Root canal obturation timing materials and techniques

Dr. Silas M. TokaMDS I (PROS)

26th January, 2016

Root Canal Obturation: Timing, Materials and Techniques

IntroductionThe rationale for root canal treatment relies

on the fact that the non-vital pulp, being avascular, has no defence mechanisms.

Debridement of the canal is therefore necessary, followed by a sealing of the root canal system.

Endodontic Success Successful root canal treatment is based on

the following principles:1. Proper diagnosis and treatment planning2. Sound knowledge of anatomy and

morphology3. Thorough debridement and disinfection4. Hermetic* obturation5. Appropriate coronal restoration

Endodontic SuccessA meta-analysis of factors influencing the

efficacy of primary root canal treatment (Ng et al. 2008) found that the following four factors influenced success:the absence of a pre-treatment periapical

lesion, root canal fillings with no voids,obturation to within 2.0 mm of the apex, and an adequate coronal restoration .

Rationale for SealingThe complex anatomy of the apical delta of

many root canals makes complete debridement virtually impossible.

It is essential therefore that endodontic therapy must include sealing of the root canal system to prevent tissue fluids from percolating in the root canal and prevent toxic by-products from both necrotic tissue and micro-organisms form regressing into the periradicular tissue.

Purposed OutcomeObturation aims at achieving the following:

1. Prevention of percolation and microleakage of periapical exudate into the root canal space.

2. Achieving a hermetic seal that obliterates the apical foramen and all other portals of communication.

3. Creates a favourable environment to facilitate healing.

TIMING OF OBTURATION

Timing of ObturationFactors influencing the appropriate time to

obturate a tooth include:the patient’s signs and symptoms,status of the pulp and periradicular tissue,the degree of procedural difficulty, andpatient management /the number of

appointments anticipated.

Timing of ObturationVITAL PULP TISSUEAt present the consensus is that one-step

treatment procedures are acceptable when the patient exhibits a completely or partially vital pulp (Trope &Burgenholtz 2002).

Timing of ObturationVITAL PULP TISSUERemoval of the normal or inflamed pulp

tissue and performance of the procedure under aseptic conditions should result in a successful outcome because of the relative absence of bacterial contamination.

Obturation at the initial visit also precludes contamination as a result of leakage during the period between patient visits.

Timing of ObturationVITAL PULP TISSUEElective root canal treatment for restorative

reasons can be completed in one visit provided the pulp is vital, to some degree, and time permits.*

Timing of ObturationNECROTIC PULP TISSUEWhen patients present with acute

symptoms caused by pulp necrosis and acute periradicular abscess, obturation is generally delayed until the patient is asymptomatic.

Timing of ObturationNECROTIC PULP TISSUEWhereas cases with soft tissue swelling

could be completed in one visit with appropriate endodontic treatment, incision for drainage, and a regimen of antibiotics (Southard&Rooney 1984) , difficulties in management could ensue should problems persist or become worse after the completion of treatment.*

Timing of ObturationNECROTIC PULP TISSUEThere is conflicting data regarding the

success of endodontic treatment completed in one appointment for teeth with periapical pathology.

There however seems to be consensus that success is most often observed in teeth that had a negative culture before obturation, whether or not the treatment was done in one or two sittings (Molander et al. 2007).

Timing of ObturationNECROTIC PULP TISSUEControlled laboratory studies support the use of

calcium hydroxide as an antimicrobial agent before obturation of teeth with pulp necrosis (Katebzadeh et al. 1999,2000).

Radiographic examination at 6 months indicated complete healing was similar for the one-visit (35.3%) and calcium hydroxide (36.8%) groups.

The calcium hydroxide group, however, had fewer failed cases (15.8% vs. 41.2%) and more improved cases (47.4% vs. 23.5%) when compared with the one-visit group.

Timing of ObturationRECOMMENDATIONSObturation can be performed after cleaning

and shaping procedures when the canal can be dried and the patient is not experiencing swelling.

An exception is the presence or persistence of exudation from the canal.

Obturation of a canal that cannot be dried is contraindicated.

Timing of ObturationRECOMMENDATIONSComplete cleaning and shaping should be

accomplished and calcium hydroxide placed as an antimicrobial and temporary obturant in necrotic cases that cannot be treated in one visit (Sjögren et al. 1997).

Without this calcium hydroxide dressing, bacteria in instrumented, unfilled canals can multiply and reach their pretreatment numbers in 2 to 4 days (Byström &Sundqvist 1981).

Timing of ObturationRECOMMENDATIONSProcedural concerns also dictate the time of

obturation.Difficult cases may require more time for

preparation and can be managed more uneventfully in multiple appointments.

