Class III Composite Restoration

Class III Composite Restoration

January 4, 2020 18 By Kody Olson


Welcome to the University of Michigan Dentistry
Podcast Series promoting oral health care worldwide. We will be doing a class III composite restoration.
First of all, we will inspect the lesion with the mirror to find the exact extent of it
in the mouth. If you notice you can see a grayish area, a grayish tan area, and we’re
outlining it with the explorer. Then we will check occlusion on this case.
The occlusion is very important to us of course in any restoration. First of all, check it
without any articulating paper and observe where the teeth strike. Then with articulating
paper have the patient close their mouth several times and then again with a mirror we will
check to see where the contact point is in relationship to the carious lesion. We see
here that it is incisal to our lesion. The next step then will be to look at the
X-ray again to see just how large this lesion is. If you notice the extent here as we come
in the dental-enamel junction is broken. We go down incisally, now actually toward the
pulp and notice as it goes to the cervical, and then back up through the dental-enamel
junction. After completion of the isolation of the tooth
with rubber dam, saliva injector and so on, we will now be ready for our cavity preparation.
This is a one-half round bur in the straight, in the high-speed fan piece. You will notice
this: the relationship of this half-round in size to the carious lesion. As we point out here this is the extent, again,
of the carious lesion with the bur. The actual cavity preparation that we’re interested
is here. Notice the lingual opening. Cavosurface margins have no bevels. As we look at it interproximally
we notice the extent of the preparation drops toward the incisal, curves with the labial,
and drops again to the cervical and then come out to the cavosurface margin on the lingual.
If you notice the retention grooves in the incisal, cervical, and labial. We will now
start with a half-round bur. But before we start I’d like to compare a number two bur
with it. Many dentists wish to use a number two but look at the difference in the size.
And as we look back and remember what our X-rays showed. Now if you notice the first
penetration point is just inside the dental-enamel junction or the marginal ridge. It’s a pendulating
motion, pendulating motion on and off the tubes. Pendulating if you notice a piece of
tooth flew out there and that will happen when you go through into the carious lesion. We’re going cervically and incisally with
that pendulating motion again. This is what produces the retentive form that I showed
you on the original model. Now it is well to stop once in a while and
look, dry it out and look at what you have done. We’re now drying it out. If you notice
now there is decalcification still in the labial portion on this preparation but we
are cutting a normal situation. If you look closely you can see that there is stain which
is possible. Carious lesion still on the actual wall but we’re paying no attention to it.
We’re going in now and forming what we would call an ideal cavity preparation. This in
itself will give us a convenience form and access to remove the rest of the carious lesion. We’ve decided that there still is that bit
of decalcified enamel and also some caries in the dental-enamel junction so we’re back
in removing this. We will not use the high speed bur to remove caries beyond the normal
depth of a cavity preparation. Notice with this arrow we are pointing out again decalcification
of the labial and this is of extreme importance to us because it leaves us with a faulty margin
if we do not remove it. Looking against the actual wall you will see there is a quite
a bit of carious lesion remaining. Now with the conventional speed and a number two round
bur now notice the difference in the size of the bur. We will come in at a conventional,
with conventional speed and slowly remove the rest of the carious lesion. Remembering
we have arrived at what we think is a normal cavity preparation. Light touch, relatively
high speed with this conventional speed. Again on and off the tooth. We do not hold it on
the tooth constantly. Notice that motion. It’s of extreme importance in any cavity preparation. Now a little water and we’ll rinse it. Dry
it out gently. Do not overdry or dehydrate the dentin. Now checking with an explorer.
Notice we’re picking out little bits of debris. We’re checking into the incisal. Now the cervical
to see whether or not that lesion is removed. We’ve decided that it’s stuck a little toward
the cervical axial. And again we’re still after that little bit of decalcified enamel.
It’s of extreme importance to us. Notice that the outline form is still the
same that we started with. The actual wall is deeper. Now we’re in with a hoe that we’ll
sharpen up that labial wall and the incisal wall and the cervical using the hoe. Scrapping motion. The straight fissure bur, a 55, or a 56, is
now utilized. Using this bur we’ll only cut enamel with it. This is very important. Only
enamel. This does not cut against the axial wall, the dentin at all. Just into the enamel
itself. This smoothes it off, it gives us a cavosurface margin that comes at 90 degrees
with the tooth. Then you will bring the bur out toward the lingual and smoothing off that
margin as much as possible. Rinse it off and examine again. If you will note there is still
some carious lesion against the axial wall. This is what we’re trying to reproduce now.
