Impaction BY DR. SHIVARAJ W

1. IMPACTION
Prof.Dr.Shivaraj.S.Wagdargi
Dept. of Oral and Maxillofacial Surgery

2. Contents:
1. Definition
2. Theories and mechanisms of tooth impaction
3. Classification - indications – contraindications
4. Anatomical landmarks
5. Assessment of Impacted teeth
6. Partly erupted and unerupted mandibular third molar
7. Flap designs
8. Lingual split bone technique
9. Operative procedure
10. Surgical management
11. Complications

3. INTRODUCTION
ORIGIN – LATIN– IMPACTUS.
Impactus: Cessation of eruption caused by physical barrier / ectopic eruption.
An impacted tooth is partially erupted or unerupted tooth and is positioned
against another tooth , bone or soft tissue so that its further eruption is unlikely
and will not eventually assume a normal arch relationship with the other teeth or
tissues

4. DEFINITION
1. IMPACTED TOOTH :
According to ROUNDS (1936) :
Impacted tooth is one which is embedded in the alveolus so that its further eruption is prevented
According to ARCHER(1975)-
It is a tooth which is completely or partially unerupted and is positioned against another tooth, bone
or soft tissue so that its further eruption is unlikely, described according to its anatomic position.
According to LYTTE (1979) :
Impacted tooth is one that has failed to erupt into normal functional position beyond the time usually
expected for such appearance . Eruption is prevented by adjacent hard/ soft including tooth bone or
dense soft tissue
According to ANDERSON ( 1997) :
Impaction is cessation of tooth caused by a clinically or radiographically detectable physical barrier in
the eruption path or by an ectopic position of tooth

5. 2. MALPOSED TOOTH :
It is a tooth, unerupted /erupted which is in abnormal position in the maxilla/ mandible
3. UNERUPTED TOOTH :
It is a tooth not having perforated the mucosa.
4. ODONTECTOMY:
It is the term used for the removal of partly erupted or unerupted teeth or retained
roots that cannot be extracted by forceps technique and therefore must be removed by
surgical excision .

6. Theories & mechanisms of tooth impaction -
Durbeck
1) Orthodontic theory : Jaws develop in downward and
forward direction. Growth of the jaw and
movement teeth occurs in forward direction,so any thing
that interfere with such moment will cause an impaction
(small jaw-decreased space).
A dense bone decreases the movement of the teeth in
forward direction.
2) Phylogenic theory: Nature tries to eliminate the
disused organs by causing slow regression of organ.
Due to changing nutritional habits of our civilization, use of
large powerful jaws have been practically eliminated.
Thus, over centuries the mandible and maxilla decreased
in size leaving insufficient room for third molars.

7. 3) Mendelian theory: Heredity is most
common cause. The hereditary transmission
of small jaws and large teeth from parents to
siblings may be important etiological factor
in the occurrence of impaction.
4) Pathological theory: Chronic infections
affecting an individual may bring the
condensation of osseous tissue further
preventing the growth and development of
the jaws.
5) Endocrinal theory: Increase or decrease
in growth hormone secretion, may affect the
size of the jaws

8. THE MOST COMMONLY IMPACTED OR UNERUPTED TEETH ARE :-
MAND. & MAX. THIRD MOLARS AND MAX. CANINES
Impacted teeth seen in the following order of frequency
(According to ARCHER )
1. Maxillary 3rd molar
2. Mandibular 3rd molar
3. Maxillary bicuspid
4. Mandibular bicuspid
5. Mandibular cuspid
6. Maxillary cuspid
7. Maxillary central incisors
8. Maxillary lateral incisors

9. PARTLY ERUPTED AND UNERUPTED
MANDIBULAR THIRD MOLAR

10. CLASSIFICATION – Impacted third molars are classified according
to the position of their long axis of the 2ndMolar
1.Long axis of the impacted tooth in relation to the long axis of
the 2nd molar angulation
Winter’s classification(1926):
Based on angulation:
1. VERTICAL- 38%
2. MESIOANGULAR- 43%
3. HORIZONTAL – 3%
4. DISTOANGULAR – 6%

