Simplified Sectional Obturation Technique

Sectional Method Of Obturation Or Chicago Technique

In this technique, small pieces of gutta-percha cones are used to fill the sections of the canal. It is also known as the Chicago technique because it was widely promoted by Coolidge, Lundquist, and Blayney, all from Chicago.

Technique:

• A gutta-percha cone of the same size of the prepared root canal is selected and cut into sections of 3–4 mm long
• Select a plugger which loosely fits within 3 mm of the working length
• Apply sealer in the canal
• One end of the gutta-percha is mounted to a heated plugger and is then carried into the canal and apical pressure is given. After this, disengage the plugger from gutta-percha by rotating it
• Radiograph is taken to confirm its fit. If found satisfactory, fill the remainder of the canal in the same manner

Read And Learn More: Endodontics Notes

Sectional Method Of Obturation Or Chicago Technique Advantages:

• It seals the canals apically and laterally
• In the case of post and core cases, only the apical section of the canal is filed

Sectional Method Of Obturation Or Chicago Technique Disadvantages:

• Time-consuming
• If the canal gets overfilled, difficult to remove sections of gutta-percha

McSpadden Compaction Or Thermomechanical Compaction Of The Gutta-Percha

McSpadden introduced a technique in which heat was used to decrease the viscosity of gutta-percha and thereby increasing its plasticity. This technique involves the use of a compacting instrument (McSpadden compacter) which resembles an inverted Hedstroem file.

This is fitted into a latch-type handpiece and rotated at 8,000–10,000 rpm alongside gutta-percha cones inside the canal walls. At this speed, the heat produced by friction softens the gutta-percha, and the designs of the blade force the material apically.

Because of its design, the blades of compaction break easily if it binds, so it should be used only in straight canals. But nowadays, its newer modification in the form of micro seal condenser has come, which is made up of nickel–titanium. Because of its flexibility, it can be used in curved canals.

McSpadden Compaction Advantages:

• Requires less chair-side time
• Ease of selection and insertion of gutta-percha
• Dense, 3-D obturation

McSpadden Compaction Disadvantages:

• Liability to use in narrow and curved canals (canal has to be enlarged to a size no. 45)
• Frequent breakage of compactor blades
• Overfilling of canals
• Shrinkage of gutta-percha on cooling

Thermoplasticized Injectable Gutta-Percha Obturation

Obtura 2 Heated Gutta-Percha System/ High-Heat System

This technique was introduced in 1977 at Harvard Institute. It consists of an electric control unit with a pistol grip syringe and specially designed gutta-percha pellets which are heated to approximately 365–390°F (185–200°C) for obturation. In this, regular β-phase of gutta-percha is used.

Prerequisites for Canal to be filed by Obtura 2

• Continuous tapering funnel shape for unrestricted flow of softened gutta-percha
• A definite apical stop to prevent overfilling

Indications for using Obtura 2

• Roots with straight or slightly curved canals
• For backfilling of canals
• For obturation of roots with internal resorption, perforations, etc.

Technique:

• Before starting the obturation, the applicator needle, and pluggers are selected. The needle tip should reach ideally 3–5 mm of the apical terminus passively
• Apply sealer along the dentinal walls to fill the interface between gutta-percha and dentinal walls
• Place obturator needle loosely 3–5 mm short of apex, as warm gutta-percha flows and fils the canal, back pressure pushes the needle out of the canal
• Now use pluggers to compact the gutta-percha; pluggers are dipped in isopropyl alcohol or sealer to prevent sticking of the gutta-percha

Continuous compaction force should be applied throughout the obturation of the whole canal to compensate for shrinkage and to close any voids if formed.

