OBTURATION
Seminar By
Dr. S. HIMAGIRI Postgraduate Student
DEPARTMENT OF CONSERVATIVE DENTISTRY & ENDODONTICS SRI RAMACHANDRA DENTAL COLLEGE AND HOSPITAL CHENNAI
CONTENTS INTRODUCTION RATIONALE FOR OBTURATION ROOT CANAL FILLING MATERIAL •
IDEAL MATERIAL: REQUIREMENTS
•
GUTTA-PERCHA
•
SILVER POINTS
METHODS OF OBTURATION LATERAL COMPACTION TECHNIQUE VARIATIONS OF LATERAL COMPACTION •
INVERTED POINT TECHNIQUE
•
TAILOR MADE / ROLL CONE TECHNIQUE
•
CHEMICALLY PLASTICIZED GUTTA-PERCHA
VERTICAL COMPACTION OF WARM GUTTA-PERCHA WARM / SECTIONAL GUTTA-PERCHA OBTURATION WARM LATERAL CONDENSATION TECHNIQUE •
ENDOTEC
WARM VERTICAL CONDENSATION METHOD •
TOUCH ‘N’ HEAT
•
SYSTEM B
THERMOCOMPACTion •
MCSPADEEN
•
MALLEFER GUTTA-PERCHA CONDENSER
•
ZIPPER THERMOCOMPACTOR / ENGINE PLUGGER
•
J S QUICKFILL
•
AUTOMATED PLUGGER
ULTRASONIC PLASTICIZING SECTIONAL METHOD •
LIGHT SPEED SECTIONAL METHOD
THERMOPLASTICIZED INJECTABLE GUTTA-PERCHA •
OBTURA II
•
ULTRAFIL
PRESOFTENED NON-INJECTABLE TECHNIQUE •
SUCCESSFIL TECHNIQUE
•
THERMAFIL
TRIFECTA SYSTEM APICAL THIRD FILLING INJECTION OF SPIRAL OBTURATION N-2 SARGENTI TECHNIQUE ERRORS IN OBTURATION SUMMARY
INTRODUCTION Success of non-surgical root canal treatment is predicated by meticulous cleaning and shaping of the canal system, it’s three dimensional obturation, and a well-fitting, “leakage-free” coronal restoration. The techniques of obturation that are available have their own relative position in the historical development of filling techniques. Over the years, pitfalls with one technique have often led to the development of newer methods of obturation, along with the recognition that no one method of obturation may satisfy all clinical cases.
Root canal obturation is defined and characterized as “the threedimensional filling of the entire root canal system as close to the cementodentinal junction as possible. Minimal amounts of root canals sealers, which have been demonstrated to be biologically compatible, are used in conjunction with the core filling material to establish an adequate seal”.
RATIONALE FOR OBTURATION The aim of filling the root canal system is to prevent recontamination by micro-organism, either from those microbes left in the canal after preparation or from new invaders from the coronal access or lateral communications. The root filling should therefore be able to
destroy residual micro-organisms and adapt adequately to root canal walls to prevent their passage or growth. It should also prevent leakage of molecules capable of supporting microbial growth or initiating a periapical defence response. The degree of seal required is dictated by the smallest molecule capable of initiating and sustaining periapical inflammation.
Unfortunately our knowledge of the pathogenesis of
periapical lesions does no extend to such detail and in the absence of such information it would seem wise to seal the canal system as well as the materials available allow.
Before going further, its important to find answers to 3 questions i.e. Why to obturate? When to obturate? With what?
Three Dimensionally well fitted obturation why?? Because it 1. Prevents PERCOLATION of periapical exudates into the root canal. 2. Prevents REINFECTION 3. Creates a FAVOURABLE BIOLOGICAL ENVIRONMENT FOR the process of tissue healing to take place.
When is the root canal ready for obturation?? 1.
The tooth is asymptomatic, no pain, no tenderness, or apical periodontitis.
2.
The canal is dry. There is no exudates/seepage.
3.
No sinus tract
4.
There is no foul odor (suggests residual infection/reinfection due to anaerobes).
5.
Temporary filling is intact (Broken/leaking filling causes recontamination of the canal).
6.
A negative culture.
With what material?? Over the years a large variety of root canal filling materials have been advocated. Material such as plaster of Paris, asbestos and bamboo to precious metals such as gold and platinum. But none of the materials satisfied the requirements of an ideal root canal filling material.
Root canal filling materials can be divided into  ORTHOGRADE  RETROGRADE
ORTHOGRADE MATERIALS: Pastes Zno Synthetic resins (Cavit) Epoxy resin (AH-26) Polyvinyl resin (Diaket) Polycarboxylate cement Silicone rubber Chloropercha paste Semisolid materials Gutta percha Acrylic Solids: They are divided into Flexible type
Rigid type
- Silver cones
- Vitallium
- Stainless steel instruments
- Cr-Co implant con
Flexible Type: They can be pre-curved before insertion and made to follow the curvatures of tortuous canal.
Rigid Type: They are inflexible, and cannot follow curvature. They are used
as
endosseous
implants/stabilizer
as
an internal strength
reinforcement cones for rot fractures and rebuilding of mutilated crowns.
Advantages: - Do not corrode - Tolerated by tissues Disadvantages: - Rely on sealer to obdurate the canal - Non-compressible
RETROGRADE MATERILAS: Silver amalgam, GIC, IRM, Super EBA, CPC, MTA etc. Used mostly in endo-surgical techniques. In cases of: a) Internal and external root resorption b) Perforations c) To seal large accessory canals d) Apical fillings
EXTENSION OF THE ROOT CANAL FILLING: The anatomic limit of the pulp space is the dentino cemental junction apically, and the pulp chamber coronally. Controversy exists about the ideal apical limit of the root canal filling.
Some endodontic advocates say canals filled to the apical dentinocemental junction are filed to the anatomic limit of the canal. Beyond this point, the periodontal structures begin. As stated by Kuttler that DCJ is at an average of about 0.5 to 0.7 mm form the external surface of the apical foramen.
Others prefer to fill to the radiographic external surface of the root or just beyond. They seek to develop a small “puff” of overfilling. Advocated by proponents of the diffusion technique or the softened gutta percha technique. It is said that the “puff” or “button” is designed to compensate for shrinkage of the filing by puling down tightly against the apex. Also as an indicator that the gutta percha has been densely packed into the apical preparation and that all the aberrations as well as the lateral and accessory canals of the root canal system have been cleaned and filled.
According to Washington study, nearly 60% of failures are caused by incomplete obliteration of the radicular space and 3.85% of the failures by overfilling.
Most the root canal sealers and solid core materials used these days are well tolerated by the tissue once they are set. The tissue reaction that does occur can be a fibrous walling off of the foreign body.
ROOT CANAL FILLING MATERIALS: A plethora of materials have been advocated over the past 150 years for root canal obturation. None of the materials fulfill all the requirements for an ideal root canal filling material. Requirements for an ideal root canal filling material. The material should be easily introduced into the root canal. It should seal the canal laterally as well as apically. It should not shrink after being inserted. It should be impervious to moisture It should be Bacteriocidal, or at least, should discourage growth. It should be radiopaque It should both stain tooth structure It should not irritate periapical tissue or affect tooth structure.
It should be sterile, or easily and quickly sterilized immediately before insertion. It should be easily removable form the root canal if necessary. It should have ease of manipulation with ample working time.
GUTTA PERCHA: Introduced to dentistry by Bowman in 1867. in its pure molecular structure, gutta percha is the trans isomer of polysioprene and has an approximately 60% crystalline form. The amorphous form is Cis isomer, is a natural rubber.
Gutta percha was taken from the sap of the Indian rubber trees indigenous to Malaysia. But now it comes from central South America. As it comes from the tree, gutta percha is white in color. It is dyed to colors like red and pink to match the color of the pulp, it has to replace.
The composition of gutta percha varies according to the manufacturer.
Composition given by Friedman and Associates in
Grossman. Gutta percha
: 20% (Matrix)
Zinc oxide
: 66% (Filler)
Heavy metal sulphates
: 11% (Radiopacifier)
Waxes/resins
: 3% (Plasticizer)
Phase transitions of trans-polyisoprene: Gutta percha at room temperature is considered to be in the βphase. In this stage gutta percha is solid, compatible and elongatible.
