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RECENT OBTURATION TECHNIQUES Introduction The final of endodontic treatment is to fill the entire root canal system and all its complex anatomic pathways completely and closely with non irritating hermatic sealing agents. Total obliteration of the canal space, perfect sealing of the apical foramen at the dentin cementum junction, accessory canals at location other than the root apex with an inert, dimensionally stable and biologically compatible material are goals for consistently successful endo treatment. Obturation of a root canal should result in a complete seal from the coronal aspect to the apex preventing the entry of microorganisms and fluid About gutta percha: Gutta percha is the most widely used material for obturation of root canals since it is relatively inert, non toxic and biocompatible. Gutta percha (GP) exists in two phases α and β. If the naturally occurring α phase GP is heated above 65°C it becomes amorphous and melts. Cooling this amorphous material extremely slowly at the rate of 5°C/hr will re crystallize the alpha form. Routine cooling of the amorphous melted material results in β form. This form is commercially used as it is solid, elongatible and compactable. The α phase gutta percha possess adequate rigidity to be placed to length along with a low melting temperature, low viscosity and increased fluidity to fill the root canal irregularity. β phase GP has a higher melting pt and viscosity that allow it to flow into canal intricacies when heated. GP harvested from trees is mainly α phase and is used in the latest thermoplasticized techniques. β from when heated to 42-49°C changes to α form. Old Techniques Lateral condesation - the most commonly used obturation technique was first advocated by Callahan in 1914. This method is time consuming difficult in curved or fine canals. In curved canals the gutta percha should be compacted by placing the spreader against the inner curve. So the more rigid spread follows the gentler outer curve. So that the spreads does not pull out the master GP. Also the success is more or less operator dependant. Vertical condensation – manually is also a method commonly used. Disadvantages of these – Pressure exerted in these two methods by the spreaders and pluggers in an attempts to condense the GP into a solid mass generates stresses. These stresses can deform the roots and create microfractures within the dentine. This deformation may propagate under occlusal load and manifest later as longitudinal root fractures especially after post preparation. These techniques may produce many irregularities in the mass of GP.

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1. It does not reproduce canal fins and irregularities. 2. The surface of the material is frequently rough and pitted with inadequate dispersion of the sealer. 3. The voids that are produced may remain empty or filled with sealer which may resorb in time, thus decreasing the effectiveness of the obturation. Chemically plasticized GP – many solvents like chloroform, eucalyptol and halothane are used to dissolve GP and obturate the canal. The main drawback of this method is that once the solvent evaporates the GP may shrink and a space may be created. To overcome these disadvantages the thermo plasticized gutta percha techniques have been introduced.

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These techniques are classified by Bhatti & Joshi (1997) as Intraradicular

Extraradicular

In this the GP is heated within the RC and allowed to flow into the RC.

In this the GP is heated outside the mouth and then placed in the RC.

The intraradicular techniques are Touch ‘n’ heat lateral condensation 1. Schilders vertical condensation 2. System B (Buchanan) 3. Endo tec 4. Thermopact MECHANICAL 1. Thermo compactor 2. Automated plugger 3. Ultrasonic plastizing 4. High speed sectional Extraradicular techniques 1. Terma fill 2. Obturation 3. Success fill 4. Ultrafil etc.

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Extraradicular techniques Endotec: Considering the ease and speed of lateral compaction and the superior density gained by vertical compaction of warm GP as stated by Schilder in 1967, Martin in developed a device that appears to achieve the best qualities of both techniques. This device is called “Endotec”, endotec is a thermal compacter consists of a cordless handpiece containing a battery that supplies energy to heat the attached spreader / plugger tips. When not in use the hand piece sits in a battery charger base. The quick change heated tips are sized equivalent to No. 30 and No. 40; 150 files. Procedure Canal preparation – continuous taper design with definite apical stop. 

Dry the canal

Sealer application

Primary adaptation with hand or finger spreader

Additional GP placed to reduce the possibility of warm plugger loosening the patient when the tip is retracted.

Endotec placed in canal to full depth

Activator button pressed and plugger / spreader moved in clockwise direction.