The number two model that we have given you. If you will look at it, you will see the retentive
form as it goes toward the labial, cervical and incisal extensions. We have not placed
any tension in our cavity preparation in the axial walls. Now with the final caries removal, with this
angle you can see there is still a carious lesion remaining on the axial wall. We will
take a spoon excavator and with gentle pressure you will notice here we can peel some of this
out. This is sometimes sufficient to remove all of it. It’s often a good time though to
take at conventional speed a number two or a number four round bur depending upon the
size of the lesion and gently, with a high speed and a gentle touch, remove the remaining
carious lesion. The cavity preparation is now ready for its
refinement and retention. We first of all check to see that there is no carious lesion
remaining. Check your dental-enamel junctions very thoroughly with an explorer and also
by inspection. Now with a half-round bur or a quarter-round in some places, we will now
start our retentive groove. We will be, the retentive groove is the slightest, in the
incisal, it gets a little larger in the labial portion and then becomes rather prominent
at the cervical. There are times in cavity preparations of four composite class III that
you can get retention only in the cervical and not the labial or incisal depending upon
the thickness of the tooth that remains in those areas. We must not undermine enamel
to gain our retention. Now our final refinement of this preparation is done again with a hoe.
If you notice the look of this enamel it’s beautifully sharp. There’s no decalcification
left on the margins. We’re using the hoe on the end to scrape the labial and then come
down to the incisal. Notice that. Rinse off your debris. You cannot see into
a cavity that is filled with debris. Notice again now the cavosurface margin is
of extreme importance. Very smooth. Coming at right angles, no bevels and then out to
the labial wall how smooth this wall is. We cannot have a smooth preparation, finished
preparation without starting with a smooth cavity preparation. This is of course one of the most important
steps in our whole procedure. This preparation as I say relates to your number two, that
you have, that you have at your desk. We will use Cavitec which is a zinc oxide
eugenol preparation to place against the deepened portion of the axial wall. We are hoping then
that the zinc oxide eugenol will be an obtundant for that pulp. You’ve all mixed Cavitec as we do here very
quickly. Very smoothly, very simple to use. And small amounts are used. Please note this.
We are going to form our pulpal protection cement bases in line, or take the exact shape
of the axial wall as it is. We use here the back, the convex surface of a small spoon,
a 17 or you can use a small ball burnisher but note now it’s just touched against the
axial wall. A thin film. This is simply to reduce the inflammation of the pulp. Notice
we’re going to cover the entire axial wall but only on dentin. After about 30 seconds
you can use a cavity liner such as Copalite that you have. Now we have to be extremely
careful that no Copalite comes in contact with the cavosurface margins or any of the
enamel really in this preparation but this is covered over the Cavitec and any dentin
that still might be exposed. Keeping it from, if you notice here, keeping it from the enamel
walls. We’re mixing zinc phosphate cement primary and secondary and while the mixing
of the cement is going on or if you’re doing it yourself before you start mixing you take
a hole and go around all of the margins. Notice this. Just in case any of that cavity liner
had touched them. That will remove any of the cavity liner. Cavity liner is not compatible
with a composite. But we’re using it here as an added protection against the acid of
the zinc phosphate cement that we’re placing. Another thing that you should remember while
we’re doing this is that composites should not be placed against a zinc oxide preparation. Zinc phosphate mixed in the regular way. A
primary and a secondary mix. Now we’re checking for the primary. Not quite ready. So we add
a little powder. Remember when you mix zinc phosphate cement you are mixing to a consistency.
Not just the amount that you put out. Each day it will vary a little bit. So you mix
to a consistency. Should draw up about an inch. There. Or an inch and a half. A little
bit more now will make it just right. Draws up about an inch, an inch and a half
and then breaks off that means that the primary consistency is just right. You note now that the operator picks up on
the point of a cow horn explorer. Notice how small that is. And he is going to touch some
retentive dots into the preparation, on the axial wall, but away from the pulp as much
as possible. You can see the two, cervically and incisally. In the meantime, the zinc phosphate
cement is being mixed to a very heavy consistency that you can roll in your fingers and it will
not stick to your fingers or the instruments. This is again rolled in powder, the powder
is zinc oxide which is good for the tooth and the liquid of course is a phosphoric acid.
