Obturation: Root Canal Procedure PDF

OBTURATION WHAT IS OBTURATION?  Obturate – to close or obstruct  Final step in endodontic treatment  It is sealing of apical foramen at CDJ & all portals of entry to periapical tissue with an inert material  The better the seal , the better the prognosis of the tooth. ...

OBTURATION WHAT IS OBTURATION?  Obturate – to close or obstruct  Final step in endodontic treatment  It is sealing of apical foramen at CDJ & all portals of entry to periapical tissue with an inert material  The better the seal , the better the prognosis of the tooth.  OBJECTIVES OF OBTURATION  The preliminary objectives of operative endodontics are * Total debridement of the pulpal space, * Development of a fluid-tight Seal at the apical foramen, and * Total obliteration of the root canal.  Micro leakage around coronal restorations, down through the root canal filling, and out the apical foramen into the Peri radicular tissues is also a potential source of bacterial infestation  WHEN TO OBTURATE THE CANAL  The root canal is ready to be filled when the canal is cleaned and shaped to an optimum size and dryness.  The smear layer lining the canal walls should also be removed.  The tooth should be comfortable.  Dry canals may be obtained with absorbent points except in cases of apical periodontitis or apical cyst, in which “weeping” into the canal persists  Adequate biomechanical preparation has been completed & confirmed.  Tooth is asymptomatic  Canals are dry  No sinus tract  No foul odor  Intact temporary filling  REQUIREMENTS FOR AN IDEAL ROOT CANAL FILLING MATERIAL 1. It should be easily introduced into a root canal. 2. It should seal the canal laterally as well as apically. 3. It should not shrink after being inserted. 4. It should be impervious to moisture 5. It should be bacteriostatic or at least not encourage bacterial growth. 6. It should be radiopaque. 7. It should not stain tooth structure. 8. It should not irritate Peri radicular tissue. 9. It should be sterile or easily and quickly sterilized immediately before insertion. 10. It should be removed easily from the root canal if necessary. NB.  Both gutta-percha and silver points meet some of these requirements.  If the gutta-percha point has a fault, it lies in its inherent plasticity, for it requires special handling to position it.  The major fault with the silver point is its lack of plasticity - its inability to be compacted.  Both must be cemented into place, however, to be effective  GUTTA -PERCHA  Over the years , many different filling materials have been used to seal root canals.  Currently, the material used most often as a solid-core filling is gutta percha.  Introduced by Bowman in 1867. GP is a desirable filling material because: - it does not shrink after insertion unless its plasticized with a solvent or heat. - Its radiopaque, non staining & impervious to moisture. - It is probably the least toxic & least irritating to peri apical tissue of all root canal filling materials. Conversely - it is difficult to introduce into a narrow root canal - It does not seal a canal apically or laterally unless it is combined with a root canal sealer. - It has limited shelf life. - It becomes brittle with age.  Composition Gutta percha (matrix) 20% Zinc oxide (filler) 66% Heavy-metal sulfates 11% (radiopacifier) Waxes or resins 3% ( plasticizer)  Obturating Technique - Many methods of obturating a root canal with gutta- percha & a sealer are used. - These techniques includes 1. Lateral condensation 2. Vertical condensation(Warm GP) 3. Sectional condensation 4. McSpaddeen or thermomechanical Compaction 5. Thermoplasticized GP technique 6. Chemically plasticized GP technique  Lateral Condensation Method - In LCT, a gutta percha cone, called the primary or master cone , is fitted to the instrumented main canal. - The primary cone is inserted into the root canal to the established working length. - It should fit snugly and should resist removal(‘’snug-fit’’) - A radiograph is taken to determine the apical & lateral fit of the primary cone. - The GP cone is adjusted; if it protrudes, the tip should be cut off & cone reinserted = ‘’tug back’’ - If the initial fit of the primary cone is 2 or 3 mm short of apex → new primary cone measured or canal should be reprepared. - Purpose of fitting the primary cone short of the canal apex → to avoid inadvertent overfilling (a) Master cone fit. b) Lateral compaction with spreader following addition of one accessory cone. (c) Continued lateral compaction.  