Patients may require multiple short appointments because of medical conditions, their psychologic state of mind, and fatigue.

MATERIALS USED FOR OBTURATION

TYPES OF SEALERSRoot canal sealers are necessary to seal

the space between the dentinal wall and the obturating core interface.

Sealers also fill voids and irregularities in the root canal, lateral and accessory canals, and spaces between gutta-percha points used in lateral condensation.

They also serve as lubricants during the obturation process.

Types of SealersIDEAL PROPERTIES (According to Grossman*)1. Exhibits tackiness when mixed to provide good

adhesion between it and the canal wall when set.

2. Establishes a hermetic seal3. Radiopaque, so that it can be seen on a

radiograph4. Very fine powder, so that it can mix easily with

liquid5. No shrinkage on setting6. No staining of tooth structure

Types of SealersIDEAL PROPERTIES (According to

Grossman)7. Bacteriostatic, or at least does not

encourage bacterial growth8. Exhibits a slow set9. Insoluble in tissue fluids10. Tissue tolerant; that is, nonirritating to

periradicular tissue11. Soluble in a common solvent if it is

necessary to remove the root canal filling

Types of Sealers1. ZINC OXIDE-EUGENOLThis sealer cement displays antimicrobial

activity and will be absorbed if extruded into the periradicular tissues.

They however exhibit a slow setting time, shrinkage on setting, are soluble and can stain tooth structure.

Types of Sealers1. ZINC OXIDE-EUGENOLBrands Available Earlier formulations stain teeth. Include:

1. Pulp Canal Sealer (SybronEndo) and Pulp Canal Sealer EWT (extended working time): Introduced by Rickert and Dixon.

2. Procosol (Procosol, Inc., Philadelphia, PA): modification of Rickert’s formula in which the silver particles have been removed (zinc oxide, hydrogenated resin, bismuth subcarbonate and barium sulfate; liquid eugenol).

Types of Sealers1. ZINC OXIDE-EUGENOLBrands AvailableGrossman modified the formulation and

introduced a non-staining formula in 1958.Formulation used in:

1. Roth’s Sealer (Roth International).2. Tubli-Seal (SybronEndo).3. Wach’s sealer (Balas Dental, Chicago, IL).

Zinc oxide Eugenol Based Endodontic Sealer Cement

Types of Sealers2. CALCIUM HYDROXIDE SEALERSCalcium hydroxide sealers were developed

to have antimicrobial activity and have osteogenic–cementogenic potential.

Unfortunately, these actions have not been demonstrated.

Solubility is required for release of calcium hydroxide and sustained activity.

This is inconsistent with the purpose of a sealer.

Types of Sealers2. CALCIUM HYDROXIDE SEALERSBrands AvailableInclude:

1. Sealapex (SybronEndo): a catalyst/base system.

2. Calciobiotic root canal sealer (CRCS) is a zinc oxide–eugenol sealer with calcium hydroxide as one ingredient.

3. Apexit and Apexit Plus (Ivoclar Vivadent, Schaan, Liechtenstein): consist of an activator (disalicylate, bismuthhydroxide/bismuth carbonate, and fillers) and a base (calcium hydroxide, hydrated colophonium, and fillers).

•Sealapex® By Kerr, is a base/catalyst system. •The base contains zinc oxide, calcium hydroxide, butyl benzene, sulfonamide, and zinc stearate.•The catalyst contains barium sulfate and titanium dioxide as radiopacifiers in addition to resin, isobutyl salicylate, and an aerosol R 972.

Types of Sealers3. NON-EUGENOL SEALERSBrands AvailableDeveloped from a periodontal dressing,

Nogenol (GC America, Alsip, IL) is a root canal sealer without the irritating effects of eugenol.

The base contains zinc oxide, barium sulfate, and bismuth oxychloride.

Types of Sealers4. GLASS IONOMER SEALERSGlass ionomers have been advocated for

use in obturation because of their dentine-bonding properties.

Types of Sealers4. GLASS IONOMER SEALERSBrands Availablei. Ketac-Endo (3M ESPE, Minneapolis, MN)

Enables adhesion between the material and the canal wall.

Has minimal antimicrobial activity.Drawbacks include:

Difficulty in treating dentinal walls in apical and middle thirds with preparatory bonding agents to receive the glass ionomer sealer.

Difficulty in removal if retreatment is required.

Types of Sealers4. GLASS IONOMER SEALERSBrands Availableii. Activ GP (Brasseler USA, Savannah, GA):

consists of a glass ionomer–impregnated gutta-percha cone with a glass ionomer external coating and a glass ionomer sealer. Available in .04 and .06 tapered cones, the sizes are

laser verified to ensure a more precise fit. The single cone technique is designed to provide a

bond between the dentinal canal wall and the master cone (monoblock).

