Impaction of 3rd Molars
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Transcript of Impaction of 3rd Molars
Oral surgery
Lecture 7
Done by: Bayan Mrayan
Impacted wisdoms
Today we are going to talk about impacted wisdoms, now what’s
the difference between impacted teeth and unerupted teeth?
,,every impacted tooth is unerupted tooth but not every
unerupted tooth is an impacted one, if we have a10 years old
child who doesn’t have the 6es and they are still in the jaw do we
call this case an impaction ? No, of course we call it unerupted
which might erupt or may not erupt, now an impacted teeth is
simply a tooth that has passed the time of eruption and it can’t
erupt any more .
Now what are the indications to take wisdoms out…..
In the past American dentists used to take the wisdoms out
whether the case indicates extraction or not, for personal gains
to take money from their patients, on the other hand British were
honest in dealing with their patients so they put specific
guidelines (medical indications to take wisdoms out).
There is a group of people called NICE Stands for National
institute for clinical excellence they are Belonging to the
Ministry of Health they are responsible for putting these
guidelines
The indications are ….
1. If there is evidence of pathology like a cyst or tumor
surrounding the wisdoms or any sort of
Pathology.
2. A tooth that is involved in osteomylitis (sclerosing
osteomylitis” Chronic focal sclerosing osteomyelitis is a
periapical lesion that involves reactive osteogenesis evoked
by chronic inflammation of the dental pulp. In most cases, this
lesion develops in the mandibular molar region in response to
a low-grade infection of the pulp that results from a deep
carious lesion. A case is presented in which incomplete tooth
fracture was the apparent cause of this type of periapical
pathosis.”
3. teeth are impeding surgery the patient has problems in
opening the mouth and the surgeon wants to move the
mandible, some time the presence of wisdoms prohibits the
movement of the jaw anteriorly or posteriorly in this case we
need to take the wisdoms out
4. Gum Infection (Pericoronitis) it’s an infection in the soft tissues
that surround partially erupted wisdom tooth When a wisdom
tooth is partially erupted, food and bacteria collect under the
gum causing a local infection. This may result in bad breath,
pain, swelling and trismus (inability to open the mouth fully).
The infection can spread to involve the cheek and neck. Once
the initial episode occurs, each subsequent attack becomes
more frequent and more severe. The patient come to you
complaining from swelling in his mouth this is what we called
MILD PERICORONITIS. After that the swelling gets bigger and
a limitation in mouth opening starts to appear this is what we
called MODERAT PERICORONITIS ,when there is severe
trismus and signs and symptoms of infection redness ,malaise
,pain that gradually increase till it reaches to its severe stage
This is called SEVERE PERICORONITIS ,now here the infection
starts to convert itself to an abscess which is problem because
this abscess can go through the spaces, like submassetric
space because this space is closed by both massetric and
buccinators muscles, it diffuse to the sulcus near 6or 7 which
we called migratory abscess of pericoronitis .Now how do we
manage this case ,if its mild we can just irrigate under the
operculum “it’s the soft tissue that covers partially erupted
tooth by using( hydrogen peroxide(extra information)),and
OHI, there is no need to give antibiotic because there is no
signs of systemic involvement ,in moderate and sever we
need to give antibiotic the eventual solution is extraction of
the tooth but according to NICE guideline pericoronitis is
considered as indication for extraction if it comes twice or
more than twice a year, but after the episode of pericoronitis
is resolved not immediately.
5. Caries, here we don’t treat wisdoms conservatively like other
teeth , extraction takes the priority here .
6. As a cause of periodontal disease to the adjacent tooth, when
the tooth is Lying on the adjacent tooth it can cause resorption
to the inter septal bone distally to the second molar
7. resorbtion to the 2nd molar due to horizontal positioning of 3rd
molar and eruption capacity when the root are still small .
8. Cyst and tumor like dentigerous cyst and odontogenic tumer
like Ameloblastoma this is dentigerous cyst ….
