Ebook Textbook of endodontics (3/E): Part 2

Part 2 book “Textbook of endodontics” has contents: Obturation of root canal system, single visit endodontics, endodontic emergencies, endodontic failures and retreatment, procedural accidents, surgical endodontics, endodontic periodontal relationship, tooth resorption, pediatric endodontics,… and other contents.

The success in endodontic treatment is based on proper

diagnosis and treatment planning, knowledge of anatomy

and morphology, debridement, sterilization and obturation

The process of cleaning and shaping determines both the

degree of disinfection and the ability to obturate the radicular

space, obturation is therefore a reflection of the cleaning and

shaping and an obturant (obturating material) must seal the

root canal system three dimensionally so as to prevent tissue

fluids from percolating in the root canal and toxic byproducts

from both necrotic tissue and microorganisms regressing

into the periradicular tissues (Figs 19.1 to 19.4).

The obturation of the prepared space have been

achieved by using a wide variety of materials selected for

their intrinsic properties and handling characteristics

These core materials have been classified as cements,

Fig 19.1 Radiograph showing three-dimensional obturation Fig 19.2 Diagrammatic representation of an obturated tooth

pastes, plastics or solids Gutta-percha, in its various forms, has remained the paragon as a root canal filling material during the course of last century The development of core materials and delivery techniques has generated carrier-based gutta-percha and resin-based system These filling materials are combined with sealers to provide an adequate obturation of the root canal space that ideally prevents the emergence of endodontic disease and encourages peripheral healing when pathosis is present This process can only succeed if the sealed root canal space prevents further ingress of bacteria, entombs remaining microorganisms and prevents their survival by obstructing the nutrient supply

Root canal obturation involves the three dimensional filling of the entire root canal system and is a critical step

19

Obturation of Root

Canal System

 Timing of Obturation

 Extent of Root Canal Filling

 Materials used for Obturation

 Methods of Sealer Placement

 Obturation Techniques

 Armamentarium for Obturation

 Lateral Compaction Technique

 Variation of Lateral Compaction

Technique

 Chemical Alteration of Gutta-Percha

 Vertical Compaction Technique

 System B: Continuous Wave of Condensation Technique

 Lateral/Vertical Compaction of Warm Gutta-Percha

 Sectional Method of Obturation/

Chicago Technique

 McSpadden Compaction/

Thermomechanical Compaction of the Gutta-Percha

 Thermoplasticized Injectable Percha Obturation

Gutta- Solid Core Carrier Technique

 Obturation with Silver Cone

 Apical Third Filling

 Postobturation Instructions

 Repair following Endodontic Treatment

Obturation of Root Canal System 283

Figs 19.3A to D Endodontic treatment of mandibular right first molar (A) Preoperative radiograph showing carious 46;

(B) Working length radiograph; (C) Master cone radiograph; (D) Postobturation radiograph

Courtesy: Anil Dhingra

Figs 19.4A and B

D C

284 Textbook of Endodontics

Figs 19.4C and D Figs 19.4A to D Endodontic treatment of mandibular left first molar (A) Preoperative radiograph showing carious 36;

(B) Working length radiograph; (C) Master cone radiograph; (D) Postobturation radiograph

Courtesy: Anil Dhingra

in endodontic therapy There are two main purposes of

obturation—the elimination of all avenues of leakage from

the oral cavity or the periradicular tissues into the root canal

system, and sealing within the root canal system of any

irritants that remain after appropriate shaping and cleaning

of the canals, thereby isolating these irritants Pulpal demise,

subsequent periradicular infection result from the presence

of microorganisms, microbial toxins and metabolites and

the products of pulp tissue degradation Failure to eliminate

these etiological factors and further irritation as a result of

continued contamination of the root canal system are the

prime reasons for the failure of nonsurgical and surgical root

canal therapy (Fig 19.5).

Fig 19.5 Leakage in an obturated canal leading to root canal failure

The importance of the three dimensional obturation of the root canal system cannot be overstated, with the ability to achieve this goal primarily dependent on the quality of root canal cleaning and shaping as well as clinical skills

Objectives of root canal obturation

1847 – Hill’s stopping was developed.

1867 – CA Bowman claimed to be the first to use gutta-percha for

root canal filling.

1883 – Perry claimed that he had been using a pointed gold wire

wrapped with some gutta-percha ( the roots of present day core carrier technique).

1887 – SS White Company began to manufacture GP points

1914 – Lateral condensation technique was developed by Callahan

1953 – Acerbach advised filling of root canals with silver wires

1961 – Use of stainless steel files in conjunction with root canal

sealer as given by Sampeck

1979 – McSpadden techniqueTIMING OF OBTURATION Patient Symptoms

• Sensitivity on percussion—indicates inflammation of periodontal ligament space, canal should not be obturated before the inflammation has subsided

• In case of irreversible pulpitis, obturation can be completed

in single visit if the main source of pain, i.e pulp has been removed

Obturation of Root Canal System 285Pulp and Periradicular Status

Vital Pulp Tissue

When patient exhibits a vital pulp, obturation can be

completed in single visit if the main source of pain, i.e pulp

has been removed It further precludes contamination as a

result of leakage during the period between patient visits

Necrotic Pulp Tissue

• Teeth with necrotic pulp may be treated in single visit if the

tooth is asymptomatic

• If patient presents with sensitivity on percussion, it

indicates inflammation in periodontal ligament space,

canal should be obturated before the inflammation has

subsided

Purulent Exudates

• Even presence of a slight purulent exudates may indicate

possibility of exacerbation If canal is sealed, pressure and

subsequent tissue destruction may proceed rapidly

• After complete cleaning and shaping procedure, calcium

hydroxide should be placed as an antimicrobial and

temporary obturant in necrotic cases that cannot be

treated in one visit because investigators noted that

bacteria in instrumented, unfilled canals can multiply and

reach their pretreatment number in 2 to 4 days

Negative Culture

Experience has shown that filling a root canal known to be

infected is risky But the reliance on negative culture has

decreased now since the researchers have shown that false

negative results can give inaccurate assessment on microbial

flora, also the positive results do not indicate the potential

pathogenicity of bacteria

Procedural Concerns

• Procedural concerns also indicates 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

EXTENT OF ROOT CANAL FILLING

• The anatomic limit of the pulp space are the

dentinocementum junction (DCJ) apically and the pulp

chamber coronally

• Canals filled to the apical dentinocementum junction are

filled to the anatomic limit of the canal Beyond this point,

the periodontal structure begins

• Kutler (1995) described dentinocementum junction (DCJ)

as minor apical diameter which ends 0.5 mm short of

apical foramen in young patients and 0.67 mm short in

• The importance of length control in obturation relates to extrusion of materials One should avoid overextension overfilling and underfilling of root canal system

Overfilling is the total obturation of root canal system with excess

material extruding beyond apical foramen.

Overextension is the extrusion of filling material beyond apical

foramen but the canal may not have been filled completely and

apex have not been sealed (Fig 19.6).

Underfilling is filling of the root canal system more than 2 mm

short of radiographic apex (Fig 19.7).

