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Single point gutta perchaobturation using a tricalciumsilicate endodontic sealerRandall G. Cohen, DDS

Lateral condensation and vertical compactionof gutta percha has been in wide use in performingendodontic obturation for decades. Historicallythis compression of gutta percha has beennecessary because the sealers were themselvesinadequate. They were hydrophobic, dimensio-nally unstable, not biocompatible, are susceptibleto degradation, and irritating to periodontal tissueif extruded beyond the apex. Accordingly, thesecondensation techniques (lateral, vertical compac-tion, and warmed carrier based) were developedin order to minimize the sealer volume. It wasacknowledged that more sealer meant moreshrinkage, more leakage and more irritation, sotechniques were developed to minimize thethickness of the sealer. In this article, the author reviews the goals forendodontic treatment and the main obturation

methods. Then, a simplified technique will bedescribed that utilizes a single gutta perchapoint with a new sealer material that overcomesthe deficiencies of the older generations of endo-dontic sealers.

Goals of endodontic therapy

The endodontic triad of biochemical preparation,microbial control and complete obturation ofthecanal forms the basis for endodontic therapy.1

The pulp space, chamber and canal must bethoroughly debrided of tissue and properlyshaped. This is done by both mechanical andchemical means and when completed, leaves acanal that is free of infection and is ready forobturation.

Introduction

1 Cohen S, Hargreaves K. Pathways of the Pulp 9th ed. Mosby, St. Louis, MO, 2006.

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A good root canal seal entombs any residualbacteria so that they are deprived of their foodsupply and are unable to replicate. In addition,the fill material should be antimicrobial so that itdoes not support further bacterial growth. It isalso important to seal off the canal from the oralcavity and from the periapical region so thatnew bacteria do not cause reinfection. To accomplish these objectives we use guttapercha, a solid core material that has the desiredproperties of being non-resorbable, has minimalreactivity with the host tissues, is well toleratedby the body, dissolves in solvents when necessaryand is dimensionally stable.The other component to the endodontic seal isthe sealer cement that functions with the guttapercha, the requirements of which are as follows:

1. Easily introduced into the canal2. Should seal laterally as well as apically3. Should not shrink after being inserted4. Should be impervious to moisture5. Should be bacteriostatic6. Should be radiopaque7. Should not stain tooth structure8. Should not irritate periapical tissues9. Should be easily sterilized immediately beforeinsertion

10. Should be easily removed from the endodonticsystem if necessary.2

Current obturation techniques

There are several current techniques for obturatingthe root canal, all of which employ gutta percha.The first is called Cold LateralCondensation where theoperator has traditionallytapered the canal by way ofa “step back” preparation.The master cone is coatedwith sealer and fitted to length,and then using a spreader,the operator condenses anumber of accessory guttapercha points until he or shebelieves that the remaining

space between the master cone and the canalwalls is fully obliterated. Another method is Vertical Compaction firstdescribed by Schilder3 where a master guttapercha cone is fitted to length, coated withsealer and inserted into the canal. The originalmethod involved heating up a plugger to cherryred then quickly stabbing it into the gutta perchamass leaving behind thermoplastic material thatis condensed with a plugger. This method hasbeen shown to generate hydraulic forces thatcan fill lateral canals as well as the irregularitieswithin the root canal system. The coronal twothirds of the master cone come out when thehot instrument is withdrawn, forming a solidapical plug so that backfilling with softenedgutta percha through an extrusion mechanismis controlled. Many advances have occurredconcerning this technique, however, it is stilldifficult to accomplish with many of the problemsassociated with lateral condensation. One issueis the need to get the hot pluggerto within 4 mm from the apex,necessitating the removal ofexcessive amounts of dentin inthe coronal two thirds of thecanal. Other drawbacks include lackof homogeneity, a high propor-tion of endodontic sealer at theapex, poor adaption to canalwalls and apical extrusion ofgutta percha.4

Of vital importance to the long term survivabilityof the tooth is the strategic preservation of thecoronal dentin of the canal. This translates tomaking not only as small an endodontic openinginto the chamber and the canal as possible, butalso in respecting this coronal dentin when crea-ting the final restoration. Unfortunately both ofthese obturation methods tend to result in canalpreparations that take away too much coronaldentin and create a weakness in the structure ofthe tooth.

2 Cohen S, Hargreaves K. Pathways of the Pulp 9th ed. Mosby, St. Louis, MO, 2006.3 Schilder H. Filling root canals in three dimension, Dent Clin of North Amer 1967;723-44.4 Tasdemir T, Er K, Yildirim T, Buruk K, Çelik D, Cora S, et al. Comparison of the Sealing Ability of Three Different Techniques in Canals Shapedwith Two Different Rotary Systems:a Bacterial Leakage Study Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2009 Sep;108(3):e129-34.

Fig. 1: Lateralcondensation.