Activ GP (Brasseler USA, Savannah, GA) glass ionomer–coated gutta-percha points and sealer.

Types of Sealers5. RESIN SEALERSResin sealers have a long history of use,

provide adhesion, and do not contain eugenol.

Types of Sealers5. RESIN SEALERSBrands Availablei. AH Plus is an epoxy-bis-phenol resin that

comes in two tubes. It exhibits a working time of approximately 4

hours.

AH Plus sealer is a resin formulation. (Courtesy DENTSPLY, Konstanz, Germany)

Types of Sealers5. RESIN SEALERSBrands Availableii. EndoREZ (Ultradent Products, South

Jordon, UT) is a methacrylate resin with hydrophilic properties.

When used with EndoREZ resin-coated gutta-percha cones the dual cure EndoREZ sealer bonds to both the canal walls and the core material.

Types of Sealers5. RESIN SEALERSBrands Availableiii. Diaket, a polyvinyl resin (3M ESPE),

consists of a powder composed of bismuth phosphate and zinc oxide and a liquid consisting of dichlorophen, triethanolamine, propionylacetophenone, and copolymers of vinyl acetate, vinyl chloride, and vinylisobutyl ether.

The material appears to be biocompatible.

Types of Sealers5. RESIN SEALERSBrands Availableiv. Other resin-based sealers, Epiphany

(Pentron Clinical Technologies, Wallingford, CT) and RealSeal (SybronEndo), have been introduced for use with a new core material, Resilon (Pentron Clinical Technologies).

Advocates of these sealers propose that they bond to the canal wall and to the core material to create a “monoblock”.

Types of Sealers6. SILICONE SEALERSBrands Availablei. RoekoSeal (Coltène/Whaledent,

Germany) is a polyvinylsiloxane that has been reported to expand slightly on setting.

Types of Sealers6. SILICONE SEALERSBrands Availableii. GuttaFlow (Coltène/Whaledent) is a cold

flowable matrix that is triturated.It consists of gutta-percha added to

RoekoSeal.The material is provided in capsules for

trituration.The technique involves injection of the

material into the canal, followed by placement of a single master cone.

GuttaFlow trituration capsule and injection syringe (Coltène/Whaledent, Cuyahoga Falls, OH).

Types of Sealers6. SILICONE SEALERSBrands Availableii. GuttaFlow (Coltène/Whaledent):

Working time:15 minutes, Setting time: 25 to 30 minutes.

Fills canal irregularities with consistency and is biocompatible, but the setting time is inconsistent and may be delayed by final irrigation with sodium hypochlorite.

Sealing ability appears comparable to other techniques in some studies and inferior in others.

Types of Sealers7. BIOCERAMICBioceramic (BC) sealer is composed of

zirconium oxide, calcium silicates, calcium phosphate monobasic, calcium hydroxide, and various filling and thickening agents.

The material is available in a premixed syringe with calibrated intracanal tips.

Types of Sealers7. BIOCERAMICAs a hydrophilic sealer it utilizes moisture

within the canal to complete the setting reaction and it does not shrink on setting.

It is biocompatible and exhibits antimicrobial properties during the setting reaction.

The manufacturer advocates expressing the sealer into the coronal one third to one half of the canal and then seating the master gutta percha cone.

Types of Sealers8. MEDICATED SEALERSSealers containing paraformaldehyde are

strongly contraindicated in endodontic treatment.

AH-26 (the predecessor to AH Plus) is a slow-setting epoxy resin that was found to release formaldehyde when setting.

AH Plus is a modified formulation of AH-26 in which formaldehyde is not released.

Types of Sealers8. MEDICATED SEALERSA paste containing 6.5% paraformaldehyde

as well as lead and mercury was advocated for use and originally marketed as N-2.

Lead has been reported in distant organ systems when N-2 is placed within the radicular space (Oswald&Cohn 1975).

Types of Sealers8. MEDICATED SEALERSOther paraformaldehyde sealers include

Endomethasone, SPAD, and Reibler’s paste.Lentulo spiral use with these cements may

lead to overextensions.This has resulted in osteomyelitis,

paresthesia, irreversible neurotoxicity manifested as dysesthesia, in cases where paraformaldehyde pastes were forced through the apical foramen into the periapical tissues (Kleier&Averbach 1988, Erisen et al.1989).

CORE MATERIALSProperties of an Ideal Obturation

Material1. Easily manipulated and provides ample

working time.2. Dimensionally stable with no shrinkage

once inserted.3. Seals the canal laterally and apically,

conforming to its complex internal anatomy.4. Nonirritating to the periapical tissues.5. Impervious to moisture and nonporous.

