1) The document discusses various theories of third molar impaction including orthodontic, phylogenic, Mendelian, and pathological theories. 2) It also covers classifications of third molar impaction based on angulation, position, eruption state, and root morphology. Historical classifications including Winter's and Pell & Gregory are summarized. 3) Surgical considerations for impacted third molar removal are outlined, including pre-operative assessment, radiographic evaluation, difficulty indices, surgical anatomy, and mucoperiosteal flap design. Complications of retained impacted teeth are also briefly mentioned.

1. Mohammad akheel
Omfs pg

2. Introduction
 The third molar has been the most widely
discussed tooth in the dental literature, and the
debatable question “….. to extract or not to
extract” seems set to run into the next century. -
Faiez N. Hattab, JOMS, 57: 389-391 (1999)

3. Theories of impaction
By Durbeck
1) Orthodontic theory : Jaws develop in downward and
forward direction. Growth of the jaw and movement of
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.

4. Theories of impaction
2) Phylogenic theory: Nature tries to eliminate the disused organs
i.e., use makes the organ develop better, disuse causes slow
regression of organ.
[More-functional masticatory force – better the development of
the jaw]
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.

5. Theories of impaction
3) Mendelian theory: Heredity is most common cause. The
hereditary transmission of small jaws and large teeth
from parents to siblings. This 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

6. What will happen if impact teeth are retained?
Complications
Infections:
 Pericoronal infection
 Acute / chronic alveolar
abscesses
 Chronic suppurative
osteitis
 Necrosis
 Osteomyelitis

7. Complications
Pain:
 Slight and restricted
 Severe or excruciating
 Intermittent, constant or
periodic
 Referred to ear, the post
auricular area, any part of
the area supplied by the
trigeminal nerve. (Eg.
Temporal pain)

8. Fractures:
 Impacted tooth proves that weakening of the mandible occurs due
to displacement of bone.
Other complications:
 Ringing, singing or buzzing sound in the ear (Tinnitus aurium)
 Otitis
 Affections of the eye such as
 Dimness of the vision
 Blindness
 Iritis
 Pain simulating that of glaucoma

9. Indications and contraindications for removal
of impacted tooth
“A strong indication for removal of impacted third
molar should be complemented with a strong
contraindication to its retention”
– Mercier P., Precious D., Risk and benefits of removal of impacted third molars,
IJOMS 21:17, 1992.
Indications:
 Pericoronitis – 27% to 34% (Swed Den J1987)
 Caries – 3% to 15% (IJOMS 1988)
 Root resorption – 5% (Swed Den J 1987)
 Formation of follicular cyst – 1 to 5%(J Oral Pathol
1998)
 Tumors arising in the follicular (Dentigerous cysts) – 0.1
to 0.2% (JOMS 1991)

10. Contraindications:
 Acute infection with pericoronitis
 Medically compromised state – uncontrolled diabetes
 Extremes of age – Old age

11. Historical background on the criteria for
removal of third molar
Historical background
 In 1979, a consensus development conference
practicing dentists and scientists, on third
molar removal was sponsored by National
Institute of Health, USA *.
 * -J Oral Surgery…Vol38,March 1980

12. ClassificationAccording to Long axis of the impacted tooth in relation to the long axis
of the 2nd molar Winter’s classification (1926)

13. Mesioangular
Vertical
Distoangular

14. Pell & Gregory's classification (1933)
Position A
Position B
Position C

15. Based on Relationship of the Tooth to the
Anterior Border of the Ramus of the Mandible
Class I Class II Class III

16. According to Supero-Inferior Position
of 3rd Molar
 Crown to crown
 Crown to cervix
 Crown to root

17. Killey & Kay’s Classification
a) Based on angulation and position:
(Same as Winter’s classification)
b) Based on the state of eruption: - Completely erupted
- Partially erupted
- Unerupted
c) Based on roots: 1) Number of roots - Fused roots
- Two roots
- Multiple roots
2) Root pattern - Surgically favorable
- Surgically unfavorable

18. ADA code on Procedures and Nomenclature
 The American Dental Association (ADA) Code describes
the amount of soft and hard tissues over the coronal
surface of an impacted tooth.
 These are described as: soft tissue impactions, partial bony
impactions, completely bony impactions, and completely
bony impactions with unusual surgical complications.