Fig. 2

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The patient, a 68 year old female came to theoffice complaining of pain and tenderness inthe lower left quadrant. She stated that shewas taking Augmentin (antibiotic) as prescribedby her physician. The x-ray revealed a periapicallucency and a diagnosis of periapical abscesswas made for tooth #20.The canal was accessed and shaped to a #30.06taper. Disinfection was accomplished with a5% solution of sodium hypochlorite. The canalwas flushed with anesthetic solution (Septocaine,Septodont) and followed with an EDTA/chlo-rhexidine rinse. After another rinse with anestheticsolution the canal was left to soak with 5% sodiumhypochlorite. The fit and length of the #30.06master gutta percha point was verified, then the

Clinical Cases

Single cone obturation

Recently there has been an increase in the useof only the master cone, es-pecially in the casesof larger cones with the larger taper sizes thatbest match the geometry of rotary nickel-titaniumsystems (NiTi.)5 This system does not requireaccessory points, lateral condensation, or warmedvertical compaction. Rather, the canals areshaped with the rotary NiTi files and filled with amaster gutta percha cone that matches the lastinstrument used. This combi-nation of the single cone withthe appropriate endodonticsealer results in a uniformmass which prevents failuresoccurring around multiplecones. This technique takesless time when used with therotary NiTi instruments, resultsin less operator fatigue, iseasier on the patient andeliminates lateral pressure onthe root.

Endodontic instrumentation

The use of NiTi rotary instrumentation sets thecase up for a simplified obturation of the canalby enabling the insertion of a snugly fitting asingle gutta percha point (corresponding to thelast instrument used) to length. When this tech-nique is employed with a bioactive, biocompatible,non-shrinking sealer, the requirements for asuccessful preparation, disinfection, shapingand seal are met, avoiding the indiscriminateremoval of dentin and leading to a higher longterm success rate.

The tricalcium silicate endodonticsealer

A tricalcium silicate endodontic sealer,BioRoot™ RCS (Septodont, Inc.) incorporatesmany improvements over the older materials.Its alkaline pH (imparting antibac-terial properties)calcium ion release, and suitable radiopacityand flow characteristics are indeed an advanceover earlier formulations. This sealer is dimen-sionally stable, biocompatible, hydrophilic,stimulates bone growth, and will provide a reliabledentin bond to the radicular dentin.

Fig. 3: Single conetechnique.

5 Pereira CA, et. al: Single-Cone Obturation Technique:a literature review. RBSO Oct-Dec 9(4):442-7 2012.

Fig. 1: Pre-Op View; Note periradicular lesion.

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Successful endodontics requires the completedebridement (mechanically and chemically) ofthe root canal plus a smooth, tapered shapingso to set the case up for its final seal.Endodontic sealers have had their shortcomingssuch as shrinkage, degradation, and tissue irri-tation. Accordingly, the traditional methods ofobturating canals involve compressing the solidcore aspect of the fill (gutta percha) so todisplace as much of the endodontic sealer aspossible. Unfortunately these obturation methodscan be time consuming, operator dependent,fatiguing to the patient and to the clinician, andpotentially hazardous in that they might causea fracture of a root due to the pressure exerted. A new method has come into practice whichinvolves the use of a single master gutta perchapoint in conjunction with a tricalcium silicate

sealer that overcomes the problems that wereassociated with earlier materials. This tricalciumsilicate sealer is antimicrobial, anti-inflammatory,bonds to dentin, and remains dimensionallystable, so that it better meets the stated objectivesof root canal sealer materials. According, it isnot necessary to use substantial force to compactthe gutta percha into the prepared canal, sincethis sealer will fill voids and prevent bacterialcolony formation. Since this sealer neither shrinksnor degrades, micro leakage is prevented apicallyand coronally. Also, the gutta percha used inthis technique slides consist-ently to length thusmaking obturation simpler and less likely toresult in a root fracture. In addition, not havingto create excessive taper strengthens the toothby preserving the coronal dentin of the rootcanal preparation.

Discussion

sealer cement ( BioRoot™ RCS, Septodont, Inc)was mixed according to manufacturer’s directions.The canal was then thoroughly dried using paperpoints and the master gutta percha point wasrolled in the sealer mix and inserted into thecanal to length, using the gutta percha to coatthe canal walls with BioRoot™ RCS sealer. Themaster cone was withdrawn, recoated, andinserted to length. The gutta percha was finishedat the level of the chamber with a hot plugger,and the seal was further refined using a #2 roundbur. (Fig. 1-4).

Fig. 2: Canal instrumented, gutta percha master cone fitted tolength.

Fig. 4: One year post-op showing complete periapical healing.

Fig. 3: Master cone coated with Bioroot™ RCS, cemented, and finished with a hot plugger at orifice.

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Author:Randall G. Cohen, DDSDr. Cohen has been in the practice of general, restorative dentistry with anemphsis on endodontics and surgery since graduating from Temple Universityin 1982.He is an instructor with the Alleman-Deliperi Center for Biomimetic Dentistry,and he has authored many papers and delivered lectures across the US.Dr. Cohen may be reached by writing to his emailbox : rgc7157@gmail.com.

When the canal is properly cleaned, dried, andshaped, a gutta percha mas-ter point that corres-ponds to the last instrument taken to the apexis coated with BioRoot™ RCS endodontic sealer,inserted to length, and finished with a hotplugger at the level of the canal orifice. Thismaterial and technique will meet the objectives

of good obturation by preventing recurrent infec-tion, avoiding procedural accidents, creating astable long lasting seal, and by preserving thecoronal dentin. Taken together, these methodswill preserve teeth longer, especially whencombined with a rational, tooth-conservingapproach to restorative dentistry.

Conclusion

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BioRoot™ RCSRoot Canal Sealer

High seal, and much more

BioRoot™ RCSRoot Canal Sealer

High seal, and much more

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