Current Philosophies

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1 Earn 4 CE credits This course was written for dentists, dental hygienists, and assistants. Current Philosophies 4527 in Root Canal Obturation A Peer-Reviewed Publication Written by Richard E. Mounce, DDS PennWell is an ADA CERP recognized provider ADA CERP is a service of the American Dental Association to assist dental professionals in identifying quality providers of continuing dental education. ADA CERP does not approve or endorse individual courses or instructors, nor PennWell does it imply is an acceptance ADA CERP of credit Recognized hours by boards Provider of dentistry. Concerns of complaints about a CE provider may be directed to the provider or to ADA CERP at Go Green, Go Online to take your course This course has been made possible through an unrestricted educational grant. The cost of this CE course is $59.00 for 4 CE credits. Cancellation/Refund Policy: Any participant who is not 100% satisfied with this course can request a full refund by contacting PennWell in writing.

2 Educational Objectives This article will review the principles of root canal obturation and obturating materials currently available. Upon completion of this course, the dental professional will be able to: 1. Know the main factors influencing endodontic success 2. Know the advantages and concerns around the use of gutta percha 3. Know the options available for root canal obturation and how these differ 4. Know the characteristics of recently introduced carrierbased obturators and their clinical application. Abstract Endodontic materials and techniques have advanced dramatically in the last two decades. Historically, gutta percha together with sealer has been the obturation of choice. Gutta percha is versatile, with a long history of use. However, it is not able to bond to obturating materials or to the tooth. Techniques for obturating root canals include the use of heat or chemically-softened gutta percha, injection techniques, ultrasonics, vibration and carriers. Carrierbased materials are available that utilize a core carrier around which obturating material is coated. The introduction of bonded obturating materials (methacrylate resins) has enabled the clinician to obtain a bonded seal to the root canal dentin in areas reached by the etch/adhesive materials. In addition, a carrier-based system is now available that combines a carrier technique and adhesive technology for bonded obturation. Introduction Root canal treatment in the mid-1700s included the use of poultices, leeches, and pulpal cauterization. 1 Since that time, much has changed. During the last two decades alone, the science and practice of endodontic therapy have advanced dramatically with the introduction of evidence-based and validated protocols as well as modern techniques and materials. These have paralleled advances in other disciplines. The introduction of surgical operating microscopes, the use of rotary nickel titanium instruments and, within the last year, twisted nickel titanium instruments, research on irrigants and smear layer removal, and the introduction of advanced bonded obturation and sealer materials and techniques have all played a role and continue to do so. 2 The final step in endodontic therapy is root canal obturation with the objectives of attaining apical and coronal seals, sealing lateral and accessory canals, and consistently filling all pathways from the root canal system to the surrounding periodontal ligament. Prior to obturation, the canals must be adequately cleaned such that they are free of debris and disinfected to remove microbes, and the shape of the prepared canals must enable clinically acceptable obturation. Removing the smear layer with an appropriate product prior to obturation reduces subsequent microbial leakage through the root canals. 3 It is important to note that the final restoration must provide excellent coronal seal; when a build-up is required it should be performed using a rubber dam to prevent contamination, and the seal created by the obturation materials must not be disturbed. Hommez et al. reported that inadequate coronal restorations resulted in a 49.1% incidence of apical periodontitis versus 23.8% for those teeth with an adequate coronal restoration, underscoring the importance of the final restoration for clinical success. 4 Research has shown that periradicular lesions are prevalent in teeth with poor coronal restorations; and that the quality of obturation is the most critical factor. 5 The success of endodontic therapy and the long-term viability of the tooth are compromised if any step in the endodontic and restorative procedure is inadequate (Figure 1). Figure 1. Failed endodontic/restorative therapy Obturating for Successful Outcomes Root canal obturation must be complete, fill all main canals to full length to provide an apical seal, and fill all accessory canals. Obturation that is of inadequate length or non-homogenous has been associated with a significantly increased presence of periapical disease assessed within one year post treatment. 