Fig 19.7 Radiograph showing underfilling of 45 Fig 19.6 Radiograph showing overextended obturation

MATERIALS USED FOR OBTURATION

An ideal root canal filling should be capable of completely

preventing communication between the oral cavity and

periapical tissue Root canal sealers should be biocompatible

or well tolerated by the tissues in their set state, and are used

in conjunction with the core filling material to establish an

adequate seal

Grossman (1982) grouped acceptable filling materials into plastics,

solids, cements and pastes He also delineated 10 requirements for

an ideal root canal filling material, these are as follows:

1 Easily introduced into a root canal.

2 Seal the canal laterally as well as apically.

3 Not shrink after being inserted.

have been used in conjunction with a sealer/cement, the

most common method of obturation involves gutta-percha as

a core material The properties of an ideal obturation material

were outlined by Grossman (mentioned above) Historically

a variety of material have been employed A common solid

material used was the silver cone, though gold, iridoplatinum,

tantalum, titanium are also available

Materials used for root canal filling

• Jasper (1941) introduced silver cones which he claimed

produced the same success rate as gutta-percha and were

easier to use

• Rigidity provided by the silver cones made them easy to

place and permitted length control

• They were mainly used for teeth with fine, tortuous, curved

canals which make the use of gutta-percha difficult

• But now-a-days their use has been declined, because of

of mandibular molars if they are straight

Contraindications

Silver cones cannot conform with the shape of root canal because they lack plasticity; so their use is not indicated:

• For obturation of anterior teeth, single canal premolars, or large single canals in molars

• In young teeth having large ovoid canals

Gutta-percha (Fig 19.8)

Gutta-percha was initially used as a restorative material and later developed into an indispensable endodontic filling material Gutta-percha was earlier used as splints for holding fractured joints, to control hemorrhage in extracted sockets,

in various skin diseases such as psoriasis, eczema and in manufacturing of golf balls

Gutta-percha is derived from two words:

“GETAH” – meaning gum

1847 – Hill introduced Hill’s stopping (a mixture of bleached

gutta-percha and carbonate of lime and quartz)

1867 – Bowman first used gutta-percha as root canal filling material

1883 – Perry packed gold wire wrapped with gutta-percha in root

1914 – Callahan did softening and dissolution of gutta-percha with

use of rosins and then used for obturation of the canals

1959 – Ingle and Levine proposed standardization of root canal

instruments and filling materials.

Fig 19.8 Gutta-percha cones

Obturation of Root Canal System 287

Sources

Gutta-percha is a dried coagulated extract which is derived

from Brazilian trees (Palaquium) These trees belong to

Sapotaceae family In India, these are found in Assam and

Western Ghats

Chemistry

Its molecular structure is close to natural rubber, which is

also a cis-isomer of polyisoprene.

Also contains tannins, salts and saccharine

Composition of commercially available gutta-percha

(Given by Friedman et al)

Chemically pure gutta-percha exists in two different

crystalline forms, i.e a and b which differ in molecular repeat

distance and single bond form Natural gutta-percha coming

directly from the tree is in a—form while the most commercial

available product is in b—form

Different forms of gutta-percha

These phases are interconvertible

• a - runny, tacky and sticky (lower viscosity)

• b - solid, compactable and elongatable (higher viscosity)

• g - unstable form

• On heating, gutta-percha expands which accounts for increased volume of material which can be compacted into the root canal

• Gutta-percha shrinks as it returns to normal temperature

percha technique to compensate for volume change when cooling occurs (Schilder et al)

So, vertical pressure should be applied in all warm gutta-• Aging of gutta-percha causes brittleness because of the oxidation process (Fig 19.9) Storage under artificial light

also speeds up their deterioration

• Brittle gutta-percha can be rejuvenated by a technique described by Sorien and Oliet In this, gutta-percha is immersed in hot water (55°C) for one or two seconds and then immediately immersed in cold water for few seconds

• Gutta-percha cannot be heat sterilized For disinfection

of gutta-percha points, they should be immersed in 5.25 percent NaOCl for one minute (Fig 19.10)

• After this, gutta-percha should be rinsed in hydrogen peroxide or ethyl alcohol to remove crystallized NaOCl before obturation, as these crystallized particles impair the obturation

• Gutta-percha should always be used with sealer and cement to seal root canal space as gutta-percha lacks adhering qualities

• Gutta-percha is soluble in certain solvents like chloroform, eucalyptus oil, etc This property can be used to plasticize gutta-percha by treating it with the solvent for better filling

2%) when solidifies

in the canal But it has shown that gutta-percha shrinks (1-• Gutta-percha also shows some tissue irritation which is due to high content of zinc oxide

Current Available Forms of Gutta-percha

• Gutta-percha points (Figs 19.2 and 19.11): Standard

cones are of same size and shape as that of ISO endodontic instruments

Fig 19.9 Brittle gutta-percha point breaks on bending

288 Textbook of Endodontics

Fig 19.10 Sterilization of gutta-percha by immersing in 5.25%

sodium hypochlorite for one minute

• Auxiliary points: Non-standardized cones; perceive form

of root canal (Fig 19.12).

• Greater taper gutta-percha points: Available in 4 percent,

6 percent, 8 percent and 10 percent taper (Fig 19.13).

• Gutta-percha pellets/bars: They are used in

thermo-plasticized gutta-percha obturation, e.g obtura system

• Precoated core carrier gutta-percha: In these stainless

steel, titanium or plastic carriers are precoated with

alpha-phase gutta-percha for use in canal, e.g thermafil

(Fig 19.14)

• Syringe systems: They use low viscosity gutta-percha, e.g

Success-fil and alpha seal

• Gutta flow: In this gutta-percha powder is incorporated

into resin based sealer

Fig 19.11 Gutta-percha points

Fig 19.12 Auxiliary points

Fig 19.13 Greater taper points

• Gutta-percha sealers like chloropercha and eucopercha:

In these, gutta-percha is dissolved in chloroform/eucalyptol to be used in the canal

• Medicated gutta-percha: Calcium hydroxide, iodoform

or chlorhexidine diacetate containing gutta-percha points

Fig 19.14 Thermafil gutta-percha

Obturation of Root Canal System 289

Advantages of gutta-percha

• Compatibility: Adaptation to canal walls

• Inertness: Makes it non-reactive material

• Dimensionally stable

• Tissue tolerance

• Radiopacity: Easily recognizable on radiograph (Fig 19.15)

• Plasticity: Becomes plastic when heated

• Dissolve in some solvents like chloroform, eucalyptus oil, etc

This property makes it more versatile as canal filling material.

Disadvantages of gutta-percha

• Lack of rigidity: Bending of gutta-percha is seen when lateral

pressure is applied So, difficult to use in smaller canals

• Easily displaced by pressure

• Lacks adhesive quality.

Medicated Gutta-percha

• Calcium hydroxide containing gutta-percha (Fig 19.16):

These are made by combing 58 percent of calcium

hydroxide in matrix of 42 percent gutta-percha They

are available in ISO size of 15 to 140 Action of calcium

hydroxide is activated by moisture in canal

• Calcium hydroxide plus points

– Along with calcium hydroxide and gutta-percha, they

contain tenside which reduces the surface tension

– Due to presence of water soluble components tenside

and sodium chloride, they are three times more reactive

then calcium hydroxide points

– They have superior pH and increases wettability of canal surface with increased antibacterial property – They have sustained alkaline pH for one week

• Iodoform containing gutta-percha

– Iodoform containing gutta-percha remains inert till it comes in contact with the tissue fluids

– On coming in contact with tissue fluids, free iodine is released which is antibacterial in nature

• Chlorhexidine diacetate containing gutta-percha

– In this, gutta-percha matrix embedded in 5 percent chlorhexidine diacetate

– This material is used as an intracanal medicament

Resilon (Fig 19.17)

• A resin-based obturation system, epiphany (Pentron Clinical Technologies, Wallingford, CT) and Real Seal (Sybron Endo) have been introduced as an alternative to gutta-percha

• The system resembles gutta-percha and can be placed using lateral compaction, warm vertical compaction or thermoplastic injection

• It consists of a resin core material (Resilon) composed of polyester, difunctional methacrylate, bioactive glass and radiopaque fillers and a resin sealer

a better coronal seal and may strengthen the root

• Resilon core material shrinks only 0.5 percent and is physically bonded to the sealer by polymerization When

it sets, no gaps are seen due to no shrinkage

The detailed description regarding the use of this system has been discussed in “obturation techniques” section

Fig 19.16 Calcium hydroxide containing gutta-percha Fig 19.15 Radiograph showing radiopaque gutta-percha

