Horizontal Mandibular Impaction and Maxillary Third Molar

Uploaded by UMichDent on 12.06.2009

Welcome to the University of Michigan Dentistry Podcast Series promoting oral health care
Twenty year old Laurie Martin has come to us today for the removal of impacted third
molars. She's had occasional symptoms from them. She has been pre-medicated with intravenous
valium 10 milligrams and local anesthesia has been administered for the inferior alveolar
and long buccal nerves on the right side. We are going to ask her to open her mouth
for the insertion of a rubber bite block to be placed between the occlusal surfaces of
the teeth on this opposite side. We'll have her then close on that and that will help
her stabilize her jaw and likewise it will take some of the stress off the temporal mandibular
joints during our surgical approach to this right retro-molar region. We are now approaching
the area of number 32. We have anesthetized this region. There are a few points we'd like
to demonstrate anatomically. The second molar is in position. As one looks at the attached
gingiva, there is a specific crease or groove on the distal buccal area right here. That
represents anatomically a position where the buccinator muscle ends its insertion on the
mandible and physiologically it's a change point in the periosteal attachment and so
we will follow that in the placement of our incision. The second consideration of the
incision is the retro-molar area where all incisions that extend posteriorly must be
placed over bone and should not at any time jeopardize the lingual nerve by going too
far medially. So with that in mind we'll proceed with the incisions on the reflection of the
flap in this area.
Before we proceed however we should look at the target which will be approached here in
the form of the uninterrupted third molar. For that we will look at radiographs.
As we see, as we see the Panorax or radiograph here on the right of the screen you will see
the right side of this patient's jaw and you will see the horizontal impaction of number
32. This tooth is relatively high in position and it is uh, approachable with a minimal
amount of bone removal.
We'll follow the anatomic area that we described and come down in that fold approaching the
vestibule along that insertion pattern which was previously identified going through completely
to bone and now we shall extend posteriorly staying over the bone that has been previously
palpated going down to again bone and crown of tooth for the access that will be required.
Following that incision with a periosteal elevator. The small end of periosteal elevator
seeks out the bone and then we'll proceed up to the position of the flap which joins
the two incisions. We'll reflect that back and when we are confronted with adhesion we'll
change the instrumentation and move to sharp dissection. The sharp dissection will release
the periosteum from the bone surface at that point and we will then gain relaxation of
the flap and in a moment or two we will see the field of exposure required for this type
of impaction. We would like to reflect the periosteum with a field that is adequate but
we would wish to avoid excessive flap reflection. We will next turn to rotary instrumentation
and we will be removing bone with the help of this number eight round bur. Before doing
that I'll change the end of the periosteal elevator to the broad end which will serve
more appropriately as the reflector of the flap. The number eight round bur will be used
now to reduce the level of the bone and the immediate contact with the molar.
[Drilling sounds]
Once again we would like to remove sufficient quantity of bone to expose the field but we
desire not to remove excessive amounts of bone. We'll next shift from the number eight
to a number five round bur and proceed with deepening of the level of the bone removal.
We are now near the cementoenamel junction, above, and we will be able to then gain access
to the tooth in question. At this point, we will make a fundamental decision regarding
the division of the tooth whether or not the buccal grooves are sufficiently developed
to permit the suctioning of this tooth. The instrument that we have just inserted is a
bi-bevel chisel or osteotome and we'll use that placed in the buccal groove here firmly
and we will hold that in position and see what the opportunities are for a sectioning
of this tooth. The patient is asked to bite down firmly on the bite block at this time
and a bit of support is added to the angle of the mandible. Using a rest finger and holding
it in this fashion we inform the patient that she'll feel a tap [tapping sounds] and as
such we get a section started. Now next I'll go to the distal buccal groove changing the
angulation. Another tap and we'll have a section. We'll see that a little more clearly now as
we expose the field once again. And we will next insert a 77R elevator and we'll use that
to dislodge the distal half of the crown. Pressure now, Laurie. And we're gaining some
separation then of the several segments of this tooth. You can see the motion that has
been obtained and that tooth is starting to yield its distal half. I'd like a small pick
elevator. We'll try this cryer elevator and see if we can gain a little bit more control.