When heated to 42° to 49° C, it undergoes a phase change to α phase (alpha). In this phase it is runny, tacky, sticky, non compactable and non elongatible.
The third or γ (gamma) phase occurs when heating is raised form 56° to 62°C. The properties are similar to the 2nd phase.
The significance of these phases in addition to change in physical properties, is that the materials expand when heated from the β to the γ/α phase from less than 1% to almost 3% when cooled down to the β phase, a shrinkage takes place, of similar percentiles, but the degree of shrinkage almost always is greater than the degree of expansion and may differ by as much as 2%. That means if gutta percha is heated above 42 to 49° C and then inserted into a prepared canal, a compaction procedure should be applied or some method used to lessen the problem of shrinkage.
Gutta percha in the β phase has a number of advantages as a root canal filling material: 1. It is compatible, compressible and has excellent adaptation to the irregularities and contours of the canal. 2. it is inert. 3. Dimensionally stable. 4. Tissue tolerance (non allergenic). 5. It is radiopaque. 6. Has known solvents – Xylene, chloroform, Eucalyptol (partially dissolves). 7. It can be easily removed form the canals, if necessary. 8. Elongability when fresh, brittle when old. 9. Does not discolor.
Disadvantages of using gutta percha: 1. It lacks rigidity, smallest standardized gutta percha cones are difficult to use unless canals are enlarged to No.25. 2. It lacks adhesive quality-sealer has to be used. 3. It can easily be displaced on pressure can lead to over extension during condensation.
Gutta percha is available as standardized and no standardized sizes. Standardized gutta percha points approximate the diameter and taper of the root canal instruments. Used as primary/master cone (Sizes No.15 to 140). Non standardized gutta percha points are more tapered from the tip or point to the top and are usually designated as extra fine, fine-fine, medium fine, fine, fine medium, medium, medium large and extra large. Mostly used as accessory or auxiliary cones.
SEMISOLID FILLING MATERIALS FOR OBTURATION: Gutta percha (β-phase) Compacted gutta-percha Injection molded: Obtura II, Ultrafil Indication to use semisolid filing materials: When the canal has irregular walls and has a non-circular shape. Whenever a condensation technique is utilized that requires a flared preparation to size 30 or greater. In cases where a lateral or an auxiliary canal is anticipated or multiple apical foramens present. Whenever there is a strong possibility of occurrence of an overfilling (as semi-solid materials are well tolerated by tissue). In cases of internal resorption In cases where apical surgery has to be performed.
Silver Points: Pure silver molded in a conical shape has also been used for root canal fillings since 1930s. Silver points may be indicted in mature teeth with small or well calcified round tapered canals-maxillary first premolars with two or three canals, or the buccal roots of mature maxillary molars and mesial roots of mandibular molars if they are straight i.e. used in teeth with fine, tortuous canals that cannot be filled properly with gutta percha cones. In youngsters, even these canals are too large and too ovoid for single point use.
Also not indicated in anterior teeth.
Single canal
premolars or large single canals in molars. Because of the stiffness of silver, this technique was easier than using gutta percha.
Obtaining good obturation with silver point is difficult, as it cannot be made to conform to the pulp space like gutta percha.
Most silver
points contain trace metals like copper and nickel (0.1%-0.2%), which adds to the corrosion of silver cones. Other reasons for corrosion of silver cones are the presence of metal restorations and posts. Corrosion products are toxic and may cause severe tissue injury. They cannot independently seal the rot canal, as they do not stick to th4e dentin walls. Therefore the metal core material must be used with a cementing material-an endodontic sealer.
METHODS OF OBTURATION: According to Grossman: 1. Lateral condensation 2. Vertical condensation (warm gutta percha) 3. Sectional condensation 4. Compaction (McSpadden technique) 5. Thermoplasticized gutta percha techniqe. 6. Chemically plasticized gutta percha (Chloropercha, Eucapercha).
According to Cohen: I. Obturation with a semisolid material – gutta percha. Fitting of primary gutta percha cone. Chloroform – dip technique Single – cone technique, fabrication of customized gutta percha cone. o Lateral condensation o Lateral and vertical condensation method. o Sectional method. o Vertical condensation wit warm gutta percha o Chloropercha method modified a) Johnston-Callahon
b) Nygaard – Ostby o Gutta percha –Eucaperhca method o Thermomechanical condensation method o Thermoplasticized
gutta
percha
(injection
method) o Pastes o Hydron, a hydrophilic plastic RCF material o Pressure –syringe injection technique o N2 and related pastes II. Canal obturation wish solid materials Silver cones o Cone selection, fitting and cementation. o Split/sectional cone technique o Technique with apical silver cones o Technique with improved silver cones Stainless steel points III. Canal obturation with rigid cones: Vitallium Co-Cr implant points According to Ingle: A) Solid core gutta percha with sealants:
molded
Lateral compaction
Variations of lateral compaction B) Chemically plasticized cold gutta percha - Essential oils and solvents o Eucalyptol o Chloroform o Halothane C) Canal warmed gutta percha Vertical compaction Sectional compaction Lateral/Vertical compaction: Endotec. Thermo mechanical compaction o Microflow, TLC, Engine-plugger and Maillefer condensation. o Quickfill o Canal finder o Ultrasonic D) Thermoplasticized gutta percha Syringe insertion Obtura Ultrafil Solid core carrier insertion
Thermafil and densifil Successfil Silver points II. Apical third filling 1. Dentin – chip 2. Ca(OH)2 III. Injection /Spiral filling 1. Calcium phosphate 2. Cements 3. Plastics 4. Pastes
As with many aspects of dental profession, a three dimensional obturation is the key to success of an endodontic treatment.
Since the late 1900’s quite a few obturation techniques have come into the picture, some of which have been discarded due to their obvious disadvantages while the others have been improved upon.
As all of us are quite familiar with the conventional methods of obturation which we have been using till date and which have stood the test of time, hence in this seminar, I will be discussing more of the
recently developed obturation methods with their advantages and disadvantages comparable to the conventional method. To overcome disadvantages of conventional obturation techniques, the thermoplasticized gutta percha techniques have been introduced. These techniques are classified by Bhatti and Joshi 1997 as:
Intraradicular
Extraradicular
In this the gutta percha is heated
In this the gutta percha is heated
Within the canal and is allowed
outside the mouth and then
To flow in to the root canal.
Placed in the root canal
The intraradicular Techniques: Warm lateral condensation - Endotec - Thermapact Warm vertical condensation - Touch ‘n’ heat - System B
The Extra radicular Techniques. Infection Pastes: - Ultrafil
- Obtura II - PAC – 160 Solid core material - Thermafil - Densfil - Successful Hybrid multiphase - Trifecta - Alpha seal Others - Vacuum pressure technique - CaPO4 pastes - Sargenti techniqe
LATERAL COMPACTION OF COLD GUTTA PERCHA: The lateral compaction of cold gutta percha points with sealer has long been the standard against which other methods of canal obturation have been judged.
STEPS: LATERAL COMPACTION METHOD:
Before selection of master cone, size of the spreader is determined. A spreader should be selected that reach within 1-2 mm of the working length. 1. A gutta percha cone called the master cone is fitted to the instrumented main canal. 2. The primary cone is inserted into the root canal to the established working length. 3. It should fit snugly feel for “tug-back� 4. Take a radiograph to determine the apical and lateral fit of the master cone. 5. Check for the length of the master cone, if less or more, adjust accordingly. 6. Canal is dried with paper points and then the walls of the canal are coated with a thin layer of cement or sealer. 7. The apical half of the master cone is coated with cement and is placed in the canal. 8. A spreader is inserted alongside the primary cone and is pressed apically. 9. The spreader is disengaged from the cone by rotating it between fingertips or when using a long handled spreader, by rotating the handle in an arc.