290 Textbook of Endodontics

Custom Cones (Fig 19.18)

• When the apical foramen is open or canal is large, a custom

cone may need to be developed

• This allows the adaptation of the cone to the canal walls,

reduces the potential for extrusion of the core material,

may improve the seal

• The technique involves selection of a master cone and

fitting the cone 2 to 4 mm short of the prepared length with

frictional resistance

• The cone is removed and the tip is softened in chloroform,

eucalyptol or halothane for 1 to 2 seconds

• Only the outer superficial portion of the cone is softened

The central core of the canal should remain semirigid

• The cone is then placed into the canal and gently tamped to

the length The process can be repeated until an adequate

impression of the canal is obtained at the prepared length

• Radiograph is obtained to verify the proper fit and position

• An alternate method to solvents is softening with heat

It can be accomplished by heating several large

gutta-percha cones and rolling the mass between two glass slabs

until an appropriate size is obtained

Fig 19.18 Custom cone made according to shape of canal

Fig 19.17 Real seal obturation system

Root Canal Sealers

• Purpose of sealing root canals is to prevent periapical exudates from diffusing into the unfilled part of the canal,

to avoid reentry and colonization of bacteria and to check residual bacteria from reaching the periapical tissues Therefore to accomplish a fluid tight seal, a root canal sealer is needed

• Sealer performs several functions during the obturation

of a root canal system with gutta-percha; it lubricates and aids the seating of the master gutta-percha cone, acts as

a binding agent between the gutta-percha and the canal wall and fills anatomical spaces where the primary filling material fails to reach

• Root canal sealer, although used only as adjunctive materials in the obturation of root canal systems, have been shown to influence the outcome of root canal treatment

• The adequate combination of sealing ability and biocompatibility of root canal sealer is important for a favorable prognosis of the root canal treatment

• Studies have shown that most commercially available sealers can irritate the periapical tissues Initially some type of cytotoxic reaction may even be partially beneficial with respect to eventual periapical healing So, for a root canal filling material, this toxicity should be minimal

and clinically acceptable at the time of obturation At a later time period, the material should become as inert as

possible

• There are a variety of sealers that have been used with different physical and biological properties The clinician must be careful to evaluate all characteristics of a sealer before selecting

Requirements of an Ideal Root Canal Sealer

Grossman listed following requirements and characteristics

of a good root canal sealer:

Obturation of Root Canal System 291

• It should be tacky when mixed so as to provide good

adhesion between it and the canal wall when set Only

polycarboxylates, glass ionomers and resin sealers satisfy

the requirement of good adhesion to dentin

• It should create hermetic seal

• It should be radiopaque so that it can be visualized in

the radiograph Radiopacity, is provided by salts of heavy

metals such as silver, barium and bismuth

• The particles of powder should be very fine so that they can

be mixed easily with the liquid

• It should not shrink upon setting All of the sealers shrink

slightly on setting, and gutta-percha also shrinks when

returning from a warmed or plasticized state

• It should not stain tooth structure Grossman’s cement,

zinc oxide-eugenol, endomethasone, and N2 induce a

moderate orange-red stain, Diaket and Tubli-Seal cause a

mild pink discoloration, AH-26 gives a distinct color shift

towards gray, Riebler’s paste cause a severe dark red stain

Diaket causes the least discoloration Leaving any sealers

or staining cements in the tooth crown should be avoided

• It should be bacteriostatic or atleast not encourage bacterial

growth All root canal sealers exert antimicrobial activity to

a varying degree and those containing paraformaldehyde

to a greater degree initially

• It should set slowly The working and setting times of

sealers are dependent on the constituent components,

their particle size, temperature and relative humidity

There is no standard working time for sealers, but it must

be long enough to allow placement and adjustment of root

filling if necessary

• It should be insoluble in tissue fluids

• It should be tolerant, nonirritating to periradicular tissue

• It should be soluble in a common solvent if it is necessary

to remove the root canal fitting

The following were added to Grossman’s basic requirements:

• It should not provoke an immune response in periradicular

tissue

• It should be neither mutagenic nor carcinogenic

Requirements of an ideal root canal sealer

• Should be tacky when mixed to provide good adhesion

between it and the canal wall when set.

Functions of Root Canal Sealers

Root canal sealers are used in conjunction with filling materials for the following purposes:

• Antimicrobial agent: All the popularly used sealers

contain some antibacterial agent, and so a germicidal quality is excreted in the period of time immediately after its placement

• Sealers are needed to fill in the discrepancies between the

filling material and the dentin walls (Fig 19.19).

• Binding agent: Sealers act as binding agent between the

filling material and the dentin walls

• As lubricant: When used with semisolid materials, sealer

act as a lubricant

• Radiopacity: All sealers display some degree of

radiopacity; thus they can be detected on a radiograph This property can disclose the presence of auxiliary canals, resorptive areas, root fractures, and the shape of apical foramen

• Certain techniques dictate the use of particular sealer:

The choropercha technique, for instance, uses the material

as sealer as well as a solvent for the master cone It allows the shape of normal gutta-percha cone to be altered according to shape of the prepared canal

Functions of root canal sealers

Fig 19.19 Sealer fills the space between gutta-percha points

292 Textbook of Endodontics

Sealers may be Broadly Classified

According to their Composition

• Eugenol

• Noneugenol

• Medicated

Amongst these, eugenol containing sealers are widely accepted.

• Eugenol group may be divided into sub-groups namely.

– Silver containing cements:

These include the group of root canal sealers which have

therapeutic properties These materials are usually used

without core materials

3 Class 3: Includes polymers and resin systems that set through polymerization

2 Resin based: Consists of an epoxy resin base which sets

upon mixing with an activator For examples, AH 26, diaket, hydron

3 GP based cements consists of solutions of gutta-percha in organic solvents Examples; Chloropercha, Eupercha

4 Dentin adhesive materials, e.g cyanoacrylate cements, glassionomer cements, polycarboxylate cements, calcium phosphate, composite materials

5 Materials to which medicaments have been added; these may be divided into two groups:

i Those in which strong disinfectants have been added

in order to decrease possible postoperative pain, like paraformaldehyde and corticosteroid preparation

ii Those in which calcium hydroxide has been added with the purpose of inducing cementogenesis and dentino-genesis at the foramen, thus creating a permanent biological seal For examples, calcibiotic root canal sealer (CRCS), sealapex and biocalex

Methacrylate resin-based sealers: There are four generations of

methacrylate resin based sealers:

1 First generation methacrylate resin based sealer, e.g hydron

2 Second generation methacrylate resin based sealer, e.g EndoReEZ

3 Third generation methacrylate resin based sealer, e.g epiphany

4 Fourth generation methacrylate resin based sealer, e.g MetaSEAL, RealSEAL

Zinc Oxide Eugenol Sealers

Zinc oxide eugenol sealers as shown in Fig 19.20.

Kerr Root Canal Sealer or Rickert’s Formula

The original zinc oxide-eugenol sealer was developed by Rickert This is based on the cement described by Dixon and Rickert in 1931 This was developed as an alternative to the gutta-percha based sealers (chloropercha and eucapercha sealers) as they lack dimensional stability after setting

Obturation of Root Canal System 293

Greater bulk than any sealer and thus makes it ideal for conden-sation techniques to fill voids, auxiliary canals and irregularities

present lateral to gutta-percha cones.

Disadvantages

The major disadvantage is that the presence of silver makes the sealer

extremely staining if any of the material enters the dentinal tubuli So

sealers must be removed carefully from the pulp chamber with xylol.

Manipulation

Powder is contained in a pellet and the liquid in a bottle One

drop of liquid is added to one pellet of powder and mixed

with a heavy spatula until relative homogenicity is obtained

Kerr pulp canal sealer completely sets and is inert within

15 to 30 minutes, thus reduces the inflammatory responses

Procosol Radiopaque-Silver Cement

• Zinc eugenolate is decomposed by water through continuous loss of eugenol, which makes zinc oxide eugenol a weak unstable compound

• Tricalcium phosphate 2 g

• Bismuth subnitrate 3.5 g

• Because of good lubricating property, it is used in cases where it is difficult for a master cone to reach last apical third of root canal.

