Obturation of the Root Canal System PDF

# Obturation of the root canal system Obturate means to fill the shaped and disinfected root canal system with a permanent filling material. - 60% of failure in endodontics, is caused by incomplete obturation of the radicular space. - Percolation of the periapical exudates into an incompletely fil...

# Obturation of the root canal system Obturate means to fill the shaped and disinfected root canal system with a permanent filling material. - 60% of failure in endodontics, is caused by incomplete obturation of the radicular space. - Percolation of the periapical exudates into an incompletely filled root canal is a main cause of endodontic failure. Evidence suggests that root canal systems cannot be completely cleaned and disinfected. - Obturation of the radicular space is necessary to eliminate leakage. Obturation prevents coronal leakage and bacterial contamination, seals the apex from the periapical tissue fluids, and seals the remaining irritants in the canal. - Coronal leakage has also been demonstrated to contribute to treatment failure. Maintaining a coronal seal and placing of a definitive restoration should be considered an essential component of successful endodontic treatment. ## Objectives: Why to fill the root canal space? The primary objective of endodontic treatment is the development of a fluid-tight seal at the apical foramen and total obliteration of the root canal space. Obturation of the root canal is done to: 1. Prevents percolation of the periapical fluid into the radicular space which leads to persistence of periapical inflammation and microleakage. 2. Prevents bacterial reinfection, due to ingress of the microorganisms into the poorly filled canals. 3. Seals within the canal, any irritants that cannot be fully removed. 4. Allows for periapical tissue healing to take place, by creating a favorable environment for healing. ## Extension of root canal filling material: ### Apical Position of The Obturating Material The cemento-dentinal junction apically is: 1. The anatomic limit of the root canal, beyond which, the periodontal tissue begins. 2. The narrowest diameter of the apical foramen. 3. It is average 0.5-0.7 mm away from the external surface of the apical foramen. ## Characteristics of Ideal Root Canal Filling - Obturation is filling of the entire root canal system, as close to the cemento-dentinal junction as possible. - There should be radiographic appearance of dense, radiopaque, 3-dimensional filling without gross overextension or underfilling. ## N.B. - **Overfilling:** Total obturation of the root canal with excess material extruding beyond the apical foramen. - **Overextension:** Extrusion of the filling material beyond the apical foramen, but the canal has not been adequately filled and the apex has not been adequately sealed. ## When to Obturate the Root Canal Space? (Timing of Root Canal Obturation) 1. The canal is cleaned & shaped to optimum size. 2. The tooth is asymptomatic (No: Pain, Swelling). 3. The canal is dry (No: pus, exudates or bleeding). 4. There is no foul odour. 5. There is no sinus tract. 6. The temporary filling is intact. ## Root Canal Obturating Materials In order to achieve perfect obturation of the radicular space, a core filling material and a sealer cement are used. Grossman grouped acceptable filling materials into plastics (semisolids), solids, cements (sealers) and pastes. ## Ten Requirements for ideal root canal filling material (By Grossman): 1. Easily introduced into the root canal. 2. Seal the canal laterally as well as apically. 3. Dimensionally stable (Should not shrink after being inserted). 4. Impervious to moisture. 5. Bacteriostatic or at least not encourage bacterial growth. 6. Radiopaque. 7. Should not stain the tooth structure. 8. Should not irritate periradicular tissues. 9. Sterile or easily & quickly sterilized before insertion. 10. Removed easily from the root canal if necessary. ## Types of root canal filling materials: 1. **Solid materials:** - **Semi-rigid (Flexible):** Silver points (Silver cones). - **Rigid:** Vitallium pins, Titanium pins. 2. **Semi-solids:** - Gutta-percha - Resilon - Combinations 3. **Pastes:** - Chloropercha - Eucapercha - Iodoform. 4. **Sealers (Cements)** ## Silver Points (Silver Cones) - Solid core filling material. - The canal prepared to receive silver point must be perfectly round and tapered. ### Composition: 1. 99.9% Silver. 2. Nickel 3. Copper. ### Properties: 1. **Hard:** Harder than dentin leads to dentin grip. 2. **Oligodynamic:** toxic effect of silver point on the cell → bactericidal effect. 3. **Corrosion potential:** Corrosion occurs in presence of fluid when: - No apical seal. - No coronal seal. - Overextension of silver point. ### Advantages: 1. Rigidity. 2. Length control. 3. Ease of placement. 4. Ability to be precurved. 5. Grip to dentin. ### Disadvantages: 1. Cannot be compacted. 