9. Prosthetic reasons, for example a patient needs a complete
denture but he has impacted teeth here there is two different
decision you can make either to extract it ,because with time
the ridge will resorbe and the tooth will reveal or you can
leave it and remove it later on.
10. orthodontic reasons :some orthodontist claim that third
molars can cause later lower anterior teeth crowding ,other
orthodontic reasons, is making space to push molars
posteriorly to make space for other teeth to move .
11. Socio economic reasons just to avoid any expected
complications that may impede their work or the patient social
life and business, the doctor Showed a picture of
ameloblastoma surrounding an impacted molar and pushing it
downward here is one picture ….
12.unexplained facial pain they found that some patient when
you examine their wisdoms you don’t find any indications for
extraction but they have pain ,when you take their wisdom out
they feel better this for small percent1-2% of people not always
right they may have TMG dysfunction syndrome that explain that
pain .
13. prevention of fracture usually wisdoms are found at the angle
of the mandible imagine that they are deeply impacted and
horizontal they will occupy most of the angle, if the patient was
beaten on his mandible the area occupied by the molar will
fracture because its weak those people advised to take wisdoms
out to lay down bone at the area of extraction
Now moving to the contra indication for extraction …
1. Extreme age, he may have medical problems ,his mandible
will be so thin so in those patient we have to weigh things
carefully in our mind before taking wisdom out .
2. medically compromised patient like systemic diseases or
bleeding problems ,local factor like radiotherapy, or a
patient who has a tumor, now if the operator is intending to
take the tumor out we remove the tooth that is involved in
that tumor , but in a case that the patient has a tumor in the
neck and the tumor is expanding to the mandible there is
no definitive management to this patient we Shouldn’t mess
with them as we may cause transferring of the tumor from
side to side .
3. potential damage to adjacent structure like if the tooth is
very close to vital structure like ID canal we may cause
parasthesia to the nerve ,if we extract it in the usual ways so
we do what’s we called decavitation to the tooth by
removing the crown and leaving the roots as not to cause
injury. or in the case of the upper were its closed to the
sinus or infratemporal space behind the maxilla, so we
don’t extract it ,we give antibiotic if its inflamed and we
treat it conservatively not to get benefit of it but rather not
to extract it .
Now moving to operative assessment related to patient it self
…..
First of all as we know we take history and what’s we called
general assessment, like the patient age and personality in
many cases of extraction the pain is not the main problem,
rather the stress is the main problem so if the patient from the
beginning is frightened his pain threshold will be very low, so
you as a surgeon has to decide whether to do it under
sedation with local anesthesia or under GA .so take into
account (personality and difficulty of the procedure).
Local assessment related to the tooth itself…..
1. Access to the tooth and make sure the width of mouth
opening is appropriate for such a procedure (rima oris
in Latin)…
Now PELL and GREGORY put a classification for wisdom
teeth it applies for upper and lower they made 2 types of
classes ,class1,2,3and class A,B,C, class A,B,C it applies
for upper and lower, class 1,2,3 it applies only for lower
wisdoms .Now lets explain each type of these classes…
CLASS1: the tooth is found completely anterior to the
anterior border of ramus of the mandible.
CLASS2: the tooth is found in the middle, part of it is found
anterior to the anterior border of the ramus and the other
part is posterior to the anterior border of the ramus .
CLASS3: The entire tooth is found posterior to the anterior
border of the ramus .And here is a picture for these
classes ….
.
1.
We will talk about class ABC later on….but you need to know that
class 1,2,3 is part of access assessment…
Lets talk about classification according to Winter based on the
inclination of the impacted wisdom tooth to the long axis of second
molar…..he created 3 lines (white line ,amber line, red line) they
are not that specific but you should know about them ….
White Line
The white line is drawn along the occlusal surfaces of the
erupted mandibular molars & extended over the 3rd molar
posteriorly. It indicates the difference in occlusal level of
the 1st & 2nd molars & the 3rd molar.