Endoflas

It is zinc oxide based medicated sealer with setting time of 35

to 40 minutes

CompositionPowder

Obturation of Root Canal System 295

This is a mixture of gutta-percha and chloroform

Modified Chloropercha Methods

There are two modifications:

– A gutta-percha cone is inserted and compressed

laterally and apically with a plugger until it gets

dissolved completely in the chloroform solution in the

root canal Additional points are added and dissolved

in the same way

• Nygaard-Ostby

– It consists of Canada balsam; colophonium and zinc

oxide powder mixed with chloroform

– In this technique, the canal walls are coated  with

Kloroperka, the primary cone dipped in sealer is

inserted apically pushing partially dissolved tip of the

cone to its apical seal

– Additional cones dipped in sealer are packed into the

canal to obtain a good apical seal

Hydron

Hydron is a rapid setting hydrophilic, plastic material used

as a root canal sealer without the use of a core This was

Appetite Root Canal Sealer

Several root canal sealers composed of hydroxyapatite and tricalcium have been promoted

These are of three types:

Type IPowder

This is an epoxy resin recommended by Shroeder in 1957

Epoxy resin based sealers are characterized by the reactive

epoxide ring and are polymerized by breaking this ring

Feldman and Nyborg gave the following composition

Bisphenol diglycidyl ether

The formulation has been altered recently with the

removal of silver as one of the constituent to prevent tooth

• The addition of a hardener, hexamethylene tetramine,

makes the cured resin inert chemically and biologically

AH-26 consists of a yellow powder and viscous resin liquid, it is mixed to a thick creamy consistency The setting time is 36 to 48 hours at body temperature and 5 to 7 days at room temperature

AH-26 produces greater adhesion to dentin especially when smear layer is removed Smear layer removal exposes the dentinal tubules creating an irritating surface thus enhancing adhesion

Thermaseal

Thermaseal has a formulation very similar to that of AH-26 It has been tested in several studies in the United States and is highly rated for both sealing ability and periapical tolerance Thermaseal may be used with condensation techniques other than Thermafil

AH Plus (Fig 19.22)

AH Plus is an Epoxide-Amine resin pulp canal sealer, developed from it predecessor AH-26 Because of color and shade stability, this is the material of choice where esthetic demands are high This easy-to-mix sealer adapts closely to the walls of the prepared root canal and provides minimal shrinkage upon setting as well as outstanding long-term dimensional stability and sealing properties

Obturation of Root Canal System 297

Although pure AH Plus contains calcium tungstate, but

calcium release is absent from this material Durarte et al

in 2003 suggested addition of 5% calcium hydroxide makes

it a low viscosity material, and increases its pH and calcium

release This higher alkalinity and enhanced calcium release

leads to improved biological and antimicrobiological

behavior, because more alkaline pH favors the deposition of

mineralized tissue and exerts an antimicrobial action

Dosage and Mixing

Mix equal volume units (1:1) of Paste A and Paste B on a

glass slab or mixing pad using a metal spatula Mix to a

formaldehyde on mixing, in nature

making it toxic in nature

Fiberfill is a new methacrylate resin-based endodontic sealer

Fiberfill root canal sealant is used in combination with a

self-curing primer (Fiberfill primers A and B) Its composition

resembles to that of dentin bonding agents

CompositionFiberfill root canal sealant

Manipulation

Mix equal number of drops of fiberfill primer A and B Apply this mix into the root canal

Calcium Hydroxide Sealers (Fig 19.23)

Calcium hydroxide has been used in endodontics as a root canal filling material, intracanal medicaments or as a sealer

in combination with solid core materials The pure calcium hydroxide powder can be used alone or it can be mixed with normal saline solution The use of calcium hydroxide paste as

a root canal filling material is based on the assumption that it results in formation of hard structures or tissues at the apical foramen The alkalinity of calcium hydroxide stimulates the formation of mineralized tissue

Fig 19.23 Metapex sealer

• There is no objective proof that a calcium hydroxide sealer

provides any added advantage of root canal obturation or has

any of the its desirable biological effects.

• Although calcium hydroxide has dentin regenerating

proper-ties, the formation of secondary dentin along the canal wall is

prevented by the absence of vital pulp tissue.

Seal Apex (Fig 19.24)

It is a noneugenol calcium hydroxide polymeric resin root

is improved, but since calcium hydroxide is not released from the cement, its main role (osteogenic effect) becomes questionable

Obturation of Root Canal System 299

CompositionPowder

It consists essentially of a silicone monomer and a silicone-• Active ingredients are hydroxyl terminated dimethyl siloxane, benzyl alcohol and hydrophobic amorphous silica Catalysts are tetraethylorthosilicate and polydime-thyl siloxane

poly-• Setting time can be controlled from 8 to 90 minutes by varying the amount of catalyst used

• If more amount of catalyst is used, it decreases the setting time and increases the shrinkage of set mass

• Its main constituent is polydimethyl siloxane

• Instead of showing shrinkage, Roeko Seal shows 0.2% expansion on setting

Glass Ionomer Sealer (Ketac-Endo) (Fig 19.25)

Recently glass ionomer cements has been introduced as endodontic sealer (Ketac-Endo) Glass ionomer cement is the reaction product of an ionleachable glass powder and a polyanion in aqueous solution On setting, it forms a hard polysalt gel, which adheres tightly to enamel and dentin Because of its adhesive qualities, it can be used as root canal sealer

• N2 was introduced by Sargenti and Ritcher (1961) N2

refers to the so called second nerve (Pulp is referred to as

first nerve)

• The corticosteroids are added to the cement separately as

hydrocortisone powder or Terra-Cortril

• Objective of introducing formaldehyde within the

root-filling is to obtain a continued release of formaldehyde gas,

which causes prolonged fixation and antiseptic action

Degree of irritation is severe with the over filling when N2 is

forced into the maxillary sinus or mandibular canal, persisting

paresthesia was observed

Endomethasone

The formation of this sealer is very similar to N2

composition

• It cannot be removed from the root canal in the event of

retreatment as there is no known solvent for glass ionomer

• However, Toronto/Osract group has reported that Ketac-endo

sealer can be effectively removed by hand instruments or

chloroform solvent followed by one minute with an ultrasonic

No 25 file.

Resilon (Fig 19.26)

A new material, Resilon (Epiphany, Pentron Clinical

Technologies; Wallingford, CT; RealSeal, SybronEndo;

Orange, CA) has been developed to replace gutta-percha and

traditional sealers for root canal obturation It offers solutions

to the problems associated with gutta-percha:

• Shrinkage of gutta-percha on cooling

• Gutta-percha does not bind physically to the sealer, it

results in gap formation between the sealer and the

gutta-percha

This resilon core material only shrinks 0.5 percent and is

physically bonded to the sealer by polymerization When it

sets, no gaps are seen due to shrinkage This new material

has shown to be biocompatible, cytotoxic and

non-mutagenic The excellent sealing ability of the resilon system

may be attributed to the “mono block” which is formed by the

adhesion of the resilon cone to the epiphany sealer, which

adheres and penetrates into the dentin walls of the root canal

• Resilon sealer a dual-cured, resin-based composite

sealer The resin matrix is comprised of Bis-GMA, ethoxylated BisGMA, UDMA, and hydrophilic difunctional methacrylates It contains fillers of calcium hydroxide, barium sulphate, barium glasss, bismuth oxychloride and silica The total filler content is approximately 70 percent

by weight The preparation of the dentin through these chemical agents may prevent shrinkage of the resin filling away form the dentin wall and aid in sealing the roots filled with resilon material

• Resilon core material: It is a thermoplastic synthetic

polymer based (polyester) rootcanal core material that contains bioactive glass, bismuth oxychloride and barium sulphate The filler content is approximately 65 percent by weight

The Monoblock concept

Monoblock concept means the creation of a solid, bonded, continuous material from one dentin wall of the canal to the other Monoblock phenomenon strengthens the root by approximately

20 percent.