11. These may occur simultaneously in:
1. BUCCOANGULAR
2. LINGUOANGULAR
3. INVERTED
4. TORSOVERSION

12. 1. Third molars with negative angles (_0°) were considered to be inverted
2. Third molars with an angle between 0° to 30° were considered to be horizontal
3. Third molars with an angle between 31° to 60° were considered to be mesioangular
4. Third molars with an angle between 61° to 90° were considered to be vertical
5. Third molars with an angle _90° were considered to be distoangular.
WINTER’S SUB CLASSES
The angle between the occlusal plane or line parallel to it and the longitudinal
axis of the impacted third molar, in turn, allowed objective classification of the
third molars within the Winter subclasses as follows:

13. 2.Pell & Gregory(1933), which includes portion of George B
Winter’s classification(1926):
A. Anterior – Posterior anatomical space – acc. to the anteropost space
between 2nd molar & ant. border of ramus .
-
CLASS-I : Enough space
to accommodate the
eruption of a mand 3rd
molar.
CLASS-II : Partial lack
of space
CLASS-III: complete lack of
space because the ramus
arises directly posterior to
2nd molar

14. B. RELATIVE DEPTH OF THE 3RD MOLAR IN THE BONE – the degree of
difficulty increases as the depth of the tooth in the bone increases
POSITION A: the highest
portion of the tooth is on the a
level with/ above occlusal line POSITION B : the highest
portion of the tooth is below
occlusal plane but above the
cervical line of the 2nd molar
POSITION C: the highest
portion of the tooth is below
the cervical line of the 2nd
molar teeth

15. 3. MEDIAL- LATERAL POSITION OF THE 3RD MOLAR
- The position of the 3rd molar in relation to the 2nd molar to the buccal
aspect ( directly behind the second molar) or to the lingual aspect (palatal
in the maxilla) of the 2nd molar
4.ACCORDING TO THE NATURE OF OVERLYING TISSUE :
1. Soft tissue impaction
2. Partially bony impaction
3. Fully bony impaction

16. 5.SUPERIOR – INFERIOR POSITION OF THE 3RD MOLAR : the position of
3rd molar in the depth of skeleton of the mandible or maxilla in relationship
to 2nd molar
CROWN-to-CROWN
relationship
CROWN-to-CERVIX
relationship
CROWN-to-ROOT
relationship

17. KILLEY & KAY CLASSIFICATION
BASED ON ANGULATION AND POSITION-
same as Winters classification
BASED ON THE STATE OF ERUPTION-
1. Completely erupted
2. Partially erupted
3. Unerupted
BASED ON ROOTS
1. No of roots – fused, two roots and multiple roots
2. Root pattern – Surgically favourable and surgically unfavourable.

18. INDICATIONS FOR THERAPEUTIC REMOVAL OF IMPACTED
MAND. 3RD MOLAR
 Peterson advocated that ,’ The ideal time for removal of impacted 3rd molar is after the
roots of the teeth are 1/3rd formed and before they are 2/3rd formed.’
 Peterson considered the indication for removal of impacted teeth to be to:
1. Periodontal diseases
2. Dental caries
3. Pericoronitis
4. Root resorption
5. Odontogenic cysts and tumors
6. Pain of unexplained origin
7. Fracture of mandible
8. To facilitate orthodontic treatment.

19. ANATOMICAL LANDMARKS

20. THE MANDIBLE
In many instances the lingual bone consists of a thin
cortical plate less than 1 mm in thickness.
Extraction can be facilitated by removal of this thin lingual
cortical plate.
This principle is employed in the lingual split bone
technique

21. INFERIOR ALVEOLAR NERVE & VESSELS
 The greatest surgical anatomical concern arises if the canal overlaps with
an impacted third molar.
 Usually, the canal will be inferior to and / or buccal to the impacted
mandibular third molars.
 Howe & Poyton & Pogrel described the probable characterization of the
radiographic image of the relationship of an impacted 3rd molar to the
inferior alveolar canal
1. The canal maybe at the same level as the 3rd molar but not in contact
2. At the area of overlap, the canal will appear without change of
dimension
3. If the tooth and the canal are in contact, the margins of the canal will
appear crisp but changed in dimension
4. If the neurovascular structures pass through or between the roots, the
canal will not be distinct
There maybe a radiolucency denoting a distortion of the roots due to the
presence of canal.
Distinct lines of
the canal and of
the roots
indicate an
overlaywithout
encroachment
Narrowing of
the canal
indicates
displacement of
the canal by
roots of the tooth
A blending of
the structures
indicates that
the roots
surround the
canal and its
contents