NB: - Root filling is complete when it is not possible to place another accessory cone further than 2 mm into the root canal. (d) Further addition of accessory cones.  Advantages of Lateral Compaction Technique 1. Can be used in most clinical situations. 2. it provides length control, thus decreases the chances of overfilling. Disadvantages 1. May not fill the canal irregularities efficiently. 2. Does not produce homogenous mass. 3. Space may exist between accessory and master cones  Vertical condensation (Warm GP) - This method is used with the step back technique of root canal preparation. - Using heated pluggers, one applies pressure in a vertical direction to the heat-softened gutta percha & thereby causes it to flow & fill the entire lumen of the canal.  Steps in vertical condensation 1. A primary GP cone corresponding to the last instrument used is fitted in the canal. 2. The canal wall is coated with a thin layer of root canal cement. 3. The cone is cemented 4. The coronal end of the cone is cut off with a hot instrument. 5. A ‘’heat carrier’’ such as plugger is heated to redness & immediately forced into the coronal third of the GP. 6. A vertical condenser of suitable size is inserted, & vertical pressure is applied to the heated GP, to force the material apically. 7. This alternate application of heat carrier & condenser is repeated until the plasticized GP seals the large accessory canals & fit the lumen of the canal. Luks Singer pluggers. long-handled Kerr pluggers. Advantages of VC - Excellent seal of the canal both apically and laterally - Obturation of larger lateral & accessory canals Disadvantages of VC - Time consuming - Risk of vertical root fracture - Periodic overfilling of GP or cement.  Sectional condensation - The sectional method of filling a root canal derives its name from the technique of using a section of a GP cone to fill a section of the RC. - The canal wall is coated with cement. - A root canal plugger that can be inserted in the canal to within 3 or 4mm of the apex is heated in the hot-salt sterilizer for 10 secs. - A gutta percha cone of approximately the size of the prepared canal is cut into sections , each 3 or 4mm. - The apical section is mounted on the heated plugger, is carried into the canal to the previously measured depth & is pressed vertically. - The plugger is disengaged carefully, to prevent lodging of the inserted section of GP. - A radiograph is taken to check the position & fit of condensed section. - The next section is warmed high over flame , & added to the previous section under vertical pressure , to condense the filling. - The entire canal is filled in this manner. - If a post-type crown – only apical section obturated. - The advantage of this filling is that it seals the canal apically and laterally. - The disadvantages - Time consuming - Difficult to retrieve the section of GP if the canal is overfilled - Difficult to condense the GP sections into homogenous mass = voids between sections  McSPADDEN or THERMOMECHANICAL COMPACTION - Uses heat to decrease GP viscosity & to increase its plasticity. - The heat is created by rotating a compacting instrument in a slow-speed contra-angle handpiece ( 8000- 15000 rpm) along side gutta percha cones inside the root canal. - Using step back technique , the canal should be enlarged to at least the size of no.45 instrument. - GP inserted in the prepared canal short of the root apex - Compactor blade selected according to the width & length of the prepared canal, is inserted between the GP & the canal wall. - With a rubber-dam stop on the compactor blade, the rotating tip of the blade is guided to within 1.5mm of the root apex. - Restriction of the blade within the canal prevents the forcing of thermoplasticized GP through the root apex. - In this technique gutta percha is plasticized by frictional heat and inserted by means of a compactor that forces the material apically. - The compactor is an engine-operated instrument resembling a Hedstroem file, but with the blades directed toward the blunt-tipped end, and operates on the principle of the reverse turning screw. Profiles of a compactor (top) and a Hedstroem file (bottom). Advantages - Ease of selection & insertion of GP cones - Economy of time - Rapid filling of canals apically & laterally, including irregular spaces within canal if one uses a sealer. Disadvantages - Inability to use the technique in narrow canals - Frequent breakage of compactor blades - Frequent overfilling of the canal - Shrinkage of the cooled set filling  Chemically plasticized gutta percha - Gutta percha can be plasticized by chemical solvents. - Gutta-percha is soluble in number of solvents viz: chloroform, eucalyptol, xylol - The resulting slightly viscous and highly plastic gutta percha can be forced into fine , tortuous canals, where other solid-core fillings can’t be inserted satisfactorily. - Softened GP cone can be inserted & compressed with pluggers to the apical juncture, to seal the RC & accessory canal. - Unfortunately, it is difficult to avoid overfilling the canal.  