2. Lack of adaptability (no lateral sealing). 3. Lack of dissolvability (not easily removed). 4. Corrosion. 5. Periapical tissue irritation. **N.B.** Silver point is not used now due to the development of new and advanced techniques for preparation and obturation. ## Gutta Percha 1. Gutta Percha is the most universally used root canal filling material and may be classified as a plastic. 2. True gutta percha is the dried sap of Brazilian tree called Manilkara Bidentata. 3. Chemically pure gutta-percha exists in two different crystalline forms "alpha and beta" that can be converted into each other. 4. The "alpha" form comes directly from the tree. 5. Most commercial gutta-percha, however, is the "beta" crystalline form. 6. There are few differences in physical properties between the two forms, merely a difference in the crystalline lattice related to the different rates of cooling from melt (Thermoplastic material). 7. If the natural "alpha" form is heated above 65°C it becomes an amorphous structure. If this amorphous material is routinely cooled, the "beta" form takes place. The "beta" form of gutta-percha has a melting point of 65°C, this form is more flexible (the commercial cones). ### a-Form - Brittle at room temperature. - Becomes tacky and flowable when heated (low viscosity). - Thermoplasticized gutta percha for warm compaction technique is in a-form. ### B-Form - Stable and flexible at room temperature. - Becomes less adhesive and flowable when heated (high viscosity). - Gutta-percha points used with cold compaction are in ẞ-form. ### The effect of heating on the volumetric change of gutta-percha is very important: 1. The material expands slightly on heating, so possible to “overfill" a root canal when heat and vertical condensation is applied because the volume of gutta percha is greater than the space it occupies. 2. Warmed gutta-percha also shrinks as it returns to body temperature. Therefore, it is recommended that vertical pressure be applied on all warm gutta-percha techniques to compensate for that shrinkage that occur as cooling takes place. ### Composition of gutta-percha cones: - Gutta-percha: 18-22% Matrix - Zinc Oxide: 60-75% Filler level leads to: ↑rigidity, ↑ tensile strength. - Waxes/resins: 1-4% Plasticizers (more compactable). - Metal sulphates (Barium sulphate): 1-18% Radiopacifiers. **N.B.:** There is a slight antibacterial activity as well as a degree of tissue irritation from the gutta-percha points related to the content of zinc oxide. ### Storage of Gutta-percha: 1. Gutta percha points become brittle as they age probably through oxidation. 2. Storage under artificial light also speeds their rate of deterioration. Age and light revert the gutta-percha in the point back to its original "alpha" phase, which is brittle. ### Availability of gutta-percha: Gutta-percha points (or cones) are supplied in two forms: 1. **The ISO standardized form,** which is standardized according to the size and shape of endodontic instruments, i.e. # 15 to #140. 2. **The non-standardized form** to conform to the shape of the root canal. It is classified to: XF – FF - MF-F-M - coarse. - Greater taper gutta percha points (4%, 6%, 8%). - Gutta percha pellets used in thermoplasticized gutta percha obturation techniques e.g. Obtura System. - Precoated core carrier gutta percha e.g. Thermafill System. - GuttaFlow: Gutta percha powder incorporated into silicone-based sealer. **Recently:** 1. Medicated gutta percha containing iodoform (inhibit bacterial growth). 2. Ca (OH)2 containing gutta percha (Roeko). 3. Chlorhexidine containing gutta percha. ### Advantages of Gutta-Percha 1. Compactability → Main Advantage. 2. Dimensional stability. 3. Inertness. 4. Tissue tolerance 5. Radiopacity 6. Solubility in common solvents, such as chloroform. 7. Ease of removal from root canal. ### Disadvantages of gutta-percha 1. Lack of rigidity: Which causes difficulty in filling narrow and curved canals. 2. Lack of length control: the gutta-percha tends to extend beyond the apical foramen during compaction (Easily displaced by pressure). 3. Lack of adhesiveness: Gutta-percha alone cannot hermetically seal the canal. 4. Brittle with aging. 5. Shrinkage of warm Gutta percha. ## Root Canal Sealers ### Rationale for using Sealers: With the discovery of X-ray, it became obvious that filling points alone are not enough to ensure a fluid tight seal and prevent leakage. - Voids and spaces were evident within the points, and at the interface between the filling material and the canal walls. - Therefore, a cementing agent was necessary to achieve the goal of FILLING the root canal space. ### Functions of root canal sealers: 1. Fill in the irregularities & minor discrepancies between the filling material & canal wall and within the filling material itself → Main Function. 2. Lubrication & aids in seating of the cones. 3. Antimicrobial. 