6 Until recently, lack of a coronal seal or disturbing the coronal seal during restoration have been problems for root canal therapy even where the obturation was otherwise clinically acceptable. Gutta percha combined with use of a sealer was historically the standard for root canal obturation. The introduction of obturation materials that can be bonded to root canal dentin and the use of bonded materials for coronal dentin have enabled improved coronal seals that are less susceptible to being compromised during restoration. In addition, the introduction of new thermoplastic techniques and carrier-based obturating materials provide the clinician with more options during obturation. 2

3 Gutta Percha Gutta percha offers a number of advantages and disadvantages as a root canal obturating material. Advantages include biocompatibility, ability to be heated and softened for canal placement, compatibility with sealer materials, and technique flexibility. It can be used with sealer coated on it, after sealer is placed in the canal, using an injection technique, used with a carrier, compacted, and placed with vibration and ultrasonics, and it is flowable. Gutta percha is also relatively inexpensive and readily available, has a long history of use, and can usually be readily removed from root canals in cases requiring retreatment. Nonetheless, there are some concerns with gutta percha. Gutta percha does not provide a seal, irrespective of the placement technique, and must always be used with a sealer. Further, if the gutta percha has been heated prior to placement, it can shrink as it cools. Use of gutta percha has been found to create the potential for significant voids if a lateral condensation technique is used. 7 Voids would be more likely to occur with use of an inadequate amount of sealer. Lastly, it bonds neither to the root canal dentin nor to the accompanying sealer, nor does it influence the coronal seal (Table 1). Excellent coronal seal is a key factor in endodontic success, and is not influenced by the presence or absence of gutta percha and, more recently, methacrylate resin sealers. Sealers fill voids between gutta percha points when multiple points are used, and are responsible for obtaining apical and coronal seals and the sealing of accessory canals to prevent microleakage and recontamination. Therefore, they are all factors in endodontic success. 14 Resin sealers based on adhesive technology bond to root canal dentin when appropriately used. Ideally, if a resin-based sealer is used it should also be able to bond to the selected root canal obturating material. If the obturating material is gutta percha, such bonding cannot occur. Resin-Bonded Obturating Materials and Sealers AH Plus is an epoxy-based resin sealer. Resin-bonded obturating and sealer materials include EndoREZ and RealSeal (also distributed as Resilon /Epiphany ) (Figures 2, 3, and 4). These are methacrylates. Neither epoxy resin nor methacrylate resin sealers can be bonded to gutta percha. Figure 2. EndoREZ Table 1. Advantages and disadvantages of gutta percha Advantages Long history of use Biocompatibility Flexibility of technique Thermoplastic Compatibility with sealers Easily removed Inexpensive Disadvantages Provides no seal Inability to bond to dentin Inability to bond to sealers Shrinks upon cooling Potential for voids Must be used with a sealer Figure 3. Resilon /Epiphany Compounds that have been used as sealers in conjunction with gutta percha include calcium hydroxide, calcium phosphate, zinc oxide eugenol, AH Plus (epoxy resin), 3

4 Figure 4. RealSeal Figure 5. Dentinal tubules Courtesy of Dr. Jeeraphat Jantarat Figure 6. Monoblock layer Both RealSeal and EndoREZ are hydrophilic and are used in the presence of a slightly moist root canal environment. EndoREZ consists of urethane dimethacrylate with zinc oxide, barium sulfate, resins, and pigments. It is a two-component sealer that is used in conjunction with gutta percha points. EndoREZ can be placed in the root canal, followed by gutta percha points or resin-coated gutta percha points. EndoREZ has been found to result in deep dentin tags when bonded to slightly moist root canal dentin and to have good clinical success when the manufacturer s instructions are followed. 