Root canal obturation techniques
- Definition of root canal filling:
According to Weine (1977): “Root obturation is the 3rd step of endodontic treatment after diagnosis and root canal preparation, it is the sealing of the entire endodontic cavity aiming to isolate the root canal system from the oral environment and the deep periodontium”
- Technical conditions for root canal sealing:
1. Asymptomatology of the tooth: The tooth must not present any pain or spontaneous sensitivity and must respond negatively to percussion. It is recommended to wait for the closure of a possible fistula before sealing the canal and never to obturate while an odor continues to rise from the canal.
2. Condition of the temporary dressing Must be intact before obturation. In case of partial destruction or obvious infiltrations due to lack of adaptation at the edges, the treatment must be resumed before sealing the canal.
3- Absence of intracanal exudation: The canal must be dry at the time of canal obturation. In case of continuous flow, the canal is obturated using a mixture of calcium hydroxide mixed with 2% methyl cellulose or with distilled water for 8 days.
4 – Rinsing the canal: It is good to repeat the last irrigation of the prepared canal before obturation to ensure better disinfection.
Physiological serum is the product of choice, one can choose, in favor of anesthetic cartridges, easy to use, and which contain 98% physiological serum.
5- Drying the canal: After rinsing, filling can only be considered if the canal is perfectly dry.
6. Negative intracanal cultures: The need to seal the canal system after obtaining a negative culture
7- Choice of the canal obturation system: This will be done based on clinical elements which will be described for each technique.
8- Importance of sealing cement: Cement is necessary to fill the finest irregularities, seal the lateral and accessory canals and ensure the hermetic seal between the plastic mass and the canal walls.
- The operating times for root canal sealing:
- Surgical field: It will be put in place under the usual conditions before removing the temporary dressing.
- Control of the canal preparation: its aim is to possibly check the length of the preparation by an additional X-ray with the file in place, or an electronic control,
- Drying: It will be practiced until the paper tips come out of the canal dry and not stained.
- Sealing of the canal system: must comply with all the requirements of obturation and for this various techniques exist and each has appropriate indications.
- Post-operative check-up:
- Immediate control: This is the classic control X-ray taken at the end of the procedure. It must be developed quickly and read after having dried, preferably on an enlarger (magnifying glass)
• Remote controls:
They will be performed systematically in the case of periapical lesions at three months, six months and one year.
- Root canal filling techniques:
- Classic techniques:
1-Simple technique (paste only): The obturation will be carried out with the paste based on zinc oxide and eugenol, for this the powder and the liquid are mixed using a spatula on a glass plate until a paste of creamy consistency is obtained. Then the paste wad mounted on a contra-angle is coated with this paste and introduced while stopped in the canal up to the working length, then the contra-angle is operated and the paste wad is gradually removed from the canal, it is only stopped once outside the canal. Several applications of paste are thus made until the canal is completely obturated.
2-Mixed technique: single cone technique
- Choice of the cone : it must reach the apical limit of the apical preparation. Its diameter corresponds to that of the last instrument used for the apical preparation. The final position of the gutta cone is checked by a retroalveolar radiograph.
- Application of the filling paste : carried out in the same way as for the simple technique.
- Insertion of the gutta percha cone: The gutta percha cone is coated with this cement and then inserted back into the canal to the working length.
Once the obturation is complete, the cone is cut at the entrance of the canal with a red-hot instrument, and with the plugger, axial pressure is exerted to pack the cone.
Root canal obturation techniques
3-Cold lateral compaction of gutta percha
- choice of the main cone: or the master cone, the diameter of the non-standardized gutta cone is chosen according to the canal volume; using an endodontic ruler, the tip of the cone is adjusted to the diameter of the master apical file (which is the last instrument having worked up to the apex).