4. Fill in the accessory canals. ### Grossman's Requirements for Ideal Root Canal Sealer: | Biological Properties | Sealing Properties | Working Properties | |-------------------------------------------|------------------------------|-----------------------------------------------| | Should be biologically acceptable. | Should produce hermetic seal (fluid-tight seal). | Should be easy to manipulate. | | Should not irritate the periapical tissues. | Should have good adhesion to the canal wall. | Should Set Slowly. | | Should not be mutagenic or carcinogenic. | Should expand while setting. | Should not stain the tooth structure. | | Should be bacteriostatic. | Should not shrink after setting. | Should be insoluble in tissue fluids. | | | Should be insoluble in tissue fluids. | Should be soluble in common solvents. | ### Classification of root canal sealers: Trials went along two main channels when suggesting new root canal sealers. One of them to use materials with therapeutic or repair potentials. Those were mainly based on zinc oxide and eugenol, calcium hydroxide, or calcium phosphate cement. The other way was to use materials with adhesive abilities. For each sealer or category of sealers, the following must be identified: - Rationale for use. - Basic composition. - Compliance with Grossman's requirements. **A. Sealers with Therapeutic potential** | Material | Rationale for use | Basic composition | Compliance with Grossman's Requirements | Suggested Modifications | |---------------------------------|-------------------------------|--------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------------| | **Zinc Oxide and Eugenol based sealers** | The ability of eugenol to alleviate tooth pain is the main reason it is so widely used in dentistry | Rickert's formula "Kerr's root canal sealer", Grossman's cement "Procosol, Roth's sealer, Endoseal". Both formulae contain ZnO in their powder and eugenol in the liquid. The essential difference between the 2 groups is that Rickert's formula contains Ag which stained the teeth while the Grossman's formula has Barium or Bisthmus salts as radiopacifier. | This sealer is sensitive to moisture. When it comes in contact with tissue fluids, hydrolysis of the matrix occurs, breaking down the seal. Moreover, eugenol in large quantities has a toxic effect on cells. | Nogenol sealers: These are non-eugenol cements where eugenol was replaced by vegetable oils. | | **Calcium phosphate-based sealers** | It was used as it induces osteogenesis and cementogensis apically resulting in biologic seal. However, infected dentin chips could prevent healing. | A formulation of calcium phosphate, antiseptic and resin called Dentinoid. Recently calcium phosphate cements yield hydroxyapatite on setting. | Biocompatible. Insoluble in tissue fluids. | | | **Calcium hydroxide-based sealers** | This category was suggested with the aim of establishing a biologic seal. The antibacterial properties of Ca (OH)2 as well as its ability for hard tissue formation (osteogenic effect) made this material a good candidate for sealing root canals. | Ca (OH)2 sealers come in 2 forms: with eugenol and without. CRCS (Calcibiotic Root Canal Sealer): consists of Ca (OH)2 added to ZnO/eugenol paste. SealApex and Apexit. | In order to be therapeutically effective, Ca (OH)2 must be partially soluble, which may affect its structural integrity and compromise the long-term seal. | | **B. Sealers with Adhesive potential** | Material | Rationale for use | Basic composition | Compliance with Grossman's Requirements | |---------------------------------|--------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------|-------------------------------------------------------------------------------------------| | **Silicone-based sealers** | Silicones dominate as sealants in kitchens, bathrooms, and since they have a moisture resistant property. They are biocompatible materials. | Silastic and EndoFill were early attempts at utilizing silicones endodontic sealers - Recently, the polydimethyl siloxane-based RoekoSeal is fulfilling the biological and sealing requirements. The manufacturer of this sealer has suggested another version, which consists of mixing gutta percha powder with the sealer to obtain "GuttaFlow". | Biocompatible. Have good sealing ability. however, they lack adhesiveness to the hard tooth tissues. | | **Glass Ionomer-based sealers** | Glass ionomer is a biocompatible material that ensures good adhesion to dentin. | Ketac-Endo is a glass ionomer sealer suggested for endodontic use. | Currently, No sealers of this group are marketed, owing to their difficulty in removal. | | **Resin-based Sealers** | There are different types of resins. Having tacky and insulating properties which make them good candidates for adhesive root canal sealers | Polyketone Diaket is a polyketone compound containing vinyl polymers. It is a resin reinforced chelate: formed between zinc oxide and the liquid B-diketone. AH 26: an epoxy resin. AH Plus is a reformulation of AH26 that avoided its drawbacks. | Has acceptable sealing and biocompatibility. | AH26: released on formaldehyde setting render it antibacterial, had long setting time and stained the tooth because of its Ag content. | | | | Epoxy | | | ## Obtaining the Master Cone "**Master point - Initial point - Primary point**" 1. When the canal is ready for filling, the fit of the primary point is most important. 