Tooth Canal Obturation System

Nawaf Hazaymeh

Mohamad A. Zou'bi

Sun. 17-3-2013

6

In this lecture we will talk about a new topic which is Tooth Canal Obturation

System ……

When we said "Tooth Canal Obturation System" that’s mean we are dealing with

more than one canal (not only the straight canal we have also the lateral canal

and the accessory one) each one with different anatomy.

If we want to define our failures in the Root Canal treatment we will find that

Obturation is the most common cause of failure so it's considered as the most

important step in root canal treatment, so to achieve the success treatment we

need to do Obturation in a right way.

However there are many different other causes that lead to failure in root canal

treatment not only the obturation such as:

1) Loss of or inadequate coronal seal.

2) Inadequate débridement and disinfection.

3) Missed canals.

4) Vertical root fractures ( to avoid this in the lab Don’t push a big files inside the

canal because this may lead to root fracture, if it I the apical part it will lead to

apical fracture and if it in the coronal part it will lead to coronal tooth fracture

which is not treatable so then you will need to send your patient to the Oral

Surgery Department in the hospital )

5) Significant periodontal disease.

6) Coronal fractures.

7) Poor aseptic technique.

8) Procedural errors such as loss of length, ledging, zipping, and perforations.

So we need to avoid these causes in order to achieve a

successful treatment.

The objective of obturation is to create a complete seal along the length of the

root canal system from the coronal opening to the apical termination.

Complete seal mean that we need to obturate in a 3D seal of the canal system

for example for one canal we don’t seal just the mesiodistal dimension we need

other dimension to be included in the sealing process, and the root after

preparation it becomes like a conical shape or you need to be confined to the

anatomy of the root canal to maintain the root canal shape; so you need to

obdurate all the spaces in the root canal system and before that you need to

clean them and/or to shape them.

And we need to obdurate these canals from the coronal part down to the apical

part, so it's not only a coronal seal or just an apical seal it's a complete seal (from

the top to the apex).

Hint: you need to be confined to the canal; your seal only in the canals we don’t

need to go beyond the apex in order to achieve apical seal.

One of the major mistake dentist make during obturation is that they missed the

coronal part or the coronal restoration where mikroleakage will happen and by

that we will have a long term failure (not immediate failure like fracture or

perforation …etc).

Persistence or development of periapical pathosis may not be evident for months

or even years after treatment.( the cause is there but the symptom will appear

later on) Therefore recall evaluation to assess the response to treatment is

important. Obturation-related failures occur in different ways.

Now let's take a look at these radiographs…

In "A" radiograph if you look at the radiolucent area which is at the side of this

premolar {area inside the white circle} and its related to the apex; so this mean

there is a lateral canal which is infected and leads to this big radiolucent area and

after obturation using a specific technique the operator will success in obturating

this space which leads tl the healing of this radiolucent area.

Failure make also could happen due to overfilled or under filled roots as well as

missed root canal so you need to obdurate only the root canal system not less

not more.

When questions arise, such as “When is treatment to be completed? Is it time to

obturate? ;to answer these question first of all you need to look at the symptom

that the patient complaining of ,the following factors are considered: signs and

symptoms, pulp and periapical status, and difficulty of procedure. Combinations

of these factors affect decisions of finishing the obturation or the whole treatment

made about the number of appointments and timing of obturation.

Desirable Properties of Obturating Materials

Grossman suggested that the ideal obturant should do the following :

1• Be easily introduced into the canal.

" By that you can handle it and introduce it into the canal ".

2• Seal the canal laterally, as well as apically.

3• Not shrink after being inserted.

"We need it dimensionally stable, because as we said previously we need a

complete sealing or a 3D seal to the root canal system … therefore when it

shrinks this will cause a spaces where microorganisms can accumulate and

cause a harmful infection"

Pay attention that as we don’t need the obturant to shrinks, also we don’t need it

to expand because this will lead to produce pressure on the root canal walls

which may lead to fracture or continuous pressure.