Angle button is released and plugger cods immediately

Now remove in counter L wise direction

This motion has now formed a space for an attributed point to be added

Procedure is repeated

Now the plugger can be used cold to compact the softened GP

Motion for using endotec plugger

Vertical sweeping lat pressure

In this manner the canal is completely obtained. To complete the procedure a cold hand plugger can be used to firmly condensed the fused GP bolus. An Air Force Group in 1993 also found that they could improve compaction in a molar with C shaped canal by using the endotec with a Zap and tap method. Tap & Tap Procedure 

Preheat the endotec for 4-5 secs before insertion (Zap).

Move the instrument in and out in short continuous strokes 10-15 times. (Tap)

The plugger was removed while still hot.

Told spreader is used and accessory points are placed.

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The two causes for concern with this treatment may be – over heating, development of stresses. Castelli in 1991 stated that there was no heat related damage to periodontium from endo tec. A US army group showed that heat produced by endotec – Max 500°C is less than that of other heat devices like the touch N and unit. They stated that even though the internal temperature may reach upto 102°C GP and dentin are poor conductors of heat so this temperature may not cause damage to periodontium. Martin in 1990 showed that endotec creates less stresses than cold lateral condensation. Touch ‘n’ heat unit The main disadvantage with schilders ‘V’ compaction is the need to warm the GP with an instrument heated over the flame. To over come these disadvantages analytic technologies develop of the first GP heating units the Touch N heat model 5001. Also models 5002, 5004 are available with different tips. The touch N heat 5003 is an electronic device specially developed for the warm vertical compaction of gutta percha. Battery /AC models are available. It exhibits the same thermal properties as the original heat carried used by schilder in 1967 but has the advantage of generating heat automatically at the tip of the instrument. This instrument is capable of providing a range of high temperatures instantly ranging from 0°-700°C. Procedure -

Master cone is fitted

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Schilders pluggers are prefitted Coronal 1/3 – wide Middle 1/3 – narrow Apical 1/3 – narrows

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Master cone is placed Touch N heat unit is carried into the canal and left there for 2-3 seconds to allow the heat to transfer.

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It is then withdrawn with slightly circular / wiping motion.

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Some of the GP gets frozen on the carrier.

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Immediately vertical compaction follows.

Precautions with this system are that the operator should restrict the use of system at the lower power setting No. 243 and increase the amount of the time the heated tip is activated. Jurcate J.J. et al in 1992 said that if it is used at the No. 6 setting the temperature might rise upto 114-51° which is a potentially damaging temperature.

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Advantages of this method are 1. No need for an open flame. 2. Some amount of control over temperature generated. System B (Buchanan 1996) Recently Analytic technology introduced the system B heat source model 1005. this instrument has a digital temperature display and a variable resistor control that allows the user to use the desired temperature. These heat carriers are designed as pluggers that concentrate the heat at the tip of the carrier. The system B is based on the schilder technique. The tapered pluggers the system B heat upto 200°C at the tip at the touch of a button. This softens the GP in ½ seconds. A wave of heat (250°-300°C) is produced as the plugger is forced through the already fitted cone is used to drive the GP into the canal. As the plugger approaches the apex the heat button released and apical pressure is maintained with the plugger for a 10 second. Sustained push to take up the shrinkage that occurs on cooling. The heat button is pushed again while maintaining pressure. A surge of heat is produced 300°C – 5 seconds. That immediately separates the plugger from the apical mass of gutta percha. Thus it can be rapidly with drawn. The canal is then backfilled with the same technique or obturation. Disadvantages 1. Breakage and kinking of spreader. Advantages -

Void elimination created during normal lateral condensation of warm GP.

Silver GK et al in 1999 conducted a study on “compression of 2 vertical condensation obturation techniques – touch and heat and system B. They concluded that system B may produce an acceptable obturation and produces less heat than touch and heat. The heat produced by system B is accurate upto ±10°C. It is generally accepted that a 10°C evaluation temperature on the root surface can irreversibility damage the periodontium silver status that the system B techniques kept the temperature normal not exceeding 10°C. also the obturation by this method was faster. Thermopact Consists of a unit containing a transformer and an electronically controlled circuit for heat generation. It also has a hand piece adapted with different sized spreaders and heat carriers. The temperature can be selected regulated and maintained at any desired level from 40°C to 70°C. Sauveur suggested that thermopact must be ideally set and maintained at 42°C for warm lateral condensation at about 59°C for warm vertical condensation.

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The main advantage of the system B over the touch N angle is that when silver tested the temperature produced by T & angle and system B system B produced less angle. Termomechanical Compactors The Mcspadden compactor was introduced in 1978. It resembles a reverse hadstrom file fitted into a handpiece and spins in the canal at speeds between 8000 and 20000 rpm. The heat generated softens the already fitted GP and the design of the blades forces the gutta percha apically.