CORE MATERIALSProperties of an Ideal Obturation Material6. Unaffected by tissue fluids—no corrosion or

oxidization.7. Inhibits bacterial growth.8. Radiopaque and easily discernible on

radiographs.9. Does not discolour tooth structure.10. Sterile.11. Easily removed from the canal if necessary.

Core Materials1. SILVER CONESIntroduced by Jasper E. in 1941.The rigidity provided by the silver cones

made them easy to place and permitted more predictable length control.

However, their inability to fill the irregularly shaped root canal system permitted leakage.

A B C

D

ESilver cones were advocated for ease of placement and length control. A. Radiograph of a maxillary right central

incisor obturated with a silver cone.B. Tissue discoloration indicating corrosion

and leakage.C. Lingual view indicates coronal leakage. D. Corroded silver cone removed from the

tooth.E. Post-treatment radiograph of the tooth.

Core Materials1. SILVER CONESCorrode when they contact tissue fluids or

saliva.Corrosion products are cytotoxic and either

produced pathosis or impede periapical healing.

The use of silver cones today is considered to be below the standard of care in contemporary endodontic practice.

Core Materials2. GUTTA PERCHAAdvantagesPlasticityEase of manipulationMinimal toxicityRadiopacityEase of removal with heat or solvents

Core Materials2. GUTTA PERCHADisadvantages3. Lack of adhesion to dentine.4. Shrinkage on setting;

Gutta-percha is the trans isomer of polyisoprene (rubber) and exists in two crystalline forms (α and β).

In the unheated β phase the material is a solid mass that is compactable.

When heated the material changes to the α phase and becomes pliable and tacky and can be made to flow when pressure is applied.

A disadvantage to the α phase is that the material shrinks on setting.

Core Materials2. GUTTA PERCHACompositionGutta-percha cones consist of approximately

20% gutta-percha, 65% zinc oxide, 10% radiopacifiers, and 5% plasticizers.

Attempts have been made to make gutta-percha more antimicrobial by the addition of materials such as iodoform, calcium hydroxide, chlorhexidene, and tetracycline.

The clinical effectiveness of adding these materials has not been demonstrated.

Core Materials2. GUTTA PERCHAα and β FormsGutta-percha can be made to flow if it is

modified by either heat or solvents such as chloroform.

This permits adaptation to the irregularities of the canal walls.

Compaction of GP at room temperature results in transmission of forces to the material and the canal wall equally and may result in root fracture.

Core Materials2. GUTTA PERCHAα and β FormsThe α form of gutta-percha melts when

heated above 65°C.When cooled extremely slowly, the α form

will recrystallize.Routine cooling results in the

recrystallization of the β form.

Core Materials2. GUTTA PERCHAα and β FormsAlthough the mechanical properties for the

two forms are the same, when α-phase gutta-percha is heated and cooled it undergoes less shrinkage, making it more dimensionally stable for thermoplasticized techniques.

The use of α-phase gutta percha for obturation has increased as thermoplastic techniques have become more common.

Core Materials2. GUTTA PERCHASizesGutta-percha cones are available in

standardized and non-standardized (conventional) sizes.

The nonstandard nomenclature refers to the dimensions of the tip and body.

Nonstandard gutta-percha cones: extra fine, fine fine,fine, medium fine, fine medium, medium, large, and extra large

Core Materials2. GUTTA PERCHASizesStandardized cones are designed to match

the taper of stainless steel and nickel–titanium instruments.

A size 40/04 has a tip of 0.4 mm and a taper of 0.04 mm per millimeter.

Unfortunately uniformity in manufacturing is not present, and the actual cone size varies.

A

C

B

D

A: Standard gutta-percha cone sizes #15 to #40.

C: Size #30 standard gutta-percha points exhibiting #.02,#.04, and #.06 tapers.

B: Standardcones #.06, taper sizes #15 to #40.

D: Standard cones ProtaperF1, F2, F3.

Core Materials2. GUTTA PERCHADisinfectionAlthough the points cannot be heat sterilized,

a study found that gutta-percha points can be sterilized before use by placing the cones in 5.25% NaOCl for 1 minute.

This study also found that 2% glutaraldehyde, 2% chlorhexidine, and 70% ethyl alcohol were not effective in killing Bacillus subtilis spores (Siqueira et al. 1998).

Core Materials3. ACTIV GPActiv GP (Brasseler USA) consists of gutta-

percha cones impregnated on the external surface with glass ionomer.

Single cones are used with a glass ionomer sealer.

Available in .04 and .06 tapered cones, the sizes are laser verified to ensure a more precise fit.

The single cone technique is designed to provide a bond between the dentinal canal wall and the master cone.