15 RealSeal and sealer have been licensed from Resilon and are identical to Resilon obturating points and Epiphany sealer. RealSeal obturating points and the self-etch sealer are used as a system and require prior removal of the smear layer. Optionally, primer can be used as well. The primer consists of an acidic monomer in water, and the RealSeal points are composed of polyester polymers, methacrylate resin, bioactive glass, and radiopaque fillers. The sealer consists of BisGMA, UDMA, EBPADMA, PEGDMA, silane-treated barium borosilicate glasses, peroxide, amines, pigment, stabilizers, barium sulfate, silica, bismuth oxychloride, calcium hydroxide, and photo initiator. By removing the smear layer with EDTA as the final step in canal preparation, the dentinal tubules are exposed to the primer (Figure 5). Once the self-etch primer has been applied, a monoblock layer is created when the RealSeal is inserted (Figure 6). This results in a bonded obturation with a contiguous structure from within the dentinal tubules to the core of the obturating material, with true sealing off of the canal possible where the primer and RealSeal contact the desmeared dentin of the canal wall. RealSeal is highly opaque and nontoxic. RealSeal can be handled almost identically to gutta percha. It can be used with a lateral or vertical condensation technique, can be compacted, and can be used in an Obtura gun (Spartan Obtura, Fenton, MO) and injected into the canal instead of used as points. An Elements Obturation Unit (SybronEndo, Orange, CA) can be used to heat the material and place it, using disposable cartridges and the SystemB obturating technique. Figure 7. Elements Obturation Unit 4

5 Since handling Resilon is essentially the same as handling gutta percha, this removes the need to learn a new technique. RealSeal (Resilon ) has been found in a number of studies to reduce microleakage in comparison to gutta percha and several different sealers, including AH Plus Based on the author s clinical experience as well as evidence in the literature, use of RealSeal offers good clinical success rates. 20 In addition to improved sealing ability and the potential for reduced microleakage, resin sealers may offer the potential for increased resistance to root fracture. There are conflicting reports in the literature. Texeira et al. found that RealSeal (Resilon ) offers superior resistance to root fracture compared to gutta percha using a vertical or lateral condensation technique. 21 A second study found that both RealSeal (Resilon ) and EndoREZ increased resistance to vertical fracture. 22 Other studies, however, have found no improvement or reduced fracture resistance compared to more traditional obturating materials Carrier-Based Obturation Carrier-based obturation materials provide a vehicle for delivery of the root canal filling material in one step. These materials are either delivered cold or thermosoftened. It has been claimed that using a carrier-based system is easier than using other obturation techniques, although this may be due to individual variations, experience, and preferences. Irrespective of the method of obturation, appropriate cleaning and shaping of the root canal(s) will determine both the success and ease of obturation for a given canal. Products that fall under the carrier-based category include Densfil (Dentsply, Maillefer N.A., Tulsa, OK), Pro- System GT Obturators (Dentsply, Tulsa Dental, Tulsa, OK), Soft-Core (Soft-Core Texas, Inc., North Richland Hills, TX), Successfil (Hygienic-Coltene-Whaledent, Inc., Akron, OH), and Simplifill (Discus Dental, Culver City, CA). All these carrier-based systems utilize gutta percha and, with the exception of Simplifill, involve thermosoftening of the gutta percha with the carrier remaining in the canal as an integral part of the obturating material. SimpliFill is a cold carrier and involves removing the carrier after it has been used as a delivery vehicle for the obturation material. Simplifil is used after preparing the canal(s) with LightSpeed instruments (Discus Dental) and matching the carrier to the file used to working length. Only the apical portion of the carrier has a coating of gutta percha or Resilon. This technique can be used with a conventional sealer or a resin-based sealer such as RealSeal or EndoREZ. Stein et al. found that a technique using a Simplifill/gutta percha master cone resulted in no apical dye leakage in in vitro testing. 26 Thermafil The original Thermafil was introduced in the United States as a metal carrier coated with gutta percha. Contemporary Thermafil is available under the name Thermafil Plus and has a flexible plastic carrier. Thermafil Plus is available in a variety of tapers, lengths, and tip sizes. Both the old metal and new plastic carrier systems have been found to be biocompatible, and equivalent in microleakage testing Thermafil (Figure 8) is used by first ascertaining the required length of the carrier for the canal, using the mm markers to set it to this length. The carrier is then heated in the heater and placed into the canal. Insertion of the carrier should take less than 10 seconds to optimize obturation and avoid reduced fill of the canal. Levitan et al. found that a rate of insertion of 18 mm/second resulted in overextension (extrusion) of the fill, while underfill resulted from a rate of insertion of 3 mm/ second. In general, the length of fill decreased with decreasing speed of insertion. 