Disadvantages - The disadvantages of using a chemical-solvent filling material are: * Inability to control overfilling, with a resultant periapical tissue reaction * Shrinkage of the filling after setting = poor apical & lateral seal.  Thermoplasticized GP technique 0r Injection technique - Gutta-percha is thermoplastically molded and ejected out of a needle into the canal. - The Obtura system uses a pressure syringe in which the gutta- percha is warmed to 200°C and expressed into the canal through a needle as fine as 25 gauge (0.5 mm diameter). - The gutta-percha leaves the needle at approximately 70°C. - Pluggers are pre fitted to ensure that they match the middle portion of the canal while not contacting the dentin wall. - A small amount of root canal cement is wiped along the canal wall and gutta-percha is passively injected into the root canal.  Place obtura needle loosely 3-5 mm short of apex, as warm gutta-percha flows and fills the canal, back pressure pushes the needle out of the canal - In 5–10 seconds the softened gutta percha will fill the apical segment and begin to push the needle out of the root. - During this lifting by the softened , flowing mass , the middle and the coronal portions of the canal are continuously filled until the needle reaches the canal orifice. - Compaction of the material follows to adapt the gutta- percha to the canal walls. Two commonly used devices to provide thermoplastic gutta-percha for injection: Obtura system (left) and BeeFill 2in1  Advantages - Advantages of the injection technique are similar to those of warm vertical compaction. - It also is useful in wide canals with an apical stop and in cases of internal resorption (a) MTA filling carried out to obtain an apical stop in a traumatized incisor. (b) The remaining coronal canal space has been filled with injectable thermoplasticized GP INTERNAL RESORPTION OF A ROOT CANAL FILLED WITH INJECTABLE THERMOPLASTICIZED GUTTA-PERCHA.  Disadvantage - The disadvantage is the difficulty of controlling the level of the root filling, with a possible under- or overfill as a result. - Shrinkage of the gutta-percha during cooling may cause voids, which may make it necessary to use continuous compaction with pluggers during the cooling phase.  ROOT CANAL CEMENTS - The ideal root canal cement should : 1. be tacky when mixed to provide good adhesion between it and the canal wall when set. 2. make a hermetic [sic] seal. 3. be radiopaque so that it can be visualized in the radiograph. 4. The particles of powder should be very fine so that they can mix easily with the liquid. 5. not shrink upon setting. 6. not stain tooth structure. 7. be bactericidal or at least discourage bacterial growth. 8. set slowly. 9. be insoluble in tissue fluids. 10. be tissue tolerant, that is, nonirritating to peri radicular tissue. 11. It should be soluble in a common solvent if it is necessary to remove the root canal filling  Functions of root canal sealers As antimicrobial agent Fill the discrepancies between the materials and dentin walls As binding agent As lubricant Give radiopacity As canal obturating material  Sealers commonly used are : Glass ionomer cement Zinc oxide and eugenol (ZnOE) Epoxy resin-AH 26 Calcium hydroxide Methacrylate resins Mineral trioxide aggregate (MTA) Polyketone- Diaket  Zinc Oxide Resin Cements - Zinc oxide–eugenol (ZnOE) sealers have been used for many years and ample clinical experience exists with these materials. - However, sealing ability and biological properties are, in general, inferior compared with other root canal sealers. - These sealers comprise a fairly large group of different preparations. (Grossman sealer) Powder Zinc oxide, reagent 42 parts Staybelite resin 27 ‘’ Bismuth subcarbonate 15 ‘’ Barium sulfate 15 ‘’ Sodium borate, anhydrous 1 ‘’ Liquid Eugenol or oil of pimenta leaf. - Some preparations contain thymol or thymol iodide for increasing the antimicrobial effects. - Also, hydroxyapatite or calcium hydroxide has been added to improve apical healing. - Root canal cement is mixed on a sterile glass slab with a sterile spatula, - The slab sterilized by an alcohol scrub & the spatula is passed through an open flame. - Small increment of cement are added to the liquid while one spatulates it to smooth creamy mix. - ‘’String out’’ & ‘’ Drop’’ test. - Because moisture accelerates the set of the cement , canal & chamber should be thoroughly dried. A, Drop test - The cement should drop off the spatula edge in 10 to 15 seconds. B, String-out test - The cement should string out for at least 1 inch when the spatula is raised slowly from the glass slab.  