Classification of Monoblock concept (Fig 19.27) based on

number of interfaces present between corefilling material and bonding substrate:

Primary: In this obturation is completely done with core material

for example use of MTA for obturation in cases of apexification.

Secondary: In this bond is there between etched dentin of canal

wall impregnated with resin tags which are attached to resin cement that is bonded to core layer, e.g Resilon-based system.

Tertiary: In this conventional gutta-percha surface is coated with

resin which bond with the sealer, which further bond to canal walls For example, Endo Rez and Activ GP system.

Fig 19.25 Ketac-Endo sealer

Fig 19.26 Resilon

Obturation of Root Canal System 301

Method of Use

• Canal is prepared with normal preparation method

• Smear layer removal: Sodium hypochlorite should not be

the last irrigant used within the root canal system due to

compatibility issues with resins Use 17 percent EDTA or 2

percent chlorhexidine as a final rinse

• Placement of the primer: After the canal is dried with

paper points, the primer is applied up to the apex Dry

paper points are then used to wick out the excess primer

from the canal The primer is very important because it

creates a collagen matrix that increases the surface area

for bonding The low viscosity primer also draws the sealer

into the dentinal tubules

• Placement of the sealer: The sealer can be placed into the

root canal system using a lentulospiral at low rpm or by

generously coating the master cone

• Obturation: The root canal system is then obturated by

preferred method (lateral or warm vertical, etc.)

• Immediate cure: The resilon root filling material can

be immediately cured with a halogen curing light for 40

with a pumping action

• Placing the sealer in the canal with a lentulospiral

• If apex is open, only apical one-third of master cone is coated with sealer to prevent its extrusion into periapical tissues

The obturation methods vary by the direction of the compaction (lateral/vertical) and/or the temperature of gutta-percha either cold or warm (plasticized) (Fig 19.30).

There are two basic procedures :

1 Lateral compaction of cold gutta-percha

2 Vertical compaction of warm gutta-percha

Other methods are the variations of warmed percha

gutta-Fig 19.27 Types of Monoblock concept

Fig 19.28 Lentulospiral for carrying sealer

Fig 19.29 Injectable syringe for carrying sealer

302 Textbook of Endodontics

Root canal obturation with gutta-percha as a filling material, can be

mainly divided into following groups:

– Vertical compaction technique

– System B continuous wave condensation technique

– Lateral/vertical compaction

– Sectional compaction technique

– McSpadden compaction of gutta-percha

– Thermoplasticized gutta-percha technique including

i Obtura II

ii Ultrasonic plasticizing

iii Ultrafil system

– Solid core obturation technique including

i Thermafil system

ii Silver point obturation

ARMAMENTARIUM FOR OBTURATION

Fig 19.30 Lateral and vertical compaction of gutta-percha

LATERAL COMPACTION TECHNIQUE

It is one of the most common methods used for root canal obturation It involves placement of tapered gutta-percha cones in the canal and then compacting them under pressure against the canal walls using a spreader A canal should have continuous tapered shape with a definite apical stop, before it

is ready to be filled by this method (Fig 19.32).

Technique

• percha cone whose diameter is same as that of master apical file One should feel the tugback with master gutta-percha point (Fig 19.33) Master gutta-percha point is

Following the canal preparation, select the master gutta-notched at the working distance analogous to the level of incisal or occlusal edge reference point (Fig 19.34)

• Check the fit of cone radiographically

– If found satisfactory, remove the cone from the canaland place it in sodium hypochlorite

– If cone fits short of the working length, check for dentin chip debris, any ledge or curve in the canal and treat them accordingly (Figs 19.35 and 19.36)

– If cone selected is going beyond the foramen, eitherselect the larger number cone or cut that cone to the working length (Fig 19.37)

– If cone shows “s” shaped appearance in the radiograph that means cone is too small for the canal Here a larger cone must be selected to fit in the canal (Fig 19.38).

Spreader helps in compaction of gutta-percha It act as a wedge to squeeze the gutta-percha laterally under vertical pressure not by pushing it sideways (Fig 19.42) It should

reach 1 to 2 mm of the prepared root length

• After placement, spreader is removed from the canal by rotating it back and forth This compacts the gutta-percha and

a space gets created lateral to the master cone (Fig 19.43).

• An accessory cone is placed in this space and the above procedure is repeated until the spreader can no longer penetrate beyond the cervical line (Fig 19.44).

• Now sever the protruding gutta-percha points at canal orifice with hot instrument (Fig 19.45).

Advantages of lateral compaction technique

• Can be used in most clinical situations.

• During compaction of gutta-percha, it provides length control, thus decreases the chances of overfilling.

Obturation of Root Canal System 303

Figs 19.31A to H Armamentarium for obturation

Fig 19.32 Tapered preparation

of root canal system Fig 19.33 Tugback with master

gutta-percha cone Fig 19.34 Notching of gutta-percha

at the level of reference point

304 Textbook of Endodontics

Fig 19.35 Gutta-percha showing tight fit in middle and

space in apical third

Fig 19.36 Gutta-percha cone showing tight fit only on

apical part of the canal

Fig 19.38 S-shaped appearance of cone in mesial canal shows that

cone is too small for the canal, replace it with bigger cone

Fig 19.37 If cone is going beyond apical foramen, cut the cone to

working length or use larger number cone Fig 19.40 Apply sealer in the prepared canal

Fig 19.39 Spreader should match the taper of canal

Obturation of Root Canal System 305

Fig 19.44 Use of more accessory

cones to complete obturation of the canal

Fig 19.43 Placing accessory

cone along master cone

Fig 19.42 Compaction of

gutta-percha using spreader

Fig 19.41 Placing spreader along

gutta-percha cone

Fig 19.45 Cut the protruding gutta-percha points at orifice with hot

instrument and place temporary restoration over it

Fig 19.46 In lateral compaction of gutta-percha, cones never fit as

homogeneous mass, sealer occupies the space in between the cones

Lateral compaction technique

• Most common method used.

• Gutta-percha cones are placed in canal and compacted against canal walls using a spreader.

POINTS TO REMEMBER

VARIATION OF LATERAL COMPACTION TECHNIQUE For Tubular Canals (Figs 19.47A and B)

• Tubular canals are generally large canals with parallel walls These canals do not have apical constriction

• These canals can be obturated by tailor made gutta-percha

or with gutta-percha cone which has been made blunt by cutting at tip

For Curved Canals (Fig 19.48)

• Canals with gradual curvature are treated by same basic procedure which includes the use of more flexible (NiTi) spreader

• For these canals, finger spreaders are preferred over hand spreaders

• For canals with severe curvature like bayonet shaped

or dilacerated canals, thermoplasticized gutta-percha technique is preferred (Fig 19.49).