31 Insertion without twisting is important to avoid removal of the thermoplasticized gutta percha from the core. 32 One potential disadvantage is denudation of the core with stripping and removal of the gutta percha coating. 33 This would result in voids and inadequate filling of the root canal that may not be visible on a radiograph. Figure 8. Thermafil carrier A number of studies have found Thermafil superior to a lateral condensation technique, while other studies have found the lateral condensation technique superior. 34 Two studies compared speed of obturation and found Thermafil to be the quicker of the two techniques, while a third found no difference in the time taken Similarly conflicting results have been found across studies comparing Thermafil to warm thermoplastic obturation techniques. Apical extrusion of Thermafil during obturation is found with its use. 38 As with other carrier-based systems, care must be taken to avoid extrusion. The increased in temperature at the root surface using Thermafil for obturation has been found to be up to 4.87 C, depending on the root surface measured, and it has been concluded that use of Thermafil would not result in damage to the periodontium. 39 Bonding adhesive resin technology cannot be used to adhere to Thermafil. Successfil Successfil utilizes a syringe system, with the pre-measured carrier length inserted into the syringe prior to extrusion of 5

6 the gutta percha onto the carrier and subsequent insertion into the canal and completion of obturation. This technique offers flexibility with respect to the shape and amount of gutta percha extruded onto the carrier. Endodontic Retreatment Endodontic (non-surgical) retreatment is necessary if apical periodontitis recurs. If obturation involved the use of retained carriers, the carrier must be removed together with the sealer and gutta percha coating. For Thermafil, this can be achieved using heat or a solvent to soften the gutta percha, then a rotary nickel titanium file. If Thermafil Plus was used, solvent can be used for the plastic core instead of a rotary file, provided the carrier was at a minimum size 45. With smaller-diameter Thermafil (sizes 40 and below), the carriers are mechanically removed. An in vitro study assessing mechanical removal of size 30 Thermafil carriers from mandibular molar root canals found that removal took 1 minute and 28 seconds using size 25 tapered files at 1500 rpm. 40 Whether or not a carrier-based technique is used, gutta percha and sealer must be completely removed and the canals recleaned and reshaped during nonsurgical retreatment. Standard gutta percha can be removed using heat, solvents, or files, or a combination of these. Carrier-Based Resin-Bonded Obturation: RealSeal One Until recently, no carrier-based system existed that would enable the use of bonding adhesive technology. With the introduction of RealSeal One Bonded Obturators (RSOne), a carrier-based bonded obturating material is available (Figure 9). RSOne contains a radiopaque core of polysulfone coated with RealSeal. Since the RSOne is one injection-molded unit, the core is always centered in the obturating point. This enables placement with the core centered and an even layer of RealSeal available around it to bond to the sealer- as with other techniques, care must still be taken to place the carrier centrally in the canal. Only methacrylate sealer can be used all other sealers are contraindicated. RSOne should be used with RealSeal SE self-etch dual cure resin sealer. Figure 9. RealSeal One The final prepared canal should be tapered appropriately from the orifice to the minor constriction in a manner that optimizes irrigation and obturation but does not put the root at risk of vertical fracture or other iatrogenenic events. The selected Size Verifier should have a passive and loose fit and match the size of the last file used to working length. The sealer is placed as a thin film using a paper point or suitable root canal instrument. The film of sealer must be thin enough to enable complete seating of the RealSeal One point. The sealer s bond strength is reduced in the presence of sodium hypochlorite or peroxide. It is therefore key that the last step in canal preparation should be to use EDTA followed by sterile water to remove any traces of these and the smear layer. The use of alcohol should also be avoided, as it would dry out the canal RealSeal (Resilon ) is hydrophilic, and a slightly moist canal is required for optimal bonding strength and sealing of methacrylate resin sealers. RSOne is heated by placing it in the RealSeal oven, with the handle on top of the holder and the rubber stop below the holder. After the obturator is heated for the appropriate length of time (30 to 75 seconds, depending on its width), it must be placed in the canal within 6 seconds before it cools to enable complete placement. If the canal is