Calcium hydroxide cement - Calcium hydroxide sealers have inferior technical properties compared with polyketone or epoxy resin preparations. - From a biological point of view, calcium hydroxide sealers are very favourable materials and they exhibit considerable antimicrobial activity. - Introduced in an attempt to stimulate periapical healing with bone repair through the release of calcium hydroxide Composition  Base paste  Catalyst paste Calcium hydroxide (32%) Disalicylates (36%) Colophony (32%) Bismuth carbonate (18%) Silicon dioxide (8%) Silicon dioxide (15%) Calcium oxide (6%) Colophony (5%) Zinc oxide (6%) Tricalcium phosphate (5%) Others (16%) Others (21%) - Calcium hydroxide sealers release OH– and Ca2+ ions. - The desired release of OH– ions may be associated with degradation of the sealer, enhancing leakage. (a) root filling with gutta-percha points and a calcium hydroxide sealer after pulpectomy ; (b) resorption or dissolution of the most apical part of the root filling after 10 months.  AH 26 - AH 26 is an epoxy resin containing a non-toxic hardener. - Its radiopacity is imparted to it by bismuth oxide. - Has strong adhesive properties & contracts slightly while hardening. - Schroeder has shown that AH 26 is well tolerated by the periapical tissues. - AH 26 had the least amount of leakage. - AH26 has antimicrobial properties the antimicrobial effect decreases with increasing setting time. - Compared with ZnOE, calcium hydroxide and GIC sealers on the model of infected root dentin, AH26 showed the strongest antimicrobial effect probably due to the initial release of formaldehyde.  Diaket - Diaket is a polyvinyl resin (polyketone) introduced in Europe. - Consists of a fine, pure white powder & a viscous, honey colored liquid. - Two drops of liquid are mixed with one scoop of powder. - changing the P/L ratio affects the hardness of the final set and radiopacity.  Mineral trioxide aggregate (MTA) - Introduced in 1993, as a root-end filling material for sealing of communications between the root canal system and the periapical tissue. - The cement, similar to calcium hydroxide, supports hard-tissue repair at root ends as well of pulpal exposures. - Therefore also been used for apexification in root-open teeth and for pulp capping and pulpotomy procedures  Composition  MTA is based on Portland cement, which primarily consists of: Tricalcium silicate, Dicalcium silicate, Tricalcium aluminate and Tetracalcium aluminoferrite  Sulfates in various amounts regulate working and setting time.  The particles of MTA are smaller than in Portland cement and bismuth oxide is added to increase radiopacity. - The long setting time may be disadvantageous in some situations because of the risk of washing out. - In general MTA was less toxic than ZnOE preparations and freshly mixed material was more toxic than set. - Finally, in teeth with immature apices promising results with formation of an apical barrier. - The hard-tissue inducing effect is not fully understood but the property may be attributed to a stimulating effect on biological molecules important for hard-tissue formation.  THE APICAL EXTENT OF ROOT FILLING - It has significant influence on outcome. - Flush root fillings have higher success rates than short or long root fillings. SHORT FLUSH LONG > 2 mm short of 0-2mm within radiographic extruded beyond radiographic apex. Radiographic apex.  Overfilling and Overextension Overfilling - “total obturation of root canal space with excess material extruding beyond the apical foramen” Overextension - “ extrusion of filling material beyond the apical foramen but canals have not been adequately filled and the apex has not been sealed. Underfilling - Underfill results when both preparation and obturation are short of the desired working length or when obturation does not extend to the prepared length. Thank you!!!