So, now you have come to the stage that you will learn about the sealers. In the previous tutorial you learnt about the various types of sealers used in obturation of the canal. They are many but surprisingly little is known about the relative clinical performance of root canal sealers and most of the time we select the sealer because of following reasons:
a) Riwaaz: You are using a sealer because it was used by your teacher at school, or you were told to use it at your school.
In one of the banquets of the conference you were told by someone to use a particular sealer or that you might have overheard that some one had lot of problem with one type of sealer or the trend now a days is to use this type of sealer.
b) Dental Dealer: Your dealer told you to use a particular brand telling you that this is the best, cheap, effective etc. Have you ever thought as to why you are using a particular sealer? When was the last time you picked-up the literature of the sealer and read to see its – composition/ingredients?
Well let us try to understand the factors to be considered when selecting a sealer.
1) Workability
You know that it is very important that the canal should have more of solid core material rather than the cement. The idea of the cement is like, if you have seen the construction of house. In that, the mason prepares the beam of the building.
He puts in lot of iron rods (Sariya) and then fills the cement in the gaps. Similarly in obturation of the canal, you fill it up with a solid core and the space in between the core is filled up with cement. Sealer acts as a gasket and provides the seal.During compaction it flows to fill irregularities. Lubricate the glide path of gutta percha into the canal. It actively suppress microbial growth and promote hard tissue repair at the root end. As a clinician what is important to you is that you should be able to coat the walls of the canal nicely.
It is important that when you mix the sealer, it should develop a consistency which can be loaded on to the lentilospiral easily, carried to the canal and when the lentilo rotates, it should sprinkle the cement onto the walls uniformly.
Many times you will notice that:
a) Cement is too thin. Try to get the consistency by adding more powder, mixing the particles well. It should be the consistency of the toothpaste or your favourite facial cream.
b) The cement is too thick. If it becomes thick, it bends the lentilo as soon as you try to pick it up the cement becomes like a dry toothpaste. Add more liquid and spatulate.
I personally believe that we hardly follow the manufacturer’s direction regarding dispensing of the powder and liquid. It is important to follow the direction of mixing the cement, as so whether to incrementally add powder with liquid or other wise etc., but when it comes to number of spoons of powder or the number of drops of liquid for a canal, we are more conservative. So it is important for you to get the feel of the consistency required for that. It is also important to know why you need
that consistency.
c) The cement mix is too sticky. Some cements becomes-so sticky that it adheres to the slab, spatula, etc. If it touches to the skin it becomes difficult to remove it. Just avoid such cements.
2) Working time/Setting time
The cement should have an ample setting time. I think the working time or the manipulation time of the cement should be enough for you to be able to mix, carry the cement into the canals. It should give enough time for adequate gutta percha compaction, even in the presence of heat and humidity. Some cements set very fast and it becomes impossible to work with them. Though DYCAL is not an obturation cement but to just give you an example, it is a fast setting cement and doesn't give any chance of proper manipulation.
3) Adhesiveness to Canal Walls
The cement should have a good adhesion to the walls and help produce a hermetic seal. This is a very important technical property of cement. It is mainly because of these two properties, the cement is used for.
4) Immune Response
The cement should not provoke immune response in the periapical tissues. You should be very careful about this property of the sealer. Many times, if the sealer extrudes in the periapical area, it initially causes acute apical periodontitis followed by swelling in the periapex area. The tooth becomes very tender and the patient needs to take few analgesics in a day. The condition may persist for several days. Many times the filling needs to be removed to give relief from pain.
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| Endofloss extruded in the periapical area causing an acute inflammatory response |
Many types of cement are soluble in tissue fluid and post obturation recall radiograph shows poor radio opacity.
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Zinc oxide eugenol is very soluble cement.left -at the time of obturation and after 12 months
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The cement should be retrievable or soluble in solvents, since sometimes removal becomes necessary. Obturate the canal keeping in mind that one day it may need to be repeated. It is better to be in a situation when you can repeat the treatment than to extract the tooth.
The sealer used should be either soluble in commonly available solvents (Obviously not water) or should be such that it can be easily removed mechanically.
7) Radioopaque
The sealer should be radio opaque so that you may come to know the extent of its flow and give a good impression of the filling.
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| Radiopacity and flow into lateral canals |
There are many other minor ones, which can be read from any standard text.
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