22. Retromolar Triangle
Behind the
third molar is a
depressed
roughened
area which is
bounded by
the lingual and
buccal crests
of alveolar
ridge; the
retromolar
triangle
Either in the
mandibular
triangle or fossa,
the mandibular
vessel branch
supplies the
temporalis
tendon,
buccinator
muscle and
adjacent
alveolus.
Although these
are small
vessels, a brisk
hemorrhage
can occur during
the surgical
exposure of the
third molar
region if the
distal incision
is carried up the
ramus and not
taken laterally
towards the
cheek

23. LINGUAL NERVE
 The lingual nerve maybe hidden
beneath or in the mucosa lateral to the
location of the mandibular 3rd molar
near the crest in an abnormal, superior
position.
 According to KISSELBACH &
CHAMBERLAIN
‘ The lingual nerve maybe located at
and sometimes slightly superior to
the crest of the bony ridge medial to
the mandibular 3rd molar region and
only 1-2mm towards the midline in
the lingual soft tissue.’

24. On an average the lingual nerve is found about
0.6 mm medial to the mandible and about 2.3 mm
below the alveolar crest in the frontal plane.

25. Based on studies by Pogrel(1995) Holzle(2001),
Behnia(2000)and Keisselbach(1984) on cadavers it
can be concluded that:
(1) the lingual nerve was observed at or above the
crest of the lingual plate in 4.6 to 17.6% of the
cases
(2) the direct contact of the lingual nerve with the
lingual plate in the retromolar region was observed
in 22.3 to 62% of the cases
(3) the horizontal distance from the lingual nerve to
the lingual plate ranged from 0 to 7 mm
(4) vertical distance from the lingual nerve to the
crest of the lingual plate ranged from 2 mm above
the crest to 14 mm below it.

26. Mylohyoid Nerve
 This nerve leaves the inferior alveolar
nerve just before the it enters the
mandibular foramen. It then penetrates
the spheno-mandibular ligament and
proceeds close to the mandible in the
mylohyoid groove.
 The nerve may be damaged during lingual
approach for the removal of impacted
mandibular third molar

27. PRE-OPERATIVE RECOGNITION OF FACTORS COMPLICATING THE
OPERATIVE PROCEDURE
1.The state of eruption or level of the tooth
- Tissue impaction
- Bony impaction
2. The angulation and position of the tooth
3. Relationship of the 2nd molar to ascertain whether
the tooth is locked below the crown of 2nd molar
4. Distance between the ascending ramus and
distal surface of the 2nd molar should be determined

28. 5. Appearance of roots- number, shape and
size
6. Condition of the tooth
7. The bone along the mesial surface of the
tooth infected or destroyed and
necessitates extraction of 2nd molar
8. Size of the follicular space  narrower
the space, more difficult the procedure will be
9. Presence of cyst

29. RADIOLOGICAL INTERPRETATION
Assessment of lower third molar
• Angulation
• The crown
• The roots
• Relationship of apices with inf alveolar canal
• Depth of tooth in alveolar bone
• Buccal / lingual obliquity
• - Crown sharp&well defined- lingual obliquity
• - Root apices sharp&well defined – buccal
obliquity
Assessment of lower second molar
Assessment of surrounding bone
ROOT PATTERN

30. RELATIONSHIP of ROOT to CANAL

31. In 1999, Rood and Shehab , in a literature review,
collected seven radiographic indicators of a close
relationship between the Lower Third Molar and the
inferior alveolar canal. (by HOWE and POYTON
1960)
Four signs were observed in the tooth
1. root darkening
2. deflection
3. narrowing of the root
4. bifid root apex
Three in the canal
5. diversion
6. narrowing
7. interruption in the white line of the canal