Pressure again. Notice how the cryer elevator fits into the pulp chamber and gives us the
control necessary to rotate that distal half of the crown out of its socket. We'll next
approach this segment. Notice the assistant, Mrs. McIntyre, supporting and avoiding the
accidental displacement of that fragment of crown down into the pharynx, a highly important
aspect for safety and next with that space that has been gained why don't we irrigate
that so that our structures are a little clearer?
[Suction sounds]
That's better. Now we'll proceed with the insertion of this 77R elevator again on the
mesial of the crown and see if we have enough space into which to rotate that tooth. We
don't. It's resistant. And if you recall the angulation of this horizontal impaction, you'll
remember that it is tight up against the distal roots of the second molar and as such we're
going to have to remove the remainder of that crown in order to draw the roots forward into
the space provided. We then are returning to the field with the help of a small number
five round bur. I'm trying to keep the periosteal flap well back. [Drilling sound] I'm penetrating
that remaining crown, a small round bur penetrates, punches well, does not cut laterally well
so we'll follow the round with a cross-cut fissure bur and that will help us to complete
the slot to divide the crown from the root mass.
Approaching again to a penetrating hole that was provided by the round bur we'll proceed
with the cutting of the slot and we hope that that slot will enable us to separate the remaining
crown from the root. Again a 77R elevator in position, in the slot, a snapping noise
here and we […] some of the separation. You'll recall our first chisel sectioning
which was placed in this mesial buccal groove that split the crown incompletely but it separates
it but these pieces are a little smaller and a little easier to handle. Our patient is
doing extremely well. Now we can rotate up that remaining mesial and we can see it's
starting to come into view. Then we'll follow that with our… This then represents the
last of the crown. And I'll take a small curette please. And we will examine the equipped area
for the possibilities of reduced enamel epithelium. There doesn't seem to be a great deal here
and so as promised we'll give our patient a little rest. Will you open now please, Laurie?
And we'll have our patient close on a sponge. Bite down again, my dear. And that will prevent
her muscles from getting too fatigued by propping her jaw open for a prolonged period of time.
We'll see where the remaining root is down in here and I'll place a traction hold into
the root [...] it laterally.
[Drilling sound]
And without any bone removal I'll see if the root will respond to this fine pick elevator.
Place the fine pick elevator in the traction hole and if you watch, you can see the root
mass beginning to advance. It comes forward, has a little rotation movement involved but
ah, it's moving, and moving well. We're careful it's blocking a little against the lingual
alveolar wall so it's been rotated up.
Still, we'll try a few other combinations. Alright […] tantalizing because of its almost
but not quite there stasis. That's one way to handle it is make the root smaller. Better
to make the tooth smaller than the hole bigger. The tooth is coming out anyway and if we minimize
the amount of bone relief then the defect is smaller. You can see that this longer,
more advanced fragment of root is the thing that was holding us up. And that the root
mass itself also has a small hook on the end which I think you can, yes, you can appreciate
that. And that also contributed a bit to the dictates of the pathway of the root mass on
We, next we'll debride the area with both irrigation [drilling sound] […] with a small
curette and this would represent probably a nerve filament if you could suction that
again, that's fine, from the pulp either that or a piece of periodontal ligament. Well the
defect looks quite clean and there is no reduced enamel epithelium here of significance. I
don't – oh yes there is too. It's a good thing we went back there because there is
not a complete atrophy and there is reduced enamel epithelium. [Drilling continues.] This
tissue has cystic potential and should be removed.
