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1. Impaction of
3rd molars
By ,
Aswanth.E.P

2. Contents
Definition
Etiology
Indications
Cntraindications
Classifications
Clinical examination
Radiographical analysis
Preoperative evaluation of difficulty of
removal of impacted teeth
Other methodrs
Conclusion
Reference

3. Introduction
 Tooth can be impacted due to various reasons
 3rd molar is commonly imapacted in adults
 Proper diagnosis is important in management of impacted teeth.
 There are many surgical techniques available to manage impacted
tooth.

4. Definition
‘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’
-Archer

5. Etiology of impaction
a) local causes of impaction
1. Irregularity in the position and pressure of an
adjacent tooth.
2. The density of the overlying or surrounding bone.
3. Long continued chronic inflammation with resultant
increase in density of the overlying mucous membrane.
4. Lack of space due to under developed jaws.
5. Unduly long retention of the primary tooth.
6. Premature loss of primary tooth.
7. Acquired diseases such as necrosis due to infection
or abscess

6. b) systemic causes of impaction :
1)Prenatal causes: Hereditary
2)Post natal causes: Rickets, anemia, congenital
syphilis
3)Rare conditions: Cleidocranial dysostosis, cleft
palate.

7. Theories of impaction
1.Discrepancy between the arch length and the tooth size.
2. Differential growth of the mesial and distal roots.
3. Retarded maturation of the third molar—dental development of the
tooth lags behind the skeletal growth and maturation.
4. Incidence of extraction of permanent molars is reduced in the mixed
dentition period, thus providing less room for eruption of third molars.
This is very relevant in the present day due to increased awareness of the
population and dental treatment started early in childhood.
5. Evolution theory.
6. Lack of development of jaw bones due to consumption of more refined
food which causes lack of functional stimulation to the growth of jaw
bone.

8. indications for removal of impacted tooth
1)Pericoronitis and Pericoronal abscess
2) Dental Caries –to preserve other
molars from caries
3) Periodontal diseases
4) Orthodontic reasons:
a) Crowding of incisors
b) To facilitate orthodontic
treatment
5) To facilitate orthognathic surgery
6) Odontogenic cysts and tumors

9. Contraindications
1)Extreme of age
2)Compramised medical status
3)Probable excessive damage to adjacent structures
4)Recently irradiated jaw
5)Tooth in tumour
Absolute contraindications:
1)Acute pericoronitis
2)Acute necrotizing ulcerative gingivitis
3)Haemophilia
4)Thyrotoxicosis

10. Classifications
1)According to angulation of the impacted tooth by winter
a)Mesioangular
b)Distoangular
c)Vertical
d)Horizontal
e)Buccoangular
f)Linguoangular
g)Inverted

11. 2)According to relationship of the impacted tooth to the anterior border of the ramus
(Pell and Gregory Classification )
Class I: Sufficient space available anterior
to the anterior border of ramus for the third
molar to erupt.
Class II: Space available is less than the
mesio distal width of the crown of the third
molar
Class III: All or most of the third molar is
located within the ramus.

12. 3)Acording to relationship to occlusal plane
(Pell and Gregory Classification)
Position A: The highest portion of the tooth
(occlusal plane) is on a level with or above the
occlusal line.
Position B: The highest portion of the tooth is
below the occlusal line but above the cervical
line of second molar.
Position C: The highest portion of the tooth is
below the cervical line of second molar.

13. Pell and Gregory Classification - summery

14. 4)According to type of tissue overlying the tooth
a)soft tissue
a)partial bony
a)complete bony impaction
5)According to state of eruption
a)Erupted
b)Partially erupted
c)Unerupted

15. WHARFE assessment
 To asses the difficulty of impaction procedure
 6 Factors involved are :
1)Winters classification
2)Height of mandible
3)Angulation of 2nd molar
4)Root shape and morphology
5)Follicle development
6)Path of exit of tooth during removal

16. Total score - 33

17. Clinical Examination
This include :
(1)History taking
(2) Extra oral examination
(3) Intraoral examination
1)History taking :
 Complaints of the patient
 Medical and dental history
Significance of Medical Evaluation
 Additional investigations: Clotting time for those with history of bleeding.
 Alteration of patient's current medication to facilitate surgery : Stopping warfarin
preoperatively
 Selection of medication : Avoid penicillin in those who reported with history of allergy
to it..

