CLEANING ROOT CANAL SYSTEMS
Q. Why chelators only in vital cases? Not in non-vital?
A. In my opinion, I like to use viscous chelators such as Glyde, ProLube or RC Prep in vital cases because they are “cocktail” reagents that break down collagen present in vital tissue. Vital tissue is tactiley more rubbery which predisposes to blocked canals and additionally is well know to obstruct the secondary anatomy. As an example, RC Prep contains EDTA, urea peroxide, glycerin, etc. which enhances file lubrication, tissue emulsification, and encourages debris flotation. Definitely, you can use RC Prep in necrotic cases, but in my opinion, necrotic tissue floats out of canals readily and doesn’t typically require a viscous chelator.
Q. I have read an article claiming that sodium hypochlorite, when heated, decomposes and is ineffective as a tissue dissolver...while you maintain that it helps to speed up tissue dissolution. In short, do you still recommend heating sodium hypochlorite to 60°C using a hot plate? Do you know of any research available that I may read on this subject matter?
A. It is true that sodium hypochlorite (NaOCl) ions disassociate over time when exposed to light and temperature. That is why the manufacturer sells this solution in an opalescent bottle and recommends storing it in a cool, dark place. This is also the reason why I recommend changing your NaOCl solutions daily, if not obtaining fresh irrigant for each endodontic procedure. Heating NaOCl to 60°C for brief periods of time (i.e.: during an endodontic procedure) will not affect its ability to digest tissue. I am not aware of any scientific article that shows NaOCl decomposes and is an ineffective tissue dissolver -- if utilized in the manner I have recommended. Following are some references for you:
1) Grey GC, The capabilities of sodium hypochlorite to digest organic tissue from root canals with emphasis on accessory canals, Master Thesis, Boston University, 1970.
2) Berutti E, Marini R, A scanning electron microscopic evaluation of the debridement capability of sodium hypochlorite at different temperatures, J Endod 1996:22(9), 467-470.
3) Cunningham W, Balekjion A: Effect of temperature on collagen-dissolving ability of sodium hypochlorite irrigating solution, Oral Surg 49:175, 1980.
There are many more references you will be led to, if you want, when you review these peer reviewed articles.
Q. Where can the desktop coffee warmer (to heat NaOCl) be purchased?
A. In our office we use the Mr. Coffee Mug Activated Beverage Warmer. If you can't find it in a large drugstore like CVS or Sav-on, I believe you can order it directly from Mr. Coffee, Part Number MW1B, tollfree phone number (800) 672-6333, or visit www.mrcoffee.com
Q. At a course, you showed a tapered bristle brush to clean the finished preparation. Who makes the brushes and did you use 17% aqueous EDTA on the brush or full strength NaOCl?
A. The EndoBrushes are still in the prototype phase and not yet available. For now, I recommend the EndoActivator (Dentsply Tulsa Dental) to agitate solutions, both full strength NaOCl and 17% aqueous EDTA. For more information on the EndoActivator and its related protocol and recommended technique, please refer to the Inventions/EndoActivator
page of this website.
Q. I have purchased a new P-5 ultrasonic unit (Dentsply Tulsa Dental) for the main purpose of using it with my irrigant for “acoustic streaming”. Do you have any suggestion on what power level I should use it at for this purpose?
A. Congratulations on purchasing the best piezoelectric ultrasonic generator available. Regarding your questions:
1) Ultrasonic activation of intracanal irrigants is a technique that has been utilized for many years.
2) Ultrasonic instruments are made out of stainless steel or titanium and, as such, can only be introduced into the straightaway portions of the canal. The diameter and length chosen is based on the dimensions of the canal. The stainless steel ProUltra ultrasonic instruments (Dentsply Tulsa Dental) have a zirconium nitride abrasive surface and work fine in a bath of NaOCl. However, on a cautionary note, research and clinical experience has shown diamond coated ultrasonic instruments (Obtura-Spartan) rapidly corrode, form sludge and within seconds, rapidly undergo surface degradation when immersed in NaOCl. Presumably it is the binding agent which attaches the diamond particles to the stainless steel instruments that turns black and corrodes.
3) If you want to activate solutions apical to a canal curvature, then you need the "File Adapter" (SybronEndo) which threads onto the Satelec handpiece. This attachment will allow you to load a precurved stainless steel file, typically a 35 or 40, and place it deeper in the canal.
4) The power setting should be low so that you see the solution agitating. Too little power and you see nothing -- Too much power and the solution splatters and the risk of a ledge or broken instrument may result. The setting is based on the length, diameter and angle of each ultrasonic instrument and the one you choose is based on the length, diameter and curvature of a canal.
Separately, I encourage you to also explore the EndoActivator System (Dentsply Tulsa Dental). This sonically-driven system is designed to safely activate various intracanal reagents and vigorously produce the hydrodynamic phenomenon. Importantly, sonic activation has been shown to be an effective method to improve disinfection. In well-shaped canals, this new technology is intended to provide a safer, better, and faster method to disinfect a root canal system compared to other currently available methods.