- The choice of accessory cones: will depend on the spreader used, for example fine medium for spreader B or Fine medium for spreader C
- Sealing the master cone: The canal walls are lightly coated with sealing cement using a pin, operated in an anti-clockwise direction. The end of the cone is itself coated with cement, and the cone is introduced into the canal up to LT.
- Lateral compaction: A first large-caliber rammer is positioned along the master cone, with an apical and lateral thrust. Check the sinking of the spreader which should penetrate up to LT- 2mm. Then it is removed by making alternating movements of a quarter turn to the right and left of low amplitude.
- Setting up the accessory cones
A cement-coated accessory cone is then introduced into this space, this cone is compacted following the same operations as previously with the lateral rammers
The operation is repeated until the spreader no longer penetrates 03-04mm into the canal. A final accessory cone will be inserted and the entire ends of the cones are sectioned using a red-hot instrument.
4- Hot vertical compaction of gutta percha: Schilder technique or multiple wave vertical compaction technique:
- choice of the master cone: will be carried out in the same way as for the lateral compaction of gutta percha
- Selection of vertical crushers:
Generally, 3 rammers of decreasing caliber are selected which will be tested in the prepared channel, they must penetrate the channel without interfering with the walls, up to “authorized” lengths.
- Sealing the master cone: in the same manner as the technique mentioned above.
- Vertical condensation:
a. Descending phase: With the first rammer (the largest diameter), the end of which has been previously dipped in zinc oxyphosphate powder, a first condensation is carried out in the apical direction.
The tip of the heater, heated to red, then penetrates the gutta to a depth of 2 to 3 mm and is immediately removed.
The same rammer penetrates the softened gutta mass again. It is necessary to withdraw it slightly and make a series of small vertical thrusts of low amplitude, trying to bring the gutta percha back towards the center to obtain as flat a surface as possible. These operations are repeated several times until the 1st rammer reaches its authorized point of penetration.
The 2nd and then the 3rd rammer can then be used to condense the middle and apical part of the canal by carrying out the successive operations already described.
Root canal obturation techniques
b. Ascent phase: take segments of gutta cones 3 to 5 mm long, and using a red-hot heater, lightly prick the already compacted gutta mass in the apical region to soften its surface. Glue the first segment of gutta to the warm end of the plugger and insert it, cold, in contact with the gutta already in place. A small rotational movement detaches the gutta segment from the plugger; the red-hot heater is then used again to soften the glued segment, which is immediately compacted by a series of vertical thrusts until a flat surface is obtained. The operation is repeated for the following segments, using pluggers of increasing caliber until the canal is completely filled.
- Recent techniques:
1-Thermomechanical vertical condensation technique:
-First chose a master cone
-The root canal sealing cement is introduced manually at the apex, using a pin that is turned counterclockwise.
– The apical part of the cone is coated with cement and placed in the canal.
-The compactor, adapted in diameter to the last instrument passed into the apical third (LAM), is introduced, while stopped, into the canal at the LT minus 2 mm.
– the micromotor is immediately activated at a high speed. The operating time is 5 to 10 seconds: you can literally see the cone sinking into the canal.
-Finally, the obturation is completed by manual vertical compaction with a channel rammer, and the excess gutta is removed.
1 2 3 4
1: insertion of the thermomechanical condenser into the channel.
2: starting the micromotor.
3: Light pumping movements in the apical direction for 10 seconds.
4: the instrument is removed at the moment when repulsion from the condenser is felt.
2- New MAC SPADDEN technique: gutta phases I and II:
This technique is based on the compaction of 2 types of gutta percha using a nickel titanium compactor: the NT condensor compactor.
Technique:
-The compactor is introduced into the syringe containing the preheated phase I gutta to be coated with a thin layer of gutta.
-The compactor loaded with phase I gutta is then introduced into the syringe containing phase II gutta, then loaded with a thin layer of phase II gutta.
-The compactor loaded with the 2 layers of gutta is introduced immediately, while stationary, into the canal up to a determined length.