10.An accessory cone is inserted in the space previously occupied by the spreader. Cones are placed parallel to the spreader blade into the opening created by the removal of the spreader. 11.This process is repeated until the entire canal is filed with a well condensed gutta percha filling. 12.Verify the obturation of the canal by radiograph 13.Excess gutta percha is removed from the pulp chamber with an instrument and cleaned. 14.Temporary restoration is placed in the access cavity.
VARIATIONS OF LATERAL COMAPCTION: There are slight variations in routine compaction technique for filling curved canals, immature open apices, or tubular canals.
Curved Canals: Virtually all canals exhibit some curvature. It may or may or may not be visible in the radiograph, especially when curve is in buccal or lingual direction. Lateral compaction of curved canals can be very effective in most cases.
Procedure is almost same; sealer
placement, primary point placement, followed by spreaders, and auxiliary points. However more vertical force will be exerted against the primary points, as the spreader will tend to catch in the gutta percha and force it apically.
Consequently, the master point should be placed 2 mm short of the apical terminus to be pushed into place by the vertical, as well as the lateral force of the spreader. Small flexible spreaders should be used to follow the curve of canal.
Immature Canals and Apices: The immature canal is complicated by a gaping foramen. The apical opening is either a no constrictive terminus of a tubular canal a flaring foramen of a “blunder buss” shape.
Apexification method should be tried, for apical closure. If fails then special methods have to be employed for obturation.
Tubular Canals: The large tubular canal with little constriction at the foramen may best be filed with a “coarse” primary gutta percha cone that has been blunted by cutting off the tip or by “tailor –made” cone.
Inverted Point Technique: “Coarse” gutta percha cone is selected as a primary point and the serrated butt end of the point is cut with the scissors/scalpel. Point is inverted and tried in the canal. Should go to the working length and should exhibit “tug back”
 Radiograph is taken to confirm its position.  Canal is obturated like in lateral compaction technique with this cone as primary cone.
Chances of overfilling are there and insufficient pressure applied during lateral condensation results in poorly condensed filling, which can lead to leakage and failure.
Tailor- Made Gutta Percha Roll/Roll Cone technique: If the tubular canal is so large that he largest inverted gutta percha point is still loose in the canal, a tailor made point must be used as a primary point.
Point is prepared by heating a number of gutta percha points and combining them, butt to tip, until a roll has been developed much the size and shape of the canal. Roll is chilled with a spray of ethyl chloride or ice water to stiffen it.
This cone is tried in the canal, if still loose, more gutta percha can be added or cut 1 mm from the tip if slightly too, large, heat it over flam e and place it in the canal, to secure canal impression. The surface may be softened by dipping in chloroform, eucalyptol or halothane also. Rest of the canal filled same as lateral compaction technique.
Simpson and Natikin have suggested a specialized filling technique for those teeth with tubular canals but closed apices (after apexification process). The canal initially filled with a warmed and softened tailor made gutta percha roll cemented to placed and severed at the canal orifice with a hot spoon excavator.
Using a heavy plugger, the gutta percha is forced to the apex and compacted to place. Pressure with the plugger will leave a void in the center of the mass when the Plugger is removed with a twisting motion. It may be necessary to hold percha with explorer when removing plugger.
Plugger dipped in ZnPO4 cement powder (to prevent sticking) is then used to collapse the gutta percha into the space created by the initial plugging. Plugger is heated to better compact the filling.
Excess gutta
percha removed till the cervical level.
Chemically Plasticized Cold Gutta Percha: Solvent is used to soften the primary gutta percha point to better conform to the aberrations in apical canal anatomy. This is a variation of a very old obturation method called “Callahan-Johnston technique� first given by Callahan in July of 1911. In which, too much of the solvent,
chloroform was used. So when it evaporated there was a 24% decrease in volume. Now only the tip of the point is dipped in the solvent for 1 second. Technique: Primary cone is blunted and fitted 2 mm short of the working length. Then it is dipped in solvent for 1 second and kept aside for partial evaporation of solvent. Meanwhile sealer is placed in the canal. Primary cone is inserted to the working length, spreader placed for 1 minute to allow softened gutta percha to flow. Rest of the canal filled in conventional way.
Earlier it was thought that chloroform is carcinogenic but recently it has been approved by FDA and ADA for clinical use. Other substitutes are halothane and eucalyptol.
In addition to dip technique, sealers are prepared by dissolving gutta percha in these solvents as well as rosin and balsam.
These
mixtures have long been popular as sealers and dips for gutta percha points.
Such mixtures are called chloropercha, kloropercha and
eucapercha.
Various studies have shown better seal with the dip technique than the use of these sealers. They observed that these sealers shrank more when compared to gutta percha dip technique. VERTICAL COMPACTION OF WARM GUTTA PERCHA: Nearly 30 years ago, Schilder introduced a concept of cleaning and shaping root canals in a conical shape, and then obturating the space “three-dimensionally” with gutta percha, warmed in the canal and compacted vertically with pluggers. By this technique all the “Portals of exit” from the canal are obturated with a maximum amount of gutta percha and a minimum amount of sealer.
Step-by-Step Procedure of vertical compaction of warm gutta percha: 1. Dry the canal with paper points. Check for canal patency. 2. Fit the appropriate gutta percha cone to the radiographic apex, which should exhibit tug back. Confirm position with a radiograph. Cut off the butt end of the cone at the incisal or occlusal reference point’s 3. Remove the cone and cut back 0.5 to 1 mm of tip, reinsert and check the length and tug back. The cone’s apical diameter should be the same diameter as the last apical instrument. Remove the cone, keep it aside. 4. Prefit the three pluggers to the canal preparation Widest plugger: 10 mm depth
Middle plugger: 15 mm depth Narrowest plugger: Within 3 to 4 mm of terminus. Mark the lengths the pluggers penetrated. 5. Once again, irrigate the canal with NaOCl and dry it with paper points 6. Lightly coat all the walls with sealer. 7. Coat the apical third of the cone with sealer. 8. Insert the cone in the canal to the working length. 9. Using a hot spoon excavator remove gutta percha cone from pulp chamber to cervical level. This transfers the heat to the coronal third of the gutta percha cone. 10.Using the widest vertical plugger (coated with cement powder to act as separating medium) the gutta percha is folded into a mass and compacted in an apical direction with sustained pressure. This is the first heat wave. The temperature of gutta percha rises 5 to 8째C above body temperature i.e. 42째C to 45째C, gutta percha remains in Beta form. So minimal shrinkage when it cools back to body temperature. 11.The second heat wave begins with the introduction of heat carrier back into the gutta percha, for 2-3 seconds and when retrieved, carries with it the first selective gutta percha removal. 12.Immediately, the mid sized coated plugger is submerged into the warm gutta percha. The vertical pressure also exerts lateral pressure.
The filling mass is compacted apically in 3 to 4 mm waves created by repeated heat and compaction cycles. 13.The seconds heating → Warms next 3-4 mm of gutta percha and an amount of gutta percha removed with plugger. 14.The narrowest plugger is immediately inserted in the canal and the surplus materials along the walls is folded centrally into the apical mass. Warmed gutta percha is then compacted vertically sealing portals of exit. 15.The apical “down pack” is over, if post is to be placed, no more gutta percha need be used. 16.“Back packing” the remainder of the canal completes the obturation. The classic method consists of packing 5 mm precut segments of gutta percha → Cold welding them to apical segment → Warming them →compacting. Procedure continued until the entire canal is obturated. 17.An alternative method of back packing is by injection Plasticized gutta percha from one of the syringes, such as obtura II. Plasticized gutta percha is compacted with vertical pluggers. 18.Remove excess gutta percha and sealer from chamber and clean it and placement of temporary/permanent restoration.
Warm gutta percha, vertically compacted, has proved most effective in filling the canals of severely curved roots and roots with accessory, auxiliary or lateral canals or with multiple foramina.
Brotherman compared lateral and vertical techniques and found “no statistically significant difference in filing efficiency”, moreover there was greater incidence of accessory canal filling with sealer by vertical compaction. He concluded that ribbon shaped canals were better filled by lateral compaction whereas ‘for centric canals, vertical condensation appears better”.
Torbinejad compared 4 methods and said there is close adaptation in middle and apical thirds by the vertical method.