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The disadvantages of this technique were 1. Fragility of the instruments as the compactor rotates at 360°C at full speed therefore leads to fatigue failure. 2. Cannot be used in narrow canals. Maillefer modified the Hedstreem type instrument as the gutta condenser and zipper called its modification the engine plugger. The zipper thermo compactor resembles an inverted K file. Mc Spadden modified his original patent and introduced the NT condenser. It is supplied as an engine driven or hand powered Nickel titanium instrument. It advantages is flexibility. The NT condensor is use with heat softened ι phase GP, Normal GP. Procedure -

Place primary GP

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Appropriate size condense coate with gutta percha (angle softned) GPI and GP II.

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The condenseris then spin in the canal at 1000-4000 rpm which flings the GP laterally and vertically.

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The speed is controlled by NT matic hand piece.

Hybrid Technique This was put fourth by Tagger of Tel Aviv in 1984. In this technique first a primary cone is fitted followed by an accessory point. An engine plugger is places and rotated at 15000 rpm after 1 second it is advanced into the canal until resistance is meet. It is then slowly backed out while still rotating. This whole procedure takes just 2-3 seconds. The hybrid technique is quicker to complete and easy to master. Also overfilling is less likely. JS Quick Fill This system is designed to be a thermomechanical solid core GP obturation technique. This system has titanium core devices resembling latch type drills. These are coated with alpha phase gutta percha. These are then fitted to the prepared root canal and then, following sealer are spin in the canal with regular low speed latch type hand piece. Frictional heat plasticizes the gutta percha and it is compacted to place by the design of the quick fill core. After compactor either the compactor may be removed and final compaction dov with hand plugger or the titanium core may be left in place and separated by an inverted cone bur. Automated Plugger The canal finder plugger is a stepwise flexible plugger sloped like a telescope. It is used in a canal finder handpiece which delives a rapid vertical stroke that varies between 3 and 1mm.

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Procedure -

Sealer placement

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Master cone placement

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Next, the vertical vituating plugger is kept.

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The edges of the plugger blades catch in the gutta percha.

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GP gets compacted vertically and laterally.

This method may have some discrepancies. Ultrasonic Plasticizing Suggested by Moreno in 1977, he used a cavitron scaler with a PR 30 inert can be used only in anterior (cavitron). Procedures -

Primary patient is placed

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Unit is placed beside GP, the US unit with the rheostat set at 1 activated for 3-4 sec.

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The ultrasound thermal energy released by vibratory motion of the ultrasonically file plastisizes the GP.

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The file is removed and the spreader is immediately inserted to make space for new cone.

Joiner in 1989 found that the heat produced was 6.35°C into 3 sec by this method. He thus concluded that the heat produced by the cavitron would not be harmful. The Inac ultrasonic unit has also been used with a certain degree of success by Baumgardner in 1997. In this unit a spreader is attached. In this method the GP was not plasticized. They felt that the spreader more easily penetrated the cross of GP than did the finger spreaders and that in the end the energized spreading led to a more hamogenous mass with less stress and less apical microleakage. The heat generated with the enac ultrasonic unit was found to be more i.e. 191°C rise in temperature to obdurate. This system is inferior to the cavitron P30 unit. Light Speed Sectional Method A two phase obturation technique has been proposed by light speed technology – Texas. This technique advocates the use of a stainless steel carrier to place and condense a 5mm section of gutta-percha into the apical portion of the canal. Once placed the carrier is termed and removed leaving a gutta percha plug. The second phase uses a rotary instrument to back fill the remainder of the canal with the Ketac Endo and a single GP cone. The technique was first studied met by Santos DM et al in 1999.

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Method A GP plug the same size as the master apical rotary was selected. MAR – is the final apical size of the instrument which is used to prepare the canal last. -

The canal and plug were coated with sealer.

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The plug was inserted and vertically condensed to WL

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By using moderate apical pressure.

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The carrier is removed by tuning its handle counter clock wise until the plug was released and the carrier could be removed and easily detached from the GP.

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The second phase, a light speed backfill instrument was used to carry the Keta endo sealer into the canal orifice.

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This was rotated at 1000-2000 RPM and advanced apically till the apical Gp plug was reached.