1. (A) Tapering funnel shape of the prepared canal is well suited for obturation using obtura II;
2. (B) Needle tip of obtura II should reach 3–5 mm of the apical end;
3. (C) Compaction of gutta-percha using plugger

Variations in the Thermoplasticizing Technique of Gutta-Percha

Ultrasonic Plasticizing of Gutta-Percha

• It has been seen that ultrasonics can be used to fill the canals by plasticizing the gutta-percha
• Earlier, cavitron US scaler was used for this purpose but its design limited its use only in anterior teeth
• Recently, ENAC ultrasonic unit comes with an attached spreader which has been shown to produce homogenous compaction of gutta-percha

Ultrafi System:

• This system uses low-temperature, (90°C) plasticized α-phase gutta-percha
• Here gutta-percha is available in three different viscosities for use in different situations
• The regular set and the film set with the highest flow properties are primarily used for injection and need not be compacted manually. Endoset is more of viscous and can be condensed immediately after injection

Technique:

• cannula needle is checked in the canal for fitting. It should be 6–7 mm from the apex. After confirming the fi, it is placed in a heater which has a preset temperature of 90°C.
• Apply sealer in the canal and passively insert the needle into the canal. As the warm gutta-percha fills the canal, its backpressure pushes the needle out of the canal
• Once the needle is removed, profited plugger dipped in alcohol is used for the manual compaction of gutta-percha

 

Solid Core Carrier Technique

Thermafi Endodontic Obturators:

Thrmafi endodontic obturators are specially designed of flexible steel, titanium, or plastic carriers coated with α-phase gutta-percha. Thrmafi obturation was devised by W. Ben Johnson in 1978.

In this, carriers are made up of stainless steel, titanium, or plastic. They have ISO standard dimensions with matching color coding in sizes of 20–140. Plastic carrier is made up of special synthetic resin which can be liquid plastic crystal or polysulfone polymer. The carrier is not the primary cone for obturation.

It acts as a carrier and condenser for thermally plasticized gutta-percha. Plastic cores allow post space to be made easily and they can be cut of by a heated instrument, stainless steel bur, diamond stone, or therma-cut bur.

Technique:

• Select a thermal obturator of the size and shape which is passively at the working length. Verify the length of verifier by taking a radiograph
• Now disinfect the obturator in 5.25% sodium hypochlorite for 1 min and then rinse it in 70% alcohol
• Preheat the obturator in the “Thrmaprep” oven for some time. This oven is recommended for heating the obturator because it offers a stable heat source with more control and uniformity for plasticizing the gutta-percha
• Dry the canal and lightly coat it with sealer. Place the heated obturator into the canal with a fim apical pressure to the marked working length
• Working time is 8–10 s after removal of obturator from oven. If more obturators are required, insert them immediately
• Verify the fi of obturation in the radiograph. When found accurate, while stabilizing the carrier with the index finger, sever the shaft level with the orifice using a prep bur or an inverted cone bur in a high-speed handpiece
• Do not use flame heated instrument to sever the plastic shaft because the instrument cools too rapidly and thus may cause inadvertent obturator displacement from the canal
• Now use a small condenser coated with vaseline or dipped in alcohol, to condense gutta-percha vertically around the shaft
• When a post is indicated, sever the obturator with the fissure bur at the selected length and give counterclockwise rotation of the shaft following insertion to disengage the instrument

1. (A) Select a thermal obturator that fis into the canal passively at the working length;
2. (B) Preheat the thermaprep oven;
3. (C) Place the heated obturator into the canal with fim apical pressure;
4. (D) Cut the thermal using thermal cut bur;
5. (E) Condense gutta-percha vertically around the shaft.

Thermafi Endodontic Obturators Advantages:

• Requires less chair-side time
• Provides dense 3-D obturation as gutta-percha flows into canal irregularities such as fis, anastomoses, and lateral canals
• No need to preserve obturators because of flexible carriers
• Since this technique requires minimum compaction, so less strain while obturation with this technique

Ultrafi 3-D:

Ultrafi 3-D is an injectable gutta-percha system which provides three viscosities to accommodate different techniques. Success-Fil (Coltene/Whaledent, Inc.) utilizes high-viscosity gutta-percha which comes in a syringe. The sealer is lightly coated on the canal walls and the carrier with gutta-percha is placed in the canal to the prepared length.

Gutta-percha is then compacted around the carrier with various pluggers depending on the canal morphology. The carrier is severed at the orifice with a bur.