I think we have it removed now adequately from the perimeter of the equipt or where
the crown was. The flap we will trim slightly. There seems to be a little bit of excess and
the bone margin we will dress down particularly where the edge has been used as a fulcrum
for the elevators. So, that's freshened up. And now we'll turn to soft tissue trimming
with the scissors would be fine. This is a small Adson tissue forcep useful in controlling
the tissue to be modified. We're casting a little shadow there but you see the matter
in which it's picked up, controlled, then the scissors can accurately control the quantity
of trimming that's done. With that fashion we can return, there may be some others a
little tag here that we can trim off and one can debride things quite well.
Before the suturing of the operative site, the bone crypt we believe is better treated
by the insertion of an antibiotic. This white material is gel foam and has been compressed.
A block of gel foam has been compressed. We can reduce the sharp edges on that to enhance
the, enhance the surface area that is available making it more spherical or globular than
a square and then that will be the vehicle in which we distribute the antibiotic. Fifty
milligrams of tetracycline have been inserted here into this sterile cup and will be placed
into a supersaturated solution. Mixed in this manner this antibiotic will be placed into
the compressed gelatin sponge that will then expand to incorporate the antibiotic in it.
As such, that will carry the antibiotic. I'll place it in and will allow the compressed
gel foam sponge to soak up the mixture of tetracycline and we'll see that it will expand
more to its original dimension the air space is being filled with the solution of antibiotic.
It has been shown that tetracycline does have affinity for calcified surfaces of bone and
the theory for its use in defects of this sort is that it does reduce the flora that
tend to produce fibrinolysis which tend to break down blood clots. And we would like
an established blood clot to remain in this defect [...] so it is then this glob of gel
[...] saturated with tetracycline that will be inserted in the central area of the bone
defect turning the flap back once again we see the defect partially filled with a good
blood clot and we will be then inserting this tetracycline sponge into the central portion
of the defecting bone so that occupies the central portion of the bony cavity. The flap
has been trimmed and is now ready for closure.
The suture being employed is silk and the suture will be placed in the corner of this
flap. We could support that flap with a tissue forcep but we seem to have it under control
here and it's important as you bring this across to anchor it into the lingual in the
most anterior posture possible and at a low level. If that is accomplished and sometimes
it's necessary to use a double pass in order to achieve that but if you able to put it
across in that fashion then it's possible to wrap the epithelial attachment around the
distal portion of the tooth and to maintain it. I'm trying to keep out of the picture
here. There we go. And we'll take the flap back and wrap it closely around the distal
of the second molar. So it is with that in mind that we're placing the suture in this
We'll next turn toward the more anterior extension of the incision and determine whether or not
a supplemental suture would be useful there. Sometimes these incisions are quite lengthy
and sometimes additional support can be used right there. I think in order to demonstrate,
although it's a little bit equivocal here but it's needed, it's a difficult suture to
place so we'll try to demonstrate it placing the needle in a fashion that is somewhat back-handed
in this way we'll approach the flap. Let's sponge that a little bit. Approach the flap
through the reflected flap into the remaining supported margin so we'll come in from behind
and we'd like to get that over and returned to the sound table of bone that is anterior.
And so with that, we're trying to come through our margin anteriorly. And we're coming a
little bit too far. There it is, where we want it. And we'll… the curve of the needle
is appropriate and we see it coming forward to anchor that flap back against the sound
table of bone. In order to get just the right amount of tension on that flap and to control
it a little bit we're going to slide – could I sponge that off again, please? We'll
just make that a little cleaner so you'll see what we're up to here. We're sliding this
slipknot down to just give the right amount of tension on that flap. That will keep it
in position and I don't believe we've overdone it but it gets that margin back nicely where
the flap will not fall into the bone defect. That aspect of it has some significance.