Core Materials4. RESILONThe resin-based obturation systems

Epiphany (Pentron Clinical Technologies), RealSeal (SybronEndo), and Resinate (Obtura Spartan, Earth City, MO) have been introduced as alternatives to gutta-percha.

Resilon is a high-performance industrial polyurethane that has been adapted for dental use.

It is nontoxic, nonmutagenic, and biocompatible.

Core Materials4. RESILONCompositionIt consists of a resin core material (Resilon)

composed of polyester, difunctional methacrylate resin, bioactive glass, radiopaque fillers, and a resin sealer.

Core Materials4. RESILONThe resin sealer bonds to a Resilon core,

and attaches to the etched root surface.The manufacturer claims that this forms a

“monoblock”.*With traditional techniques there is a gutta-

percha–sealer interface and a tooth–sealer interface.

With Resilon the resin sealer bonds to both the canal wall and the cone.

A: Epiphany system (Pentron Clinical Technologies,Wallingford, CT) with the primer, thinning resin, sealant, andstandard Resilon points. (Courtesy SybronEndo, Orange, CA.)

A

B

B: Resilon #.02, #.04, and #.06 tapered points and athermoplastic plug for use in the Obtura II system (Obtura Spartan,Earth City, MO).

Core Materials4. RESILONManipulationAfter cleaning and shaping procedures an

appropriate master cone is placed into the prepared canal and a radiograph/image is exposed to verify the apical position.

Because NaOCl may affect the bond strength of the primer, EDTA should be the last irrigant used before rinsing the canal with sterile water, saline, or chlorhexidine.

Core Materials4. RESILONManipulationAfter drying the canal, a self-etch primer* is

used to condition the canal walls and prepare them for bonding to the resin sealant*.

Two or three drops are placed in the canal with a pipette, a syringe, or a paper point that wicks the material to the working length.

Core Materials4. RESILONManipulationThe excess primer is removed, the resin

sealer is dispensed onto a mixing slab, and the viscosity is adjusted with the thinning resin.

The sealer is applied with a paper point, Resilon point, or lentulo spiral.

Core Materials4. RESILONManipulationThe system resembles gutta-percha and

can be placed by lateral compaction, warm lateral or vertical compaction, or thermoplastic injection.

The sealer takes approximately 25 minutes to set, so it is recommended that the coronal surface of the material be light cured for 40 seconds.

Scanning electron microscopy view of Resilon tags extending into the dentinal tubules forming a “monoblock”.

Core Materials4. RESILONPresentationThe core material is available in

nonstandard and standard cone and pellets for use in thermoplastic techniques.

Resilon #.02, #.04, and #.06 tapered points and athermoplastic plug for use in the Obtura II system (Obtura Spartan,Earth City, MO).

Core Materials4. CUSTOM CONESFabricated when the apical foramen is open or a

canal is large.An impression of the canal is obtained by softening

the outer superficial portion of the cone in chloroform, eucalyptol, or halothane for 1 or 2 seconds.

The central core of the cone should remain semi-rigid.

A radiograph is exposed to verify proper fit and position.

An alternative to solvents is softening with heat.

A: Pre-treatment radiographB: Softening the apical 2 to 3 mm in chloroform.C: The completed custom cone represents an impression of the apical portion of the canal.D,E: The post-treatment radiographs with post space prepared. F:1-year follow-up radiograph demonstrating osseous regeneration.

A B C

D E F

Core Materials4. CUSTOM CONESA large master cone may fabricated for large

canals by heating several large gutta-percha cones and rolling the mass between two glass slabs until an appropriate size is obtained.

METHODS OF OBTURATION

METHODS OF OBTURATIONLittle evidence exists to support one

method of obturation as being superior to another and the influence of treatment technique on success/failure.

The prospective Toronto studies have suggested that warm vertical compaction may be superior to lateral compaction; however, definitive evidence is lacking (de Chevigny et al. 2008).

Methods of Obturation1. COLD LATERAL COMPACTION This technique provides for length control

during compaction. A disadvantage is that the technique may

not fill canal irregularities as well as warm vertical compaction or thermoplastic techniques.

Methods of Obturation1. COLD LATERAL COMPACTION

A B

C

D E

A: Working length radiograph. B: Coronal access opening, demonstrating the prepared mesiobuccal canal.C: Standardized master cones with coronal reference marked. D: Standard master cones fit to length as they exhibit minimal taper and permit deeper penetration of the spreader. E: Master cone radiograph E

Methods of Obturation1. COLD LATERAL COMPACTIONThis “master cone” is measured and

grasped with forceps so that the distance from the cone tip to the forceps is equal to the prepared length.

A reference point on the cone can be made by pinching the cone.