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The instrument was then removed while wiping against one wall.

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This was repeated till the canal was filled with sealer.

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The master cone was then coated with sealer and placed till the apical plug.

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The excess GP was then removed at the level of canal orifice.

The HS techniques is similar to the sectional method described by grossman and Coolidge. The difference with this technique is that slight apical force seates the tapered plug into a parallel apical preparation whereas in the sectional technique the master cone is passively seated to working length. Because of this modification a right apical seal should be produced. Although not specifically measured the time involved in this method is lesser than the conventional technique. Extra radicular techniques Thermo plasticized gutta percha, in these techniques the gutta percha is heated outside the mouth and is already softened before insertion. These can be classified as 1. Injectable systems -

Obturation

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UF

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PAC 100

2. Solid core carried insertion systems -

Termofil

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Densfil

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Success fil

3. Multiphase techniques -

Microseal

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-

Alphaseal

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Trifecta

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Injectable systems

This technique involves injecting molten GP into the root canal system. Important points to remember regarding these methods. 1. The delivery middle should be 3-5 mm within working 2. Inadequate temperature control leads to poor results. 3. As the GP cools it shrinks condensation pressure is needs 4. Over extension may result Introduced 1st in 1977 by Yee called gutta gun, obturation is a convenient delivery system. Relatively flexible silver needles of different sizes 18, 20, 25 gauge are used to introduce the plasticized GP into the canal. The injection – averages less than 20 seconds. Upon completion of the injection the GP remains sufficiently plasticized for upto 2 minutes which is enough time for manual condensation. extruted GP has a temperature of 62-65°C and may remain soft for 3 minutes. To counter balance the effect of dimensional change continuous condensation force must be exceeded during cooling. Today, through further improvements this system is marketed obturation II heated GP system (exceed). Temperature range  160°-200° Needle size  20 gauge 60 file 23 gauge 40 file β phase GP is used. Preparation  continuously tapering funnel from apex to canal orifice. This ehances the flow the plasticized material. Advantages 1. Piston grip syringe is more resistant to higher temperature. 2. Control is equipped with digital read out of the temperature 3. silver needle is disposable and better designed for added advantages and infection control. Used in -

Irregular shaped wide canals.

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Internal resorption defects.

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Incompletely formed roots with induced apical barriers.

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-

Retrofilling after surgery.

Important patient to be remembered -

A denitive apical matrix is very important.

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Use only the GP which is made for the system which has a high molecular weight.

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Once it is heated it should be used within 15 minutes.

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A slow setting sealer should be used which is not affectably heat.

Procedure Two methods may be used. I. Sealer placement (½ drops) -

An increment of GP with obturation.

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Compacted (for segmental filling) apically and laterally.

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Then back fill with obturation GON

II. The second method is to place a master gutta percha cone. -

Then the obturation needle tip deposites the GP all around the master cone.

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Lateral and vertical compaction is done.

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Apical 1/3 to middle 1/3 is the most critical area of preparation.

Gutta percha is heated in a prototype pressure syringe which warms it to the required temperature. This second method is better as less chances for GP extrusion are seen. The main disadvantage of this method is that it is operator dependent and it takes time to master this technique. Efficacy of Obtura II One doubt that arises is about the intracanal temperatures rise at the time of injector. Mean and temperature in vitro studies was 63.7°C. the temperature rise on the overlying bone was 1.1°C / 60 seconds. This is said to be as after temperature level according to Gutt man 1987. Bone injury occurs with a temperature rise of 10°C if maintained for 1 minutes. Wilson 1987, Stavos 1986, Martin in 1986 this system fills fins, euldesacs internal resorbtion cavities, C shaped canal, accessory canals and carorized foramina. PAC – 160 (Whale dent Int /NY) In 1981 Schoeffel designed and built a prototype delivery system to operate indefinitely and accurately at 160°C. This unit uses standardized gutta percha. This device is called PAC-160 as it gives precision apical control at 160°C. Cavity preparation: Slight flare coronally definite apical constriction. Advantages

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-

Fills multiple formina

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Irregular configurations of the root canal

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Temperature is not more than 160°C.