-The compactor is activated, held in place for a few seconds (2 to 6 seconds on average) then raised in the coronal direction
-The high viscosity gutta occupies the central region of the canal while the fluid gutta percha is propelled into all the diverticula and canal crevices, all that remains is to manually compact the entrance to the canal.
3-System B: or single wave centered vertical compaction technique;
-choice of the master cone.
– select and test the corresponding rammer that arrives, at most LT-5 mm
-The canal is then dried using sterile paper points and the sealing cement is introduced into the canal using a pin so that the end of the cone is brushed.
-The temperature of system B is set to 200°C and the power to 10,
-The gutta cone is sectioned hot at the level of the canal orifice, then a manual vertical compaction rammer is used to cold compact the gutta cone by 1 or 2 mm at the entrance of the canal, in order to create a plateau.
– The heated System B rammer is then centered on the surface of the gutta to compact it for 3 to 4 seconds, then the heat emission is stopped.
-The vertical pressure on the rammer remains maintained until the depth indicated by the stop is reached. The pressure is maintained with the rammer cold for 10 seconds in order to counterbalance the retraction of the gutta percha during its cooling.
-The sealing of the free space left by the rammer can be done in several ways, among them:
Injection of hot gutta using a gutta gun. This very rapid technique gives excellent results; it is the ideal complement to continuous preparation.
4- The Thermafil System:
The first step:
– the choice of Thermafil: A Verifier of the same diameter as the last shaping instrument is used to gauge the apical diameter of the canal.
-The Thermafil shutter is blocked by a silicone stop at LT.
STEP 2: Inserting the shutter
-removal of excess coronary gutta percha using a scalpel blade.
-A paper point or a straight probe will be used to bring a light quantity of cement and brush the walls of the coronal third of the canal.
-The obturator is then placed in a tank which allows preheating and homogeneous plasticity of the gutta percha.
-the Thermafil is retrieved and inserted into the canal with a slow, firm and continuous movement up to the working length marked by the silicone stop.
– a manual vertical compaction rammer is used to compact the gutta around the plastic stake at the coronal level.
3RD STEP: section of the shutter: The shutter is sectioned at the entrance of the channel by a “thermacut” cutter used on a waterless turbine.
-To prepare a tenon housing, this is done during the session using “Post Space Bur”, mounted on a turbine without spray, positioned at the entrance of the canal, in contact with the plastic stake, operated on site for one to two seconds so as to soften the stake.
5-Shutter technique:
This device allows gutta percha to be injected directly into the canal prepared using a syringe fitted with a metal tip, previously softened in the plastic phase.
A slow-setting sealing cement should be used as a lubricant during injection and compaction of the gutta. During injection, full pressure should be kept on the trigger of the device to allow the gutta percha to flow by itself to the tip of the needle.
A plugger type compactor is used. Compaction with this technique gives the sensation of a putty or clay consistency without much resistance when pushing the rammer through the mass.
6-GuttaFlow® technique:
*Master cone choice
*Placing a capsule in a mixer and inserting it into the gun
*Insert the gun tip into the LT-3mm
*Press the trigger and raise the tip as the material flows
*Coat the gutta cone with guttaflow and insert into the canal
7-The JSQuick-Fill® system:
- Equipment and materials: uses a prefabricated Niti compactor coated with alpha phase gutta
- Technique:
- Choice of instrument
- Positioning the instrument at the canal entrance
- Rotating the instrument
- Pushing the instrument to the working length -1mm
- Removing the rotating instrument
8-The Microseal® system:
Materials and equipment: uses an alpha phase gutta cone, a paste based on alpha phase gutta as well, and a compactor.
Root canal obturation techniques
Technique:
- Choice of instrument
- Setting the master cone to the working length
- Coat the compactor with the previously heated gutta paste
- Insert the compactor, previously coated with gutta, into the canal up to the working length in rotation, then remove it in rotation as well.
Root canal obturation techniques
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