Read trope.pdf text version

Endodontics

Advances in Endodontic Obturation

a report by

F a b r i c i o B Te i x e i r a , D D S , M S c , P h D 1 and M a r t i n Tr o p e , B D S , D M D 2

1. Associate Professor; 2. JB Freedland Professor and Chair, and Director, American Board of Endodontics, University of North Carolina School of Dentistry

Endodontics or root canal therapy is the treatment of apical periodontitis.This can be divided into two main aspects-prevention by treating vital pulp where no bacteria are present in the root canal system; or elimination by treating the necrotic infected pulp. Root canal therapy comprises two principal phases. The first is the microbial control phase, in which the root canal is prepared to ensure that the remaining bacteria in the root canal are at a minimum. The second phase-or filling phase-consists of sealing the space created in the first phase, and includes both the root filling and the crown filling. According to Figdor,1 there are three principal functions of root canal filling: 1. entombing remaining bacteria within the root canal system; 2. stopping the influx of periapical tissue-derived fluidwhich feeds surviving bacteria-into the root canal and; 3. preventing coronal leakage of bacteria. Gutta-percha is the gold standard in root filling material. First introduced in 1847, there have been few fundamental changes to gutta-percha root fillings since 1914. However, despite its many advantages, guttapercha does not completely fulfill the functions of a root filling material. Studies have questioned the ability of gutta-percha to fully entombing remaining bacteria.2 Furthermore, coronal leakage studies clearly indicate that the gutta-percha fill does not seal the canal adequately.3-5 This points to gutta-percha as the weak point in endodontic therapy. Indeed, it could be argued

that success in endodontics is related more to the quality of the coronal restoration than to the filling of the canal.6

T h e r m o p l a s t i c S y n t h e t i c Po l y m e r s

The limitation of gutta-perca to prevent coronal microleakage has led to the development of alternative materials. One such alternative is ResilonTM (Resilon Research, LLC), a thermoplastic synthetic polymer. Resilon is based on polymers of polyester and contains bioactive and highly radiopaque fillers.The polymer has an improved flexural strength and, when used in conjunction with a resin-based sealer, offers improved bonding potential, when compared with gutta-percha. Resilon is the central component of the EpiphanyTM Soft Resin Endodontic Obturation System (Pentron Clinical Technologies, LLC), and RealSealTM (SybronEndo). These systems include three primary components: 1. The Resilon core material--a thermoplastic synthetic polymer-based root canal core material containing bioactive glass, bismuth oxychloride and barium sulfate. The filler content is approximately 65% by weight. 2. The resin sealer--a dual-curing, resin-based composite sealer. The resin matrix is composed of bisphenol-A-glycidyldimethacrylate (BisGMA), ethoxylated BisGMA, urethanedimethacrylate (UDMA) and hydrophilic difunctional methacrylates. It contains fillers of calcium hydroxide, barium sulfate, barium glass, and silica.The

Fabricio B Teixeira is an Associate Professor in the Department of Endodontics at the University of North Carolina. Dr Teixeira's research interests include root canal disinfection and filling, endodontic techniques and microsurgery, and dental trauma. Dr Teixeira was previously an Assistant Professor in the Endodontic Department at the State University of Campinas, Sao Paulo, Brazil. He gained his DDS from Gama Filho University and a PhD in Endodontics-Clinical Dentistry from the State University of Campinas.

1. Figdor D,"Apical periodontitis: a very prevalent problem", Oral Surg Oral Med Oral Pathol Oral Radiol Endod (2002);6: pp. 651­652. 2. Sjögren U, et al., "Influence of infection at the time of root filling on the outcome of endodontic treatment of teeth with apical periodontitis", Int Endod J (1997);30: pp. 297­306. 3. Madison S,Wilcox LR,"An evaluation of coronal microleakage in endodontically treated teeth. Part III. In vivo study", J Endod (1988);14: pp. 455­458. 4. Khayat A, Lee S-J,Torabinejad M,"Human saliva penetration of coronally unsealed obturated root canals", J Endod (1993);19: pp. 458­461. 5. Trope M, Chow E, Nissan R, "In vitro endotoxin penetration of coronally unsealed endodontically treated teeth', Int Endod J (1995);11: pp. 90­94. 6. Ray HA,Trope M, "Periapical status of endodontically treated teeth in relation to the technical quality of the root filling and the coronal restoration", Int Endod J (1995);28: pp. 12­18.