Ultrafil System Rather than using traditional b phase GP this method depends upon a patented alpha phase GP supplied in disposable cannules with 22 gauge middles attached. The GP becomes plasticized when warmed to 70°C in a special heater. The warmed cannulas are then placed in a special piston grip syringe for injecting into the canal. The cannules are supplied in 3 different viscosities. Regular Set – doesn’t require condensation, (White cannule). Endo set – must be condensed (Green Cannule). Firm set – Condensation possible but not required (Blue cannule). The α phase gutta percha is made by plasticized the β phase GP under advancing heat. It takes 15 minutes to come to a flowable state in the special heater. Preparation – Continuous taper at 8-10 mm from apex at least upto 50 files definite apical stop is very important or the GP will extrude into the tissues limitlessly. Procedure by Michanowicz in 1984 I. Check for needle fil surgery 8 –10mm from apex. -

WT 6-=70 seconds

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Cannules are heated 15 minutes

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Placed into the injector

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Place in the canal

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Squeeze / release the triggel

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Wait for 3 seconds

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Squeeze / release

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This sends a bolus of GP towards apex.

The needle is not moved till a ‘lift’ is felt. As the material flows to the apex and backflow tends to displace the needle. Pressureless injection is continued as the GP flows and pushes the cannules out of the canal. II. Master cone placement Mich in 1992 Hand spreader creates space -

Needle positioned beside the point

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2 increments of squeeze / release are made.

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After this material sets a little.

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The canal is backfilled allowing the needle to be gradually displaced by the deposit.

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The regular set: cannot be compacted because of its soft consistency. Also it does not reach a full set for 30 minutes. Endoset – the high viscosity GP that has less flow can be compacted hence either vertical / lateral compaction can be done. Procedure with Endoset Sealer application – two squeezes of the endoset are injected 8-10 mm from apex and immediately compacted apically and laterally with prefilled plugges. Coafirm apical seal radiographical. Back fill with increments of endoset condensed with increasingly large pluggers. Endoset is completely set in two minutes. Firmset – light bodied and good flow properties. May be used to dypars the broken instruments is loose in the canal or fill resorbtive defects. In 1988 Ritchie G.M et al found a method to control the apical extrusion of this system. The apical foramen is first blocked with sealer. A section of silver point is left behind as the remainder of the point is twisted off where it was scored with a bur followed by warm GP. The Michano Wicz group reported that the low temperature GP will flow into the dentinal tubules thus improving the apical seal. Precautions to be take with this method. 1. The trigger should be squeezed slowly and steadily under haste may cause excessive pressure which may fracture the cannula. Efficacy of ultrafil There have been repeated warmings of warm GP shrinking as it cools. Ultrafil regular and firmest are thus questionable as the shrink 2.2% yet all too fluid and cant even be compacted. Possibly the fact that they flow into the dentinal tubules is their saving geace. Thus to use these systems smear layer removal is very important. Tragic and Frightening cases of over extrusion beyond the apex have been reported by Gatot in 1989, haconebe reported significantly more over extension with low temperature GP than lateral compaction. Thus with this method the apical stop becomes crucial. Solid core carrier section Thermofil: In 1978 Johnson described a unique yet simple method of canal obturation with thermoplasticized alpha phase gutta percha carried on an endodontic file. In 1988 this system finally got recognition and was introduced as Thermofil. Thermofil is patented endodontic obturator consisting of a flexible central carrier, sized and tapered to match standard endodontic files that are uniformly coated with refined and tested alpha phase gutta percha. Initially stainless steel carriers were introduced. here they may be heated in flame and then introduced into the canal. Later the carriers were made of titanium radio opaque plastic.

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It is recommended that all three types should preferrebly be heated in the thermapreparation over at 115째C for 3-7 minutes depending on the size which ranges from 20-140. The GP coating extends beyond the carriers by 1-2mm. Preparation continues taper preparation. The coronal portion of the carrier has markings with a rubber stop. The GP normally cools the 1st 2/3 graduation meter at 18, 19 / 20mm. Plastic carries are used nowadays -

These are relatively flexible.

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Small sizes 25, 30, 35 have a incrementally greater taper than the normal 25, 30 / 35 sized files.

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Sizes below 40 are made of a liquid plastic crystal and are not soluble.

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Sizes above 45 are made from a polysulfone polymer and may be dissolved in organic solvents.

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Dry canal

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Apply thin coal of sealer, thermoseal, AH 26, Selabex, ZnOE Cen this acts as an adhesive + lubricant.

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Warm the oburator and carry it slowly to full working length.

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Radiographically confirm the position of the oburator

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Sever the shaft in the coronal cavity, with a HO 37 no cone beel.

