Impacted third molars

IMPACTION
PRESENTER –
DR AVINASH RATHORE
DEPT OF OMFS

CONTENTS
• INTRODUCTION
• TERMINOLOGIES
• DEFINITIONS OF IMPACTION
• THEORIES OF IMPACTION
• ETIOLOGY
• INDICATIONS AND CONTRAINDICATIONS OF REMOVAL OF
IMPACTED TOTH
• CLASSIFICATION OF IMPACTED THIRD MOLARS
• ASSESSMENT OF IMPACTED THIRD MOLARS
• SURGICAL PROCEDURE
• COMPLICATIONS
• IMPACTED MAXILLARY THIRD MOLAR
• REFERENCES
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).
• Got their name „Wisdom teeth‟ from the age during which
they erupt: 17 to 25. This is the age at which men and
women become adults, and, presumably wiser.

• Origin – Latin– Impactus
• Impactus: Cessation of eruption caused by physical barrier /
ectopic eruption.
• Heironymous cardus -Dens sensus et sapientia et intellectus.
• Dens sapientia
• Dens serotinus – lateness

DEFINITIONS
IMPACTED TOOTH
IMPACTED TOOTH IS DEFINED AS THE TOOTH WHICH HAS ALREADY
PASSED CHRONOLOGICAL AGE OF ERUPTION AND FAILED TO COME TO
ORAL CAVITY INSPITE OF NORMAL ERUPTIVE FORCES DUE TO SOME
MECHANICAL OBSTRUCTION.
American society of oral surgeons
1971

According to WHO –
An impacted teeth is any tooth that is prevented from reaching its normal position
in the mouth by tissue, bone or another tooth.
According to ARCHER(1975) –
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 ANDERSON(1997)-
An impacted tooth is a tooth which is prevented from completely erupting into a
normal functional position due to lack of space, obstruction by another tooth or
an abnormal eruption path.

According to PETERSON
A tooth is considered impacted when it has failed to fully erupt into the
oral cavity within its expected time period and can no longer
reasonably be expected to do so.
According to J. Michael McCoy-
An impacted tooth is one that either fails to erupt into its natural
position or one that is hindered from such eruption by adjacent
teeth, dense bone, or an overgrowth of soft tissue.

ERUPTION- defined as the movement of tooth from its
developmental position within the jaw toward the functional position
within the occlusion.
PRIMARY RETENTION- defined as a cessation of eruption before
gingival emergence without a recognizable physical barrier in the
eruption path and ectopic position.
SECONDARY RETENTION- is related to the cessation of eruption
of a tooth after emergence without physical barrier in its path or
ectopic position of a tooth.

ANKYLOSED TOOTH- when the cementum of the tooth is
fused to the bone and there is no periodontal soft tissue in
between.
MALPOSED TOOTH- a tooth, unerupted or erupted that is
in abnormal position in the maxilla or mandible.

INCIDENCE
Mandibular 3rd molar exhibit the highest rate of impaction..
According to different authors:-
HELLMAN-9.5%
BJORK-25%
RICHARDSON-50%
RICKETTS-35%

TWO HYPOTHESIS
Nature and Nurture Hypothesis:
John hunter (1771)- stated that as the successive teeth
erupt the jaws grow to make room for them. If the jaws
are not big enough then there will not be room for all
teeth, and last to erupt will become misplaced.

Darwin (1881)-he had previously noted that the posterior
dental portion of the jaws always shortened in more
civilized races of man and Darwin attributed this to
“civilized mans habitually feeding on soft cooked food”

By Durbeck
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

2) Phylogenic theory: Nature tries to eliminate the
disused organs i.e., used 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
have practically eliminated needs for large powerful
jaws, thus, over centuries the mandible and maxilla
decreased in size leaving insufficient room for third
molars.

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.
Pathological theory: Chronic infections affecting an
individual may bring the condensation of osseous tissue
further preventing the growth and development of the
jaws.

Endocrinal theory: Increase or decrease in growth
hormone secretion may affect the size of the jaws.
The Skeletal theory - Several studies have demonstrated
that when there is inadequate bony length, there is a higher
proportion of impacted teeth.

DEVELOPMENT OF THIRD MOLARS
7-8 yrs: initiation of tooth bud formaton
9 yrs: tooth germ visible in the radiograph
11 yrs: completion of cusp mineralisation- anterior border of
ramus
14 yrs: crown development completed
16 yrs: approx. 50% root developed
18 yrs: root development completed
20- 24 yrs: 95% of lower third molars erupt

The Belfast Study Group
They claim that there may be differential root growth
between the mesial and distal roots, which causes the
tooth to either remain mesially inclined or rotate to a
vertical position depending on the amount of root
development.
Underdevelopment of mesial root- mesioangular impaction
Overdevelopment of mesial root- distoangular impaction

• LOCAL CAUSES
Berger lists the following local causes of
impaction :
• Irregularity in the position and presence of an adjacent
tooth.
• Density of the overlying or surrounding bone.
• Long – continued chronic inflammation with resultant
increase in density of the overlying mucous membrane.

