Root canal filling
General definition of the concept:
Sealing the root canal system consists of isolating the root canal and its secondary or accessory collaterals from the rest of the body to maintain the result obtained by the root canal preparation.
Root canal obturation therefore represents the final stage of endodontic intervention and is comparable to a biocompatible substitution unit, the hermeticity of which is the only thing capable of ensuring the durability of the treatment, the prevention of the appearance of periapical lesions or their recurrences as well as the prevention of possible microbial swarming at a distance.
The obturation of the endodontium must literally sequester the canal system from its periodontal environment, leaving in contact with the latter only the cementum, the only living element capable of repair in the periapical zone.
2) Objectives:
2-1-Technical objective:
The technical objective is to fill the entire canal system as completely as possible with an obturation mass capable of sealing the main, lateral and accessory canals, ensuring a perfect seal at the level of the main and accessory foramina.
2-2-Biological objective:
The maintenance of the endodontic result depends on the quality of the canal obturation which must prevent any secondary modification of the periapical environment by bacterial or toxic elements, which could reach this region through insufficient sealing, or unobstructed accessory canals.
Some definitions:
Various situations which are not in fact comparable are classified under the generic term of overruns.
Over-Oburation : Is an excess of paste extruded in mass into the periapex, the canal being obturated in a dense and homogeneous manner.
Overextension : Is the excess of a minimal quantity of non-rounded paste which generally indicates an insufficiency of the filling in which voids remain.
Underfilling : This is an incomplete filling of the canal system with the presence of voids.
4) Technical conditions of root canal obturation:
Before proceeding with root canal filling, a certain number of conditions must be met and a certain number of rules respected:
The tooth must be completely asymptomatic
The tooth should respond negatively to percussion.
The temporary dressing: must be intact before obturation; in the event of partial destruction or obvious infiltration due to lack of adaptation at the edges, the treatment must be resumed before obturating the canal.
No bleeding, suppuration or bad odor should emerge from the canal and the canal should be perfectly dried with sterile absorbent paper tips of suitable diameters.
Absence of fistula
No swelling in the apical area.
Root canal filling materials:
- Root canal cements
- Gutta percha
Different families of sealing cement are available:
Zinc oxide eugenol base: presented in powder and liquid form, the powder consists essentially of zinc oxide with various other constituents such as silver and di-iodothymol, to be mixed with a liquid consisting of eugenol
Epoxy resin based
Based on calcium hydroxide
Based on bioceramics
Root canal filling
SEM view of a cross-section of an obturated canal. We can observe a perfect adaptation at the micrometric scale of the bioceramic cement (BC) at the interfaces with the dentin (DE) and with the gutta percha (GP).
Gutta percha:
Root canal filling
It is used in Endodontics in the form of standardized or non-standardized cones. These cones are largely composed of zinc oxide, with gutta percha representing less than 20% of the total composition. of a dye and a radiopaque material of wax and an oxidant.
Non-absorbable and biocompatible
Gutta percha Malleable and plastic.
Cold deformable.
Molds but does not adhere.
Root canal filling
Scanning electron microscopy (SEM) view. It is possible to distinguish the empty spaces between a classic cement (SE), gutta percha (GP) and dentin (DE).
The operating times for root canal obturation :
Surgical field : It will be put in place under the usual conditions before removing the temporary dressing.
Control of the canal preparation: Its purpose is to possibly check the quality of the canal preparation.
.Testing the master cone:
Visual inspection: penetrates LOT -1mm
Touch control: tug back resistance
X-ray control: checking the correct position of the gutta cone in place
Irrigation : to eliminate any organic debris and especially serous exudation which may have invaded the last apical millimeters of the canal.
Drying : This will be done with sterile absorbent tips, until they come out of the canal dry and unstained.
Root canal filling
Immediate post-operative control : This is the classic control X-ray taken at the end of the operation; it must be developed quickly.
Root canal filling techniques:
Technique using dough alone:
This technique consists of sealing the canal system with a paste.
Different approaches have been proposed to insert the dough:
=> Injection of the paste into the canal.
=> Its installation using a lentulo
Technique:
• wise choice of Lentulo;
• The rotation speed is set (slow)
• The direction of rotation is counterclockwise
• The lentulo is coated with paste and introduced into the canal
• Remove the 1mm lentulo and start the contra angle
• Remove the lentulo gradually from the canal
• The operation is repeated as many times as necessary until the canal is blocked.
• Removal of excess and a control X-ray is taken.
Single-cone (mixed) obturation:
It is an obturation with a root canal paste inserted using a paste pack and the insertion of gutta-percha cones, acting as wedges. It is an obturation technique that can be used regardless of the chosen preparation technique.
Root canal filling
Cold lateral condensation technique of gutta percha:
Materials and equipment:
– Standardized and non-standardized gutta cones.
– Spreader .
– Heat source.
– Root canal sealing cement.
– Endodontic ruler.
– Plugger vertical rammer.
Surgical technique:
Master Cone Choice
Testing the master cone
Choosing and trying on the rammer:
Finger spreader: side compaction rammer
Diameter Corresponding to the diameter of the LAM Stop at the LOT -2 mm.
Sealing and compaction :
Dry canal (sterile paper point at the apical diam.). The canal walls are lightly coated with canal sealing cement. The end of the cone is itself coated with cement, and the cone is introduced into the canal up to the apical limit of preparation.
Introduction of the selected compactor along the master cone with an apical and lateral push, then removed by making alternating quarter-turn movements to the right and left, of low amplitude.