short, it is possible to trim the coronal portion to match the length of the RealSeal to the length of the root canal. If a multi-canal tooth is being treated, placing a paper point or cotton wool pledget over the other canals that still require obturation will prevent the excess material from entering these canals. As with all obturation techniques, upon completion, a radiograph is taken to check the obturation. If the canal is completely filled, as long as the coating material obturated the canal to the working length even if the core of the obturator did not, obturation is complete. Conversely, if the radiograph shows incomplete fill, the obturating material should be removed, files used to reclean the canal, and the obturation reworked. Upon completion of obturation, light curing of the external surface of the RSOne will provide a coronal seal of up to 1 mm depth; the material in the length and depth of the canals will take approximately 45 minutes to completely cure. Should retreatment be necessary, the obturation material, including the core, can be removed using solvent. The core can be dissolved in up to 8 minutes. One set of in vitro tests found that dissolution occurred in 1-3 minutes. Under laboratory conditions, the average time required to retreat a canal that had been obturated using RSOne was 6.23 minutes. 41 The obturating material can be removed by using the solvent or a small amount of chloroform and rotary and Hedstrom files. A recent in vitro study comparing the use of RSOne, Thermafil with sealers (Securaseal), and Onestep with Securaseal found that RSOne resulted in significantly less microleakage; under the conditions of the test, only 6

7 RSOne demonstrated adequate sealing ability at 90 days. It was concluded that the new material had excellent sealing ability under test conditions. 42 It can be expected that RSOne will provide the same benefits as RealSeal and Resilon, with the potential for reduced microleakage, and a monoblock bonded obturation of the root canal(s). The cases below show the clinical results using carrierbased bonded obturation. Clinical Cases Figure 10. Upper first molar treated with RealSeal One Bonded Obturator Figure 11. Lower first molar treated with RealSeal One Bonded Obturator Figure 12. Upper second bicuspid treated with RealSeal One Bonded Obturator Summary The science and practice of endodontic therapy have changed dramatically with the introduction of evidencebased and validated protocols along with highly advanced techniques and materials. Regardless of the method and materials used, appropriate cleaning and shaping of the canal and removal of the smear layer are required prior to obturation. Root canal obturation should provide an apical and coronal seal and should seal all lateral and accessory canals. Gutta percha together with a root canal sealer has been the obturation material of choice and has a long history of use. Gutta percha is unable to bond to adhesive sealer materials that offer the ability to provide a bonded seal to the root canal dentin to reduce microleakage and recontamination. Bonded root canal sealers and fillers are available as methacrylate resins. Paralleling materials developments, vehicles for the delivery and placement of obturating materials have also evolved, with numerous methods available, including heat, injection, vibration, compaction, ultrasonics, and carrier-based systems. The introduction of a methacrylate-based obturator has resulted in the availability of a carrier-based obturation material that utilizes adhesive technology for obturation and sealing of the root canals. References 1 Grossman LI. Endodontics : a bicentennial history against the background of general dentistry. J Am Dent Assoc Jul;93(1): Mounce R, Glassman G. Bonded Endodontic Obturation: Another Quantum Leap Forward for Endodontics. Oral Health; 2004 Jul; Clark-Holke D, Drake D, Walton R, Rivera E, Guthmiller JM. Bacterial penetration through canals of endodontically treated teeth in the presence or absence of the smear layer. J Dent May;31(4): Hommez GM, Coppens CR, De Moor RJ. Periapical health related to the quality of coronal restorations and root fillings. Int Endod J Aug;35(8): Siqueira JF Jr., Rôças IN, Alves FR, Campos LC. Periradicular status related to the quality of coronal restorations and root canal fillings in a Brazilian population. Oral Surg Oral Med Oral Pathol Oral Radiol Endod Sep;100(3): Hommez GM, Coppens CR, De Moor RJ. Periapical health related to the quality of coronal restorations and root fillings. Int Endod J Aug;35(8): Epley SR, Fleischman J, Hartwell G, Cicalese C. Completeness of root canal obturations: Epiphany techniques versus gutta-percha techniques. J Endod Jun;32(6): Trope M, Chow E, Nissan R. In vitro endotoxin penetration of coronally unsealed endodontically treated teeth. Endod Dent Traumatol Apr;11(2): Chailertvanitkul P, Saunders WP, Saunders EM, MacKenzie D. An evaluation of microbial coronal leakage in the restored pulp chamber of root canal treated multirooted teeth. Int Endod. J 1997 Sept;30(5):