The cone is placed in the canal, and if an appropriate size is selected, there will be resistance to displacement or “tug back.”*

Methods of Obturation1. COLD LATERAL COMPACTIONThe master cone placement is confirmed

with a radiograph.The canal is irrigated and dried with paper

points.Sealer is applied to the canal walls, and a

spreader is prefitted so as to allow it to be inserted to within 1.0 to 2.0 mm from working length.

Appropriate accessory points are also selected to closely match the size of the spreader.*


A

F. Finger spreader in place.G.Fine-medium accessory cone placed in the space

created by the spreaderH.Accessory cones placed in the space vacated by the

instrument, repeating the process until the spreader no longer goes beyond the coronal one third of the canal.

I. The cones are then removed at the orifice with heat, and the coronal mass is vertically compacted with a plugger.

F G H I


J. Interim radiograph may be exposed to assess the quality of obturation.

K.Post-treatment radiograph demonstrating adequate length, density, and taper. The gutta-percha is removed to the level of the orifice, and a coronal seal has been established with an adequate provisional restoration.

J K

Methods of Obturation1. COLD LATERAL COMPACTIONOnly light pressure is required during

lateral compaction because the gutta-percha is not compressible, and because as little as 1.5 kg of pressure is capable of fracturing the root.

Mandibular left first molar in which a deep isolated periodontal probing defect was associated with the buccal aspect of the mesiobuccal root. Flap reflection revealed a vertical root fracture.*

Methods of Obturation1. COLD LATERAL COMPACTIONPotential DrawbacksLateral compaction does not produce a

homogeneous mass.The accessory and master cones are

laminated and remain separate, hoping that the space between the cones is filled with sealer.

The method also predisposes to root fracture.

Methods of Obturation2. WARM VERTICAL COMPACTIONSchilder H. (in 1967) introduced warm

vertical compaction as a method of filling the radicular space in three dimensions.

Preparation requirements for the technique include preparing a canal with a continuously tapering funnel and keeping the apical foramen as small as possible.

Methods of Obturation2. WARM VERTICAL COMPACTIONA B C D

Warm vertical compaction of gutta-percha employs heat and various condensers.A. Nonstandard cones are selected and fit short of the prepared

length because they more closely replicate the prepared canal.B. Heated pluggers or spreaders are used to apply heat to the

master cone and remove the excess coronal material.C. A room temperature plugger is used to compact the heated gutta-

percha.D. Apical compaction is complete. A gutta-percha segment is placed

in the canal, and heat is applied.

Methods of Obturation2. WARM VERTICAL COMPACTION

E F G H

E. The heated segment is compacted. F. The process is repeated for the coronal portion of the

canal by placing and heating a segment of gutta-percha.

G.A plugger is again used to compact the heated material.

H.Completed obturation.

2. WARM VERTICAL COMPACTIONAdvantages of warm vertical compaction

include filling of canal irregularities and accessory canals.

The Touch ‘n Heat unit (SybronEndo) is an alternative to applying heat with a flame-heated instrument because it permits temperature control.

Methods of Obturation

The Touch ’n Heat unit. (Courtesy SybronEndo, Orange,CA.)*

Methods of Obturation2. WARM VERTICAL COMPACTIONDisadvantages3. Risk of vertical root fracture because of

compaction forces.4. Less length control than with lateral

compaction.5. Potential for extrusion of material into the

periradicular tissues.

(cont’d)

Methods of Obturation2. WARM VERTICAL COMPACTIONDisadvantages (cont’d)4. Difficult in curved canals, where the rigid

pluggers are unable to penetrate to the necessary depth.

5. To allow the rigid carriers to penetrate within 4 to 5 mm of the apex, the canals must be enlarged and tapered more, in comparison with the lateral compaction technique; however, excessive removal of tooth structure weakens the root.

Methods of Obturation3. CONTINUOUS WAVE COMPACTION

TECHNIQUEA variation of warm vertical compaction is

the continuous wave compaction technique.

The continuous wave compaction technique employs an electric heat carrier, the System B unit, and tapered stainless steel pluggers consistent with various instrument and gutta percha systems.

Continuous wave obturation uses the System B unit. A, The System B unit. B, System B plugger with a nonstandard cone of similar taper. C, System B pluggers. (Courtesy SybronEndo, Orange, CA.)

A B

C


TECHNIQUEThe System B unit has varied temperature

settings of 200° C, 250° C, and 300° C.2 studies carried out have shown that with its

use (unlike the Touch ‘n Heat), the critical 10° C rise with any temperature setting or tip configuration was not observed (Sweatman et al. 2001, Venturi et al. 2003).

However, >250 ° C is potentially hazardous (Floren et al. 1999).


