a closed-end and side-vent (for patient safety). I find that it is quite difficult to use an irrigation needle bigger than a 30 gauge needle, unless the root canal is very large.
2. Prepare the root canal to an adequate apical size and taper such that a small gauge irrigation needle can be placed within 1-2 mm of the working length, or at least in the apical third.
3. Use very gentle finger pressure! A high irrigation flow rate (e.g. high finger pressure) is not required; recent research shows that high pressure/high flow rates does not correlate to “better cleaning”.
4. Activate your irrigants! Use of a sonic or passive ultrasonic tool, such as the EndoActivator by Tulsa, or the Irrisafe file by Clinical Research Dental can make your irrigation more effective. There are many options for agitating your irrigants, and I try to “energize” each irrigant that I use for at least 45-60 seconds per canal, per irrigant, after the majority of the cleaning and shaping has been done.
If you like reading journal articles, here is my recent paper on the “theoretical measured pressure” that the periodontal ligament might feel when we are irrigating root canals. We also have a review paper on irrigation of the apical third in the journal Endodontic Topics, have a read. Send us a message if you can’t find it. Park Shen Haapasalo 2013 irrigation JOE
“Pure lateral or vertical compaction rarely occurs. The vectors of force applied during obturation techniques are an integrated blend of forces and result in composite of forces that are neither true vertical or lateral.” [Pathwyas of the Pulp-7th Ed.]
So, I guess we all pretty much use the same combined obturation technique. Downward force of finger-/hand-spreaders or pluggers and the resultant force moving the obturation material laterally. Some of you have asked me for a demonstration of my obturation technique:
After complete shaping and cleaning, I fit a sealer-coated master cone to 0.5-1mm short of the apex. I then use a heat source (Calamus Dual) and a series of 2-3 pluggers (S-Kondensers) to perform the down pack. Finally, I use the Calamus Dual again to back-fill to the level of canal orifice.
Many clinicians are interested in techniques that produce sealer puffs and show off apical ramifications. Here is a brief summary of an article that I had read a couple of years ago and it pretty much explains my stand on this issue:
“Chemomechanical preparation partially removes necrotic tissue from the entrance of lateral canals or apical ramifications, whereas the adjacent tissue remaines inflamed, sometimes infected, and associated with periradicular disease. Vital tissue in lateral canals or apical ramifications is not removed by preparation. In cases in which lateral canals appears radiographically ‘‘filled,” they are actually not obturated, and the remaining tissue in the ramification is inflamed and enmeshed with the filling material… The belief that lateral canals must be injected with filling material to enhance treatment outcome is not supported by literature.” [J Endod 2010;36:1–15]
So, clinician’s skill or the technical ability of producing sealer puffs will not necessarily result in successful endodontic therapy. In many cases, extrusion of sealer into lateral canals and ramifications as a result of specific techniques (use of patency files, removal of smear layer, use of warm vertical compaction technique, etc.) is unavoidable, but this should not be the aim in obturation.