2. Gutta-percha have been standardized in size and shape to match the standardized instrument. Presumably, a primary point the same size of the file or reamer that prepared the apical third of the cavity will fit exactly. 3. Before trial insertion, the initial point should be sterilized for 5 minutes in sodium hypochlorite (5.25%) or hydrogen peroxide (3%) or chlorhexidine (2%). 4. However, the point must be tested in place. This is known as the trial point measurement. ### The Master cone should fulfill the following criteria: 1. Its adjusted length is sufficient to reach the apical end of the canal. 2. The diameter of its apical end fits the diameter of the apical foramen. 3. Its apical third completely fills the apical third of the canal. ### The three methods used to determine the proper fit of the master cone are: 1. **Visual Test:** - The master cone is measured and grasped with a tweezer at a position equal to the working length of the canal. - The point is then carried into the canal until the pliers touch the external reference point of the tooth. - If the working length of the tooth is correct and the point goes completely to position, the visual test has been passed. - Whether the point can be pushed apically beyond this position may be determined by grasping 1 mm farther back on the point and attempting to push it apically. If the point can be extended beyond the apex, it means that the apical foramen was originally large, or it has been perforated. The next larger size point should be tried. If this larger point does not go into place, the original point may be used by cutting 1 mm off the tip. Each time the tip is cut back, the diameter becomes larger. The point is retried in the canal until it goes to the correct position. 2. **Tactile Test** - In this method the practitioner depends on tactile sensation to determine whether the point tightly fits the canal. - If the apical 3-4 mm of the canal has been prepared with parallel walls: - Some degree of force should be required to seat the point. - And once it is in position, a pulling force should be required to withdraw it. This is known as "tugback" action → Slight resistance felt upon withdrawal. - If the point is loose in the canal: - The next larger size point is tried → if short, - The method of cutting segments from the tip of the master point, followed by trial-and-error positioning, should be used. 3. **Radiograph Test:** - After the visual and tactile tests for the trial point have been passed, its position must be checked radiographically. - The radiography must show the point extending to within 1 mm from the radiographic apex. - If the radiography shows the point forced well beyond the apex → recheck the working length and recreate an apical stop. ### If the cone fits shorter to the desired length: May be due to: 1. Dentin chips packed in the canal. 2. Canal may be ledged at a position shorter to the WL. 3. Enlarging instrument was not used to its fullest extent. 4. The master cone selected, may be too large. 5. Improper 3-D canal shaping in the apical to middle third of the tooth. ## Techniques of Root Canal Obturation 1. **Cold gutta-percha technique:** (Lateral compaction technique). 2. **Chemically plasticized (softened) cold gutta-percha technique:** - Chloroform. - Eucalyptol. - Halothane. 3. **Warmed gutta-percha technique:** - Vertical compaction technique. - Sectional compaction technique. - Lateral/vertical compaction technique. 4. **Thermo-mechanical compaction:** - Mc Spadden technique. - Thermo-mechanical solid-core gutta percha obturation (Quickfill). - Automated plugger (canal finder). - Ultrasonic plasticizing. 5. **Thermoplasticized injectable gutta-percha** - Syringe Injection: - Obtura II. - Ultrafil. - Solid-core carrier insertion: - Thermafil. - Successfil. - Trifecta - Soft core. 6. **Apical third filling:** - Carrier based system: Simplifill - Biological seal: MTA which is placed in the apical 1/3 act as a biological seal. ## Lateral Compaction Technique (Cold Gutta-Percha Points): It is one of the most common methods used for root canal obturation. It involves placement of tapered gutta-percha cones in canal and then compacting them under pressure against the canal walls using a spreader. A canal should have continuous tapered shape with a definite apical stop, before it is ready to be filled by this method. ### Technique: 1. **Spreader size determination and selection after the canal preparation:** - A spreader is chosen that will reach to within 1-2 mm of the working length besides the master cone. - A rubber stop should be placed on the shaft of the spreader to mark the true working length minus 1-2 mm. - Auxillary cones selection are gutta-percha cones that have the same size of the selected spreader or one size smaller. 