TECHNIQUEManipulationAfter selecting an appropriate master cone,

a plugger is prefitted to fit within 5 to 7 mm of the canal length.

With the continuous wave technique the heat source is placed only to within 5 to 7 mm from the tip of the gutta-percha; the apical portion of the gutta-percha remains essentially a single cone technique as the heat transfer does not take place in the apical 2 to 5 mm of the gutta-percha.


TECHNIQUEManipulationThe heat is inactivated while firm pressure

is maintained on the plugger for 5 to 10 seconds.

After the gutta-percha mass has cooled a 1-second application of heat separates the plugger from the gutta-percha, and it is removed.

Methods of Obturation3. WARM LATERAL COMPACTIONLateral compaction of gutta-percha

provides for length control, which is an advantage over thermoplastic techniques.

The Endotec II device (Medidenta) provides the clinician with the ability to employ length control while incorporating a warm gutta-percha technique.

Endotec II device (Medidenta, Woodside, NY) for warm lateral compaction.

Methods of Obturation3. WARM LATERAL COMPACTIONLateral compaction of gutta-percha provides

for length control, which is an advantage over thermoplastic techniques.

The Endotec II device (Medidenta) provides the clinician with the ability to employ length control while incorporating a warm gutta-percha technique.

Compared to cold lateral compaction, warm lateral compaction technique creates less stress during obturation.

Methods of Obturation4. THERMOPLASTIC INJECTION TECHNIQUESInvolves heating of gutta-percha outside the

tooth and injecting the material into the canal.The apical terminus should be as small as

possible to prevent extrusion of gutta-percha.Canal walls are coated with sealer.Gutta-percha is preheated in the gun, and the

needle is positioned in the canal so that it reaches within 3 to 5 mm of the apical preparation.

Methods of Obturation4. THERMOPLASTIC INJECTION

TECHNIQUESGutta-percha is then gradually, passively

injected by squeezing the trigger of the “gun.”

The needle backs out of the canal as the apical portion is filled.

Pluggers dipped in alcohol are used to compact the guttapercha.


TECHNIQUESA segmental technique may also be used,

in which 3- to 4-mm segments of gutta-percha are sequentially injected and compacted.

In either case, compaction should continue until the gutta-percha cools and solidifies to compensate for the contraction that takes place on cooling.


TECHNIQUESThe difficulties with this system include

lack of length control.Both overextension and underextension are

common results.To overcome this drawback, a hybrid

technique may be used, in which the clinician begins filling the canal by the lateral compaction technique.

Methods of Obturation4. THERMOPLASTIC INJECTION TECHNIQUESWhen the master cone and several accessory

cones have been placed so that the mass is firmly lodged in the apical portion of the canal, a hot plugger is introduced, searing the points off approximately 4 to 5 mm from the apex.

Light vertical compaction is applied to restore the integrity of the apical plug of gutta-percha.

The remainder of the canal is then filled with thermoplasticized gutta-percha.


TECHNIQUESAvailable Systems

Obtura III unit with silver tips, gutta-percha plugs, and cleaning solution (Obtura Spartan, Earth City, MO).



The Ultrafil 3D system consists of an injection syringe, gutta-percha cannulas, and heating unit (Coltène/Whaledent, Cuyahoga Falls, OH).



The Calamus thermoplastic unit (DENTSPLY Tulsa Dental Specialties, Tulsa, OK) for heating and injecting gutta-percha.



The Elements obturation unit (SybronEndo, Orange, CA)for injecting and compacting gutta-percha. Note the System B heatsource.



The battery-powered HotShot unit (Discus Dental, Culver City, CA) for heating and injecting gutta-percha.


TECHNIQUESAdvantages

Thermoplastic techniques are often used in cases with significant canal irregularities.A. Pre-treatment radiograph of a maxillary central incisor exhibiting internal

resorption.B. Post-treatment radiograph demonstrates a dense obturation of the

resorptive defect with gutta-percha.

A B

Methods of Obturation5. GUTTAFLOW

GuttaFlow trituration capsule and injection syringe (Coltène/Whaledent, Cuyahoga Falls, OH).

Methods of Obturation5. GUTTAFLOWGuttaFlow (Coltène/Whaledent) is a cold,

flowable polydimethylsiloxane matrix filled with finely ground gutta-percha.

It is provided in capsules for trituration in an amalgamator.

The technique involves injection of the material into the canal and placing a single master cone to length.

It provides a working time of 15 minutes and cures in 25-30 minutes.

Methods of Obturation5. GUTTAFLOWThe material fills canal irregularities with

consistency and is biocompatible.The setting time is inconsistent and may be

delayed by final irrigation with sodium hypochlorite.