Blank plastic carries are available to gauge the appropriate size for a canal The obturator may be heated in a Flame

Thermopeepove

Obturator must be passed in the blue zone if passed thru the hotlest yellow zone they may ignite. The obturator is ready when it takes on a sheer and expands. Johnson suggested that final compaction can be completed and improved if a 4-5mm piece of regular GP is then inserted into the softened GP. A large plugger can also be used to apically compresses the gutta percha all around the central carrier. Final set is reached in 2-4 minutes. When the GP reaches the apical stop the metal or plastic carrier still continues apically more compaction apically and laterally. Important Point 1. In teeth with multiple canals the other orifices must be sealed with damp cotton wool or the GP may back the other orifices. 2. The coronal excess may also be pretrimmed to avoid blockage of other canals. Potential problems 1. Extrusion 2. Post space creation

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3. Retreatment Prepi These are strongly recommended if a post is to be placed. The latest device to melt the gutta percha and plastic carries is the prepost preparation instrument ‘Prepi’ that is used in a latch type handpiece. Frictional heat generated by this hot cutting bladeless metal ball melts the material. Metal carries GP is removed at the required level using here. The carries is noteched with a diamond bur. Cross sectional diameter of the carries is reduced to 0.6mm. The heated carries is reached to WL without rotation. Once fully separated the coronal part of the carries is separated by applying apical pressure and turning the handle clockwise. If post space preparation has to be delayed then the rubber stopper is slid towards the orifice and only the carrier is removed. Vertical compaction is then done with a moist cotton pledge. For metal carries they are scored at the breakage point 4-5mm from the apex and then twisted off counter clockwise after the obturator fully reaches the apex. Advantages -

Quick & easy

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They can be curved to fill curved canals.

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To fill internal resorbtive defects.

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Open apices.

Efficacy of thermofil in 1989 christensen stated that thermal allows simple fast predictable filling of root canals. Especially useful for small or curved canals, technique sensitive. Shoen Rock in found that the plastic carriers provided the most complete system. In 1997 Weller N.R. studied adaptation to the canal walls of these techniques and found that the order of perfect adaptation was -

Plastic

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Titanium

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Stainless steel

Retreatment of canals may prove difficult because carriers jammed in the canals all very difficult to remove. Success Fill System In completion with thermal the hygienic corporation introduced success fill. The only difference between these two systems is that here the GP in a warm plasticized shape is added to the carrier just before it is inserted into the canal. These syringes contain high viscosity GP that sets in two mintues.

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Carriers – titanium r’op plastic They are inserted to the measured depth in the syringe and are then extended by forcing the plunger. Rapid withdrawal tapering shape. Slow with drawal  cylindrical shape Procedure -

Core section full to length without binding

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Then carrier is coated with GP and inserted to full depth.

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A plugger is used to compact the GP around the core.

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The core is separated by holding the handle and severing the core shaft 2 mm above the orifice.

To date no reports have been published regarding this technique. Multiphase GP The multiphase GP obtained tech uses 2 different kind of GP tooth --- the canal. α phase  rigid enough to place in the canal and low in point, low viscosity and more fluidity to fill the RC irregularities. β phase  high M point and viscosity to flow into canal intricacies when heated. These techniques involve the use of both α and β phases of gutta percha. They may also be a combination of the above techniques. Trifecta system This method uses the combination the success fill and ultra fill. Procedure 2-3 mm of warm GP is retrieved from the success fill syringe on the tip of an endo file. Which is one size smaller than the last file used. This plug of GP is then carried down the sealer coated canal. When it reaches WL the file is twisted counter clockwise and retrieved. Compaction is done with a pleages. After confirming the placement with radiograph. Ultra fill may be used to back fill the canal. AF Dewani N et al conducted an evaluation of the trifecta obturation technique. They concluded that under laboratory conditions bifecta has more sealability but poorer radio graphic quality than lateral condensation. Alphaseal Alphaseal is one of the systems which attempts to overcome the cooling shrinkage of α phase gutta percha. In this system nickel titanium condensers are coated with β phase GP followed by α phase GP. The dimensionally stable b phase forms the coll and the low viscosity of alpha permits it to flow into the irregularities of the root canal. The gutta percha is speen into the canal by rotating the condenser at speeds of between 1000 and 4000 rpm. It is then withdrawn as the canal fill from the apex to the coronal aspect.