Martin Trope is a JB Freedland Professor in the Department of Endodontics at the University of North Carolina. The JB Freedland professorship recognizes significant contributions to the specialty. Dr Trope also serves as a Director of the American Board of Endodontics and he is an Associate Editor of Endodontics and Dental Traumatology and serves on the editorial boards of International Endodontic Journal; Oral Surgery, Oral Medicine, Oral Pathology; and Practical Periodontics and Aesthetic Dentistry. A noted authority in his field, Dr Trope has been actively involved in clinical research in all phases of endodontics. He was previously Chairman of the Department of Endodontology at Temple University, Philadelphia.

U S D E N T I S T RY 2 0 0 6

45

Endodontics

Figure 1: Scanning Electronic Microscopy Picture Demonstrating the 'Monoblock' Concept

1). Gutta-percha does not form a monoblock, even with the use of a resin-based sealer, because the sealer does not bind to gutta-percha. Moreover, the sealer tends to pull away from the gutta-percha on setting.

C l i n i c a l Te c h n i q u e s W i t h R e s i l o n

Clinically, Resilon can be manipulated in the same manner as gutta-percha. Resilon can also be softened with heat or dissolved with solvents such as chloroform for retreatment purposes. As with gutta-percha, Resilon is available as master cones and accessory cones in different sizes, and as Resilon pellets, which can be used for the backfill in the warm thermoplasticized techniques. During the instrumentation protocol, a smear layer of organic and inorganic material is created along the root canal walls. Flushing the root canals with 17% ethylenediaminetetraacetic acid (EDTA) and/or 2% chlorhexidine removes this smear layer and residual sodium hypochlorite. After flushing, the root canals are dried using sterile papers points. Resilon points or plugs are placed into a disinfectant for 60 seconds.Two to three drops of the primer are dispensed into a mixing well and this is applied to the walls of the root canal using a pipette, syringe or paper point soaked in primer. Excess primer is removed using paper points, leaving the internal surfaces moist with primer. The remaining solvent can be evaporated by a gentle air spray for five seconds. Sealer is dispensed onto a mixing pad and placed with a master cone or lentulo spiral kept three millimeters from the apex and no faster than 300rpm.The canal is then filled with Resilon core material (main and accessory points or thermoplastic Resilon material) using the preferred technique--`passive' lateral condensation technique or vertical condensation using System BTM and Obtura IITM.

Studies With Resilon

Coronal Microleakage

total filler content is approximately 70% by weight. 3. The primer--a self-etch primer that contains sulfonic acid-terminated functional monomer, 2hydroxyethylmethacrylate (HEMA), water and a polymerization initiator. HEMA enhances the bonding of resin to dentin. These new materials have been approved for endodontic use by the US Food and Drug Administration (FDA) and have been shown to be biocompatible, noncytotoxic and nonmutagenic. The concept of dentin bonding has been used in restorative dentistry and this is now being applied to endodontic treatment. Gutta-percha provides a poor barrier to the coronal to apical migration of bacteria after obturation, as it does not bond to canal walls. In comparison, promising results have been reported with resin sealers.7 Early studies debated the use of resins, due to questionable results owing to difficult and unpredictable methods of delivery of the material into the root system and the inability to retreat the canal if necessary.8 However, it was acknowledged that these materials may have the potential to overcome the significant limitations of gutta-percha by enhancing the root canal seal, thus reducing microleakage from both an apical and a coronal direction. Because Resilon is a synthetic polymer, the resin sealer attaches to it, as well as to the bonding agent/primer used to penetrate into the dentin tubules. As a result, a `monoblock' is formed, consisting of filling materialresin sealer-bonding agent/primer-dentin (see Figure