306 Textbook of Endodontics

Fig 19.48 Radiograph showing curved canal

Figs 19.47A and B (A) Carious 12 with tubular canal; (B) Radiograph

showing obturation of 12

Blunderbuss/Immature Canals (Figs 19.50 to 19.52)

• Blunderbuss canals are characterized by flared out apical foramen So a special procedure like apexification is required to ensure apical closure

• percha or warm gutta-percha technique is preferred

For complete obturation of such canals, tailor made gutta-Technique of Preparing Tailor made Gutta-percha

• Tailor made gutta-percha is prepared by joining multiple gutta-percha cones from butt to tip until a roll is achieved

• This roll is then stiffened by using ice water or ethyl chloride spray

• If this cone is loose fitting, more gutta-percha points are added to this

• If this roll is large, it is heated over a flame and again rolled

• For use in the canal, the outer surface of tailor made cone

is dipped in chloroform, eucalyptol or halothane and then cone is placed in the canal By this, internal impression of canal is achieved

• percha solvent

Finally cone is dipped in alcohol to stop action of gutta-CHEMICAL ALTERATION OF GUTTA-PERCHA

Gutta-percha is soluble in number of solvents, viz chloroform, eucalyptol, xylol This property of gutta-percha is used to adapt it in various canal shapes which are amenable

to be filled by lateral compaction of gutta-percha technique

Indications:

• In teeth with blunderbuss canals

• Root ends with resorptive defects, delta formation

• In teeth with internal resorption

Fig 19.49 Radiograph showing obturation of curved roots

Figs 19.50A and B (A) Carious 22 with blunderbass canals;

(B) Obturation of 22 done, using tailor made gutta-percha point

Obturation of Root Canal System 307

Figs 19.51A to C (A) Preoperative radiograph showing maxillary central incisor with blunderbass canal and periapical radiolucency;

(B) Working length radiograph; (C) Postobturation radiograph Obturation done using custom made cone

Figs 19.52A to J Esthetic rehabilitation of maxillary central incisor by endodontic retreatment and crown placement.(A) Preoperative photograph;

(B) Preoperative radiograph; (C) Old gutta-percha removed; (D) Working length radiograph; (E) Custom made gutta-percha cone; (F) Radiograph taken with master cone; (G) MTA plug given for apical stop; (H) Obturation done using gutta-percha and MTA; (I) Postobturation radiograph; (J) Postobturation photograph

seconds into a dappen dish containing solvent (Fig. 19.55)

• Softened cone is inserted in the canal with slight apical

pressure until the beaks of plier touch the reference point

• Here take care to keep the canal moistened by irrigation,

otherwise some of softened gutta-percha may stick to the

desired canal walls, though this detached segment can be

easily removed by use of H-file

• Radiograph is taken to verify the fit and correct working

length of the cone When found satisfactory, cone is

removed from the canal and canal is irrigated with sterile

Fig 19.54 Checking the fit of gutta-percha cone

Fig 19.55 Softening of gutta-percha cone by placing in chloroform

Fig 19.56 Application of sealer in the canal Fig 19.53 Cleaned and shaped canal

water or 99 percent isopropyl alcohol to remove the residual solvent

• After this canal is coated with sealer (Fig 19.56) Cone

is dipped again for 2 to 3 seconds in the solvent and thereafter inserted into the canal with continuous apical pressure until the plier touches the reference point

(Fig 19.57).

• A finger spreader is then placed in the canal to compact the gutta-percha laterally (Fig 19.58).

• Accessory gutta-percha cones are then placed in the space created by spreader (Fig 19.59).

• Protruding gutta-percha points are cut at canal orifice with hot instrument (Fig 19.60)

Though this method is considered good for adapting gutta-percha to the canal walls but chloroform dip fillings have shown to produce volume shrinkage which may lead to poor apical seal

Obturation of Root Canal System 309

Fig 19.58 Compaction of gutta-percha using spreader

Fig 19.57 Softened gutta-percha placed in the canal

VERTICAL COMPACTION TECHNIQUE

Vertical compaction of warm gutta-percha method of filling

the root canal was introduced by Schilder with an objective of

filling all the portals of exit with maximum amount of

gutta-percha and minimum amount of sealer This is also known as

Schilder’s technique of obturation In this technique using

heated pluggers, pressure is applied in vertical direction to

heat softened gutta-percha which causes it to flow and fill the canal space (Fig 19.61).

Basic requirements of a prepared canal to be filled by vertical compaction technique are:

• Continuous tapering funnel shape from orifice to apex (Fig 19.62).

• Apical opening to be as small as possible.

• Decreasing the cross sectional diameter at every point apically and increasing at each point as canal is approached coronally.

Fig 19.59 Complete obturation of the canal using accessory cones

Fig 19.60 Sever the protruding gutta-percha

cones using hot burnisher

310 Textbook of Endodontics

Technique

• Select a master cone according to shape and size of the

prepared canal Cone should fit in 1 to 2 mm of apical

stop because when softened material moves apically

into prepared canal, it adapts better to the canal walls

(Fig 19.63).

• Confirm the fit of cone radiographically, if found

satisfactory, remove it from the canal and place in sodium

hypochlorite

• Irrigate the canal and then dry by rinsing it with alcohol

and latter using the paper points

• Select the heat transferring instrument and pluggers

according to canal shape and size (Figs 19.64 to 19.66).

Fig 19.63 Select the master

gutta-percha cone Fig 19.64 Select the plugger

according to canal shape and size

• Pluggers are prefitted at 5 mm intervals so as to capture maximum cross section area of the softened gutta-percha

• Lightly coat the canal with sealer

• Cut the coronal end of selected gutta-percha at incisal or occlusal reference point

• Now use the heated plugger to force the gutta-percha into the canal The blunted end of plugger creates

a deep depression in the center of master cone

(Fig.  19.67) The outer walls of softened gutta-percha

are then folded inward to fill the central void, at the same time mass of softened gutta-percha is moved apically and laterally This procedure also removes

2 to 3 mm of coronal part of gutta-percha

• Once apical filling is done, complete obturation by doing backfilling Obturate the remaining canal by heating small

Fig 19.65 Larger sized plugger may

bind the canal and may split the root Fig 19.66 Small plugger is

ineffective for compaction

Fig 19.61 Vertical compaction

of gutta-percha using plugger Fig 19.62 Completely cleaned

and shaped tapered preparation

Fig 19.67 Heated plugger used to compact gutta-percha

Obturation of Root Canal System 311

of heat carrier pluggers, thereby delivering a precised amount

• While down packing, apply a constant firm pressure.

POINTS TO REMEMBER

Technique

• Select the Buchanan plugger which matches the selected gutta-percha cone (Fig 19.69) Place rubber stop on the

plugger and adjust it to its binding point in the canal 5 to 7

mm short of working length

• Confirm the fit of the gutta-percha cone (Fig 19.70).

• Dry the canal, cut the gutta-percha ½ mm short and apply sealer in the canal

• With the System B turned on to “use”, place it in touch mode, set the temperature to 200°C and dial the power setting to 10 Sever the cone at the orifice with preheated plugger Afterwards plugger is used to compact the softened gutta-percha at the orifice Push the plugger smoothly through gutta-percha to with 3 to 4 mm of the binding point (Fig 19.71)

• Release the switch Hold the plugger here for 10 seconds with a sustained pressure to take up any shrinkage which might occur upon cooling of gutta-percha (Fig 19.72).

• Maintaining the apical pressure, activate the heat switch for 1 second followed by 1 second pause, and then remove the plugger (Fig 19.73).

• After removal of plugger, introduce a small flexible end

of another plugger with pressure to confirm that apical

Fig 19.68 Back filling of the canal

segments of gutta-percha, carrying them into the canal

and then compacting them using heated pluggers as

described above (Fig 19.68).

• Take care not to overheat the gutta-percha because it will

become too soft to handle

• Do not apply sealer on the softened segments of

gutta-percha because sealer will prevent their adherence to the

body of gutta-percha present in the canal

• After completion of obturation, clean the pulp chamber

with alcohol to remove remnants of sealer or gutta-percha

Advantages

Excellent sealing of canal apically, laterally and obturation of lateral

as well as accessory canals.

Disadvantages

• Increased risk of vertical root fracture.

• Overfilling of canals with gutta-percha or sealer from apex.

• Time consuming.

Vertical compaction of warm gutta-percha

• Also known as Schilder’s technique of obturation.

• Use small segments of gutta-percha, carry into canal and

compact as described above.