Lebansese group stated there are more chances of overfill Schilder in his studies reported 100% success after 2 years and stated canal should be thorough cleaned and shaped – “failure is the result of inadequate cleaning and shaping of the root canal system and /or inadequate obturation.
Warm/Sectional Gutta Percha Obturation: The use of small warmed pieces of gutta percha, the so-called sectional obturation technique was proposed by Webster in 1911. later it was promoted by Coolidge, Blayney and Lundquist from Chicago and named it “Chicago” technique.
Technique: Fitting the plugger to the prepared tapered canal should fit loosely and extend to within 3 mm of the working length and stopper is placed. Primary gutta percha point is blunted and carried to place 1 mm short of working length and confirmed radiographically. Upon removal 3 mm of the tip is excised with scalpel and luted to the end of warmed plugger. Sealer is placed in the canal, gutta percha tip warmed by passing through alcohol flame and carried in the canal. Under apical pressure the plugger is rotated to separate the gutta percha and is thoroughly packed in place. Radiograph is taken to confirm the position.
Remaining space is filled in a similar way, or if post is required. The compaction can stop after second piece leaving 5 to 6 m of apical gutta percha or even gutta percha can be softened by dip technique in chloroform or halothane. Backfilling may also be done with thermoplasticized gutta percha from one of the gutta percha “guns”.
WARM LATERAL CONDENSATION TECHNIQUE: Basic devices employed are: Endotec Thermopact
ENDOTEC: Considering the ease and speed of lateral compaction as well as superior density gained by vertical compaction of warm gutta percha as stated by Schilder in 1967, Martin developed a device that appears to achieve the best qualities of both techniques.
The device called “Endotec” is a thermal compactor consisting of a cordless handpiece containing a battery that supplies energy to heat the attached spreader/plugger tips. When not in use, the handpiece sits in a battery charger base.
The tips used are: 30 size file-in curved canals for greater flexibility, a large tip equal to size 45 files. The heat is thermostatically controlled by a activator button to soften the gutta percha. it is capable of achieving temperatures upto 350°C.
Procedure: Canal preparation with continuous taper design and with definite apical stop. Dry the canal and apply sealer. Primary or master cone adaptation with hand/finger spreader. Additional gutta percha placed to reduce the possibility of warm plugger loosening the point when the tip is retracted. Endotec is placed in the canal to full length along side the gutta percha. Later activator button is pressed and plugger/spreader moved in clockwise direction. Release the heat button, and the plugger cools immediately. Now remove it in anti-clockwise direction. This motion creates a space for additional point to be added procedure is repeated.
 Now the cold plugger can be used to compact the softened gutta percha. In this manner the canal is completely obturated by using Endotec plugger.
Vertical Pressure with sweeping lateral pressure: Martin in 1990 showed that Endotec creates less stresses than cold lateral condensation. To complete the procedure a cold hand plugger can be used to firmly condense the fused gutta percha bolus.
An air force group in 1993 also found that they could improve the gutta percha compaction in a molar with C shaped canal by using the Endotec in a ZAP and TAP method.
ZAP: Pre heat the endotec for 4 to 5 seconds before insertion into the gutta percha filled RC space. TAP: Move the instrument in and out in short continuous strokes 10-15 times. The tip is removed form the canal when it is still hot. Later cold spreader is used and accessory points are placed.
The two causes of concern with this treatment may be - Overheating
- Development of stresses
Castelli in 1991 stated that there was no heat related damage to periodontium from Endo-tech.
A US army group showed that heat produced by Endotec is maximum 500°C and is less than that of other heat devices like the touch ‘n’ heat (700-800°C).
They stated that even though the internal temperature may reach upto 102°C gutta percha and dentin are poor conductors of heat, so the temperature may not cause damage to periodontium.
Advantage: The technique follows the lateral condensation procedure and produces three dimensional filling superior to that obtained with usual cold lateral condensation.
According to COHEN: 1. The technique is time consuming relative to other methods of lateral compaction. 2. The equipment comes with a limited number of sized tips for heat distribution even though the tips appear to be similar to a root canal
spreader, it is difficult to apply compaction forces with these tips as their use is primarily for heating the gutta percha cones in the tooth. THERMOPACT: It consists of unit containing a transformer and an electronically controlled circuit for heat generation and control, and a handpiece adapted with different sized spreaders and a heat carrier. The temperature can be selected, regulated and maintained at any desired level from 40° to 70°C. Gutta percha → α: 42-49°C γ: 56-62°C
Souvenir suggested that thermopact must be ideally set and maintained at 42°C for warm lateral condensation and at about 59°C for warm vertical condensation.
When one is using thermopact device, the operating temperature should be set precisely and maintained constant. It should range within the limits of the groups going from β (or solid) phase to alpha (or plasticized) phase at approximately 42°C, or from the alpha plasticized phase to the amorphillic γ phase where partial decomposition begins to occur, approximately at 60°C.
Warm lateral condensation using thermopact device: The warm spreaders soften and depress the gutta percha laterally, allowing the instruments to gently and deeply penetrate to the desired apical level.
Therefore more gutta percha cones can be added
successively in the space created by the warm spreaders and coalesced into a denser mass.
Advantages: The technique produces a homogeneously compacted filling with accurate control of apical extrusion, maximum gutta percha and minimal sealer. Regular spreaders may also be heated and stocked in a glass bead container with the temperature of 60°C. When inserted into the root canal, the spreader would have a temperature of around 45°C. This temperature is sufficient to heat gutta percha from Beta solid phase to Alpha plasticized phase allowing for a more effective lateral condensation. Warm lateral condensation effectively provides a dense more compact obturation with a maximum amount of gutta percha and a minimum amount of sealer (the minimal condensing pressure used
to obtain a compact and accurate filing is a decided advantage in the prevention of numbers). Warm gutta percha vertical compaction method is used, then thermopact device is adapted with a heat carrier. The temperature is set and maintained at 60°C. This temperature is sufficient to heat the gutta percha from Beta solid phase through α plasticized phase to the γ amorphilic phase.
WARM VERTICAL CONDENSATION METHOD: Touch ‘n’ heat System B The touch ‘n’ heat unit is used with the Schilder’s technique.
The touch ‘n’ heat 5003 is an electronic device, especially developed for the warm vertical compaction of gutta percha.
Battery/AC models are available. It exhibits the same thermal properties as the original heat carrier used by Schilder in 1967 but has the advantage of generating heat automatically at the top of the instrument. The instrument is capable of providing a range of high temperatures
instantly ranging from 0-700°C. The device may also be used for pulp testing/bleaching by changing the tips and adjusting the heat level.
Procedure: The softened warm gutta percha can be readily compacted apically into the irregularities of the RC system.
The objective of this technique is to continuously and progressively carry a wave of warm gutta percha along the length of the master cone starting coronally and ending apically.
1. The Schilder’s pluggers are selected and pre fitted for coronal 1/3 rd wide and middle and apical 1/3rd narrow.
Down Packing: The prepared canal walls are first coated with sealer. The selected master cone is a non standard GP point with the apical tip cut off. It is fitted to achieve apical tug-back at about 1 mm from the working length (if the canal diameter is wider than the first point a second point is fitter).
Gutta percha protruding from the canal orifice is removed with a hot instrument. The widest plugger is now used to compact the gutta percha into the canal using 2-3 mm vertical strokes. A series of overlapping strokes are used if the canal is wider than the plugger. The heat transfer instrument, heated to cherry red, is again plunged into the mass of gutta percha to a depth of 3-4 mm and quickly with drawn (this high temperature ensures a mass of gutta percha to be removed with the carrier). The appropriate pre fit plugger is then used as already described. Each time this sequence is repeated; some gutta percha is removed with the heat carrier and a smaller plugger is placed close to the working length. It is rarely necessary to compact closer than 5 mm form the working length.
Advantages: - Fills accessory canal. - Homogenous filling Disadvantages:
- Voids (inadequate control of the depth of insertion of the filler) - Small plugger is ineffective - Plugger binding apically may split root.
This cycle is completed by a sustained firm apical pressure held for a few seconds till the clinician feels that the thrmosoftened mass has cooled. This 3 dimensional adaptation and apical and lateral movement of gutta percha is termed as “Wave of condensation”.