4• Be impervious to moisture.

5• Be bactericidal or at least discourage bacterial growth.

"We don’t need these material to encourage the bacterial growth , we need it at

least to stop its growth"

6• Be radiopaque.

7• Not stain tooth structure.

8• Not irritate periapical tissues or affect tooth structure.

9• Be sterile or easily sterilized.

10• be easily removed from the root canal.

"Why we need to remove it?..

If failures happened and you need to retreat

this case you need to be able to remove this

material easily"

Note: At this time, no material satisfies

all these criteria.

The best material we have now is the "Gutta-

Percha" because it satisfies most of these

criteria, which consist mainly of :

zinc oxide up to ( 60 -70)%.

About (15-20)% gutta-percha which is a

naturally present material from certain trees.

Other materials ( which Dr didn’t mention them)

The gutta-percha has been made manufactured according to the need for them

(they made it cone shape to fit the shape of the root also to be easily inserted).

filling endodontic percha-Gutta

contain to found were points

-gutta 20% approximately

oxide zinc 66% (matrix), percha

metal heavy 11% (filler),

3% and ),(radiopacifier sulfates

resins and/or waxes

(plasticizer).

dental of Journal Reference:

research

http://jdr.sagepub.com/content/

54/5/921

-if we look at the top corner of it, it will represent the same size of your file so it

come with different colors each color represent the size of the file of its color, So

it’s a standard gutta –perha cones.

Ex: if you look at the red one it will represent file size 25 and so on

Types :

A. Standardized cone Nos. 15 to 40.

B. Standardized cones No. 0.06, taper sizes No. 15 to 40.

C. Standardized cones Protaper .

-We have also conventional gutta-percha cone which is use as accessory cones,

used in conjugation with the master cone, so first we need to choose the master

cone "standard" and do the obturation and then obturate the remaining of the

canal space with a conventional cone (accessory) .

Types: extra fine, fine fine, fine medium fine, medium, large, and extra large.

So first of all we need to look at the final file we prepared the apical part by it

(apical enlargement step),and then we choose a master cone to fit our canal

after preparation according to that final file size in order to create apical sealing,

and then obturate the remaining of the canal space with a conventional cone

(accessory).

However gutta-percha is not the only material used in root canal obturation we

have also:

Resin-based obturation system contains primer, sealer, and cones.

The cones resemble gutta-percha and can be placed using lateral or warm

vertical compaction, but till now there is no enough research on this material

compared to gutta-percha.

Pellets are available for thermoplastic injection.

silver cones are no longer recommended as an obturating material,

because it's hard to compact these material laterally ( it’s a metal ) and

difficult to be taken out during retreatment and the corrosion products

which may produced by time.

In order to have a complete seal of the canal we need to seal in between these

cones "gutta-percha" because no matter how much we compact it we will still

have spaces between them; so in order to seal these spaces between these

cones also the irregularities in the canal wall which we didn’t prepare it in a nice

and smooth way so because of this we need to use the Sealers.

Sealers:

A basic concept is that sealer is more important than the core obturating material.

Sealer accomplishes the objective of :

•providing a fluid-tight seal; the core occupies space, serving as a vehicle for the

sealer.

• Sealer must be used in conjunction with the obturating material, regardless of

the technique or material used.

This makes the physical properties and placement of the sealer important.

How to use the sealer?

We cover the master cone with the sealer material and then insert it into the dry

canal and try to touch the whole wall in the canal with this sealer and then as

previously mentioned insert the master cone followed by the accessory one using

the finger spreaders.

So what the technique should we use in obturation the root canal space?

The two traditional techniques are lateral and vertical compaction of gutta-

percha; seal ability is similar in both.

The choice is dictated primarily by preference and custom, although there may

be special situations indicating a particular use of each technique, Both must be

used with a sealer.