32. RELATIONSHIP OF INFERIOR ALVEOLAR NERVE TO THE ROOTS OF THE THIRD
MOLAR.
Darkening of root Deflection of root Narrowing of root Dark & Bifid apex
Roots impinge on
canal. Density of
roots - altered
Close proximity to
root / tooth
Division - bucally,
lingually or both
Deep grooving or
perforation of root
into the IAC
Double periodontal
membrane shadow

33. Interruption of white Narrowing of canal Diversion of canal
line of canal
Deep grooving of root
/tooth in the canal
Displacement of root and
canal towards each other.
Hue glass appearance
Close proximity to
root / tooth

34. WINTER’S LINES OR WAR LINES.
Position and depth of impacted tooth:
This is determined by a method described by
George Winter. In this technique three
imaginary lines are drawn on the radiograph.

35. Difficulty Index for removal of impacted mand third
molars - Pedersen 1988
CLASSIFICATION DIFFICULTY INDEX
VALUE
 ANGULATION
 Mesioangular 1
 Horizontal / transverse 2
 Vertical 3
 Distoangular 4
 DEPTH
 Level A 1
 Level B 2
 Level C 3
 RAMUS RELATIONSHIP / SPACE AVAILABLE
 Class I 1
 Class II 2
 Class III 3
Difficulty index
Very difficult : 7 to 10
Moderately difficult : 5 to 7
Minimally difficult : 3 to 4

36. WHARFE’S ASSESSMENT
1. Winter's classification
Horizontal 2
Distoangular 2
Mesioangular 1
Vertical 0
2. Height of mandible
1-30mm 0
31-34mm 1
35-39mm 2
3.Angulation of 3rd molar
1- 59° 0
60 -69° 1
70 -79° 2
80 -89° 3
90° & above 4
4. Root shape- Root development
Favourable curve 1
Unfavourable curve
( less than 1/3 complete) 2
Complex
( more than 2/3 complete) 3

37. 5.Follicle
Normal 0
Possibly enlarged 1
Enlarged 2
6. Path of exit
Space available 0
Distal cusp covered 1
Mesial cusp covered 2
Both covered 3
TOTAL SCORE 33

38. SURGICAL MANAGEMENT - Steps in surgical removal:
John Tomes 1849 – First to describe surgical access
Anesthesia Incision and
mucoperiosteal
flap
Removal of bone Tooth removal Wound
debridement
Arrest of
haemorrhage
Wound closure Postoperative
follow-up

39. DIFFERENT TYPES OF INCISIONS
WARD’s
INCISION
FLAP
ENVELOPE
FLAP
L-SHAPED
FLAP
BAYONET
FLAP
TRIANGULAR
FLAP

40. BONE REMOVAL

41. BONE REMOVAL
BUR TECHNIQUE
(a)Postage stamp technique
(b)Moore and Gillby’s guttering technique
(c)Bowdler Henry’s Lateral trephination(1969)-for
germectomy, partialy formed and unerupted third
molar(9-18 years age)
CHIESELAND MALLET
(a) through Buccal approach
(b) Lingual split technique

42. LINGUAL SPLIT TECHNIQUE – KELSEY FRY-
Modified Distolingual Splitting Technique
The lingual split – bone technique for the removal
of impacted 3rd molars was originally proposed by
Fry and originally described by Ward in 1956
Application – removal of deeply positioned horizontal and
distoangular impactions provided that they are not in
buccoversion .
This technique involves splitting the lingual cortex and elevating the tooth in
distolingual direction.

43. Surgical steps
1. Incision  starting in the buccal sulcus
and extended upwards to the distal
aspect of the 2nd molar
2. Incision courses backwards behind
2nd molar distobuccally over the
external oblique ridge
3. Flap elevation is done bucally and
lingually
4. A vertical stop 5mm in height made
with chisel in the buccal cortex distal to
2nd molar
5. A second vertical stop about 4mm
distobuccal to 3rd molar crown join
the two cuts  buccal plate covering
crown is removed.