19. Combined ADA and AAOMS Classification
 soft tissue impaction (incision of overlying soft tissue & removal of
tooth)
 partial bony impaction (incision of overlying soft tissue, elevation of
flap, either removal of bone & tooth or sectioning & removal of tooth)
 complete bony impaction (incision of overlying soft tissue, elevation of
flap, removal of bone & sectioning of tooth for removal)
 complete bony impaction with unusual surgical complication (incision of
overlying soft tissue, elevation of flap, removal of bone, sectioning of
tooth for removal &/or presents unusual difficulties & circumstances)

20. Pre-Operative Assessment
 HISTORY
 Patients might be asymptomatic
 when symptomatic- pain, swelling of the face, trismus
 Symptoms of acute pulpitis or abscess
 In denture wearers if denture no longer fits & at the same time show the
symptoms of pericoronitis.
 General medical history & assessment of physical condition
 EXAMINATION
Clinical
 Extra oral
 Intra oral
Radiographs
 DECISION
Diagnosis
Treatment planning – type of anesthesia
- surgical procedure

21. Local Examination
 EXTRA ORAL:
• Signs of swelling & redness of the cheek
• LN’s - enlargment & tenderness,
• TMJ
• Anesthesia or paraesthesia of lower lip,
 INTRA ORAL:
• Mouth opening & any evidence of trismus
• State of eruption of tooth, signs of pericoronitis
• Condition of 1st & 2nd molars
• Space present b/w 2nd M & ascending ramus
• Elasticity of oral tissues
• Size of tongue

22. Radiographs
 Periapical film
 OPG
 Occlusal film
1. Access
2. Position & depth (WAR lines)
3. Shape of the crown
4. Texture of investing bone
5. Position & root pattern of 2nd Molar & impacted tooth
6. Inferior alveolar canal
7. External oblique ridge --vertical & ant. to third molar – poor access
-- oblique & post. – good access
Interpretation

23. Relationship of Root to Canal
Related but not involving the canal
Separated
Adjacent
Superimposed
Related to changes in the roots
Darkening of root
Dark and bifid root
Narrowing of root
Deflected root
Related with changes in the canal
Interruption of lines
Converging canal
Diverted canal

24. Relationship of Inferior Alveolar Nerve to the
Roots of Third Molar
Darkening of root Deflection of root Narrowing of canal Dark & Bifid apex
Roods Radiographic Criteria

25. WAR (Winter’s) Lines
White line amber line red line
 Red line <5mm: extraction - easy, there after every 1mm increase in
depth increases the difficulty three folds & if it is >9mm then plan the
surgery under GA.
 As a general rule DA teeth are more difficult than MA impaction of
similar depth & root pattern

26. DIFFICULTY INDEX :
Category Values
Spatial relationship Mesioangular
1
Horizontal
2
Vertical
3
Distoangular
4
Depth Level A
1
Level B
2
Level C
3
Ramus relationship Class I
1
Class II
2
Class III
3

27. Category Score
1. Winters classification Horizontal
Distoangular
Mesioangular
Vertical
2
2
1
0
2. Height of mandible 1-30mm
31-34mm
35-39mm
0
1
2
3. Angulation of 3rd molar 1 - 50
60 - 69
70 -79
80 - 89
90 +
0
1
2
3
4
4. Root shape Complex
Favourable curvature
Unfavourable curvature
1
2
3
5. Follicles Normal
Possibly enlarged
Enlarged
0
1
2
6. Path of exit Space available
Distal cusp covered
Mesial cusp covered
Both cusp covered
0
1
2
3
Total 33
WHARFE’s ASSESSMENT by McGregor (1985)