Cold Gutta-Percha Compaction Technique:

Gutta Flow

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

Composition:

Gutta flow consists of a polydimethylsiloxane matrix filled with powdered gutta-percha, silicon oil, paraffin oil, platinum, zirconium dioxide, and nanosilver.

Cold Gutta-Percha Compaction Technique Advantages:

• Easy to use
• Time-saving
• Does not require compaction
• Does not require heating
• Biocompatible
• Can be easily removed for retreatment

Obturation With Silver Cone

The use of silver cones is not the preferred method of obturation, mainly because of corrosion. Their use is restricted to teeth with fie, tortuous, curved canals which make use of gutta-percha with difficulty.

Indications for the use of silver cones:

• In round and straight canals, like canals of maxillary premolars, mesial canals of mandibular molars, and buccal canals of maxillary molars
• In mature teeth with small calcified canals

Contraindications:

• Teeth with open apex
• Large ovoid-shaped canals, like maxillary incisors, premolars with oval single canals, etc.

Steps:

• Select a silver cone conforming to the final shape and size of the prepared canal. Check if it is radiographically. If found satisfactory, remove it from the canal and sterilize it over an alcohol flame
• Dry the canal and coat the canal walls with sealer
• Insert the cone into the canal with a sterile cotton plier or Stieglitz forceps
• Take a radiograph to see the fi of the cone. If satisfactory, fill the remaining canal with accessory gutta-percha cones
• Remove excess of sealer with a cotton pellet and place restoration in the pulp chamber

Obturation With Silver Cone Advantages:

• Easy handling and placement
• Negotiates extremely curved canals
• Radiopaque in nature
• Mild antibacterial property

Obturation With Silver Cone Disadvantages:

• Prone to corrosion resulting in loss of apical seal
• Difficult to retrieve if it is snugly fitting
• Nonadaptable, so does not seal accessory canals

Stainless Steel:

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

Apical Third Filling

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

Apical third filing:

• Carrier-based system
  • Simplified obturator
  • Fiberfil obturator
• Paste system
  • Dentin chip filing
  • Calcium hydroxide filing
  • MTA filing

Simplified Obturator:

It was originally developed at light-speed technology so as to complement the canal shape formed by using light-speed instruments. In this, the apical gutta-percha size is the same ISO size as the light-speed master apical rotary.

Here a stainless steel carrier is used to place gutta-percha in the apical portion of the canal.

Steps:

• Try the size of the apical GP plug so as to ensure an optimal apical fitting. This apical GP plug is of the same size as the light-speed master apical rotary
• Set the rubber stop 4 mm short of the working length and advance the GP plug apically without rotating the handle
• Once GP plug fis apically, rotate the carrier anticlockwise without pushing or pulling the handle of the carrier
• Now backfilling of the canal is done using a syringe system

1. (A) Check the fi of the apical gutta-percha (GP) plug;
2. (B) condense apical GP plug to working length;
3. (C) Once GP plug fis apically, rotate the carrier anticlockwise without pushing or pulling the handle of the carrier;
4. (D) Backfilling of the canal is done using a syringe system.

Fiberfil Obturator:

• Ths obturation technique combines a resin post and obturator forming a single until and apical 5–7 mm of gutta-percha
• This apical gutta-percha is attached with a thin flexible filament to be used in moderately curved canals
• The advantage of this technique is that due to the presence of dual-cure resin sealer, chances of coronal microleakage are less
• But it poses difficulty in retreatment cases

Dentin Chip Filling:

Dentin chip filing forms a Biologic seal. In this technique, after thorough cleaning and shaping of the canal, H-fie is used to produce dentin powder in the central portion of the canal, which is then packed apically with the butt end of the paper point.

Technique:

• Clean and shape the canal
• Produce dentin powder using Hedstroem fie or Gates Glidden drill
• Using the butt end of a paper point, push and compact dentin chips apically
• 1–2 mm of chips should block the apical foramen. The density of the pack is checked by resistance to perforation by #15 or 20 fie
• Backpacking is done using gutta-percha compacted against the plug

Dentin Chip Filling Advantages:

• Biocompatible
• Promotes healing and decreases inflammation
• Prevents extrusion of filling material from the canal space

Dentin Chip Filling Disadvantage:

Care must be taken in this technique because infected pulp tissue can be present in the dentinal mass.