8 10 Torabinejad M, Ung B, Kettering JD. In vitro bacterial penetration of coronally unsealed endodontically treated teeth. J. Endod Dec; 16(12): Saunders WP, Saunders EM. Assessment of leakage in the restored pulp chamber of endodontically treated multirooted teeth. Int. Endod J Jan;23(1): 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: Barrieshi KM, Walton RE, Johnson WT, Drake DR. Coronal leakage of mixed anaerobic bacteria after obturation and post space preparation. Oral Surg 1997;84: Ørstavik D, Kerekes K, Eriksen HM. Clinical performance of three endodontic sealers. Endod Dent Traumatol. 1987;3: Zmener O, Pameijer CH. Clinical and radiographical evaluation of a resin-based root canal sealer: a 5-year followup. J Endod. 2007;33: Shipper G, Ørstavik D, Teixeira FB, Trope M. An evaluation of microbial leakage in roots filled with a thermoplastic synthetic polymer-based root canal filling material (Resilon). J Endod May;30(5): Maltezos C, Glickman GN, Ezzo P, He J. Comparison of the sealing of Resilon, Pro Root MTA, and Super-EBA as root end filling materials: a bacterial leakage study. J Endod Apr;32(4): Stratton RK, Apicella MJ, Mines P. A fluid filtration comparison of gutta-percha versus Resilon, a new soft resin endodontic obturation system. J Endod Jul;32(7): Veríssimo DM, do Vale MS, Monteiro AJ. Comparison of apical leakage between canals filled with gutta-percha/ah- Plus and the Resilon/Epiphany System, when submitted to two filling techniques. J Endod Mar;33(3): Debelian G. Treatment outcome of teeth treated with an evidence-based disinfection protocol and filled with Resilon. J Endod. 2006;32: Abstract #PR4. 21 Teixeira FB, Teixeira EC, Thompson JY, Trope M. IADR/ AADR/CADR 82nd General Session, March 10-13, Hammad M, Qualtrough A, Silikas N. Effect of new obturating materials on vertical root fracture resistance of endodontically treated teeth. J Endod Jun;33(6): Epub 2007 Apr Ribeiro FC, Souza-Gabriel AE, Marchesan MA, Alfredo E, Silva- Sousa YT, Sousa-Neto MD. Influence of different endodontic filling materials on root fracture susceptibility. J Dent Jan;36(1): Ulusoy OI, Genç O, Arslan S, Alaçam T, Görgül G. Fracture resistance of roots obturated with three different materials. Oral Surg Oral Med Oral Pathol Oral Radiol Endod Nov;104(5): Ungor M, Onay EO, Orucoglu H. Push-out bond strengths: the Epiphany-Resilon endodontic obturation system compared with different pairings of Epiphany, Resilon, AH Plus and gutta-percha. Int Endod J Aug;39(8): Stein KE, Manfra Marretta S, Siegel A, Vitoux J. Comparison of hand-instrumented, heated gutta-percha and enginedriven, cold gutta-percha endodontic techniques. J Vet Dent. 2004;21(3): Chu CH, Lo EC, Cheung GS. Outcome of root canal treatment using Thermafil and cold lateral condensation filling techniques. Int Endod J Mar;38(3): Sutow EJ, Foong WC, Zakariasen KL, Hall GC, Jones DW. Corrosion and cytotoxicity evaluation of Thermafil endodontic obturator carriers. J Endod Aug;25(8): Chohayeb AA. Microleakage comparison of apical seal of plastic versus metal Thermafil root canal obturators. J Endod Dec;18(12): Levitan ME, Himel VT, Luckey JB. The effect of insertion rates on fill length and adaptation of a thermoplasticized gutta-percha technique. J Endod (8): Ibid. 33 Rapisarda E, Bonaccorso A, Tripi TR. Evaluation of two root canal preparation and obturation methods: the McSpadden method and the use of ProFile-Thermafil. Minerva Stomatol. 1999;48(1-2): (Italian) 34 Mounce R, McCarty D. Thermafil: A review of the clinically relevant literature. Endod. Pract Sept; Dummer PM, Lyle L, Rawle J, Kennedy JK. A laboratory study of root fillings in teeth obturated by lateral condensation of gutta percha or Thermafil obturators. Int Endod J (1): Gulabivala K, Holt R, Long B. An in vitro comparison of thermoplasticized gutta percha obturation techniques with cold lateral condensation. Endod. Dent Traumatol (6): Scott AC, Vire DE, Swanson R. An evaluation of the Thermafil endodontic obturation technique. J Endod (7): Robinson MJ, McDonald NJ, Mullally PJ. Apical extrusion of thermoplasticized obturating material in canals instrumented with Profile 0.06 or Profile GT. J Endod (6): Behnia A, McDonald NJ. In vitro infrared thermographic assessment of root surface temperatures generated by the thermafil plus system. J Endod. 2001;27(3): Royzenblat A, Goodell GG. Comparison of removal times of Thermafil plastic obturators using ProFile rotary instruments at different rotational speeds in moderately curved canals. J Endod. 2007;33(3): Data on file. 42 Gambarini G. Sealing ability of a new obturating material: Epiphany one with Resilon carrier technology.e Sapienza Universita de Roma Author Profile Richard E. Mounce, DDS Dr. Mounce lectures globally and is widely published. He is in private practice in Endodontics in Vancouver, WA, USA. He can be reached at RichardMounce@ MounceEndo.com. Disclaimer The author(s) of this course is a consultant for SybronEndo, the sponsors or the providers of the unrestricted educational grant for this course. Reader Feedback We encourage your comments on this or any PennWell course. For your convenience, an online feedback form is available at 8