28. Surgical Management
John Tomes (1849) – first to describe surgical access
Steps in surgical removal
Anesthesia
Incision and mucoperiosteal flap
Removal of bone
Tooth removal
Wound debridement
Arrest of haemorrhage
Wound closure
Postoperative follow-up

29. Surgical Anatomy
 Location: lower 3rd molar is situated
at the distal end of the body of the
mandible where it meets a relatively
thin ramus.
 Embedded b/w thick buccal alv bone
buttressed by external oblique ridge &
the narrow inner cortical plate.
 Ramus offset by 20°
 Retro Molar triangle- depressed
roughned area post. to 3rd molar

30. Muscles:
 Vestibule is formed by the attachment of buccinator buccally and mylohyoid
lingually.
 Along the anterior border of the ramus - tendinous insertion of temporalis Excessive
stripping of these muscle will cause hematoma, pain and trismus.
 Lingual pouch – perforation of roots along the lingual cortical plate.
- may cause # of lingual cortical plate
-displacement of fractured root fragments below the mylohyoid

31. Arteries
• Facial artery & facial vein run in close approximation with lower 2nd
molar near the anterior border of masseter.
• Mandibular vessels in retro molar triangle which supply temporalis
tendon.
• Hemorrhage can occur during surgical removal of impacted tooth if
distal incision is not taken laterally towards cheek.

32. Inferior Alveolar Nerve
• Lies just below the roots of mandibular
molars but slightly buccally placed in
inferior dental canal.
• In case of deep seated impaction special care should be taken to
protect this neurovascular bundle during bone drilling & tooth
sectioning.
• Calcification of inferior alveolar canal is completed before the roots of
3rd molar are formed. Thus growing roots may impinge upon the
canal or get deflected. So blind elevation is not advisable.

33. MUCOPERIOSTEAL FLAP
Incision – 3 parts: Anterior, posterior & intermediate limb
Not to be extended too distally-
Bleeding from buccal vessels & other arteries
Postoperative trismus – temporalis muscle damage
Herniation of buccal fat pad
Damage to lingual nerve (lingual extention)

34. Factors Governing Planning of Incision
Surgical access
Healing of sutured wound – dry socket
Periodontal health of II molar – distal pocket
Suture line must rest on normal bone
Partly visible crown: de-epitheliazation

35. Types of Flaps
L – shaped flap
(2nd molar para
marginal Flap with
vestibular extension)
Envelope flap
(2nd molar
sulcus incision)
Bayonet – shaped flap
(2nd molar sulcus incision
With vestibular extension)

36. Buccal extension flap Triangular flap
Ward’s incision Modified Ward’s incision

37. Bone Removal
Aim
1. To expose the crown by removing the bone overlying it.
2. To remove the bone obstructing the pathway for
removal of the impacted tooth.
Types
1. By consecutive sweeping action of bur (in layers).
2. By chisel or osteotomy cut (in sections).
How much bone has to be removed?
1. Bone should be removed till we reach below the height of contour, where
we can apply the elevator.
2. Extensive bone removal can be minimized by tooth sectioning.

38. Sl.No Criteria. Chisel&Mallet Bur
1. Technique Difficult Easy.
2. Control over bone cutting Uncontrolled Controlled.
3. Patient acceptance. Not tolerated in
L.A.
Well tolerated in
L.A.
4. Healing of bone. Good Delayed Healing
5. Postoperative edema Less More.
6. Dry socket. Less. More.
7. Postoperative Infection. Less. More.
Chisel v/s Bur

39. Bone Removal Techniques
Moore & Gillbe’s Collar Technique
- Conventional tech of using bur.
- Rosehead round bur no.3 is used to create a gutter along the
buccal side & distal aspect of tooth.
- A point of elevation is created with bur.
- Amount of bone sacrificed is less.
- Can be used in old patient.
- Convenient for patient.