•More recent approaches have been introduced that depend on warming and

softening formulations of gutta-percha with special devices and instruments and

then placing the gutta-percha incrementally

1. Lateral compaction: widely used, using a finger spreader we will push the

gatta-percha cones to the side and keep on pushing these cones to the

same side through all the obturating procedure; if you start from mesial to

distal keep on compacting gutta-percha toward this side.

Indications for lateral condensation :

Lateral compaction of gutta-percha may be used in most situations,Exceptions

are

severely curved or abnormally shaped canal ,because you can't insert your

spreader to the full length so you will not be able to condensate laterally.

canals or those with gross irregularities such as internal resorption (appear

in radiograph like a circle inside the canal space, so no matter how much

force you applied to the lateral surface the cone will not fit the shape of the

empty space which is circular in shape).

-However, lateral compaction may be combined with other obturation

approaches. In general, if the situation is not amenable to lateral (or vertical, if

that is the usual approach) compaction, it is too difficult for the general

practitioner and the patient should be referred to an endodontist.

Advantages of lateral condensation :

•Lateral compaction is relatively uncomplicated, easy requires a simple

armamentarium, and seals and obturates as well as any other technique in

conventional situations.

A major advantage of lateral compaction over most other techniques is length

control, with an apical stop and with careful use of the spreader, the length of the

gutta-percha filling is managed well.

Additional advantages include ease of retreatment, adaptation to the canal walls,

positive dimensional stability, and the ability to prepare post space.

Disadvantages of lateral condensation:

• A disadvantage of lateral compaction is that the resultant obturation is a series

of sealer-welded cones and thus not a homogeneous mass. There are no other

major disadvantages to lateral compaction other than difficulties in obturating

severely curved canals, an open apex, and canals with internal resorptive

defects.

What is the technique for the lateral condensation:

The steps of lateral compaction:

A. The master cone is fitted.

B. A finger spreader or plugger is inserted, ideally to 1 to 2 mm of the

prepared length.

C. The spreader is rotated and removed, and an accessory cone is placed in

the space created.

D. The process is repeated.

First we need to clean and dry the canal by using a paper point then to apply the

gutta-percha using a finger spreader and then put the sealers to seal any

remaining spaces.

Now Doctor move to the other slide which is (obturation) and do a slide show

from slide (6-21) ,so please go back and see them I will type what he talked

about in a form of points.

You need to have a master cone that fits the full working length and slightly

resistant to withdrawn.

When you measure the length you can create a notch by the tweezer, you

hold the cone with the tweezer on the working length and squeeze it; this

will create an impression/mark which do the same function as the rubber

stopper in the file.

Hold it with the tweezer, place it in the canal space and check if it reach

the full working length , check also its resistant.

Take care that your spreader when you place it may push the master cone

further down( so be careful to this point in the lab)

Tug-back means resistant to withdrawn; to make sure about this point take

a radiograph and look at the tip of the gutta-percha if ht reach the full

working length.

Caught the master cone with a sealer and insert it to the canal to fill the

spaces and give you the desired retention.

There are many different ways for applying the sealer to the canal walls

,one of them is by

Using the "gutta-percha cone" itself, you caught the tip of the master cone

only (we call it the master point) and apply it, then caught the tip of the

other one and then the accessory and so on… other ways is to caught the

whole length of the master cone and apply it to the walls, some others

proffered to insert the sealers using the lentola spiral ( Dr said that he don’t

preferred using this procedure because this way will make the canal

flowed by the sealer and by this we will not have enough spaces for the

gutta-percha and the sealer may be dissolved later on if it exposed to

microleakage and leave space behind ,remember that the function of the

sealer is to seal the tight spaces that I can't seal it with the gutta-percha)

Place the finger spreader, now the question is to which point I'm allowed to

insert the spreader?

This will depend on the amount of length of adhesion of the gutta-percha to

the apical part, so the spreader may go to a length 1-3 mm less than the

working length, but if the gutta-percha master point is loose the spreader

may go all the way and maybe beyond the apex.

However the finger spreader has a rubber stopper as the file this will help

in indicating how much length we should go.