18. 2)Extraoral Examination
 Face and neck is examined for signs of swelling or redness of the cheek
suggestive of infection.
 Regional lymph nodes are palpated for enlargement and tenderness.
3)Intraoral Examination
 Mouth opening - In retrognathic mandible accessibility to third molar area is
restricted, while in prognathic mandible accessibility is better
 General examination of oral cavity & 3rd molar area - Oral mucosa, teeth, oral
hygiene.
 Condition of impacted tooth - Carious or with fillings, internal resorption,
angulation of tooth, locking of crown of third molar beneath second molar.
 Amount of space available between the distal surface of second molar and the
ascending ramus
 Fracture may complicate the removal of an impacted third molar.

19. Radiography of Impacted Third Molar
1)Periapical radiograph

20. 2)Occlusal x-ray
 Helps in viewing buccal / lingual
version of impacted tooth
3)Lateral oblique view of mandible :
To provide additional information like vertical height of mandible in the
area, amount of bone beneath deeply buried impacted tooth

21. 4)Orthopantomogram
 OPG is considered the gold standard for surveying the maxilla and
mandible for diseases and other pathological conditions in the lateral
plane.

22. Interpretation of Periapical X-ray
a. Access
b.Position and depth of impacted tooth
c.Root pattern of impacted tooth
d.Shape of crown
e.Texture of investing bone
f. Relation to inferior alveolar canal
g.Position and root pattern of second
molar.
Factors include :

23. a)Access :
 By noting the inclination of the radioopaque line cast by the external
oblique ridge the ease of access can be determined. If this line is
vertical the access is poor and if horizontal, access is good.

24. b)Position of impacted tooth :
 determined by a method described by George Winter
 three imaginary lines are drawn on the radiograph, described as WAR
lines / Winter’s lines which include
White line
Amber line
Red line
1)White line :
 Drawn along the occlusal surface of the erupted mandibular molars and
extended posteriorly over the third molar region.
 From this the axial inclination or position of impacted tooth can be
assessed
 Eg : parallel to the occlusal surface of a vertically impacted tooth

25. 2)Amber line
 Drawn from the surface of the bone lying distal to the third molar to the
crest of the interdental septum between the first and second molar.
 Indicates the margin of the alveolar bone enclosing the tooth.
3)Red line
 It is a perpendicular dropped from the 'amber' line to an imaginary 'point
of application' of an elevator
 With the exception of disto-angular impaction, the CEJ on the mesial
surface of the impacted tooth is used for this purpose(in disto angular,
cemento-enamel junction on the distal side of the impacted tooth used to
draw red line)
 Used to measure the depth at which the impacted tooth lies within the
mandible

28. c)Root pattern of impacted tooth
 Number, shape and curvature
of roots are noted.
 Limited root development
leads to a "rolling" tooth,
which can be difficult to
remove.
 Roots with severe curvature,
however, are more difficult to
remove than less curved or
straight roots

29. d)Shape of crown
 Teeth with large square crowns and prominent cusps are more difficult
to remove than teeth with small crowns and flat cusps.
 size and shape of the crown of third molar acquire importance when the
'line of withdrawal' of the tooth is obstructed by the crown of the
second molar, a condition referred to as 'tooth impaction' or 'locking of
the crown'
e)Texture of the investing bone
 more dense the bone, the less the degree of bony expansion
during luxation and more time required for its removal with a bur
f)Inferior alveolar canal:
 This structure is frequently seen to be crossing the roots of
the third molar

30. g)Position, root pattern and nature of crown of second molar:
 closer the third molar is to the second molar, the more difficult
the surgery becomes
CT evaluation
OPG has following disadvantages :
 Does not provide a coronal view of the third molar
area.
 Does not show the relationship of the root apices
to the inferior alveolar canal in all planes of space.
 Does not provide predictable evidence of bone
density
Ct provides all these informations.