Amber Line
The amber line represents the (height of the) bone level.
The amber line is drawn from the surface of the bone on
the distal aspect of the 3rd molar (or from the ascending
ramus) to the crest of the inter-dental septum twixt the 1st
& 2nd molars. This line denotes the margin of the alveolar
bone covering the 3rd molar and gives some indication to
the amount of bone that will need to be removed for the
tooth to come out.
Red Line
The red line is an imaginary line drawn perpendicular from
the amber line to an imaginary point of application of an
elevator. Usually, this is the cemento-enamel junction on
the mesial aspect of the impacted tooth (unless, it is the
disto-angular impacted tooth where the application point
is the distal cemento-enamel junction). The red line
indicates the amount of bone that will have to be removed
before elevation of the tooth i.e. the depth of the tooth in
the jaw & the difficulty encountered in removing the tooth as
the red line become longer extraction become harder its not
that much applicable.
Now the classification for Winters are (mesio-angular,disto-
angular, horizontal, vertical) ,to differentiate between them..
we draw a line on the long axis of the next-door tooth the 7
and a line on the long axis of the 8 and we check the angle
between them.
If the lines are parallel its vertical look at the picture…..
If the long axis of third molar is horizontal the angle will
be 90 so it’s Horizontal…..
Disto-Angular. The long axis of the 3rd molar is angled
distally / posteriorly
awayfrom the 2nd molar.
Mesio-Angular. The impacted tooth is tilted toward the
2nd molar in a mesial direction….
2. Now the second assessment is according to the depth of the
tooth inside the bone……Now we apply Pell and Greogory
classA,B,C…
Class A. The occlusal plane of the impacted tooth is at the same level as
the
occlusal plane of the 2nd molar. (The highest portion of impacted 3rd
molar is on a level with or above the occlusal plane).
Class B. The occlusal plane of the impacted tooth is between the occlusal
plane
& the cervical margin of the 2nd molar. (The highest portion of impacted
3rd
molar is below the occlusal plane but above the cervical line of the 2nd
molar).
Class C. The impacted tooth is below the cervical margin of the 2nd
molar. (The
highest portion of impacted 3rd molar is below the cervical line of the of
2nd
molar). Note that it’s only the depth that is changing not the distance from
the anterior border of the ramus as in Class1,2,3
Now what’s about obliquity…in general in.most of the
cases third molar positioned lingual to the rest of the
teeth….
Buccal / Lingual Obliquity. In combination with the above,
the tooth can be
buccally (tilted towards the cheek) or lingually (tilted
towards the tongue)
impacted.we call it bucco or linguo-version tooth, look at
the pictures below…
3. You have also to asses number and shape of the roots
….
If we have a tooth with one root and its conical in shape
we expect that the extraction is easy..
If we have a tooth with 3 roots and they are erratic we
expect the extraction to be difficult…here we think of
surgical extraction, we open a flap ….
Another thing to consider is the point of application when
the tooth is mesioangular the POA is mesial and when its
distoangular the POA is distal….. All of these we could
specify them by the proper assessment of the tooth and X-
rays…
Some time the problem is not the third molar it self but the
problem is with the next-door tooth, so we afraid that there
will be some sort of trauma to the next -door tooth so if you
have amesioangular third molar adjacent to an overfilled 7
you may cause fracture to the filling or even the tooth it
self so its better to do surgical extraction in this case so
always check third molar and next door tooth .if you have
a third molar with a big crown and small root you may
think its easy to remove it ,you are wrong its so difficult to
extract it in non –surgical procedure. And it will be more
difficult to have a ball in socket when the tooth is not fully
formed a follicle surrounds the crown so the tooth starts to
rotate in its place when you try to remove it …
4. Assess shape of the root…
If we have a second molar with a conical shape root and
we put the elevator between 7and 8 to extract the 8 we will
definitely extract the 7 because it will be easy to remove it
due to the shape of it’s’ root
5. Assess bone texture for older people bone is much harder
than younger age groups who have resilient bone
texture…in sclerotic bone its more difficult to take teeth
out. .