Fig 19.69 Selection of plugger

according to shape and size of

the canal

Fig 19.70 Confirm fit of the

cone

312 Textbook of Endodontics

Fig 19.71 Filling the canal by turning on System B

Fig 19.72 Compaction of gutta-percha by keeping the plugger for

10 seconds with sustained pressure

Fig 19.73 Removal of plugger

mass of gutta-percha has cooled, set and not dislodged

(Fig 19.74).

Following radiographic confirmation, canal is ready for

the backfill by any means

Advantages of System B

• It creates single wave of heating and compacting thereby

compaction of filling material can be done at same time when

it has been heat softened.

• Excellent apical control.

• Less technique sensitive.

• Fast, easy, predictable.

• Thorough condensation of the main canal and lateral canals.

• Compaction of obturating materials occurs at all levels

simultaneously throughout the momentum of heating and

compacting instrument apically.

LATERAL/VERTICAL COMPACTION

OF WARM GUTTA-PERCHA

Vertical compaction causes dense obturation of the root canal, while lateral compaction provides length control and satisfactory ease and speed

Advantages of both of these techniques are provided by

a newer device, viz Endotec II which helps the clinician to

employ length control with warm gutta-percha technique

It comes with battery which provides energy to heat the attached plugger and spreader (Fig 19.75).

Technique

• Adapt master gutta-percha cone in canal

• Select endotec plugger and activate the device

• Insert the heated plugger in canal beside master cone to be within 3 to 4 mm of the apex using light apical pressure

Fig 19.74 Apical filling of root canal completed

Obturation of Root Canal System 313

Fig 19.75 Obturation using Endotec II device

• Afterwards unheated spreader can be placed in the canal

to create more space for accessory cones This process is

continued until canal is filled

technique because it was widely promoted by Coolidge,

Lundquist, Blayney, all from Chicago.

• One end of gutta-percha is mounted to heated plugger

and is then carried into the canal and apical pressure is

McSpadden introduced a technique in which heat was used to decrease the viscosity of gutta-percha and thereby increasing its plasticity This technique involves the use of

a compacting instrument (McSpadden compacter) which resembles reverse Hedstorm file (Fig 19.76) This is fitted

into latch type handpiece and rotated at 8000 to 15000 rpm alongside gutta-percha cones inside the canal walls At this speed, heat produced by friction softens the gutta-percha and designs of blade forces the material apically

Because of its design, the blades of compaction break easily if it binds, so it should be used only in straight canals But now-a-days, its newer modification in form of microseal condenser has come which is made up of nickel—titanium Because of its flexibility, it can be used in curved canals

This technique was introduced in 1977 at Harvard institute

It consists of an electric control unit with pistol grip syringe

Fig 19.76 Thermomechanical compaction of gutta-percha

314 Textbook of Endodontics

and specially designed gutta-percha pellets which are heated

to approximately 365 to 390°F (185–200°C) for obturation In

this, regular beta-phase of gutta-percha is used

For canal to filled by obtura II, it should have:

• Continuous tapering funnel shape for unrestricted flow of

softened gutta-percha (Fig 19.77).

• Apply sealer along the dentinal walls to fill the interface

between gutta-percha and dentinal walls

• Place obtura needle loosely 3 to 5 mm short of apex, as

warm gutta-percha flows and fills the canal, back pressure

pushes the needle out of the canal (Fig 19.79).

• Now use pluggers to compact the gutta-percha, pluggers

are dipped in isopropyl alcohol or sealer to prevent sticking

of the gutta-percha

Continuous compaction force should be applied

throughout the obturation of whole canal to compensate

shrinkage and to close any voids if formed

Variations in Thermoplasticizing Technique of Gutta-percha

Ultrasonic Plasticizing of Gutta-percha

• It has been seen that ultrasonics can be used to fill the canals by plasticizing the gutta-percha

• Earlier cavitron US scaler was used for this purpose but itsdesign limited its use only in anterior teeth

• Recently ENAC ultrasonic unit comes with an attached spreader which has shown to produce homogenous compaction of gutta-percha

Ultrafil System

• This system uses low temperature, (i.e 70°C) plasticized alpha phase gutta-percha

• Here gutta-percha is available in three different viscosities for use in different situations

• Regular set and the firm set with highest flow propertiesprimarily used for injection and need not be compacted manually Endoset is more of viscous and can be condensed immediately after injection

Technique

• Cannula needle is checked in canal for fitting It should be

6 to 7 mm from apex (Fig 19.80) After confirmation it is

placed in heater (at 90°) for minimum of 15 minutes before use

• Apply sealer in the canal and passively insert the needle into the canal As the warm gutta-percha fills the canal, itsbackpressure pushes the needle out of the canal

Fig 19.77 Tapering funnel

shaped of prepared canal

is well suited for obturation

using obtura II

Fig 19.78 Needle tip of obtura II

should reach 3–5 mm of apical end

Fig 19.79 Compaction of

gutta-percha using plugger Fig 19.80 Needle should reach

6–7 mm from the apical end

Obturation of Root Canal System 315

• Once needle is removed, prefitted plugger dipped in

alcohol is used for manual compaction of gutta-percha

Difference between obtura II and ultrafil II

SOLID CORE CARRIER TECHNIQUE

Thermafil Endodontic Obturators

Thermafil endodontic obturators are specially designed

flexible steel, titanium or plastic carriers coated with alpha

phase gutta-percha Thermafil obturation was devised by

W Ben Johnson in 1978 This technique became popular

because of its simplicity and accuracy

In this carriers are made up of stainless steel, titanium or

plastic They have ISO standard dimension with matching

color coding in the sizes of 20 to 140 (Fig 19.81).

Plastic carrier is made up of special synthetic resin

which can be liquid plastic crystal or polysulfone polymer

The carrier is not the primary cone for obturation It acts as

carrier and condenser for thermally plasticized gutta-percha

(Fig 19.82).

Plastic cores allow post-space to be made, easily and

they can be cut off by heated instrument, stainless steel bur,

diamond stone or therma cut bur (Fig 19.83).

Technique (Figs 19.84A to D)

• Select a thermafil obturator of the size and shape which

fits passively at the working length (Fig 19.85) Verify the

length of verifier by taking a radiograph (Figs 19.86 to

19.88).

• Now disinfect the obturator in 5.25 percent sodium

hypochlorite for one minute and then rinse it in 70 percent

alcohol

• Preheat the obturator in “Thermaprep” oven for sometime

(Fig 19.89) This oven is recommended for heating

obturator because it offers a stable heat source with more

control and uniformity for plasticizing the gutta-percha

• Dry the canal and lightly coat it with sealer Place the

heated obturator into the canal with a firm apical pressure

(Fig 19.90) to the marked working length (Figs 19.91

and 19.92).

Fig 19.81 Thermafil cones

Figs 19.84A to D Root canal of mandibular second premolar using

thermafil obturator (A) Preoperative radiograph; (B) Working length radiograph; (C) Thermafil cone in place; (D) Postobturation radiograph

Courtesy: Anil Dhingra

A

C

B

D

Fig 19.82 The carrier is not primary cone for obturation It acts as a

carrier for carrying thermoplasticized gutta-percha

Fig 19.83 Therma cut bur

316 Textbook of Endodontics

Fig 19.85 Selection of thermafil obturator

Fig 19.86 Thermafil obturator

Fig 19.87 Taking thermafil obturator for obturation

Fig 19.88 Checking fit of cone up to marked working length

Fig 19.89 Thermaprep oven

Fig 19.90 Placing heated

obturator in the canal with firm pressure

Fig 19.91 It should reach up to the

working length

• Working time is 8 to 10 seconds after removal of obturator

from oven If more obturators are required, insert them

immediately

• Verify the fit of obturation in radiograph When found

accurate, while stabilizing the carrier with index finger,

sever the shaft level with the orifice using a prepi bur or

an inverted cone bur in high speed handpiece (Figs 19.93

and 19.94).