The activated heat carrier becomes red hot almost instantly and is allowed to plunge about 3-4 mm into the gutta percha coronally. Note the progressive apical transfer of heat through the gutta percha master cone.
The heat carrier is deactivated and after momentary hesitation, the cooling instrument is removed along with a bite of gutta percha. There is progressive apical transfer of heat along the master cone to another 4-5 mm.
The removing of bite of gutta percha is that a smaller 2 nd prefit plugger can be placed progressively deeper into the preparation. Thus producing a “2nd wave of condensation”.
This procedure is done for about 4 to 5 times depending on the length of the canal.
It is important to note that it is impossible to
overextend gutta percha periapically. Reported by carrying heat carries 4-5 mm from apex and condense with prefit condensers. Precautions: There should be a continuous tapering canal preparation whose diameter is narrowed apically. Master cone is fitted correctly. Temperature of touch ‘n’ heat instrument should not exceed 45°C. Heated pluggers should not be placed closer than 4 to 5 m of canal terminus.
Back Packing Phase: The most effective and efficient B-P technique is obtura II gutta percha gun.
The smaller 23-gauge needle is attached to the obtura II gutta percha gun until it come in contact with the previously packed gutta percha apically. The hot tip, will ensure homogeneity during procedure. The obtrua gun is held firmly and slowly squeeze the trigger injecting a controlled 4 to 5 mm segment of uniformly thermosoftned gutta percha
against the previously packed apical 3rd. if this is performed properly the clinician feels the gun back out of the canal easily. The smallest prefit plugger is used to condense the gutta percha. Through a series of gutta percha injection end condensation the RC is completely obturated. A confirmatory radiograph is taken. SYSTEM B: Recently analytic technology introduced system B heat source model 100. This instrument has a digital temperature display and a variable resistance control that allows the user to attain a desired temperature.
These heat carriers are designed as pluggers that concentrate the heat at the tip of the carrier. This system B is also based on the Schilder technique. The tip of the pluggers can be heated to 200°C, this softens the gutta percha in ½ second.
A wave of heat (250-300ÂşC) is produced as the plugger is forced through the already fitted cone and is used to drive the gutta percha into the canal.
As the plugger approaches the apex, the heat button is released and apical pressure is maintained with the plugger for 10 seconds. It sustains
push to take up the shrinkage that occurs on cooling. The heat button is pushed again while maintaining pressure. A wave of heat is produced 300ºC in 5 seconds that immediately separates the plugger from apical mass of gutta percha. Thus it can be rapidly withdrawn. The canal is then backfilled with the same technique with obtrua. Advantages: Voids elimination, created during normal lateral condensation of warm gutta percha.
Disadvantages: - Breakage - Kinking of spreaders. Silver G.K. et al in 1999 conducted a study on “comparison of 2 vertical condensation obturation techniques-Touch ‘n’ heat and system B.
They concluded that: System B may produce an acceptable obturation and produces less heat than Touch ‘n’ heat. He also concluded that the obturation by this method was faster.
THERMOCOMPACTION:
In this technique friction between gutta percha and the rotating “reverse file� generates heat to soften the gutta percha and forced apically.
Thermocompactors available have different designs, which
determine their properties.
1. Old Mc Spadden 2. New McSpadden nikel titanium thermocompacter 3. Maillefer gutta condenser 4. Zipperer 5. Quick fill
McSadden: A new concept of heat softening gutta percha was introduced by McSadden in 1979.
Initially called the McSpadden
compactor.
It resembles the reverse H-file which fits into a latch type handpiece, rotates at 8,000-20,000 rpm and generates frictional heat that softens gutta percha and force the material apically an laterally. As canal is filled, the compactor is forced out coronally.
Disadvantages of this technique were 1. Fragility of the instruments hence prone to fracture could not be used in curved canals. 2. Overfilling of the canals. 3. Difficulty in mastering technique 4. Overheating 5. Resorption and ankylosis To overcome these disadvantages, it came with different shapes and forms.
McSpadden in the meantime modified its original design and introduced the NT condensers. It is supplied as an engine driven/hand powdered Ni-Ti instruments. It has increase number of compacting blade Shallower grooves Decreased sharpness Made of NiTi for flexibility
Used: With heat softened gutta percha (Alpha-phase) and Beta gutta percha. Used mainly in curved canals.
Procedure: Place primary gutta percha cone in root canal. Select the appropriate size condenser, coat it with gutta percha (heat softened) gutta percha I (α) or gutta percha II (β). The condenser is then spun in the canal at 1000-4000 rpm, which fillings the gutta percha laterally and vertically. The speed is controlled by NT matic handpiece. Open apex cases: At the apex low heat gutta percha I bolus with a large NT condenser allowed to cool and harden → apical plug remaining canal is obturated with gutta percha points and additional heat softened gutta percha.
Maillefer Gutta Condenser: Mailefer modified the headstrom type instrument as gutta condenser. It has less number of compacting blade. Increased sharpness Deeper grooves
Used: For back filling of canals already filled at apical third by either a) Warm vertical compaction b) Sectional compaction
c) Cold lateral compaction
Zipprer thermocompactor/Engine plugger - This thermocopactor resemble an inverted K-file. - Increased number of flutes - Used for backfilling canals already filed at apical third - In hybrid technique (Tagger). J.S Quickfill: This system is designed for a thermo mechanical solid core gutta percha 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, the sealer is applied. As the instrument spins in the canal with regular low speed, latch type handpiece frictional heat is liberated. This heat plasticizes the gutta percha and it is also compacted.
After compaction either the compactor may be removed and final compaction done 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 shaped like a telescope. It is used in a canal finder hand piece, which delivers a rapid vertical stroke varied between 0.3 to 1.0 mm.
Procedure: Sealer placement with the plugger ↓ Master cone placement ↓
Next, the vertically vibrating plugger is kept ↓ The edges of the plugger blades latches the gutta percha ↓ Gutta percha gets compacted vertically an laterally ↓ Accessory gutta percha points are added each time the plugger is used to compact the filling
This method may have some discrepancies, not commonly followed, as shown by Photomicrogrpahs of sectioned teeth.
Use of this does not warm and plasticized the gutta percha.
No shrinkage from cooling as gutta percha remains in a cold state. Final obturation resembles traditional lateral compaction of cold gutta percha points.
ULTRASONIC PLASTIZING: Suggested by Moreno in 1977. He used a cavitron scaler with a PR 30 insert. Can be used only in anterior. Procedure: Primary point is placed ↓ Unit is placed besides gutta percha ↓ The ultrasonic unit with the rheostat set at right angles is activated for 3-4 seconds. ↓ The ultrasound thermal energy released by vibrating motion of the ultrasonic file plasticizes the gutta percha ↓ The file is removed and the spreader is immediately inserted to make space for new cones ↓ Obturation is completed in this way Joiner in 1989 found that the heat produced was 6.3 seconds by this method. He thus concluded that the heat produced by the cavitron would not be harmful.
II. The Enac Ultrasonic unit has also been used with a certain degree of success by Baumgardnee in 1997. In this unit a spreader is attached. They felt that the spreader penetrated the gutta percha more easily than did the finger spreader and the energized spreading led to a more homogenous mass with less stress and less apical microleakage. There is 19.1°C rise in temperature as it took 141 seconds to plasticized the mass.
SECTIONAL METHOD: Light speed sectional method: A two-phase obturation technique has been proposed by light speed technology by “Texas”. This technique advocates the use of a stainless steel carrier to place and condense a 5 mm section of gutta percha into the apical portion of the canal.
Once placed, the carrier is turned and
removed leaving a gutta percha plug.
The second phase uses a rotary instrument to backfill the remainder of the canal with the Ketac-endo and a single gutta percha cone. The technique was first studies by Santos D.M. et al in 1999.
Method: A gutta percha cone, the same size as the master apical rotary (MAR) instrument was selected. [MAR: Is the final apical size of the
instrument whihch is used to prepare the canal last]. The canal and the gutta percha plug were coated with sealer.