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Advantage Canals can be prepared with NiFi files and then obturated with the condensor. Disadvantage Control of material within the canal is difficult. In 1999 Davalou et al studied the Microseal Endodontic obturation technique. In this technique a master GP cone is first compacted laterally with a spreader an then thermoplasticized GP is delivered and compacted with an electric stainless steel compactor in order to unite with the master cone and fill the canal (stainless steel). Procedures -

Sealers

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Master Cone

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Spreader inserted

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Compacted and removed

The appropriate composite is inserted into a GP cartridge and coated with GP. Compactor inserted carefully, rotates at 6000 rpm slowly backed out till canal is filled. Surplus is condensed with hand plugges. The main advantages with this technique is that since the gutta percha has been already thermoplasticized and it unifies with the master GP cone to an even mass. Other Experimental Techniques 1. Vacuum pressure technique 2. New method for open apex 3. Hydron 4. Calcium PO4 cement Vacuum pressure Russi, Suter and Grosrey in 1997 published an article about obturation of root canal in vivo with a new vacuum technique. A nozzle was fitted on the tooth and the root canals were dried by applying vacuum from a 4 stage vacuum pump. As soon as the required absolute pressure reached a stable value of 10 m bar = 7.5mm Hg the pulp was stopped. Filling paste was then mixed and evaluated by the same pump. -

Reservoir fill with obturating material

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Steel ball placed on the filling material.

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V. pump was turned on

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The desired vacuum was reached again

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A top connects the reservoir with the root canal this was opened.

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The material was sucked into the canal by the vacuum.

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Surprisingly this method did not produce any discomfort to the patient on whom it was tried.

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-

An internal resorbtion cavity in the apical 1/3 which is difficult to fill had been filled.

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Radiographs show that the fillings seen to be dense.

This method appears to have promise as a daily office procedure producing radiographically dense root fillings. CaPO4 obturation Recently calcium phosphate cement has been suggested as a total root canal filling material. ADA – Paffen barger Dental research center have developed a simple mixture of calcium phosphates that sets to become hydroxyapatite. They state that 2 CaPO4 Compounds Acidic

Basic

When mixed with water set into a hardened mass – hydroxyapatite. Base – Tetracalcium phosphate Acid – Dicalcium PO4 dihydrate dihydrous dicalcium PO4. Water is a vehicle for the dissolution of the reactants. Glycerin may be added to extend setting time. Mild phosphoric acid – speeds the dissolution of the components. This cement Not soluble – water No soluble – blood and saliva May be soluble in strong acids Glycerin may also help to make the mixture to a consistency where it can be extruded from a syringe 19 gauge. A funnel shaped needle is also being considered. Tissue reaction studies have shown new bone formation adjacent to the filling and no signs of PA tissue irritation. As a sealer it seems to adhere well to the canal wall. If a delivery system can be found this may be the sealer filler for further endodontics. Firstly – H.A. is a naturally occurring product bone grows into it and replaces extruded material. -

It is very biocompatible

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It may replace CaOH in treating open apex and # root cases.

Lasers Recently, a theory has bee part forth relating lasers to HA. A cross linked collagen HA has bee placed in the RC and melted into place with a laser beam through a fiber optic. There is no published data about this technique. Hydron – A hydrophilic plastic RC filling material. Hydron is an injectable RC filling material. It is get passed on the alcoholic reesterification of methylmethacrlate with ethelene glycol.

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Properties WT – 6-8 mins. R’op – lower than that of GP some authors have reported exceller bio compatibility while others have shown long term inflammation, material absorption and have questions hydrons ability to effect a permanent seal. Some investigates have shown that overfillings with hydron cause longteen severe PA inflammatory response and activates a large number of macrophages containing particles of hydron. But hydron is said to replace fins, irregulation etc excellently. In view of the foregoing controversies further evaluation of hydron as an RC filling is need. Method for open apex Rarezoudis et al in 1999 put forth a new method of adapting gutta percha master cones for obturation of open apex cases using heat. In this method the end point of the primary GP cone is elasticized with a heated instrument and inserted into the root canal to record the internal morphology of the apical portion. Usually 2/3 attempts are needed to obtain satisfaction adaptation. Then the cone sealed in place with a sealer and obturation is complete with lateral condensation. This method was also mentioned by stock and gulabivala. The efficacy, advantages and disadvantages of this method have not been studied yet.

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