• Do not use flame heated instrument to sever the plastic

shaft because instrument cools too rapidly and thus

Obturation of Root Canal System 317

Fig 19.92 Silicone stop should be used for confirming the length of cone

may cause inadvertent obturator displacement from the canal

Advantages

• Requires less chair side time.

• Provides dense three dimensional obturation as gutta-percha flows into canal irregularities such as fins, anastomoses, and lateral canals, etc.

• No need to precurve obturators because of flexible carriers.

• Since this technique requires minimum compaction, so less strain while obturation with this technique.

Success-Fil (Figs 19.95 and 19.96)

• Success-Fil (Coltene/Whaledent, inc.) is a carrier based system associated with ultrafill 3D

• Gutta-percha used in this technique comes in a syringe Sealer is lightly coated on the canal walls, and the carrier with gutta-percha is placed in the canal to the prepared length

• The gutta-percha can be compacted around the carrier with various pluggers depending on the canal morphology

• This is followed by severing of the carrier slightly above the orifice with a bur

Cold Gutta-percha Compaction Technique

Gutta Flow

Gutta flow is eugenol free radiopaque form which can be injected into root canals using an injectable system It is self-polymerizing filling system in which gutta-percha in powder form is combined with a resin sealer in one capsule

Fig 19.93 Cut the thermafil using therma cut bur

Fig 19.95 Success-Fil obturation system

Fig 19.94 Complete obturation using thermafil

318 Textbook of Endodontics

Composition: Gutta flow consists polydimethyl siloxane

matrix filled with powdered gutta-percha, silicon oil, paraffin

oil, palatinum, zirconium dioxide and nano silver

OBTURATION WITH SILVER CONE

Silver cones are most usually preferred method of canal

obturation mainly because of their corrosion Their use is

restricted to teeth with fine, tortuous, curved canals which

make the use of gutta-percha difficult (Fig 19.97).

Indications for use of silver cones

the remaining canal with accessory gutta-percha cones

• Remove excess of sealer with cotton pellet and place

restoration in the pulp chamber

Fig 19.96 Success-Fil carrier based cone

Fig 19.97 Cross-section of canal obturated with silver cone showing

poor adaptation of the cone in irregularly shaped canal

Stainless Steel

They are more rigid than silver points and are used for fine and tortuous canals They cannot seal the root canals completely without use of sealer

APICAL THIRD FILLING

Sometimes apical barriers are needed to provide apical stop in cases of teeth with incomplete root development, over-instrumentation and apical root resorption Various materials can be used for this purpose They are designed to allow the obturation without apical extrusion of the material

in such cases

Apical third filling

• Carrier-based system – Simplifill oblurator – Fiberfill obturator

• Paste system – Dentin chip filling – Calcium hydroxide filling

Simplifill Obturator

It was originally developed at light speed technology 80 as

to complement the canal shape formed by using light speed instruments In this the apical gutta-percha size is same ISO size as the light speed master apical rotary Here a stainless steel carrier is used to place gutta-percha in apical portion of the canal (Figs 19.98 and 19.99)

Steps

• Try the size of apical GP plug so as to ensure an optimal apical fitting This apical GP plug is of same size as the light speed master apical rotary (Fig 19.100)

• Set the rubber stop 4 mm short of the working length and advance GP plug apically without rotating the handle

Obturation of Root Canal System 319

Fig 19.99 Simplifill stainless steel carrier with

apical gutta-percha plug

Fig 19.98 Simplifill obturator

Fig 19.100 Check the fit of apical gutta-percha (GP) plug

Fig 19.102 Once GP plug fits apically, rotate the carrier anticlockwise

without pushing or pulling the handle of carrier

Fig 19.101 Condense apical GP plug to working length

Fig 19.103 Backfilling of canal is done using syringe system

• Coat the apical third apical rotary

• Again set the rubber stop on carrier to working length and

coat the GP plug with sealer

• Penetrate the GP plug to the working length without

rotating the handle (Fig 19.101)

• Once GP plug fits apically, rotate the carrier anticlockwise

without pushing or pulling the handle of carrier (Fig

19.102).

• Now backfilling of canal is done using syringe system (Fig 19.103).

Fiberfill Obturator

• This obturation technique combines a resin post and obturator forming a single until and apical 5 to 7 mm of gutta-percha

• This apical gutta-percha is attached with a thin flexible filament to be used in moderately curved canals

Dentin Chip Filling

Dentin chip filling forms a Biologic seal In this technique

after through cleaning and shaping of canal, H-file is used to

produce dentin powder in central portion of the canal, which

is then packed apically with butt end of paper point

Technique

• Clean and shape the canal

• Produce dentin powder using hedstroem file or Gates-

Glidden drill (Fig 19.104).

• Backpacking is done using gutta-percha compacted

against the plug (Fig 19.107)

Care must be taken in this technique, because infected pulp tissue

can be present in the dentinal mass.

Calcium Hydroxide

It has also been used frequently as apical barrier Calcium

hydroxide has shown to stimulate cementogenesis It can be

used both in dry or moist state

Fig 19.104 Dentin chips produced by use of Gates-Glidden drills

Fig 19.105 Chips being compacted with blunt

end of instrument/paper point

Fig 19.106 Compaction of dentin chips apically

Fig 19.107 Compaction of dentin chips in apical 2 mm from working

length to stimulate hard tissue formation

Obturation of Root Canal System 321

Moist calcium hydroxide is placed with the help of plugger

and amalgam carrier, injectable syringes or by lentulospirals

Dry form of Ca(OH)2 is carried into canal by amalgam

carrier which is then packed with pluggers (Fig 19.108)

Calcium hydroxide has shown to be a biocompatible material

with potential to induce an apical barrier in apexification

procedures

Mineral Trioxide Aggregate

Mineral trioxide aggregate was developed by Dr Torabinejad

in 1993 (Fig 19.109) It contains tricalcium silicate, dicalcium

silicate, tricalcium aluminate, bismuth oxide, calcium sulfate

and tetracalcium aluminoferrite

pH of MTA is 12.5, thus having its biological and

histological properties similar to calcium hydroxide Setting

time is 2 hours and 45 minutes In contrast to Ca(OH)2, it

produces hard setting nonresorbable surface

Because of being hydrophilic in nature, it sets in a moist

environment It has low solubility and shows resistance to

marginal leakage It also exhibits excellent biocompatibility

in relation with vital tissues

To use MTA, mix a small amount of liquid and powder

to putty consistency Since, MTA mix is a loose granular

aggregate, it cannot be carried out in cavity with normal

cement carrier and thus has to be carried in the canal with

messing gun, amalgam carrier or specially designed carrier

(Fig 19.110) After its placement, it is compacted with

micropluggers

Advantages of MTA include its excellent biocompatibility,

least toxicity of all the filling materials, radiopaque nature,

bacteriostatic nature and resistance to marginal leakage

However it is difficult to manipulate with long setting time

(3–4 hours)

Coronal Seal

Irrespective of the technique used to obdurate the canal,

coronal leakage can occur through well obturated canals

Fig 19.108 Placement of Ca(OH)2 in the canal

Fig 19.109 Mineral trioxide aggregate

resulting in infection of the periapical area Coronal seal should be enhanced by the application of restorative materials (like Cavit, Super EBA cement, MTA) over the canal orifice

POSTOBTURATION INSTRUCTIONS

Sometimes patient should be advised that tooth may

be slightly tender for a few days It may be due to sensiti vity to excess of filling material pushed into periapical tissues For relief of pain, NSAID and warm saline rinses are advised Anti-inflammatory drugs such as corticosteroids and antibiotics should be prescribed in severe cases Patient

is advised not to chew unduly on the treated tooth until it is protected by permanent restoration

Patient Recall

Patient should be recalled regularity to evaluate tissue repair and healing progress

Fig 19.110 Due to loose, granular nature of MTA, a special carrier like

messing gun or amalgam carrier is used for carrying it