40. Split Bone / Lingual Split Technique
Sir William Kelsey Fry(1933)
- Quick & clean tech
- Reduces the size of blood clot by means of saucerization
of socket.
- Decreased risk of damage to the periodontium of the second
molar.
- Less risk of inferior alveolar nerve damage.
- Decreased risk of socket healing problems
- Can use regional anaesthesia but endotracheal anaesthesia is
preferred one.
- Only suitable for young adults whose bone is elastic
- Inconvenience to patients due to chisel useage.

41. Vertical stop cut
Split of Disto
lingual bone
Elevation
Horizontal cut
Removal of distal
& buccal bone
Removal of disto
lingual bone
Incision
Closure

42. Tooth Division
“Rationale of tooth sectioning is to create a space into which impacted tooth can
be displaced & thence removed.”
Tooth is sectioned in various ways depending on the type & degree of impaction.
Mesioangular Impaction Horizontal Impaction

43. Vertical Impaction
Disto Angular Impaction

44. Debridement of Wound & Closure
 Thorough debridement of the socket by Periapical curettage.
 Smoothening of sharp bony margins by Bone file / burs.
 Thorough irrigation of the socket Betadine solution + Saline .
 Initial wound closure is achieved by placing 1stsuture just distal to
2ndmolar, sufficient number of sutures to get a proper closure.

45. Post Operative Instructions
 Pressure pack – 1hr
 Ice application
 Soft diet –1st two days
 1st dose of analgesic should be taken before the anesthetic effect of LA
wears off.
 Avoid strenuous exercises for 1st 24 hrs.
 Avoid gargling / spitting / smoking / drinking with straw.
 Warm water saline gargling after 24 hrs + mouth wash regularly
thereafter.
 Suture removal on 5th POD.

46. Complications
Intra Operative
1. During incision
a. Injury to facial artery
b. Injury to lingual nerve
c. Hemorrhage – careful history
2. During bone removal
a. Damage to second molar
b. Slipping of bur into soft tissue & causing injury
c. Extra oral/ mucosal burns
d. Fracture of the mandible when using chisel & mallet
e. Subcutaneous emphysema
3. During elevation or tooth removal
a. Luxation of neighbouring tooth/ fractured restoration
b. Soft tissue injury due to slipping of elevator
c. Injury to inferior alveolar neurovascular bundle
d. Fracture of mandible
e. Forcing tooth root into submandibular space or inferior
alveolar nerve canal
f. Breakage of instruments
g. TMJ Dislocation – careful history

47. Nerve Injuries
 0.6-5% of all the third molar surgeries are involved with nerve
damages of which 0.2% are irreversible
 IAN: immediate disturbance - 4-5% (1.3-7.8%)
permanent disturbances - <1% (0-2.2%)
 Lingual N: immediate - 0.2-22%
permanent - 0-2%
 96% IAN injuries show spontaneous recovery within 9 months,
better than lingual nerve which is about 87%
 Beyond 2yrs recovery is unlikely

48. Post-operative Complications
 Immediate
- Hemorrhage
- Pain
- Edema
- Drug reaction
 Delayed
- Alveolitis
- Infection
- Trismus

49. Dry Socket
 20% of extraction of mandibular 3rd molar
 2% of routine extraction
 Moderate-severe pain develops generally on 3rd/4th day.(with no signs
of infection)
 Dull aching pain usually radiates to ear
 Empty socket
 Bad odour & taste
 Etiology - unknown
 Possibly excessive fibrinolytic activity
 Subclinical infection

50. Management
 Gentle irrigation with warm saline followed by superficial suctioning.
 Pack iodoform gauze socked with medications change every day for 3-6
days.
 Intra-alveolar medicaments(controversial)
-with eugenol
-topical LA
-antifibrinolytic agents.
 Analgesics.

51. Thank you…