The goal of Endodontic treatment has generally been defined as "the prevention or elimination of Apical Periodontitis". As many of you have read in past issues of The EndoFiles Fax, I have begun to use orifice-bonding techniques in an attempt to enhance coronal seal and prevent canal recontamination. This is potentially a big problem in Manitoba because of the high numbers of patients who (for financial reasons) choose to delay restoration of endodontically treated teeth until the next insurance calendar year. This can sometimes be 6 to 8 months or more. Protracted delays can result in eventual recontamination and endodontic failure that necessitates retreatment or eventual extraction. Coronal seal is so important to success that some American endodontists will now only accept cases for treatment if they are allowed to place build-ups (bonded cores or post/cores) at the time of completion of endodontics. Many have lost referrals due to this but they believe that in the long run they perform fewer retreatments and that their cases are much less likely to become recontaminated.
During the weekend of April 25th, I attended a Hands-On Workshop at the University of Toronto that featured a new filling material - Resilon. Dr. Martin Trope (co creator of Resilon) challenged the 75 participants to ask more of an endodontic filling material other than merely occupying space in a canal. Instead of using a material from the 20th century, he suggested that it was now time to use modern technology to create a RETREATABLE bondable endodontic filling material that by nature could not only seal a canal but also prevent re-occurrence of canal infection.
I was intrigued by this new material because I believe it has the potential of revolutionizing Endodontics by offering solutions to two of Endodontics' greatest filling problems:
(1) Shrinkage of Gutta Percha after application of heat. It is a fact that Gutta Percha shrinks 5-7% after it is heated. Warm Gutta Percha users solve this shrinkage problem by application of sealer and use of vertical plugging forces during obturation. That is why it is so important to "press and hold" when you pack the canal. You should never "bounce" the plugger (like condensing amalgam) since this does allow for shrinkage and does not allow the gutta percha/sealer to obtain optimal flow after heat is applied. The other problem that occurs because of the shrinkage during cooling is that Gutta Percha does not physically bind to Kerr sealer. Although sealer can be shown in the dentin tubules and is closely bonded to the canal wall, SEM studies have shown that a "gap" develops between the sealer and the gutta percha because of this shrinkage during cooling. This is the "weak link" in the system. This new Resilon core material only shrinks 0.5%, even when heated and unlike Gutta Percha, it is physically bonded to the sealer by polymerization. When it sets, no gaps are present due to shrinkage.
(2) Enhanced Coronal Seal. Although it is very difficult to quantify exactly how many endodontic failures are the result of lost coronal seal, there is evidence in the literature to support the idea that it can significantly contribute to failure of treatment. (Ray and Trope 1992) We know that temporary restorations have minimal ability to protect against recontamination. Most studies have shown that 30 days is about the most we can expect from a temp, less if the tooth is in greater function. Gutta Percha simply is a lousy material for coronal or orifice sealing. Many endodontists have now moved toward orifice bonding or application of bonded pulpal "subfloors" with flowable composites to seal the orifices and furca areas that can occasionally harbor accessory canals. Resilon is used with a Dual Cure Sealer. This coronal 2 mm of the canal filling is polymerized with a curing light, thereby enhancing coronal seal and binding directly to both the core material and the dentin.
RESILON - What is it? Resilon is an FDA approved thermoplastic synthetic polymer material, based on Polyester. It also contains Bioactive Glass, Bismuth Oxychloride and Barium Sulphate. (65% filler by weight) It is a fully polymerized resin, slightly stiffer than Gutta Percha but it can go around curves as well due to the filler components that make it flexible. It is slightly MORE radio-opaque that Gutta Percha. It is available in Standard and Non Standard cones as well as Obtura pellet form. These look exactly like Gutta Percha except for the white color. The Resilon Material is sold with a Dentin Primer and a dual cure sealer (Epiphany).
1. Prepare the canal space using your normal preparation methods.
2. Use 17 %EDTA or 2% Chlorhexidine as a final rinse.
3. DO NOT use NaOCL as a final rinse since it can disrupt the sealer bond. DO NOT use overproof (95%) alcohol to dry the canal because the dentin walls must not be 100% dry - the sealer is hydrophilic.
4. Apply Primer (it is self etch) to the level of the apex (not beyond!) with a well fitting paper point. The Primer is very important because it creates a collagen matrix that increases the surface area in which to bond. The low viscosity Primer also draws the Sealer into the dentinal tubules.