9 Notes 9

10 1. Root canal treatment in the mid-1700s included the use of. a. worms b. pulpal cauterization c. sea salt 2. The final step in endodontic therapy is root canal obtura tion. 3. The objective of obturation includes. a. attaining apical and coronal seals b. sealing lateral and accessory canals c. filling all pathways from the root canal system to the surrounding periodontal ligament d. all of the above 4. Inadequate coronal restoration subsequent to endodontic therapy is one of the factors in endodontic failure. 5. The standard for root canal obturation has been. a. silver points with use of a sealer b. gutta percha alone c. gutta percha combined with use of a sealer 6. Advantages of gutta percha include its. a. biocompatibility b. ready availability c. technique flexibility d. all of the above 7. Gutta per cha provides a seal for root canal obturation. 8. AH Plus is resin based. a. methacrylate b. epoxy c. ethacrylate 9. Ideally, if a resin-based sealer is used, it should also be able to bond to the selected root canal obturating material. 10. Both epoxy resin and meth acrylate resin sealers can be bonded to gutta percha. 11. Removing the dentin smear layer with EDTA as the final step in canal preparation exposes the to the primer. a. enamel b. dentinal tubules c. gutta percha Questions 12. Methacrylate-based resin can be used with a lateral or vertical condensation technique. 13. There are conflicting reports on whether or not methacrylate resin sealers may offer the potential for increased resistance to root fracture. 14. Carrier-based obturation materials. a. have yet to be developed b. provide a vehicle for delivery of EDTA for smear layer removal c. provide a vehicle for delivery of the root canal filler in one step 15. The ease of use experienced using a carrier-based system may be due to. a. individual variations b. experience c. preferences d. all of the above 16. All carrier-based systems utilize gutta percha. 17. Irre spective of the method of obturation, appropriate cleaning and shaping of the root canal(s) will determine success for a given canal. 18. All carrier-based systems involve the carrier remaining in the canal as an integral part of the obturating material. 19. When using Thermafil Plus, insertion of the carrier taking less than 10 seconds optimizes obturation. 20. Plastic-core carrier systems have been found to be biocompat ible. 21. If endodontic retreatment is necessary, and obturation involved the use of a carrier-based system, the carrier. a. can be left in position as long as the sealer and coating are carefully removed b. must be removed together with the sealer and coating c. should be ultrasonically removed in all cases d. b and c 22. A methacrylate-based resin carrierbased system exists, enabling the use of. a. lead-based sealer b. bonding adhesive technology c. silver points 23. Endodontic (nonsurgical) retreatment is necessary if apical periodontitis recurs. 24. Standard gutta percha can be removed using heat, solvents, or files, or a combination of these. 25. The bond strength of the sealer used with methacrylate-based carriers is reduced in the presence of. a. sodium hypochlorite b. peroxide c. moisture d. a and b 26. The use of alcohol to dry out the canal is optimal for bond strength and sealing of methacrylate resin sealers. 27. Methacrylate-based, carrier-based obturating material cures in approximately minutes of placement into the canal(s). a. 15 b. 30 c. 45 d The science and practice of endodontic therapy have changed dramatically with the introduction of evidence-based validated protocols, along with highly advanced techniques and materials. 29. Vehicles for the delivery and placement of obturating materials have evolved to include. a. heat b. carrier-based systems c. injection d. all of the above 30. Bonded root canal sealers and fillers are available as. a. epoxy resins b. methacrylate resins c. acrylic d. all of the above 10