6. Assess the tram line (skeet al7adeed) when you look at the
x-ray you will find 2 lines for ID canal if they are away from
the tooth we are in the safe side ,extraction will not affect
the nerve .
There is a study done in 1990 by Roods an Shehap in which
they brought patients with wisdom teeth and they took X-rays
for them, they started looking at the teeth in relation to the ID
they found different situations….
if there is radiolucecy on the root of the wisdom (at the
apical third)
if the ID canal is derooted as it change its direction .
if one of the tram line at the region of the root of third
molar disappeared either at the upper or the lower .
if the root are straight and suddenly you notice
deflection at the ID canal region .
if the roots of the molar start as normal in shape when
they arrive to the ID canal region they either appear
constricted or flared .
If any of these cases is noted the possibility of having
numbness after extraction is higher..
One of the students asked about the diameter of ID canal
I think?
The doctor answered that he doesn’t have a specific
number but its not less than 4mm.
Now lets talk about some definitions related to this study
….perforation, grooving,notching,
Notching: the tooth has one root but it has a notch or a
small opening at the end (apical third) this is where the
ID canal enters and passes the tooth.
Perforation: during the growth of teeth, part of it will
grow above the canal and the other part under the canal
it seems perforated …. Its unlikely to see such cases, its
used for academic reasons mainly, what I want you to
know that if we have such these appearances or cases we
think of surgical extraction, because when you do simple
extraction you may do sectioning for the tooth in small
pieces, always think before doing any thing … I really
tried hard looking for more obvious definitions of these
terms, this is what I found according to radiographic
appearance …
1- Notching: Radiolucent band at the apex of the roots, a break in the
continuity of the upper radio dense border, and narrowing at the expense
of the top of the canal.
2- Grooving: Radiolucent band across the root above the apex, interruption
of both superior and inferior borders of the canal and narrowing of the
canal space.
3-. Perforation: Radiolucent band crossing the root above the apex with
loss of both superior and inferior borders of the canal at the area where
they cross the roots and constriction of the canal maximal in the middle of
the root. This is perforation …..
.
( Notching, grooving and perforation were regrouped as
true relation)
Let’s talk about different terms of sensation …..
Parasthesia of the lip and tongue
Anesthesia full loss of sensation
Hypoesthesia reduction in sensation still feel
sensation
Paresthesia is abnormal sensation there is
something going wrong in sensation It is more generally
known as the feeling of "pins and needles
Dysesthesia : unpleasant sensation they feel like electric shock after surgical procedure abnormal
sense of touch
Hyperalgesia increase response to stimulus which
may be caused by damage
to nociceptors or peripheral nerves
There is a third sensation I couldn’t here it but it
means that the patient feel pain spontaneously in
the lips even without touching them,
The doctor showed a picture about Roods
classification this is what I found….
. A, darkening of apex;
B, reflexion of apex; C, narrowing of apices; D, bifid apices on
canal; E, deviation of canal; F
narrowing of canal; G island-shaped apex.
We can take wisdoms in three ways or under three
sources of anesthesia
Local anesthesia
Local with sedation (nitrous oxide for children not as
useful for the adult , midazolam,or we can ask the
patient to take diazepame orally 5 mg the day before
the surgery ,midazolam is more effective and have
immediate action .the way we use, is determined by
the patient personality and cooperation .
But the question is why do we use local anesthesia for
a patient to be treated under GA?
For vasoconstriction and for Pre-emptive analgesia to
anesthetize C-fibers which are responsible for pain
transduction, so the patient will feel lesser pain after he
wakes up …
The end of part 1
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Done by: Bayan Mrayan
Sorry for any mistake
سل المعالَي عنا إننا َعَرٌب *********شعاُرنا: المجُد يهوانا ونهواه هي العروبة لفظ إن نطقت به *********فالشرق، والضاد، واإلسالم معناه