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)
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)
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
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)
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
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
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.