11 ANSWER SHEET Current Philosophies in Root Canal Obturation Name: Title: Specialty: Address: City: State: ZIP: Country: Telephone: Home ( ) Office ( ) Requirements for successful completion of the course and to obtain dental continuing education credits: 1) Read the entire course. 2) Complete all information above. 3) Complete answer sheets in either pen or pencil. 4) Mark only one answer for each question. 5) A score of 70% on this test will earn you 4 CE credits. 6) Complete the Course Evaluation below. 7) Make check payable to PennWell Corp. Educational Objectives 1. Know the main factors influencing endodontic success 2. Know the advantages and concerns around the use of gutta percha 3. Know the options available for root canal obturation and how these differ 4. Know the characteristics of recently introduced carrier-based obturators and their clinical application Course Evaluation Please evaluate this course by responding to the following statements, using a scale of Excellent = 5 to Poor = Were the individual course objectives met? Objective #1: Yes No Objective #3: Yes No Objective #2: Yes No Objective #4: Yes No 2. To what extent were the course objectives accomplished overall? Please rate your personal mastery of the course objectives Mail completed answer sheet to Academy of Dental Therapeutics and Stomatology, A Division of PennWell Corp. P.O. Box 116, Chesterland, OH or fax to: (440) For immediate results, go to to take tests online. Answer sheets can be faxed with credit card payment to (440) , (216) , or (216) Payment of $59.00 is enclosed. (Checks and credit cards are accepted.) If paying by credit card, please complete the following: MC Visa AmEx Discover Acct. Number: Exp. Date: Charges on your statement will show up as PennWell 4. How would you rate the objectives and educational methods? How do you rate the author s grasp of the topic? Please rate the instructor s effectiveness Was the overall administration of the course effective? Do you feel that the references were adequate? Yes No 9. Would you participate in a similar program on a different topic? Yes No 10. If any of the continuing education questions were unclear or ambiguous, please list them. 11. Was there any subject matter you found confusing? Please describe. 12. What additional continuing dental education topics would you like to see? AGD Code 074 PLEASE PHOTOCOPY ANSWER SHEET FOR ADDITIONAL PARTICIPANTS. AUTHOR DISCLAIMER The author(s) of this courseis a consultant for the sponsors or the providers of the unrestricted educational grant for this course. SPONSOR/PROVIDER This course was made possible through an unrestricted educational grant from SybronEndo. No manufacturer or third party has had any input into the development of course content. All content has been derived from references listed, and or the opinions of clinicians. Please direct all questions pertaining to PennWell or the administration of this course to Machele Galloway, 1421 S. Sheridan Rd., Tulsa, OK or macheleg@ pennwell.com. COURSE EVALUATION and PARTICIPANT FEEDBACK We encourage participant feedback pertaining to all courses. Please be sure to complete the survey included with the course. Please all questions to: macheleg@pennwell.com. INSTRUCTIONS All questions should have only one answer. Grading of this examination is done manually. Participants will receive confirmation of passing by receipt of a verification form. Verification forms will be mailed within two weeks after taking an examination. EDUCATIONAL DISCLAIMER The opinions of efficacy or perceived value of any products or companies mentioned in this course and expressed herein are those of the author(s) of the course and do not necessarily reflect those of PennWell. Completing a single continuing education course does not provide enough information to give the participant the feeling that s/he is an expert in the field related to the course topic. It is a combination of many educational courses and clinical experience that allows the participant to develop skills and expertise. COURSE CREDITS/COST All participants scoring at least 70% (answering 21 or more questions correctly) on the examination will receive a verification form verifying 4 CE credits. The formal continuing education program of this sponsor is accepted by the AGD for Fellowship/Mastership credit. Please contact PennWell for current term of acceptance. Participants are urged to contact their state dental boards for continuing education requirements. PennWell is a California Provider. The California Provider number is The cost for courses ranges from $49.00 to $ Many PennWell self-study courses have been approved by the Dental Assisting National Board, Inc. (DANB) and can be used by dental assistants who are DANB Certified to meet DANB s annual continuing education requirements. To find out if this course or any other PennWell course has been approved by DANB, please contact DANB s Recertification Department at FOR-DANB, ext RECORD KEEPING PennWell maintains records of your successful completion of any exam. Please contact our offices for a copy of your continuing education credits report. This report, which will list all credits earned to date, will be generated and mailed to you within five business days of receipt. CANCELLATION/REFUND POLICY Any participant who is not 100% satisfied with this course can request a full refund by contacting PennWell in writing by the Academy of Dental Therapeutics and Stomatology, a division of PennWell END0810DE 11