44. 5. When completed, the rectangular window
should permit insertion of elevator
6. Then, chisel is inserted on the inside of the
lingual plate at the 45° to the upper border
with its cutting edge parallel to the external
oblique line and bevel facing lingually.
7. Few light taps using mallet – separate the
lingual plate from the alveolar bone making it
to hinge on the lingual soft tissues
8. Bone which remains distally between the
lingual and buccal cut is removed

45. 9. Removal of the impacted teeth by
application of an elevator from the buccal
aspect
10. Wound debridement smoothening of
the lingual plate
11. Mucoperisteal flap returned to its
position and fixed with a single suture
placed distal to 2nd molar

46. Complications of Impaction Surgery
Complications may occur:
A. During the surgical procedure
B. Immediate postoperative period
C. Late postoperative period

47. Complications during the Surgical procedure:
These are a found to occur during each major step of
the surgical procedure
1. Incision
2. Bone removal
3. Tooth sectioning
4. Elevation of the tooth

48. Accidental burns:
An improperly
maintained hand
piece with a
damaged bearing
can get heated up
during usage.
Laceration of soft
tissues: During use
the bur may slip and
get driven into the
buccal or lingual soft
tissue .
The micromotor has
stopped completely
before these acts
Injury to inferior
alveolar neurovascular
bundle:
While 'guttering' bone on the
buccal side of the impacted
tooth, as the bur reaches
the apex of the tooth, the
mandibular canal may be
inadvertently opened. This
will result in brisk
hemorrhage from inferior
alveolar vessels
MANAGEMENT- can
be controlled with
pressure pack or bone
wax.

49. Complications during sectioning of tooth- BUR
1. Incorrect line of sectioning of crown:
The ideal site for sectioning of the crown is the cervical
portion of tooth i.e. apical to the cemento -enamel junction
with bur held at right angles to the long axis of the tooth.
If the bur cut is not correctly angulated or bur cut is done at
different sites, it will be difficult to separate the crown and
remove it.

50. 2.Injury to mandibular canal:
 If the bur is carried to the full width of the tooth in the
superior inferior direction – damage to the canal - severe
bleeding & numbness of the lower lip.
 MANAGEMENT: The entry of the bur is limited to three-
fourths of the width of the tooth. The rest of the tooth is
separated using an elevator.
3. Breakage of bur: This can occur either due to
the application of a heavy pressure or due to the
repeated use of the same bur.
Used burs should be discarded and a fresh bur used
in each case.
Binding of the bur in the tooth structure is another
reason for fracture.

51. 3.Complications during elevation of tooth
1. Fracture of impacted tooth/ root
2. Injury to second molar
3. Fracture of mandible:
Fracture is caused by the application of
excessive tensile or shear forces across
the superior border of the mandible in the
third molar area
Management: Removal of the remaining
portion of the impacted tooth followed by
fixation of fracture by eyelet wiring and
maxillary mandibular fixation or bone
plating or other methods of fixation

52. (A) While elevating the tooth; as the crown
moves upwards, the roots may be forced
downwards with the apices piercing
the mandibular canal
Injury to mandibular canal:
While elevating the tooth as the crown moves
upwards, the roots may be forced downwards
with the apices piercing the mandibular canal and
injuring the neurovascular bundle.
This happens more commonly in cases of
mesioangular and horizontal impactions.
Injury to vessels can result in brisk hemorrhage.

53. Post Surgical Sequelae and Complications
Hemorrhage
REACTIONARY HEMORRHAGE- Physical
exertion or raise in blood pressure or due to any
of the local or systemic causes post operative
bleeding can occur
SECONDARY HEMORRHAGE- seen after a
week of the procedure

54. 2. Edema
Postoperative swelling usually subsides rapidly in
two or three days
MANAGEMENT :
- Parenteral administration of corticosteroids
• Administration of dexamethasone prior to third molar removal have profound effect on
the speed of recovery of the patient.
• Ice pack applied intermittently for the first 24 hours and reduces the pain
• Pressure bandages also have a role in minimizing the edema.
• The swelling usually reaches its maximum by the end of the second postoperative day
and is usually resolved in a week's time

55. 3.Trismus:
Mild difficulty in opening the mouth is also an expected sequelae of
third molar surgery
When severe trismus occur the possibility of hematoma formation,
excessive stripping of muscle and infection especially in the
submasseteric space should be considered
TREATMENT: If this happens, active jaw exercise, hot
fomentation, short wave diathermy and massage have to be
considered