Now with the back of the same spoon that you used for the Cavitec, you can place a small
amount and it will cover this wall contouring it to the area that was remaining from removing
of the carious lesion. Notice the small amount. Notice the small amount. This is of extreme
importance. Put it in and gently tap it and burnish it to place. And if you mixed it correctly,
this is all the time that it takes to place. Not on any enamel. Not on any enamel. If you
notice it, like there was a little piece on the enamel wall then just go back in with
your instrument and pop it out and keep it out of your retentive groove also. If you
look closely you can see the retentive groove and the labial where we’re pointing is very
clean and out the incisal. Now it shows there was a spot so out it comes. So take your explorer
and just check. Now in the cervical. Maybe a tiny spot but much. Notice the contour of
it, it is not built out to replace the lost dentin. Matrix replacement. The matrix of course is
of extreme importance because this really is the beginning of the finishing of your
preparation. Now on your model we have a curved matrix. We will pretest the matrix in the
mouth. We’ll show you that in just a moment. But note how they pull this matrix. You will
place it on the tooth and you will put the pressure on the lingual or labial opening
whichever you have and then pull the strip. Now note when we pretest so that we know how
this contours to the tooth itself. Now as we pull it this way –there!— can you see
now that there is a good cervical adaptation. We do wedge these preparations. The wedge
does two things really. It’ll sometimes help maintain the strip for you and we use a soft
Stim-U-dent wedge. The second thing that it does of course is give you a good cervical
adaptation. So now we will pretest this wedge. We want to see just where it will go. Once
you mix your materials you do not have time to do any guessing or trying, everything,
you have to know exactly what to do as you place the material. We don’t need the full
length of that and we notice that as we placed it into the preparation or beneath it at the
cervical, it was a little too high. This would result in a concavity of our preparation at
the cervical. Which you know of course would give us a gingival problem and also have a
good place for plague and food particles to catch and thus recurrent decay. Now that cervical,
or wedge, is very nice at the cervical. Back goes the strip. We know now how we’re
gonna adapt this strip. We place it in place before we start mixing or getting anything
out on the pads. We want that in place but the wedge is removed. In the manipulation of the materials and placement,
we will use, in placement especially, we will be using a Teflon, a premier Teflon instrument.
It is a flat-bladed instrument on both ends and it is used to burnish the material into
place. Then we have a carrier for the composite itself. It consists of, sort of a barrel and
a plunger and then it has a disposable plastic tip which has its own little plunger to go
into it. This plastic tip will be filled with material, the plunger tip placed in it such
as you’re seeing here and then that will be placed into the syringe. We’re using a toupee system here in which
we will use equal amounts of the catalyst and the universal paste. This toupee system happens to have tints.
Now there are many times when you do need tints and we will have them out in the dispensing
area for you. The one thing to remember about using tints is that you have to use a tiny
amount and it would be well to mix a little bit and place a tint so that you know what
you are doing. If you notice the spatula is square on the right end and rounded on the
left end. This is so you will use one end in the catalyst and one end in the universal
paste. You cannot combine these two with any amounts or the entire mix, or the entire batch
of materials you have will be spoiled. So in the catalyst we use the curved or the round,
‘C’ for ‘C’. And of course this spatula is disposable.
You use it only the once. Small amounts taken out and will be dispensed. It’s a very expensive
material and you do not need a lot of it to fill most of our preparations. With this paste
system we now turn the spatula and we’ll take out the universal paste but we use equal amounts
of each. A very simple method, a very simple method of mixing. We are stirring this as
you notice we stirred the catalyst and now we stir the universal paste. Some of the manufacturers
say this is not necessary that it’s homogenized but we feel we get better results if every
day at least these are stirred. Now the ladies in the dispensing clinic will take care of
this for you. And they will dispense it on a pad such as this for you. Now we are ready
to mix. It’s a matter of putting the two of them together for 20 seconds. Mixing, padding,
keeping it in a small area because you have a small amount. It will become one color. They were very close
to begin with so you have to watch this and it is best to time it. Now this is transferred
to the small, disposable, plastic tube. Right from the spatula. The plastic insert is now
placed in here and pressed just even with the orifice. Now it is placed into the syringe. Into the syringe and a little pressure is
placed on the handle to squirt out some of the material. There. You see the material
come out. Now it is placed into the furthest point of
the cavity preparation. Very important. Keeping it in contact with tooth structure and squirting
and withdrawing at the same time that you are squirting. You have to overfill but do
not overfill. Then you saw the Teflon instrument come in and wipe off the access. And if you
notice now the thumb is placed over the lingual opening and it is pulled to the labial and
the wedge is placed in with pressure. After five minutes, the wedge is removed.