The plug was inserted and vertically condensed to working length by using moderate apical pressure. The carrier is removed by turning its handle counter clockwise until the plug was released and the carrier could be removed, easily detached from the gutta percha. The 2nd phase: A light speed backfill instrument was used to carry the Ketac endo sealer into the canal orifice. This was rotated at 1000-2000 rpm and advanced apically till the apical gutta percha plug was reached.
The instrument was then removed while against one wall. This was repeated till canal was filled with the sealer. The master cone was then coated with the sealer and placed till the apical plug. The excess gutta percha was then removed at the level of canal orifice.
The light speed technique is similar to the sectional method described by Grossman and Coolidge. The difference with this technique is that slight apical force seats the tapered plug into a parallel apical preparation.
THERMOPLASTICIZED
INJECTABLE
GUTTA
PERCHA
OBTURATION: The two major injectable gutta percha techniques available to the clinician are the Obtura II and the Ultrafil. Third is PAC –60.
These techniques have also been referred to as high heat technique and a low heat technique respectively.
This is mainly due to the
temperature required to soften the gutta percha for delivery into the canal.
OBTURA II TECHNIQUE: Guttaman emphasizes that canals to be obturated must have a continuously tapering funnel form, the apical matrix to the canal orifice.
Of significance is a properly shaped canal in the apical to milled mainstand area particularly in curved canals.
The proper shaping is
essential to confine and retain the gutta percha in the canal system, a filling beyond the end of the root canal easily occur. Apical 25/30 and coronal 60 file.
Obtrua was first introduced in 1977 (J Martin) from this early model a more efficient system was developed and presented. The device marketed now is obtura II heated gutta percha system.
The silver needle size has been reduced to either 20 gauge (equal to 60 file) or 23 gauge (40 no. file). Silver needle is used for flexibility, wit digital readout of temperature it consists of:
Electrical control unit A pistol grip syringe Specially designed gutta percha pellets. The gutta percha extrudes from the “needle tip” with a temperature range of 62 to 65°C. The pistol syringe is more resistant to higher temperature. The control is equipped with a digital readout of temperature and fact safe circuitry with precise temperature control. Regular Beta phase gutta percha is used. Gutta percha is heated approximately to (160 to 200°C, Ingle) (185-200°C) (Cohen).
Indicated: It is beneficial when managing.
Canal irregularities such as - Film webs/Curl-de-sacs - Internal resorption - C shaped canals - Accessory/lateral canals - A bridged foramina Easy flow gutta percha: Maintains its smooth flow consistency at lower temperature and has a longer working time. It favours the management of complex cases in which Extensive compaction is necessary Small curved canals Favours in experience need clinicians Regular flow gutta percha is a homogenized formulation with superior flow characteristics and aids in infection control.
Advantages: The removal of the smear layer and obturation of canals with the injectable system results in the movement of gutta percha and sealer into the dentinal tubules.
 The adaptation of the injected thermoplasticized gutta percha to the canal walls has been shown to be significantly better than lateral compaction.
Disadvantages:  Potential for extrusion of the gutta percha and sealer beyond the apical foramen.  The possibility of heat damage to the periodontium has been identified as a possible drawback to this technique. Method of Use: Sealer and compaction is necessary for this method. Sealer serves its usual role of filling the microscopic interface between the dentin and gutta percha as well as a lubricant.
Compaction became necessary to close spaces and gaps while forcing the gutta percha laterally and vertically. It also compensates for shrinkage as the gutta percha cools.
With the needle in its proper position in the canal, the gutta percha is passively injected into the root canal system, avoiding apical pressure on the needle. The needle is introduced into the canal at the junction of the middle and apical third. The applicator tip is prefitted to ensure that it
does not bind against the canal walls; pluggers are also prefitted for compaction. In case of curved canals NiTi pluggers are used.
In 2 to 5 seconds, the softened material fills the apical segment and begins to lift the needle out of the tooth.
During this lift in, by the softened, flowing mass, the middle and coronal portions of the canal are continuously filled until the needle reaches the canal orifice. Sealer must be carefully placed in the canal to prevent its movement beyond the confines of the canal apically and to ensure the placement of gutta percha at the terminus of the canal system. ½ drop of sealer is placed with an instrument of choice to the approximate depth of the prefitted needle. A fast setting sealer is not recommended.
Controlled compaction with the prefitted plugger to adapt the gutta percha to the prepared canal walls.
If necessary additional amounts of gutta percha can be easily injected to achieve complete obturation.
Do not use excessive
compaction pressures but fold the material in on itself as previously
described for vertical compaction. Multiple variations exist with this technique.
The softened material can be placed in the apical 2-3 mm and compacted at that point. Subsequently the remaining of the canal can be filled as above/segment additions can be added and compacted. It is used in conjunction with - Lateral compaction technique - Vertical compaction technique.
The Ultrafil System: Given by Dr.Michanowic - Continuously tapering canal - Proper shaping (apical – 25/30 and coronal 60) - Sealer and compaction - Same requirements as those described for Obtura II.
Ultrafil system comes with gutta percha prepackaged in canules with attached 22 gauge needle. The material is in Alpha-phase. It softnes at a temperature approximately 158° to 194°F (70-90°C) in a special heater. The warmed cannules are placed in a special sterilizable syringe for delivery to the prepared canal.
The gutta percha comes 3 consistencies based on viscosity. Regular (Low viscosity): White cannule. Firm set (Moderate viscosity): Blue Endoset (High velocity): Green
Placement of the needle and sealer are somewhat similar to the obtura II technique. Needle placement is usually further from the apical matrix (8-10mm). Working time is approximately 60-70 seconds.
The delivery of the regular set (White cannule) The syringe trigger is squeezed and released, and after a wait of 3 seconds, squeezed and released again. This sends a bolus of gutta percha towards the apical preparation. Te needle is not withdrawn but is left in place until the mass of softened gutta percha is felt to lift the needle (backflow) from the canal. It reaches a full set after 30 minutes. Because of low viscosity the extrusion of the material is of major concern. As it cannot be compacted, the possibility of shrinkage must be considered and this cannot be compensated by increased amount of sealer.
Restricted to cases with a substantial apical matrix and minimal apical foramina opening. Moderate to high viscosity gutta percha controlled compaction can follow the injection delivery of the material. Here, as with the Obtrua II, the material can be segmentally / bulk delivered before compaction. The time available for compaction varies based on the material chosen.
The high viscosity gutta percha has less flow and can be compared with plugger gutta percha and spreader i.e. vertical/lateral compact.
Endoset completely sets in 2 minutes: Because of the flow characteristic of the light bodied endofil regular /firm set, broken instruments may be bypassed if loose in the canal or internal resorptive defects may filled. Microleakage studies showed ultrafil obturation to be as good as lateral compaction and some studies showed ultrafil firmest leaks less than obtura and thermafil.
PAC-160: In 1981 Schoeffel designed heat built, a prototype delivery system to operate indefinitely and accurately at 160°C. This unit uses
standardized gutta percha. the device is called PAC –160 as it gives “Precision apical control at 160°C:.
Cavity preparation: - Slight flare coronally. - Definite apical constriction. Advantages: - Fills multiple foramina - Irregular configurations of the root canal. - Temperature is not more than 160°C PRESOFTENED NON-INJECTABLE TECHNIQUES: The development of gutta percha in different isomeric form such as alpha and beta phase led to creation of thermafil and successful, whereby alpha phase gutta could be heated, placed on a carrier and delivered into the canal in the thermoplasticized state without an injection system.
Successfil Technique: Introduced by the hygienic corporation, consists of a solid core carrier coated with Alpha-phase gutta percha. Gutta percha in a warm plasticized state is added to the carrier just before it is inserted in the canal. The successfil syringes contain high viscosity gutta percha that
sets in 2 minutes.
Successfil core carrier is titanium or radiopaque
plastic.
A successfil core, the same number as the last apical file is selected and tested for size in the canal. It should go the full working length without binding. Canal is dried and sealer applied.
The core coated with gutta percha is immediately inserted to full depth without twisting. With a vertical plugger dipped in alcohol the gutta percha is better compared around the carrier. Core is severed 2mm above the orifice with bur.