2. **Drying the canal by an absorbent paper points to absorb any moisture that might accumulate.** 3. **The root canal sealer should then be mixed and placed in the canal by (file, reamer, master cone, Lentulo spiral, ultrasonic). ** The sealer should not be mixed too thin or too thick (viscous). It must not be so viscous that it will not flow between the gutta-percha points or penetrate accessory and lateral canals. ### Testing the proper consistency of Sealers: - **Drop Test:** The cement mass should not drop off the spatula's edge in less than 10 to 12 seconds. - **String Out Test:** The cement should string out at least an inch without breaking. 4. **The premeasured master cone is coated with sealer and slowly pushed in the canal to full working length.** 5. **The premeasured spreader is then introduced into the canal alongside the master point and used to compact the master cone in a lateral and vertical direction.** 6. **The spreader is removed by a watch-winding motion and is immediately followed by first an auxillary cone, inserted to the full depth of the space left by the spreader.** 7. **This point is followed by more spreading and more points until the entire canal is filled.** 8. **Obturation is considered complete when the spreader can no longer penetrate the filling mass beyond the cervical line.** 9. **The protruding points and sealer are then removed at the orifice of the canal with a very hot instrument.** All of the sealer and gutta-percha should be removed from the pulp chamber and a final radiograph is taken. ### Advantages: - Can be used in most clinical situations. - Positive dimensional stability of root filling. - During compaction of gutta-percha, it provides length control, thus decreases the chances of overfilling. ### Disadvantages: - Presence of Voids. - Increased sealer: GP ratio. - Does not produce homogenous mass (Space may exist between accessory and master cones). - Time-consuming. - Less able to seal lateral canals and intracanal defects. ## Variations of Lateral Compaction Technique (Variation of master cone) (incomplete root formation = wide apical foramen) Sometimes the wide variations in root canal shape require variations in master point technique. ### Inverted cone technique This technique is applicable in the tubular canals found in the teeth that suffered early death of the pulp. A "Coarse" gutta-percha cone is selected, and the serrated end of the point is carefully removed with a scalpel. The point is inverted and tried in the canal. It should visibly go to full depth, and it should exhibit "tugback" when an attempt is made to remove it. Radiographically, it should appear to be in optimum position. ### Tailor-made gutta-percha technique - If the tubular canal is so large that the largest inverted point is still loose in the canal, a tailor-made point must be used as a primary point. This point may be prepared by heating a number of gutta-percha points and combining them, butt end to tip, until a roll has been developed that match the size and shape of the canal. The roll must be chilled with a spray of ethyl chloride or ice water to stiffen the gutta-percha before it is fitted in the canal. - If it is too loose, more gutta-percha points must be added. - If it is only slightly too large, the outside of the roll can be heated over the flame and the roll forced to proper position in the canal. - By this method an impression of the canal is actually secured. - The rolled gutta-percha should be tested for "tugback" as well as radiographically. It should then be cemented into place by sealer. - The spreader should then be marked just short of the working length of tooth and used for lateral compaction. Lateral compaction is necessary in conjunction with the tailor-made gutta-percha to ensure obliteration of the canal space. - The gutta-percha protruding from the crown should be severed at the base of the pulp chamber with a hot instrument. **N.B.** The outer surface of the gutta-percha roll may also be softened by dipping in chloroform, eucalyptol, or halothane and inserted into the canal. By repeating this exercise an internal impression of the canal is taken. A mark is made on the buccal of the roll and it is dipped in alcohol to stop the action of the solvent. ### Chemically Plasticized (softened) Cold Gutta-Percha technique: 1. This technique involves the use of a solvent to soften the primary gutta-percha point in an effort to ensure that it will better conform to the irregularities in root canal anatomy. 2. Solvents used: - Chloroform → Chloropercha. - Eucalyptol → Eucapercha. - Resins, such as rosin, were added to chloropercha to provide better sealing qualities. This was called Kloropercha. 