5. Remove excess primer with dry paper point6. Express a small amount of the dual syringe Epiphany sealer into a mixing pad and apply liberally to the canal. Remove excess with paper points. (Sealer is Dual Cure Bis GMA, Ethoxylated Bis GMA, UDMA, hydrophilic (important!) difunction methacrylate. Fillers are CaOH, Ba Sulphate, Barium Glass. Total filler content 7% by weight. Sealer shrinks 2-3% on polymerization. As with Gutta Percha, try to get the maximum core material with the best cone fit.
7. Use your USUAL OBTURATION TECHNIQUE ie/ System B, Warm vertical. Lateral etc. Obturate just as you would a normal Gutta Percha case.
8. Use curing light to cure the coronal aspect and enhance coronal seal. Then use the same primer and a flowable composite to close the orifices. The material in the canal cures in about 1 hour.
9. Clinicians using the Obtura Gun with Resilon Pellets should reduce the temperature setting about 20 degrees (to approx. 167-170). Your temperature setting may vary depending on the actual individual Obtura Gun.
The Monoblock Concept: An ideal endodontic filling material would create a "monoblock". This term refers to a continuous solid layer that consists of: - An etched layer of canal dentin impregnated with resin tags that are attached to: - A thin layer of resin cement that is bonded to: - A core layer of Resilon which makes up the bulk of the filling material The Monoblock concept means the creation of a solid, bonded, continuous material from one dentin wall of the canal to the other. One added benefit of the Monoblock is that research has shown that it STRENGTHENS the ROOT by approximately 20%.
Who makes it? Resilon and Epiphany Sealer are currently being manufactured by Pentron (www.pentron.com) and available in Canada through Synca. It is available in starter kits (Cones or Pellets and Primer/Sealer) at approx. $150 US. Refill boxes of 20 Resilon Cones are about $8 US each, which works out to about $.50 per cone - more expensive than Gutta Percha but not exorbitant. Sealer ($60 US) and Primer ($30 US) refills are also available.
Who sells it? - In the US, Resilon is available for sale online at (www.pentron.com). Pentron does not ship internationally and sells through representatives. Canadians wishing to purchase should contact Synca Canada (www.synca.com)
My initial impressions: I have not used this material on patients as of yet. The Toronto course provided an opportunity to use this material on teeth that I had prepared myself. I obturated 9 teeth with an entirely Obtura-based technique (called System S or "Squirt") that I have been successfully using with Gutta Percha for about 2 years. Two others were filled with standard Warm GP technique. There is no question that this material is stiffer and more difficult to pack. It also cools MUCH more quickly because it does not have the heat retention properties of Gutta Percha. A thinner is also available for the sealer so you can change its consistency. Some clinicians expressed concern that the sealer had not set after several hours but Dr. Trope explained that exposure to air can retard set and this is of no concern when seen on a mixing pad. It will set in the tooth. Most importantly, both the Resilon material and the sealer are both soluble in Chloroform so that if you need to retreat the case, it can be removed. This is the single most important factor in motivating me toward its use…retreatability. If there is sufficient local interest, I may offer a local Demo in Winnipeg. Contact my office if you are interested in participating.
ROOTS Summit IV June 23 - 26, 2004 Salt Lake City, Utah
The ROOTS Internet Discussion Group is again meeting for 4 days of intensive Endodontic Education.
Lectures June 24 - 25 and 26th -- Full Days - Lunch Provided - Tuition $425 US
Dr. Ken Hargreaves---------------- -Pain Control in Endodontics
Dr. Martin Trope-------------------- Dental Traumatology Update
Dr. P. Cancellier--------------------- Ultrasonics--tip selection and use
Dr. E. Cotti ---------------------------The AET System--in-vivo results
Dr. G. Debelian ----------------------RaCe Instrumentation and Resilon Root Filling
Dr. C. Pameijer ----------------------Properties of Endodontic Sealers Pulp Capping
Dr. T. Pannkuk ----------------------Endo-Puzzle solving
Dr. C. Boveda-------------------------Ergodontics
Dr. J. Avillion -------------------------Protaper-GT Hybrid & System A Obturation
Dr. A. Castelucci--------------------- Treatment Planning---Rescuing Hopeless Teeth
Dr. R. Mounce------------------------ Maximizing NiTi Efficiency and Safety
Dr. G. Cantatore ---------------------Thermafil vs. SystemB Obturation
Dr. B. Watson ------------------------The Plains Technic
Daily ----------------------------------Gattling Gun Case Presentations----Exhibits,----- and more.
Limited Attendance (extra fee) Microscope, Rubber Dam and Restorative Hands on Demos also available on June 23. Hotel: The Grand America Hotel
555 South Main Street
Salt Lake City, Utah 84111
REGISTER ONLINE by checking www.ultradent.com or www.sybronendo.com
JOIN ROOTS at www.rxroots.com and become part of Endodontic's best education experience!