Sealing ability appears comparable to other techniques in some studies and inferior in others (Brackett et al. 2006, Kontakiotis et al. 2007, Monticelli et al. 2007, Ozok et al. 2008).

Methods of Obturation6. CARRIER-BASED GUTTA-PERCHASystem in which a carrier (such as a plastic core)

coated with α-phase gutta-percha is used as the obturant.

Grossman formulation sealers and resin sealers consistent with AH-26 and AH Plus are acceptable; however, Tubli-Seal and Wach’s paste are not recommended.

The carrier is then placed in the heating device. When the carrier is heated to the appropriate

temperature the clinician has approximately 10 seconds to retrieve it and insert it into the canal.

A B

C

A: GT obturator and instrument (DENTSPLY Tulsa DentalSpecialties, Tulsa, OK).B: The Thermafil oven with carrier in place (DENTSPLYTulsa Dental Specialties, Tulsa, OK).C: Thermafil carrier placed in the distal canal.

Methods of Obturation6. CARRIER-BASED GUTTA-PERCHAVertical compaction of the coronal gutta-

percha can be accomplished. When necessary, gutta-percha can be

added, heat softened, and compacted. An advantage to this technique is the

potential for movement of gutta-percha into lateral and accessory canals

However, material can extrude beyond the apical extent of the preparation.*

Methods of Obturation7. SOLVENT TECHNIQUES (no longer in

use). Gutta-percha can be plasticized with

solvents such as chloroform, eucalyptol, and xylol.

Disadvantages include shrinkage caused by evaporation, voids, the inability to control the obturating material, and irritation of periradicular tissues.

Example is the Callahan and Johnston technique which utilized chloroform.

References

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2. Trope MB, Burgenholtz G: Microbial basis for endodontic treatment: can a maximal outcome be achieved in one visit? Endod Topics 1:40, 2002.

3. Southard DW, Rooney TP: Effective one-visit therapy for the acute periapical abscess. J Endod 10:580, 1984.

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References5. Katebzadeh N, Hupp J, Trope M: Histological periapical

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References10. Kleier DJ, Averbach RE: Painful dysesthesia of the inferior

alveolar nerve following use of a paraformaldehyde containing root canal sealer. Endod Dent Traumatol 4:46,1988.

11. Erisen R, Yucel T, Kucukay S: Endomethasone root canal filling material in the mandibular canal: a case report. Oral Surg Oral Med Oral Pathol 68:343, 1989.

12. Siqueira JF, Jr, da Silva CH, Cerqueira M das D, Lopes HP, de Uzeda M: Effectiveness of four chemical solutions in eliminating Bacillus subtilis spores on gutta-percha cones. Endod Dent Traumatol 14:124, 1998.

13. de Chevigny C, Dao TT, Basrani BR, et al: Treatment outcome in endodontics: the Toronto study—phase 4: initial treatment. J Endod 34:258, 2008.

14. Peng L, Ye L, Tan H, Zhou X: Outcome of root canal obturation by warm gutta-percha versus cold lateral condensation: a meta-analysis. J Endod 33:106, 2007.

References15. Sweatman TL, Baumgartner JC, Sakaguchi RL:

Radicular temperatures associated with thermoplasticized guttapercha. J Endod 27:512, 2001.

16. Venturi M, Prati C, Capelli G, Falconi M, Breschi L: A preliminary analysis of the morphology of lateral canals after root canal filling using a tooth-clearing technique. Int Endod J 36:54, 2003.

17. Floren JW, Weller RN, Pashley DH, Kimbrough WF: Changes in root surface temperatures with in vitro use of the system B HeatSource. J Endod 25:593, 1999.

18. Brackett MG, Martin R, Sword J, et al: Comparison of seal after obturation techniques using a polydimethylsiloxane-based root canal sealer. J Endod 32:1188, 2006.

References19. Kontakiotis EG, Tzanetakis GN, Loizides AL: A 12-

month longitudinal in vitro leakage study on a new silicon-based root canal filling material (Gutta-Flow). Oral Surg Oral Med Oral Pathol Oral Radiol Endod 103:854, 2007.

20. Monticelli F, Sadek FT, Schuster GS, et al: Efficacy of two contemporary single-cone filling techniques in preventing bacterial leakage. J Endod 33:310, 2007.

21. Ozok AR, van der Sluis LW, Wu MK, Wesselink PR: Sealing ability of a new polydimethylsiloxane-based root canal filling material. J Endod 34:204, 2008.

22. Cohen’s Pathways of the Pulp, 10th Edition, by Kenneth M. Hargreaves and Stephen Cohen, Copyright © 2011 by Mosby, Inc., an affiliate of Elsevier Inc., St.Louis, Missouri.

Root canal obturation timing materials and techniques

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