56. 4. Pain
The post surgical pain begins when the effect of the local anesthesia subsides and reaches
its maximum intensity during the first 4 to 8 hours
There is a strong correlation between postoperative pain and trismus, indicating that pain
may be one of the principle reasons for limitation of mouth opening after the removal of
impacted third molars
Usually, postoperative pain lasts up to the third post operative day. Should it persist after
that period, patients should be recalled for evaluation

57. 5. Infection
 Infection after third molar surgery have been reported to vary from 0.8 to 4.2%.
 It may develop either in the early or in the late postoperative period.
 Mandibular sites are more commonly affected.
Nearly half of the infections are the
localized subperiosteal abscess
which occurs 2-4 weeks post-op
This usually happens due to debris
left under the mucoperiosteal flap.
MANAGEMENT: It is treated by
surgical drainage and antibiotic
therapy.

58. 6. Alveolar osteitis (Dry socket):
• Alveolar osteitis is inflammation of the alveolar bone. Occurs
where the blood clot fails to form or is lost from the socket.
• This leaves an empty socket where bone is exposed to the oral
cavity, causing a localized alveolar osteitis limited to the lamina
dura
• Is associated with increased pain and delayed healing time
• Oral prophylaxis and controlling gingival inflammation before
surgery. Lavaging the surgical site with warm normal saline and
placing in the alveolous a 1cm wide ,2-3 cm long iodoform
gauze soaked in a medication containing eugenol. The
dressing should be changed every 3-4 days as needed.
• Prophylactic administration of metronidazole in adose of 200 mg
eighth hourly starting on the day of the procedure and continued
for three days.

59.  Surgical removal of mandibular third molar may cause injury of the lingual and
inferior alveolar nerve resulting in anesthesia or paresthesia.
CAUSES :
1. It may be the result of instrument slippage (e.g. scalpel),
2. Cutting too deeply with a bur (e.g. while sectioning a tooth),
3. Over-zealous retraction (e.g. of a lingual or buccal flap),
4. Pushing root tips into a canal or foramen
5. Mechanically damaging the canal contents with an instrument
7. Nerve Injury

60. Injury to the inferior alveolar nerve
IAN injury is caused by injudicious
instrumentation or elevation
Elevator should not be forced beneath the
tooth if it lies close to the mandibular canal
Any force that will crush the bony walls of the
mandibular canal can cause compression of the
nerve
The IAN maybe partly or completely torn during odontectomy
because the roots of the 3rd molars have completely
surrounded it In such , if recognised preoperatively, the
nerve should be freed by resecting one root before
attempting elevation of the tooth.

61. If the nerve is torn or divided,
repositioning in the
mandibular canal can be made
so that the ends are closely
approximated
(as long as the nerve lies in the
mandibular canal being
unobstructed , there is good
chance for regeneration and
repair)
In favourable cases, nerve
regeneration will take place in
5 weeks to 6 months.
But after 6months, it is unlikely
that the condition will improve if
partial return of sensation has
not already taken place

62. Injury to lingual nerve :
Causes:
a. Poor flap design
b. Uncontrolled instrumentation
c. Fracture of the lingual plate
d. Stretching and compression of the nerve while retracting the lingual flap
e. Trauma to nerve as a result of local anesthetic injection penetration through or into the nerve
by the injection needle.

63. CONCLUSION
Surgery for removal of impacted third molar surgeries may be
associated with several postoperative complications; these
complications are best prevented.
However, the surgeon should be prepared to manage them
should they occur.
All third molars need not be removed independent of disease
findings and patients need not unnecessarily have to accept
adverse consequences associated with the surgery risks and
discomforts in the absence of pain, radiographic findings of
pathology, and or marked clinical evidence of disease

64. REFERENCES
1. IMPACTED TEETH
- Charles C.Alling
2. TEXTBOOF OF ORAL AND MAXILLOFACIAL SURGERY VOL.2
-Daniel M.Laskin
3. TEXTBOOK OF ORAL AND MAXILLOFACIAL SURGERY
- Peterson Vol.1
4. TEXTBOOK OF ORAL AND MAXILLOFACIAL SUREGRY
- SM Balaji
5. A PRACTICAL GUIDE TO THE MANAGEMENT OF IMPACTED TEETH
- K.George Varghese