3. This is a variation of the old obturation method, called Callahan-Johnston technique, where the solvent chloroform is used to dissolve small pieces of gutta-percha to form a thick creamy mix (paste) ready for immediate filling of the root canal. ### Disadvantages: - It was found that as the chloroform is volatile and evaporates in the canal, so it produces a 24% shrinkage of the filling material leaving voids and leads to serious leakage. - Inability to control the obturating material. - This paste was toxic because of chloroform content. - Irritation of the periapical tissue. 4. Modification is done (Dip Technique), where: - The apical 2-3 mm of the master cone is placed in the solvent for about 4 seconds. - Master cone is placed into the canal, followed by auxillary cones as lateral compaction method. - This allows a satisfactory imprint of the apical 1/3 of the canal. ### Warmed Gutta-Percha Technique: - **Vertical Compaction Technique.** Schilder introduced a concept of obturating the canal with gutta-percha warmed in the canal and compacted vertically with pluggers. **N.B.** Following the preparation of a thoroughly cleaned and continuously tapering canal, the critical step of fitting the master cone is the key to success in this technique. A suitable gutta-percha cone is chosen and placed in the canal to reach the radiographic working length of the canal. The cone must fit tightly in the apical third, i.e. have "tugback", and have diminished taper toward the middle and coronal thirds as well. - **A set of pluggers** should be used for vertical compacting of warm gutta-percha. A wider plugger for the coronal third of the canal, a narrower plugger for the middle third, and the narrowest plugger for the apical third. Rubber stoppers are adjusted on these pluggers to the occlusal reference point corresponding to 2 mm short from root canal binding point (coronal, middle or apical thirds). - **An instrument "heat carrier"** is used to transfer heat from flame to the gutta-percha. It is heated "cherry-red", immediately carried into the canal, penetrated into the gutta-percha, and left there for 2 to 3 seconds to allow the heat to transfer. It is then withdrawn in a slightly circular wiping motion. It will be noticed that some of the gutta-percha comes out attached to the heat carrier. Vertical compaction immediately follows by pluggers. - **There are electronic devices specially developed for the warm gutta-percha technique as "Touch 'n' Heat" and "System B – Continuous wave of obturation".** They exhibit the same thermal profile as the original heat carrier but has the advantage of generating heat automatically at the tip of the instrument and also permit for "Temperature Control". ### Step by step procedure of vertical compaction of gutta-percha: 1. Dry the root canal with paper points. 2. Fit the appropriate gutta-percha cone to the radiographic terminus. It should visually go to full working length and exhibit "tugback". Confirm the position radiographically. Cut off the butt end at the incisal or occlusal reference point. 3. Pre-fit the three pluggers to the canal preparation, i.e. the widest (coronal), the middle, and the narrowest (to within 3 to 4 mm of the apical constriction). 4. Lightly coat the walls of the canal with the root canal sealer using a handy Lentulo spiral. 5. Coat the apical third of the gutta-percha cone with a thin layer of sealer and insert it fully into place. ### Apical Down-packing: 6. Using a hot heat carrier or the "Touch 'n' Heat" instrument, trim off the cone surplus in the pulp chamber down the cervical level. This transfers heat to the coronal third of the gutta-percha cone. Using the widest plugger, the gutta-percha is compacted in an apical direction with sustained pressure. This is the "first heat wave” in which the temperature of gutta-percha has been raised 5 to 8 degrees above body temperature. At this temperature (42°C to 45°C) the gutta-percha retains its crystalline "beta" form with minimal shrinkage as it cools back to body temperature. 7. The "second heat wave” begins by introducing the heat carrier back into the gutta-percha, where it remains for 2 to 3 seconds, and when retrieved carries with it a small piece of softened gutta-percha (selective gutta-percha removal). 8. Immediately, the mid-size plugger is submerged into the warm gutta-percha. The gutta-percha is compacted apically in 3 to 4 mm waves created by repeated heat and compaction cycles. The vertical pressure also exerts lateral pressure. 9. Heating with the heat carrier warms the next 3 to 4 mm of gutta-percha and again a small amount is removed on the end of the heat carrier. 10. The narrowest plugger is immediately inserted in the canal and the surplus material along the walls is folded centrally into the apical mass. The warmed gutta-percha is then compacted vertically and the material flows into the seals the apical foramen. 