Hint: if your spreader goes to the same length after each insertion of a gutta-

percha cone then you should know that there is something wrong in your

work!! Because with each gutta-percha inserted it should obliterate part of the

apical part, so the spreader should reduce in length each time.

Hold the spreader in its place for 15 seconds to allow the gutta-percha to

adapt, twist and remove.

Fill the resulting space in your canal with a gutta-percha point matched to

the spreader used and coated in sealer.

Work quickly as the space will be lost due to elastic recoil of the gutta-

percha that already placed.

Repeat until the whole canal is filled, until the spreader is no longer goes

further than level with cementoenamel junction CEJ.

Take a final radiograph to check for quality of root filling after you obdurate

the whole canal.

Heat the plugger to the "red point heated" and cut the excess of gutta-

percha.

At which level you need to cut the gutta-percha?

Posterior at the orifice, anterior beyond the orifice for esthetic reason.

We need to do a Coronal seal by restoring the cavity; first we do lining by a

resin modified glass ionomer RMGI and then put a permanent filling.

What are the common problem we face it :

1- Unable to get the canal dry.

2- Gutta-percha point gets bent in the canal.

3- No tug-back achieved.

4- Gutta-percha point come out with the spreader.

5- Sealer pasts sets too quickly.

6- Excessive pressure can cause root fracture.

7- Final radiograph shows:

Root filling to be short

Root filling to be through the apex

Voids in the canal

2. Vertical compaction: we start from the apical part and go to the coronal

part of the crown.

Vertical compaction is also an effective technique; studies show its sealability is

comparable to that of lateral compaction.

Although vertical compaction is not widely taught in dental schools, the technique

is becoming more popular.

With the introduction of new devices and techniques, the warm vertical

compaction technique is somewhat more user friendly and is less time

consuming.

Technique

•The warm vertical compaction technique requires a heat source and various

sized pluggers for compaction of the thermoplasticized gutta-percha.

Thermoplasticized Injection:

•With this technique, specially formulated gutta-percha is warmed and then

injected into the prepared canal with a device that works like a caulking gun.

When used in conjunction with a sealer, thermoplasticized injection provides an

adequate seal. This technique is useful in special situations However, lack of

length control and shrinkage on cooling are disadvantages.

This is an internal resorption which we talked about previously..

Radiolucencies

•Voids within the body or at the interface of obturating material and dentin wall

represent incomplete obturation.

Density

•Material should be of uniform density from coronal to apical aspects.

The coronal region (and large canals) are more radiopaque than the apical

region because of differences in mass of material. The margins of gutta-percha

should be sharp and distinct, with no fuzziness, indicating close adaptation

Length

•The material should extend to the prepared length and be removed apical to the

gingival margin (anterior teeth) and orifices (posterior teeth).

Taper

•The gutta-percha should reflect the canal shape (i.e., it should be tapered from

coronal to apical regions). Taper need not be uniform but should be consistent.

Ideally, the apical region should taper nearly to a point unless the canal in this

region was not small before preparation.

•Restoration

•Whether permanent or temporary, the restoration should be contacting enough

dentin surfaces to ensure a coronal seal.

•Indications for the vertical condensation :

•vertical compaction can be used in the same situations as lateral compaction. It

is preferred in a few circumstances, such as with internal resorption and with root

end induction.

•Advantages of the vertical condensation:

•The principal advantage of vertical over lateral compaction is the ability to adapt

the warmed and softened gutta-percha to the irregular root canal system.

Disadvantages of the vertical condensation:

Disadvantages include difficulty of length control, a more complicated procedure,

and a larger assortment of required instruments. Also, a somewhat larger canal

preparation is necessary to allow manipulation of the instruments.

This is the last lecture in the midterm exam… and for the root canal preparation chapter there is a section about rotary instrumentation, this part will not be included in the exam.

-Dr didn't mention many things in the slides I tried my best to cover them in this lecture as much as I can, so please try to take a look at the slides. Forgive me for any mistake……

Done By:

Mohamad Al.zou'bi