Opening space for an accessory cone
Coronal filling of the canal and compaction:
An accessory cone, coated with cement, is then introduced into this space. This cone is compacted following the same operations as previously with the condensers. We continue to add accessory cones until the condenser only penetrates 3 or 4 mm into the canal: a last cone is then inserted, and all the ends of the cones are sectioned using a red-hot instrument.
Root canal filling
Thermomechanical Compaction described in 1978 by JT Mc Spadden:
Sterile materials and specific materials:
Gutta percha cones
Vertical compaction crushers or pluggers
Sterile compresses
Blue ring contra angle
Gutta condenser in diameter from 25 to 80
Sealing cement
Compactor Selection:
Same size as LAM
Fitting: no blockage
Choice of master cone (diameter adapted to that of the canal and the working length minus 1 mm)
Brush the walls of the canal with sealing cement, compaction is based on 5 operating stages:
Insert the compactor over the entire length of the work minus 2 to 3mm
Compactor rotation at 8000…10,000 rpm without any apical pressure during the 1st sec.
As soon as the frictional heat has plasticized the gutta and a decrease in resistance is felt, the compactor is pushed in the apical direction to 1.5 mm from the working length.
-at this length, keep the instrument rotating in place for about 4 to 10 sec, then remove it while still rotating.
The obturation is completed in the coronal 1/3 by manual vertical compaction
Thermafil system:
This original system was proposed by B. Johnson in 1978. It has since undergone many improvements, it only appeared in France in 1992, marketed by Septodont.
Material:
•check: or resin gauges corresponding in diameter to the ISO standards for numbering endodontic instruments used in order to be able to choose the caliber of thermafil to use.
Obturator : composed of a thin biocompatible plastic tutor coated with gutta percha whose conicity varies with that of the canal to be obturated
Heating device : precise (special oven) to soften the gutta (at around 130°C) and allow the insertion of the Thermafil obturator into the canal.
Technical:
• Trying on the gauge corresponding to the diameter of the master apical file, it must reach the working length.
• Heating the shutter in the device provided for this purpose. (The selected shutter is of the same caliber as the check). The heating time varies depending on the diameter of the chosen shutter. (A beep signals that the thermafil is ready for use).
• During this time, drying and placement of the root canal loosening cement can be undertaken. Only a very small amount of cement should be placed at the apical level, using a pin turned counterclockwise.
• The warmed obturator is then introduced into the canal, slowly with firm pressure, up to the apical limit.
• After 1 minute, the shutter handle and the rod protruding from the channel entrance are cut using a turbine-mounted cutter.
The Obtura II system:
This system, currently in its third generation, presents gutta-percha in the form of “ends” placed in an obturator gun and kept in a softened state at a pre-set temperature. The practitioner then presses the gun so that the latter comes out through a needle of a pre-defined diameter.
Once the gutta-percha is in place, the operator can compact it using a standard rammer.
System B:
Buchanan System B single wave centered vertical compaction
Heating and compacting with the same instrument
Sterile materials and specific materials :
Non-standardized gutta-percha cones
System device B
Buchanan Heating Rammers:
Fine, fine medium, medium, medium wide
Descending phase:
1. Selection and fitting of the Master Cone:
Adaptation of the Master Cone to LOT –1mm
Visual, tactile AND radiographic control
The second step is to select the appropriate plugger which is capable of penetrating up to 5mm of the working length, and which must be fitted with a silicone stopper to prevent contact with the canal walls.
The third stage corresponds to the descent phase, the temperature is set to 200°C, the power to 10, the heat source being activated
Cut the cone at the entrance of the channel with the previously heated rammer
The heated ram (contactor pressed) is lowered into the channel to 2-3 mm from its operating limit. The heat is then turned off (contactor released, ram cools in 2-3 seconds) and the ram is held while applying pressure to bring it to its depth limit.
Once the apical plug has formed, an X-ray can be taken to check its quality; and the coronal 2/3 of the canal is obturated.
Recovery phase:
For this we can use 2 different techniques:
2nd heated and condensed cone
3rd condensed cone if necessary
By thermo compaction or hot gutta injection
Criteria for successful endodontic treatment:
The criteria for clinical success are:
– the functionality of the tooth on the arch.
– the absence of any signs of infection (fistula, swelling, etc.).
– the absence of clinical signs of failure (mobility, sensitivity to percussion/palpation, etc.).
– physiological mobility,
– the absence of subjective signs of discomfort,
-No symptoms
The criteria for radiographic success are:
– the disappearance or non-appearance of bone rarefaction,
– a dense obturation, without apparent lack, of the entire canal network,
– the absence of desmodontitis (desmodontal space less than 1mm),
– a lack of resorption.
– a normal lamina dura similar to that of the adjacent tooth
Endo-prosthetic continuum:
It is now established that root canal filling alone does not constitute a sufficient barrier against bacteria in the oral cavity. Coronal restoration is an essential complement to root canal filling for the sealing and durability of the treatment. Coronal restoration should be placed as soon as possible after the end of root canal treatment.
Conclusion :
The success of endodontic treatment depends directly on the ability of the operator to hermetically and stably seal all endo-periodontal communications . Each technique is well codified. Compliance with the rules of each generally leads to success. But skill and experience are two factors that can modulate the advantages and disadvantages of each technique. As for the choice of the best technique, for the general practitioner, it is the one with which he obtains reliable and reproducible results .
Root canal filling
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Composite fillings are discreet and durable.
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