Shipper et al. compared bacterial leakage using Streptococcus mutans and Enterococcus faecalis through guttapercha and Resilon using both lateral and vertical condensation techniques during a 30-day period.9 In the in vitro study, 120 roots were prepared and randomly divided into eight groups of 15 roots each. Roots were filled with gutta-percha and AH-26 sealer (groups 1 and 2) or with gutta-percha and Epiphany sealant (groups 3 and 4). Groups 5 and 6 were filled with Resilon and Epiphany sealant using the lateral or vertical condensation

7. Leonard JE, Gutmann JL, Guo IY, "Apical and coronal seal of roots obturated with a dentine bonding agent and resin", Int Endod J (1996);29: pp. 76­83. 8. Rawlinson A, "Sealing root canals with low-viscosity resins in vitro: a scanning electron microscopy study of canal cleansing and resin adaption", Oral Surg Oral Med Oral Pathol (1989);68: pp. 330­338. 46

U S D E N T I S T RY 2 0 0 6

Endodontic Success... Sealed!

Dentin Tubules

ResilonTM Material Epiphany® Sealer/Hybrid Zone

The Epiphany Obturation System.

®

Dentin

It's just like gutta percha, only with the improved sealing properties of ResilonTM* Filling Material.

The Epiphany® System creates a true monoblock that significantly reduces the pathways for bacteria to travel from the coronal end to the apex. How? The resin-based sealer and primer bond to the dentin, and

AH26 Gutta percha +AH26

Gap between dentinal surface and gutta percha

Dentin

the sealer seamlessly bonds to the ResilonTM soft resinobturation material. The result? Improved sealing with less chance of leakage and a stronger root that is 20% more fracture resistant than with

ResilonTM +RCS sealer monoblock

** traditional gutta percha obturation.

ResilonTM sealer and dentinal surface form a monoblock

And the technique you'll use for Epiphany® obturations is no different than what you're currently using with standard gutta percha systems. So, the only thing you need to change is your material... and your expectations.

To learn more about the Epiphany® system, or to order, visit www.pentron.com or call 1-800-551-0283.

Epiphany® | FibreFill®

FREE Shipping!

Pentron Clinical Technologies, LLC | 800.551.0283 | www.pentron.com In Canada call SYNCA at 800.667.9622

Free shipping available when you order online!

For details call us or visit our website.

*Resilon is a trademark of Resilon Research, LLC. ** For test results see www.resilonresearch.com

Additional shipping charges my apply. Subject to change or cancellation without notice. No other offers apply. Orders subject to credit approval.

Copyright © 2006 Pentron Clinical Technologies, LLC. All rights reserved.

Endodontics

Table 1: Force (Newtons) Required to Cause Vertical Root Fracture (N = 16)

Groups Mean Standard Deviation

sealer (19%) and roots in the negative control (22%).

Fracture Resistance

1. Control--no obturation 2. Lateral gutta-percha 3. Vertical gutta-percha 4. Lateral Resilon 5. Vertical Resilon

465.39a,b 391.51a 392.37a 504.22b 498.23b

76.85 146.79 77.0. 195.94 135.32

Notes: a=control versus gutta-percha (p<0.05); b=control versus Resilon (p<0.05)