That is five minutes from the time you start mixing. The wedge is removed and the matrix
chip is removed. We now wait another five minutes before we will actively start the
finishing. It is well to look at this preparation and see that we do have it filled completely. The finishing procedure as I mentioned before
actually starts with your filling material, when you’re filling the tooth and also with
the adaptation of the matrix but now we will go into the final finishing. On the left you
see a 12 blade, a very sharp curved blade that you have in your kits on the right with
a Wedelstaedt chisel. Now as we pass across these stones, there’s the green stone round
and carrot-shaped, the white Arkansas point, round and carrot-shaped. And the 7901 bur,
a Midwest jet bur, for finishing. If you use a green bur or a green stone rather you have
to follow that area with a white Arkansas point and the 7901. Now at the end we see
a mandrill or our sandpapered disks. These are waterproof disks. And the one on the left
of course is fine, the one on the right is coarse. And we use the K-Y sterile lubricant
jelly, water soluble for our polishing with the disks. There is, oh there is a strip as you can see
at the bottom of this sterile lubricant tube. It has a coarse grip on the right, an open
space in the middle, and a finer grit on the left. In this case, we’re going to start by using
a round, green stone on the lingual portion because we did have a bit of excess which
most of us will have as we fill these. This again is a light touch, relatively high
speed but very light we want to reduce the friction and the heat generated as much as
possible. You notice the on and off motion. This is
true of nearly everything that we do in dentistry with a rotating instrument. On and off. Not
holding it in contact with the material or the tooth at all times. Taking off the excess
with the green stone. You’re starting now to see I think the cavity outline. This is
the 12-blade that we mentioned before. A little dryness shows you just where that is. Now
this instrument is used to score the material away from the margin. Do not try to score
this right at the margin or you will have a void in your margin and then after scoring
it is lifted out as you could see. Now the carrot-shaped stone is run along the marginal
ridge to develop the outer incline of the marginal ridge and also at the cervical to
take off any of the excess we might have. It is very important for you in the finishing
procedure to not touch onto the enamel, if possible. We’re all going to touch it a little
as we do it but keep that to a very, very minimum because these stones will roughen
it. Now we check. We notice there’s a little heaviness
here and there. The white Arkansas point is now brought into play and we will go over
any area that has been touched which in this case has been the entire lingual portion on
the preparation. Anything that has been touched by the green stone must now be touched by
the white stone or it will leave a roughness. Roughness of course will not be comfortable
to the patient and it will also have a tendency to collect plague and have recurrent caries
more readily. Carrot-shaped stone brought into play. This
can also it depends on the contour of the tooth how you use these stones. This again
is mainly for the contouring of that outer incline of the marginal ridge. Now look closely
at the cervical. You’ll see we still have a little excess but at this point with, it’s
rather a spade-shaped central so that we were able to get our carrot-shaped stone in on
the entire surface which gives us a very beautiful contour of the tooth itself. Now he’s going
at the cervical slightly. Check again. Always inspect. Always keep checking.
Don’t overdo. One of our problems when we’re first doing these things is that we have a
tendency to over finish. Now this 7901 bur, it’s a 12-bladed carbide
bur. Run at conventional speed and very light touch. Very light touch. You’ll notice we’re
at the cervical now. Being so careful not to touch the cervical enamel. The K-Y jelly is now placed over the restoration
and we can come back. We noticed that there were a few little grooves placed on that lingual
surface so we will come back with a white Arkansas point, the very fine one, with the
lubricant and just gently touch again. Patient’s tongues are very susceptible to any change
and they’ll often say to you, “Doc that feels rough.” So after we get the rubber dam off
this is a final check really what we can do. Now with the disks we will break the back
of the disk on our fingernail just gently press it against the back of the disk against
your fingernail and press and it loosens that up for us so that we do not cut ridges into
our restoration. I think you can see the cavity outline, now
the cavity preparation outline and how smooth it really is. It turned out very nicely but
we will check again. There is really no indication when we are going from tooth to restoration
or from restoration to tooth. We have to remember that this did have a slight
tendency to come out toward the labial so now we will check the labial portion on this
tooth. If you look at it from the labial you will see that there is a slight bit of excess
at the cervical and even down to the incisal a little. So with our 12-blade we will now trim. We
will trim that labial area, cutting with the blade touching the tooth and the restorative
material. Now checking again. Now placing our lubricant because we will put a little
disk in there just to smooth up what we have done and this fine waterproof disk gives us
a very nice finish. I think you can see the cervical now. You
can see the labial extension of it. Look very closely. Checking once more because checking you can’t
do it too often. You have to have a feel and know what you’re look for. Now the strip that you saw earlier. The coarse
side is on my, on the left but there is a placement no grip on it in the middle so that
we do not touch contact. Now notice that was placed through and then pulled and rubbed
against the cervical. You place your thumb or finger against the tooth and the strip
on the lingual. And then pull it out and that finishes the
cervical down very beautifully for you. Keeping contact with the finger or thumb against the
lingual. Rinse it off and check. And now we are ready to remove the rubber
dam because we still have to check occlusion and have the patient feel the restoration
with their tongue. With the rubber dam removed, before we put
carbon paper on anything put your finger on the tooth you’ve been working on and have
the patient close. You can sometimes feel a jar or a knot. This is a good indication.
Then the final check with the articulating paper and as you notice the lowers you can
two or three places it’s marked now look back on, into the mirror, and you will see we have
the contact to incisal to the restoration where it was in the beginning. You have been listening to a presentation
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