Radiograph taken for confirmation of
position. THERMAFIL: Solid Core Carrier Insertion: In 1978, Ben 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, was introduced as Thermafil and copycat daughter densfil.
Thermafil is patented endodontic obturator consisting of a flexible centrally carried, sized core and tapered to match standard endodontic files that are uniformly coated with refined and Alphs-phase gutta percha.
Initially: The stainless steel caries were introduced, they were heated in a flame and then introduced in to the canal. Later the carriers were made of titanium or radiopaque plastic.
Plastic core carrier
obturators can only be heated in special oven, the “Therma prep”.
It is recommended that all three types of obturators should be heated in the oven at 115°C for 3-7 minutes depending on the size of the carrier, which ranges from size No.20 to 140. The gutta percha coating extends beyond the carrier by 1-2 mm. Preparation: Continuous taper preparation is required. The coronal portion of the carrier has markings with a rubber stop. The gutta percha normally covers the first graduation marks at 18,19 and 20 mm. Plastic carriers are used now days. They are relatively flexible, small sizes 25,30,35 have a incrementally greater taper than the normal 25, 30, 35 sized files.
Sizes below 40 are made of a liquid plastic crystal and are not soluble.
Sizes above 45 are made from a polysulfide polymer and may be dissolved in organic solvents. Johnson suggested that final compaction can be completed and improved if a 4-5 mm piece of a regular gutta percha is then inserted into the softened gutta percha. A large plugger can also be used to apically compress the gutta percha all around the central carrier. Gutta percha reaches its final set in 2-4 minutes. When the gutta percha reaches the apical stop te metal or plastic carrier still continues apically, compacting gutta percha vertically and laterally.
Potential Problems: 1. Extrusion 2. Post space preparation 3. Retreatment
Plastic carriers are strongly recommended if a post is to be placed. The latest device to melt back the gutta percha and plastic carrier is the non-cutting “Prepost preparation instrument; Prepi” that is used in a latch
type handpiece. Frictional heat generated by this bladeless metal ball melts the material.
Method: The step back technique is effective for this obturation technique. A thermafil obturator is selected which corresponds to the master apical twisted/rotated. The canal is coated very lightly wit a suitable sealer-Thermaseal, AH-26, Sealapex or ZnO. The thermafil obturators are heated over an open flame/in Therma preoven. It offers more stable heated source and uniformity for plasticizing the gutta percha. Once the gutta percha attains a surface shine it is introduced in to the canal with firm apical pressure to the established working length. After radiographic verification the carrier shaft is severed to a point 1 to 2 mm above the canal orifice while applying firm plugger to the obturator handle. The handle is removed and discarded.
For Post preparation – Using metal carriers:
Metal carrier is scored on the break off point 4 to 5 mm from the apex and then twisted off counterclockwise after the obturator fully reaches the apex.
Advantages: 1. Quick and easy 2. They can be curved to fill curved canals. 3. To fill internal resorptive defects. 4. In case of open apices
Efficacy of thermafil obturation: In 1989 Christensen stated that thermafil Allows simple, fast, predictable filling of root canal. Specially useful for small/curved canals. Technique sensitive (Walton) Shoenrock felt that the plastic carriers provided the most complete system.
In 1997 Weller N.R. studied adaptation to the canal walls with these techniques and found the order of perfect adaptation was plastic >titanium> stainless steel.
Retreatment of canals may prove difficult because carriers jammed in the canals are very difficult to remove.
TRIFCTA SYSTEM: A variation on the successfil and ultrafil techniques, uses the best of both approaches to canal obturation. A small amount (1-2mm) of alpha phase successfil gutta percha is placed on the tip of a carrier, one to tow placed in the canal. The carrier is placed to the depth of ht ecanal and is slowly rotated counterclockwise and withdrawn from the canal. This is followed by compaction of the small mass of gutta percha in the canal. The coronal position of the canal is backfilled with one of the 3 types of ultrafil gutta percha, which is compacted if appropriate. Evaluation studies have shown this technique to be quite easily mastered with good adaptability of the gutta percha and a canals a seal comparable to that of other commonly used techniques. APICAL THIRD FILLING: Dentin chip apical filling: A method in which there is apical dentin chip plug against which other materials are then compacted. There is a “biologic seal� rather than a mechano-chemical seal. It has being found in many studies that dentin filings will stimulate osteo or cemetogenesis i.e. either osteocementum or osteodentin closure is seen.
Advantages: Prevents overfilling Confines the irrigating solutions & filling materials to the canal space. Leads to quicker healing Minimal inflammation Apical cementum deposition, even when the apex is perforated.
Disadvantages: If infected dentin chips than they are a serious deterrent to healing, may irritate and hinder repair.
Procedure: Totally debride and shape the canal, dentin not contaminated ↓ Gates glidden drill or Hedstrome file used to produce dentin powder in central portion of the canal. ↓ Dentin chips pushed apically with butt end than blunted tip of paper point ↓ Finally packed with file, one size larger than MAF ↓ 1-2 mm of ships should block the foramen (blockage checked with small size file)
↓ Final GP obturation is then compacted against the plug *Apical leakage can be prevented totally by injecting0.02 ml of clearfil new bond dentin adhesive into the coronal half of the dentinal apical plug.
In a study done in Loma Linda on monkeys it was stated that the inorganic component of dentin, hydroxyapatite, is the principal stimulant in producing more hard tissue formation and less inflammation than fresh dentin chips or demineralized dentin.
Calcium Hydroxide Apical Filing: Cementogenesis, stimulated by dentin filings, appears to be replicated, as well by calcium hydroxide. Calcium hydroxide resorbs away from the apex faster than dentin chips.
INJECTION OR “SPIRAL� OBTURATION: Filling the entire root canal by injection, or pumping, r spiraling material into place has great appeal but unfortunately the methods fall short, either because the technique is inappropriate or the materials used are inadequate.
When warm gutta percha is injected from one of the syringes to fill the entire canal, deficiencies are encountered. These inadequacies are caused by shrinkage from the heated to the cooled state or by failure to compact and eliminate voids or by extrusion overfilling.
Another method of filling the canal with chloropercha and pumping it into place wit gutta percha points, failed because of the severe shrinkage from chloroform evaporation.
This method was followed by totally filling the canal with injected zinc oxide eugenol cement, which will provide an immediate seal, but is often subject to dissolution and leakage over the years leading to failure.
Endofil is the silicone-based material for total canal obturation by injection. It is less toxic but chances of overfilling are high.
The use of lentulo spiral with various sealer, leads to overfilling or under filling, if not carefully monitored.
Use of hydroxyapatite as an injecting filling material. In this case the calcium phosphate powders are mixed with glycerin and the paste is injected into the canal. The moisture left in the
canal and the apical moisture causes the paste to set hydroxyapatite. If the material is extruded, it resorbs and will be replaced by bone.
SILVER CONE METHOD: Silver cones have been used to fill root canals successfully for over 50 years. Generally their use is restricted to teeth with fine and tortuous canals that can not be filled with gutta percha.
Although silver cones are machined to precise measurement corresponding to the instruments used for canal preparation they require the addition of a rot canal cement to compensate for their poor sealing qualities. Gutta percha may be laterally condensed around the cone to ensure a proper lateral seal.
Procedure: When filing a root canal with a silver cone and cement. Select a cone corresponding in size to the largest instrument used in the preparation of the canal. Sterilize the cone either by alcohol flaming 3 times or by passing through open flame 2-3 times. Inset the cone in the canal using silver cone pliers or stieglitze forcesps and press it apically.
The cone should fit snugly and should bind at the apical foramen because it corresponds to the diameter and taper of the prepared canal. Take a radiograph to check the fit of the cone in the canal. Take a radiograph to check the fit of the cone in the canal. If it protrudes beyond the apex, cut off the excess at the tip so that final fit will terminate 0.5 m short of the root apex. If the silver cone is tot short, either select another, that fits or reprepare the canal so that the selected cone seats properly. Coat the canal with cement and insert the sterilized silver cone with slight pressure to the measured length. Take another radiograph to ensure that the filling is properly positioned. Laterally condense gutta percha cones around the primary silver cone. To complete the filling of the canal with silver cone and gutta percha, remove the excess gutta percha, wipe the walls clean with chloroform or alcohol, and fill the crown with zinc phosphate cement, which may serve as a temporary restoration.
