Filling and obturation of the root canal

Today the lecture talks about filling or obturation of root canal systemwe finished the cleaning and shaping then comes the major important step which is the filling so the steps becomes like this :1- access cavity2- cleaning and shaping with files and gates glidden and dont forget making the canal flare (means the orifice is wider than foramin at the apexof the tooth)3- filling (obturation)now if the access cavity and cleaning and shaping is good , the filling will be good but if one of them is incorrect we have to correct them: if the access cavity is incorrect we can correct it in most of the times in clinics because we can see it by our naked eyesbut the cleaning and shaping we cant see it by our naked eyes so we'll make a judgment for it when we fit the cones of gutta percha in the canal ,, if it goes easily then the cleaning and shaping is good, and if it doesnt go easily then the cleaning and shaping isnt good

Objective of canal obturation:

-The final stage of endodontic treatment is to fill the entire root canal space completely and densely with an inert (nonirritating) impermeable filling material.impermeable means that it doesnt allow water and air to pass) )-It is the substitution of an inert material in the space previously occupied by the pulp tissue to prevent recurrent infection

A three-dimensionally well filled root canal system does the following:

1- Prevent percolation and microleakage of periapical exudate the root canal space.

2- Prevent reinfection.

(*) (* Here if the filling goes out up to 1-2 mm its okay, but 5 mm isnt okayanother point sometimes we have an infection called "periapical lesion" but when we remove the bacteria by cleaning and shaping and we obdurate the space, this in turn will allow the tissue around here to heal and it takes one year to 6 months and within this time the patient shouldnt have any symptoms , this is the tissue healing ) (Look at the lateral canal (accessory canal) on the side, there's a little bit of filling and sealer in it and goes out , this is okay because it is irritating and does not harm the tissue, BUT dont think that's okay let's put anything out of the canal, that happens only in some cases in filling the root canal not always) (Now we have a big cavity and as we know we shouldnt leave any cavity inside the body empty so we should fill it. This is the filling how it looks like in the radio graph. look at the orifice how it's wide and flare )3- Create a favorable biologic environment for the tissue healing to take place.

When to obturate the root canalThe root canal is ready to be filled when the following criteria have been met:

1- The tooth is asymptomatic.Means that the patient doesnt have any pain or swellings ,, but if hes got a periapical lesion it's ok because it will heal

2- The canal is dry . after we clean and shape we irrigate the canal after that we have to dry it by paper point

3- There is no foul odor. If it exists that means that theres still bateria and infections within the canal so the clean and shape isn't enough yet so have to continue clean and shape and irrigate untill the odor is gone

Requirement for an ideal RC filling material1- 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 insertion.

4- It should be impervious to moisture. (doesn't allow exudates to go through it)

5- It should be radiopaque to see it on x-ray

6- It should be bacteriostatic or at least not encourage bacterial growth.

7- It should not stain tooth structure.

8- It should not irritate periapical 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. If we want to do retreatment if the root canal treatment fails and tissue didnt heal >> if the retreatment didnt make an effect and the tissue didnt heal we should make a periapical surgery >> if the surgery didnt make an effect and the tissue didnt heal we extract the tooth

(This is the Silver point , it is more radio opique than gutta percha and it's recognised by its straight parallel shape , while the gutta percha gives some flare conical shape )11- Unaffected by tissue fluids and insoluble: not corrode or oxidize. So the material will stay as it is .. we use the word corrode for metals, and we used it here because some of the filling material are made of metals such as silver point material

Types of Root Canal Filling Materials1- Silver Points Silver point introduces in 1930 as a root canal filling material, but it did not last long for it major fault Its lack of plasticity Its inability to be compacted. So we dont use it now

2- Gutta-Percha

Is the main one used and it's the most universally. Used as a solid core root canal filling material. It was introduced by Bowman in 1800s. But its used after hundreds of years after the improvements that was made on it

Gutta-percha composition:20% Gutta-Percha (Matrix).

66% Zinc Oxide (Filler). mainly

11% Heavy metal Sulfates (Radiopacifier).

3% Waxes or Resins (Plasticizer).

Notes:-Slides 14-22 the Dr skipped them but you have to read and study them , he said its written in the slides and he skipped them to finish the techniques that are mentioned later in the final parts of this lecture

-The most used sealer in lateral condensation is AH26

Types of Gutta-Percha1- Standardized which has sized corresponding to file sized such as 15, 20, 25 etc. .. this type is the one used in the main cones with sizes 30,, 35 ,, 40 ,, 45

2- Conventional which has greater taper than the standardized one and comes in size like: fine, medium, large-the size fine is mainly used to accessory cones In lateral condensation not medium or large or 25 or 15 as they will tell us in the lab or clinic

Note: 25-28 >> the Dr skipped them

The role of the cement (sealer) are: (the Dr said these points are important)

1- To fill in irregularities and minor discrepancies between the gutta-percha and the canal wall.

2- It acts as a lubricant and aids in the seating of the cones.

3- It also fill the accessory canal and multiple foramia.

Filling the root canal with lateral condensation method ..

32+33 note: skipped

Several important steps must be first completed:

Spreader size determination.

Master cone size determination.

Drying the canal. (by paper point)

Mixing the sealer and placement into the canal

now we will talk about each step :

Spreader size determination:

It mandatory to fit the spreader that will reach within 1mm short of the working length. . This is the most important step and it should go loose ( canal cleaning and shaping )

A rubber stop should be placed on the shaft of the spreader to mark true working length minus 1mm.

It is then set a side for immediate use.*Working length is the canal length so we put the rubber stop on the shaft of spereader after the working length we measured minus 1mm *

(finger spreader.. it looks like the file but without the cutting edges, this is the type we will use.) (handle spreader we shake the handle to use it in filling the canal )

Master cone size determination

1- The primary master cone should be selected to match the last file (master file) used to the full working length.

2- It should fit snugly and should resist removal Tug Back at the last 3-4 mm of the canal and this means its fitnote: We compromise the tug back for the length, that means that the Length is more important than the tug backin another meaning if the cone we used didnt produce a tug back because its small in size but It's through the full length its okay ,, we dont have to use a larger cone to produce this tug back because its not going to reach the full length , and the length is more important than the tug back actually

3- A radiograph must be taken to determine the apical fit of the master cone. To check if the last 3-4 mm has got a tug back or not

4- If the master cone protrudes through the apical foramen, then a larger size cone should be fitted snugly and this is better than cuting the end of it

5- If the master cone is 2-3mm short of the apex, a new smaller cone should be measured

6- Another radiograph should be taken to verity the fit of the cone.

(After the master cone has passed the trial test, it should be removed with cotton pliers that scar (by tweezer) the master cone at the external reference point (which is the working length).) (It's wrong when the cone go out of the canal , we can know its right length by the master fileanything we want to enter into the canal should be measured before and it stays with us for the final steps and it should have a rubber stop as we mentioned before in the spreader , and each file should have a rubber stop, dont remove it from any one and replace it on the other,, the Dr said we should have a dozen of rubber stop with us always ) (The tug back isnt here ,,,, its at the apical area as shown in the picture on the right ) (the tug back at the last 3-4 mm)

drying the canal by paper point slides 48+49 and he skipped them

mixing and placement of the sealerthe sealer can be cream (paste) and cream , or cream and powder , whatever they are we mix them untill its tacky

Placement of the sealer into the canal. There are 2 ways of doing it:1- Using the lentulo spirals: by carrying the sealer on the lentulo into the canal while rotating the lentulo spir