31. Pederson Scale for preoperative evaluation of difficulty of removal of teeth:

32. Surgical management of impacted 3rd molar
 wipe the patient's face with an antiseptic solution like
povidoneiodine (Betadine), followed by the administration of
local anesthetic injection.
1. Incision and Designing the Flap
 First step in removing the impacted tooth is to reflect a mucoperiosteal
flap
 Flap should be of adequate size to permit access, allow adequate
visibility and to ensure unhindered healing without periodontal pocket
formation distal to second molar

33.  most commonly used flap is the
envelope flap which extends from just
posterior to the position of the
impacted tooth anteriorly to the level of
the first molar.
 Posterior end of the incision is directed
buccally along the external oblique ridge.
 If more access needed , triangular flap
used.
 This incision is started from a point
approximately 6 mm down in the buccal
sulcus and then extended obliquely
upwards to the gingival margin to a point at
the junction of the posterior and middle
thirds of the second molar

34. Ward incision
Incision begins 6.4mm in buccal sulcus at the junction of
middile & posterior third of 2nd molar
Passed upward to distobuccal angle of 2nd molar.
Cervically behind the tooth to midline of its posterior
surface.
Taken back & laterally to prevent vesselinjury to retromolar
area.
In final continuation,it penetrates mucosa of cheek.
Modified ward incision
Anterior incision is commensed at the distobuccal corner of
crown of mandibular 1st molar instead of 2nd molar.

35. 2. Bone Removal
 Amount of bone removal varies with the depth of impaction.
 Accomplished either by use of bur, or chisel and mallet or a combination
of the two methods
 To free the tooth from obstruction and to provide a point of application
for the elevator.
 most common technique using a chisel is the 'lingual split bone
technique' introduced by Ward ,in which section of bone lingual to the
wisdom tooth is fractured off to facilitate the removal of the impacted
tooth.
 buccal bone removal should be kept to minimum to avoid weakening of
the mandible and subsequent fracture.
 bone on the buccal and the distal aspect of the impacted tooth is
removed down to the level of the cervical line. Further if need, drilling a
deep vertical gutter alongside the buccal aspect and if required on the
distal aspect of the tooth. This 'guttering method ' will ensure that the
height of the buccal plate is maintained without weakening the mandible

36.  Elevation of tooth from the socket
 Excessive force can result in unfavourable root fracture, buccal or lingual bone
loss, damage to the adjacent second molar or even fracture of mandible.
 Thus, Elevators with less mechanical efficiency like Warwick James elevator
(straight and curved type) and Coupland chisels are recommended
3. Sectioning and Tooth Deliver
 For easy delivery from the socket
 Sectioning of tooth reduces operating time and also avoids the need to
remove additional amount of bone to accommodate the elevated tooth.
 Performed either with a bur or a chisel
 In the standard technique, first section is generally done at the neck of
the tooth using bur. This will facilitate the removal of the crown
followed by the roots in one piece

41. 4. Debridement
 Debriding the wound of all particular bone chips and other debris
 Debriding the socket and the area under the flap with a periapical cruet
 A bone file is used to smooth any rough and sharp edges of the bone
 socket and the wound margins (including under surface of
mucoperiosteum) is irrigated with saline to remove bone and tooth
debris.
5. Wound Closure
 Bleeding from the socket is completely arrested before attempting
closure
 Flap is then returned to its original position and the initial suture
placed just distal to the second molar
 The needle is passed from the buccal to the lingual side.
 Sutures should be just tight enough to hold the flap
 patient is then asked to bite firmly on a gauze piece for 30 mts. to
one hour or till the bleeding stops.

42. Other methods :
1)Sagital split ramus osteotomy :
 Used for the surgical correction of mandibular excess (push back) and for
mandibular deficiency (advancement).
 Provide good access, conserves bone that would otherwise have been removed,
and allows the nerve to be seen and avoided.

43. 2)Buccal Corticotomy
 A trapezoidal mucoperiosteal flap is
raised in the mandibular molar region.
 Rectangular window is made over the
deeply impacted tooth using a narrow
fissure bur, with the mesial and distal
cuts almost reaching the inferior
border of the mandible
 Buccal corticotomy window is removed
with an osteotome. The deeply
impacted molar is exposed, divided
with a bur and removed.

44. Conclusion
 Impaction of 3rd molar have different etiologies.
 Dental caries,pericoronitis… are indications for management of
impacted tooth
 In aged patients,it is contraindicated.
 Impaction can classify based on angulation,position…
 History,intraoral and extraoral examinations used in diagnosis
 Radiographs are also beneficial.
 There are many surgical techniques available for management of
impacted tooth.

45. Reference
1)A practical guide to management of impacted tooth By K George Varghese
2)Textbook of oral & maxillofacial surgery by S M balaji