11. The apical "down-pack" is now completed, and if a post is to be placed at this depth, no more gutta-percha needs to be used. ### Backpacking: 12. The rest of the canal may be filled by "backpacking". This method consists of placing 3 mm segments of gutta-percha in the canal, cold-welding them with the heat-carrier, and then compacting. This "sectional" procedure is continued with heat and the next wider plugger until the entire canal is obturated. 13. An alternative method of "backpacking" may be done by "injecting plasticized gutta-percha" from one of the syringes, such as Obtura. The plasticized gutta-percha must be compacted with vertical pluggers to ensure its flow into accessory canals, to weld it to apical mass, and to minimize shrinkage. 14. Finally, thorough cleansing of the pulp chamber is done, and a permanent restoration is placed coronally. ### Advantages: - Excellent sealing of canal apically, laterally and obturation of lateral as well as accessory canals. - Oval canals get better filled than with lateral compaction technique. ### Disadvantages: - Increased risk of vertical root fracture. - Overfilling of canals with gutta-percha or sealer from apex. - Time-Consuming. - Difficult to use in curved canals where rigid pluggers are unable to penetrate to required depth. ## Sectional Compaction Technique. The use of small, warmed pieces of gutta-percha, the so-called sectional compaction (obturation) technique, is one of the earliest modifications of the vertical compaction technique described above. Eventually this became known as the "Chicago" Technique. - After fitting of the master cone. - 2-3 mm of the tip of the point is removed with a scalpel and then luted to the end of warmed plugger. - Sealer is placed in the canal then gutta percha is warmed by passing it through the flame, coated with sealer and then packed in place by a plugger. - The remainder of the canal is filled by compacting additional pieces of warmed gutta percha. ## Lateral / Vertical Compaction Technique. Considering the ease and speed of lateral compaction as well as the superior density gained by vertical compaction of warm gutta-percha, a device called "Endotec" was developed to achieve the best of both techniques. It is also called “Warm Lateral Compaction Technique). **N.B.** - Spreaders (which have pointed ends) used for lateral compaction. - Pluggers (which have flat ends) used for vertical compaction. Both may be supplies as hand or finger spreaders and hand or finger pluggers. ## Thermomechanical Compaction of Gutta-Percha ### Mc Spadden Technique: 1. The concept of heat softening and compacting gutta-percha was introduced by Mc Spadden and the device was called "Mc Spadden Compactor". 2. **Mc Spadden Compactor:** - Resembles a reverse Hedstrom file. - Fits into a latch-type handpiece and speed between 8000 and 10000 rpm. 3. **At this speed:** - The heat generated by friction softens the gutta-percha. - The design of the blades forces the material apically. 4. **Disadvantages:** - Fragility and fracture of the instrument. - Overfilling. - Because of its design, the blades of compactor break easily if it binds, so it should be used only in straight canals **N.B.** Mc Spadden modified his original device and brought out a newer, gentler, slower-speed model called the "NiTi Condenser". It is made of nickel-titanium for flexibility. ### Thermomechanical Solid-Core Gutta-Percha Obturation (QuickFill) 1. **Consists of:** - Titanium solid core (carrier) device coated with alpha phase gutta percha. - Spun into the canal with regular low speed handpiece. - Friction heat plasticizes the gutta percha. 2. **After compaction, either:** - Remove the compactor and final compaction completed with a hand plugger, - Or the titanium solid core may be left in its place in the canal. In this case the titanium core is separated in the coronal cavity with an inverted cone bur. ### Automated Plugger (Canal finder Plugger) This is a flexible plugger used in a special handpiece called a "Canal Finder handpiece" which delivers rapid vertical strokes that varies between 0.3 and 1 mm strokes. ### Ultrasonic Plasticizing This technique depends on plasticizing gutta-percha in the canal with an ultrasonic instrument. ## Thermoplasticized Injectable Gutta-Percha Obturation 1. The canal must have: - A continuously tapering funnel from the apical end to the canal orifice (this proper shaping is essential for the flow of the softened material). - A definite apical matrix is essential to confine and retain the gutta percha in the canal system. 2. The efficiency of thermoplasticized gutta percha in filling of: - Internal resorption. - C-shaped canals. - Accessory and lateral canals. ### Syringe Injection: 1. **Obtura II** - Gutta percha comes in pellet form, that is inserted into a heat delivery system, where ẞ phase gutta percha is heated approximately to 160