We have considerable variability in the approach, in the maxilla, depending upon how high we
must reflect the flap for access. In this instance, you may recall from the X-ray that
the impaction is not very high. I'm beginning an incision over the tuberosity region and
I'm making it up toward the distal of the second molar. Our next, after contacting the
distal of the second molar, we'll start to come around the epithelial attachment of the
second molar. What we do vertically here depends upon the access, whether or not we make an
oblique incision or not. For this particular impaction, which is not particularly high
in location, we're going to initiate just a free gingival margin flap to start with.
So we'll get into this papilla and then start the reflection of the flap around the circumference
of the second molar and following our incision posteriorly, we'll begin to reflect the flap
outward in that manner. After we have a plane for dissection, we'll next, we'll take the
broad end of the periosteal elevator, insert that beneath the flap, and see what access
this degree of flap reflection affords. Now if this impaction were one that was high in
location, we would make an oblique incision here, in this fashion, and carry this papilla
up which would reflect the flap to a greater distance without any tension or tendencies
for tearing it because we would like not to tear a flap and if one needs a large flap
for access by all means one should reflect it. However, we'll get more rapid healing
here if we can minimize that reflection. So holding things apart and suctioning we should
see here the occlusal surface of impacted number one. There is a small amount of bone
right here. The instrument that we are introducing is a mono-bevel gardner chisel and the bone
in the maxilla tends to be rather soft so with hand pressure alone we'll tell the patient
that we want to exert some pressure here. But it's possible to relieve some bone there
to gain access. Then after that access is gained we'll take again our 77R elevator and
insert it on the mesial aspect of the crown and rotate this elevator toward the tooth
to be removed, toward the occlusal. So in rotating, lots of pressure here for just a
moment, Laurie. As the elevator is inserted, the crown begins to deliver and as it delivers
we advance the elevator up the alveolar wall and in that fashion that tooth will deliver.
So we have it then already for plucking with a small hemostat [...] and that should give
us the control that we need. We see that it is here in its entirety and all present and
accounted for. We'll next return and remove this reduced enamel epithelium. We'll take
a curette once again being sure we have it all out and following that debridement with
a small bone file in case we have in any way damaged or crushed the alveolar wall. We'll
smooth that off with this small end of this bone file.
The suture is placed at the base of the papilla and then proceeds under the contact point
in the interproximal. We continue to advance it. We'll pick up the needle then on the palatal
side and pull it through all except the terminal inch or two. We'll reverse the needle and
approach the palatal side in the same manner that we approached the buccal and anchor this
same suture at the base of the papilla on the palatal side. So we have a figure of eight
suture which we now will proceed to tie and if we can have this elevated a little, we'll
see more of the field I believe. That's good. And the suture will hold the papilla up in
place in the embrasure giving it full support so that the peripheral epithelial attachment
will be anchored where it belongs. You might sponge that lightly after it's tied and we
will see that there's full security of the suture and we'll cut it about that length.
Our next suture will be placed over the crest of the tuberosity of the maxilla. I'll take
this once again please and we'll retract the tissue. I'm going through the full thickness
of this flap gaining complete control of it and we'll pass through the palatal side and
now that we'll secure the incision. Why, I suppose one would ask, is one not inserting
the same gel foam tetracycline sponge in this area? And the answer to that is that healing
in the maxilla is infinitely simpler than that in the mandible. The blood supply is
10 times that of the mandible, the complications and repair, the loss of blood clots and similar
things are far less frequent in the maxilla than they are in mandible. So we found certainly
that the removal of this tooth was, can we have another sponge please? Was certainly
simpler, the bone was softer, the overall approach was easier and that will be true
of the – I wonder if we can see that distal suture? It's a little hard to get light in
there but the concept of the flap I think was satisfactory. We certainly have had an
ideal patient to work with today. We will place a moist sponge over the operative fields
so that the patient, while biting down, will exert appropriate pressure on those flaps,
reduce the quantity of extravasated blood to avoid hematomas and we'll now follow our
prescribed post-operative instructions and we hope that we've been able to demonstrate
a few points concerning the instrumentation involved in the removal of uninterrupted third
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