Improved Silver Points: Improved silver points were developed and introduced by Weine in 1968. These improved points were easier to use in routine cases and much easier to use with various types of sectional procedures.
Specifications: They resemble the enlarging instrument of corresponding size as closely as possible. Point has a color plastic handle attached at 25 mm from the tip and has a standardized taper, which is equivalent to that of the enlarging instrument (So Do + 0.32 mm = D16) and extends 16 mm up the shaft of the point.
Advantages over conventional silver points: 1. Conventional silver points are inserted with pliers or a hemostat held in the operator’s hand. When these points encounters an obstruction, curvature, or irregularity, forceful apical pressure will often cause a buckling or bending of the point. Whereas with improved silver point these hazards are immediately felt by the fingers, and a slight back and forth rotation along the long axis of point enable it to reach apex, by passing the problem. 2. The force needed for seating with pliers is not applied along the long axis of the point but merely parallel to it. Point placement along the long axis allows greater pressure to be developed at the tip of the point than when the pressure is applied parallel to the long axis. Clinically this means thick sealer may be used without the fear of preventing the point from reaching its intended seat. Also, with the greater pressure the point may force its penetration into the softer dentin walls so that dentin actually gain a grip on the point.
3. With improved silver points, same angle of insertion is utilized for point placement whereas when plies are sued, angle differs. This is important factor in treating molars, in which the angle of insertion is tricky to reproduce consistently. 4. Since the handles of the improved silver points are color coded, the size is immediately recognizable.
SECTIONAL OR “TWIST OFF� TECHNIQUE: Indications: The treatment plan may not call for the use of a post and core type of restoration for the treated tooth. However, there is always the possibility that a post and core may be needed at some later date. This may occur if - A new carious lesion develops - A portion of tooth fractures - The treated tooth becomes part of bridge or partial denture abutment - Or greater retention within the tooth is needed. For this purpose, twist off or sectional technique should be used.
In case of multiple rooted tooth if all canals are filled with silver points, at least in one canal a sectional technique should be used to allow for that canal carrying a post, if needed. Usually the largest canal is
selected. Palatal canal in maxillary molars and distal canal in mandibular molars.
Technique: Selection, preparation, and verification of apical fit for a trial points are obtained as in conventional case.
Silver point pliers or hemostat is used to hold the points for twisting off. But in case of posteriors it is not possible as they are bulky so either improved silver points are used or measurement control handles, also called test handles are used. After determining the apical fit handle is attached to the point. Test handle comes wit a tightening wrench, to tighten the point to the handle securely to prevent slippage during apical pressure.
Point notcher is used to cut partially through and weaken the silver point at the desired position. Has got four slots to accommodate various point widths.
The sealer is placed in the canal and applied on the tip of silver point. Point is forced with apical pressure to its seat. Once the correct depth is reached, with continuing apical pressure the handle is rotated
until a decrease is resistance to the rotation is felt. This indicates that the apical portion has separated.
Radiograph is taken to verify the
correctness.
Rest of the canal is filled with gutta percha, if post has to be given then post preparation can be started in same visit. As the dentist is familiar with the angulation and width of the canal.
CALCIUM PHOSPHATE CEMENT OBTURATION: Years ago Nevins and his associates were using cross-linked collagen-calcium phosphate gels to induce hard tissue formation. Herbert also suggested using tricalcium phosphate as an apical plug, much like dentin shadings or calcium hydroxide have been used. Recently, calcium phosphate cement (CPC) had been suggested as a total root canal filling material. Tetracalcium phosphate is the basic constituent and the acidic component is either dicalcium phosphate dihydrate or anhydrous dicalcium phosphate. Water is used as a vehicle for dissolution of the creactants. Setting time may be extended by adding glycerine. It is radiopaque as bone.
Glycerin was used in mixing the CPC to improve its extrudability from the from a 19 gauge needle. It might be a mild irritant to periapical tissue for some time, otherwise well tolerated by tissues. New bone formation is seen when CPC is used.
N2-SARGENTIC TECHNIQUE: The term N2 was coined by Sargenti to describe the second nerve, that placed during treatment. N2 filling material has red color to match the color of pulp it replaces.
The technique employed canal preparation with engine-driven instruments, no intracanal irrigant, and canal filling wit a formaldehyde paste. The whole treatment is done in single sitting. Artificial fistulation was recommended in certain cases but without raising the flap. Sargenti called it apical fenestration.
Composition of N2 (RC, RC2B etc) Zinc oxide eugenol Paraformaldehyde Organic mercury compound (Phenyl mercuric borate) Lead oxide Corticosteriods
Paraforamldehyde containing cement causes toxicity, severe periapical inflammation.
It can lead to ankylosis, root resorption.
Chances of over extension are there.
It can even led to paraesthesia of the nerve particularly in case f mandibular posteriors. As it is in the form of paste when introduced can result in over extension, under extension and voids.
Pressure Syringe Injection Technique: Krakow and Berk popularized the pressure syringe developed by Greenberg.
The pressure syringe provides an effective method of
introducing the sealer into the canal. The entire root canal may be filed with cement without a solid core of gutta percha or silver cone.
Technique: Cement is mixed, loaded in the pressure syringe, introduced with a fine needle to about 2 mm from the apical foramen. ↓ Position of needle determined by marker and verified by a radiograph. ↓ Cement is extruded – by giving quarter term to the handle of syringe ↓ Cement is extruded until whole canal is filled.
Technique is useful in cases of filling fine and tortuous canals that cannot be negotiated with instruments, filling primary teeth, and filling some large canals.
Disadvantages: Chances of over extrusion, voids, under filling.
ERRORS/CAUSE OF FAILURE: 1. Regarding the fit of the filling material, it either does or does not obliterate the canal, if it is not at the correct length, it is either too long (over extended) or too short (under extended).
Four Possibilities exist: The canal is obliterated but the filling material extends beyond the apical foramen. In case of GP, does no lead to failure as it is well tolerated by the periapical tissue. The canal is not obliterated and the filling material extends beyond the apical foramen.
Leads to failure: Because of possible periapical irrigation from the filling material.
ďƒ˜ Tissue fluids entering the unfilled canal to form irritating breakdown products that results in additional tissue irritation and a chronic periapical lesion. ďƒ˜ The canal is obliterated to a point short of the apical foramen. Chances of failure are more. ďƒ˜ The canal is not obliterated and the filling material does not extend to the apical end of the preparation. Prognosis for a canal filled in this manner is very poor. 2. Failure to use a sectional technique when using silver cones results in a treatment dilemma when post room is necessary. Either attempts must be made to remove the cone and refill the canal by means of a technique that allows the preparation of post room or another, less desirable method of obtaining retention for the crown must be provided. 3. Failure to condense the filling material in the cervical portion of the canal and into the floor of the pulp chamber may result in a failure to seal accessory canals that occasionally occur there. Lesions that seem to be of periodontal origin may be of endodontic origin if canal irritants are able to transverse these accessory canals. 4. Some sealers, containing precipitated silver particles, may produce unsightly discoloration of coronal tooth structure if the material enters the dentinal tubule of the crown.
Considerable care should be
exercised to remove sealers form the pulp chamber following canal filling if the sealer has staining properties. 5. Silver cones or other solid filling materials may be dislodged during subsequent restorative procedures. Movement of the solid core filling material may break the seal between the sealer the cone, and the canal wall → resulting in an incomplete fill and a subsequent treatment failure.
SUMMARY: The astute practitioner must recognize that no one particular obturation technique will satisfy the myriad of clinical cases that require endodontic therapy. The obturation method selected, whether it be a conventional method or one of the contemporary ones, must be consistent
with the overall goals of clinical practice; i.e. to provide care for our patients. Although all obturation techniques have their advantages as well as their disadvantages, the clinician should be open minded enough to accept and master a number of obturation techniques and not just focus on one.
At the same time, he or she should be able to provide a
biologically sound rationale for the method he or the chooses. In time, this philosophy will generate dental practitioners who cannot only solve problems but who can also to think critically.