Calcium Hydroxide:

It has also been used frequently as an apical barrier. Calcium hydroxide has been shown to stimulate cementogenesis. It can be used both in a dry or moist state. Moist calcium hydroxide is placed with the help of a plugger and amalgam carrier, injectable syringes, or by lentils
spirals.

A dry form of Ca(OH)₂ is carried into the canal by an amalgam carrier which is then packed with pluggers. Calcium hydroxide has shown to be a biocompatible material with the potential to induce an apical barrier in apexification procedures.

Mineral Trioxide Aggregate:

Mineral trioxide aggregate was developed by Dr. Torabinejad in 1993. It contains tricalcium silicate, dicalcium silicate, tricalcium aluminate, bismuth oxide, calcium sulfate, and tetra calcium aluminoferrite. pH of MTA is 12.5, thus having biological and histological properties similar to calcium hydroxide.

The setting time is 2 h and 45 min. In contrast to Ca(OH)₂ , it produces a hard setting non-resorbable surface. Because of being hydrophilic in nature, it sets in a moist environment. It has low solubility and shows resistance to marginal leakage. It also exhibits excellent biocompatibility in relation to vital tissues.

To use MTA, mix a small amount of liquid and powder to putty consistency. Since MTA mix is a loose granular aggregate, it cannot be carried out in a cavity with a normal cement carrier and thus has to be carried in the canal with messing gun, amalgam carrier, or specially designed carrier. After its placement, it is compacted with microbloggers.

Advantages of MTA include its excellent biocompatibility, least toxicity of all the filing materials, radiopaque nature, bacteriostatic nature, and resistance to marginal leakage. However, it is difficult to manipulate with a long setting time (3–4 h).

Coronal Seal:

Irrespective of the technique used to obturate the canal, coronal leakage can occur through well-obturated canals, resulting in infection of the periapical area. The coronal seal should be enhanced by the application of restorative materials (like Cavit, super EBA cement, MTA) over the canal orifice.

Postobturation Instructions

Postoburation pain can be seen in some cases. Since pain is a subjective symptom it is related to many factors like the presence of preoperative pain, periradicular infection, retreatment, etc. Sometimes, pain is due to the extrusion of root canal filling or a tiny bubble of air, which can be forced out periodically causing pressure and pain.

Pain is most likely to occur in the first 24 h and decreases as time passes. The patient is advised not to chew unduly on the treated tooth until it is protected by permanent restoration.

Patient Recall:

The patient should be recalled regularly to evaluate tissue repair and healing progresses. In the case of periapical radiolucency, radiographs should be taken at 3, 6, and 9 months interval periods to see the continued new bone formation.

A radiograph of a successful endodontic treatment shows uniformly thickened periodontal ligament and continuous lamina dura along the root.

Repair Following Endodontic Treatment

Repair of the tooth being treated begins as soon as the infection is controlled.

Repair occurs in the following steps:

1. Organization of blood clot
2. Formation of granulation tissue
3. Development of scar tissue by laying down of collagen fiers

• In the periapical area, bone is there. Her healing process is more complicated because soft tissue must be converted to hard tissue
• Bone contains a protein matrix filled with calcium compounds like calcium phosphate and calcium carbonate. This protein matrix is formed by osteoblasts
• Osteoblasts produce an enzyme called alkaline phosphatase, which separates in organic phosphorus from organically bound phosphorus
• This increase of phosphate ions forms a saturated solution of calcium phosphate, which precipitates into the matrix. The precipitated areas of calcium phosphate join to form spongy trabeculae
• Resorption and deposition of bone may occur simultaneously depending upon the degree of periapical damage; repair usually takes 6–12 months after endodontic treatment
• Since repair proceeds from the periphery to the center, the granulation tissue formation, fibrous connective tissue maturation, and finally matrix for bone formation occur in steps
• In some cases, connective tissue matures into dense fibrous tissue instead of bone. These areas represent as areas of rarefactions in radiographs, though histologically healing has taken place