techniques. Groups 7 and 8 were identical to groups 5 and 6; however, E. faecalis was used to test the leakage. Positive controls were filled with Resilon (12 roots) and guttapercha (12 roots) without sealer and tested with bacteria, whereas negative controls (12 roots) were sealed with wax to test the seal between chambers. Resilon showed significantly less coronal leakage (1 or 2 of 15 specimens) than gutta-percha, in which approximately 80% of specimens with either technique or sealer leaked. In an in vivo study in dogs, vital roots were aseptically treated, as in the in vitro study.10 The roots were randomly divided into four experimental groups and one negative control group and filled as follows: lateral condensation of gutta-percha and AH26 sealer (group 1, n=12); vertical condensation of gutta-percha and AH26 sealer (group 2, n=12); lateral condensation of Resilon with Epiphany primer and sealer (group 3, n=12); vertical condensation of Resilon with Epiphany primer and sealer (group 4, n=10); negative control (n=10), filled with gutta-percha and AH26 sealer or Resilon with Epiphany primer and sealer root fillings using lateral or vertical condensation techniques as in groups 1 to 4. Positive control, consisted of 57 additional premolar roots that were instrumented, infected and not filled. The premolars in groups 1 to 4 were accessed again, inoculated with dental plaque scaled from the dog's teeth, and temporized. This fresh innoculum of micro-organisms was repeated on two more occasions at monthly intervals. The teeth in the negative control group were not accessed again and remained undisturbed. At the 14-week postcoronal inoculation, dogs were euthanized, and jaw blocks prepared for histological evaluation under a light microscope. Mild inflammation was observed in 82% of roots filled with gutta-percha and AH26 sealer.This was statistically more than roots filled with Resilon with Epiphany primer and

One of the potential disadvantages of root canal treatment is the weakening of the root through removal of dentin during instrumentation and also via filling techniques (lateral or vertical condensation). Since Resilon is a bonded resin system, it has the potential to strengthen the root. An in vitro study demonstrated that root canals filled with Resilon were more resistant to fracture than roots filled with gutta-percha and AH-26 sealer, indicating that the monoblock concept-whereby the Resilon core is able to bond to the resin sealer, which, in turn, attaches to the self-etched root-is important not only to resist bacterial penetration through the material but also to hold the root together, thereby increasing the resistance to fracture.11 Eighty single-canal extracted teeth were prepared and randomly divided into five groups: lateral and vertical condensation with gutta-percha, lateral and vertical condensation with Resilon and a control group with no filling material. Comparison among groups was performed. Table 1 shows the means and standard deviations for each experimental group. The ANOVA revealed a significant difference between treatments (p=0.037). The root resistance fracture values of the Resilon vertical and lateral groups were superior to the gutta-percha and AH26 sealer lateral and vertical groups. However, no significant difference was observed among the filled groups and the non-filled control group.

Summary

Research with Resilon indicates that it is superior to gutta-percha in terms of coronal bacterial leakage, although long-term studies are still needed to confirm this. Studies in in vitro dog studies have demonstrated that the Resilon system is more resistant to fracture compared to gutta-percha. However, at present the clinically relevance of these studies are unknown and further studies will need to be performed to support these studies. Clinically, Resilon is highly radiopaque and handles well with both cold and heated root canal filling techniques. It appears to be biocompatible, and the sealant has considerable flow through accessory canals. No untoward postoperative pain has been reported by clinicians using the system, and some cases are showing healing in a short period of time.

9. Shipper G, et al.,"An evaluation of microbial leakage in roots filled with a thermoplastic synthetic polymer based root canal filling material (ResilonTM)", J Endod (2004);30: pp. 342­347. 10. Shipper G, et al., "Periapical inflammation after coronal microbial inoculation of dog roots filled with gutta-percha or resilon", J Endod (2005);31: pp. 91­96. 11. Teixeira FB, et al., "Fracture resistance of endodontically treated roots using a new type of filling material", J Am Dent Assoc (2004);135: pp. 646­652 [published erratum appears in J Am Dent Assoc (2004); 135:868]. 48

U S D E N T I S T RY 2 0 0 6

Information

4 pages

Report File (DMCA)

Our content is added by our users. We aim to remove reported files within 1 working day. Please use this link to notify us:

Report this file as copyright or inappropriate

301919


Notice: fwrite(): send of 199 bytes failed with errno=104 Connection reset by peer in /home/readbag.com/web/sphinxapi.php on line 531