• Lack of space due to underdeveloped jaws.
• Unduly long retention of the primary teeth.
• Premature loss of the primary teeth.
• Acquired diseases, such as necrosis due to infection or
abscesses and inflammatory changes in the bone due to
exanthematous diseases in children.

SYSTEMIC
Prenatal
 Heredity
 Miscegenation
Postnatal Causes
 Rickets
 Anemia
 Congenital Syphilis
 Tuberculosis
 Endocrine Dysfunctions
 Malnutrition
Rare Causes
 ClediocranialDysostosis
 Oxychephaly
 Progeria
 Achondroplasia
 Osteopetrosis
 Cleft Palate

PREDICTION OF THIRD MOLAR
ERUPTION

INDICATIONS
PAIN
• Inflammation
• Food lodgement
• Trauma to adjacent mucosa
• Pressure on adjacent tooth
• Rule out MPDS& TMDs

PERICORONITIS
• It refers to the inflammation of soft tissue in relation to the crown of
an incompletely erupted tooth including gingiva and dental follicle.
• Greek word- peri- around Corona –crown itis-inflammation
• HISTORY-
• 1844-GUNNEL –PAINFUL AFFECTION
• END OF 19TH CENTURY-FOLLICULITIS (as the tooth breaches
the follicle)
• 20th century- term PERICORONITIS
• Also k/a-OPERCULITIS

• INCIDENCE-
• AGE GROUP- 20 – 29years
67%-VERTICAL CASES
12%-MESIOANGULAR CASES
14%-DISTOANGULAR CASES
7%-OTHER POSITIONS
Bilateral pericoronitis is rare- may be in Infectious
mononucleosis

UNRESTORABLE DENTAL CARIES
• Inability to effectively clean the area
• Inaccessibility

PATHOLOGIES/ PREVENTION OF CYSTS AND TUMORS
RISK OF CYST & TUMOR
DEVELOPMENT:
•Most common age : 20- 25
years.
•Incidence of cyst formation-
2.31% (Guven et al,2000)
•Incidence of dentigerous cyst-
1.6% (Keith,1973)
•Incidence of ameloblastoma –
0.14- 2% (Shear,1978)
•Risk of surgical morbidity
increases with age.

ORTHODONTIC CONSIDERATION
Crowding of mandibular incisors
Obstruction of orthodontic treatment
Interference with orthognathic surgery

PATHOLOGIC RESORPTION OF ADJACENT TEETH

PROPHYLATIC REMOVAL-
In persons who are involved in contact sports.

CONTRAINDICATIONS
 Extreme of age
 Compromised medical status
 Probable excessive damage to adjacent structure
(unfavorable risk /benefit ratio)
Third molars needed as abutments
Recently irradiated jaw
Tooth in tumour.

Absolute contraindications
Acute pericoronitis
Acute necrotising ulcerative gingivitis
Haemangioma,Haemophilia,leukaemia
Thyrotoxicosis

ORDER OF IMPACTED TEETH
(ARCHER)
Maxillary third molar
Mandibular third molar
Maxillary cuspids
Mandibular bicuspids
Supernumerary tooth
Maxillary bicuspids
Mandibular cuspids
Maxillary central incisors
Maxillary lateral incisors

CLINICAL FEATURES
Pain
Pericoronitis
Mobility of adjacent teeth
Unexplained TMJ pain
Crowding of lower anterior teeth
Trismus
Bulge distal to second molar
Distal proximal caries on second molar

SURGICALANATOMY OF MANDIBULAR 3RD MOLAR
Temporalis
muscle
Buccinator
Retromolar
foramina

Retromolar Foramina and Their Canals
• The retromolar foramina (RMF) and the retromolar canal (RMC) are
anatomic variants in the mandible located distally to the last molar.
The retromolar nerve, which runs through the RMC is a type 1 bifidity
of the mandibular canal.
• The RMF is located posteriorly to the last molar in the retromolar
trigone, which is bounded
• anteriorly by the third molar,
• medially by the temporal crest,
• laterally by the anterior border of the ramus

 The nerve that runs through the
RMC might arise from the early
accessory branches of the inferior
alveolar nerve (IAN) or long
buccal nerve. This area is
commonly invaded during
mandibular third molar surgery,
autologous bone harvesting, and
sagittal split osteotomy.
 The most common variation of the
RMC is a branch of the
mandibular canal below the third
molar. The nerve travels in a
posterosuperior direction and
opens in the retromolar fossa
those posterior to the third molar

Clinical relevance
Contents of the Retromolar Canal
The RMC originates from the mandibular canal, follows a recurrent
path, and ends in either RMF or in nearby foramen. The contents of the
RMC are derived from their inferior dental homologues and include a
myelinated nerve, one or more arterioles, and one or more venules.
After departing the body of the mandible, these entities distribute
mainly upon the temporalis tendon, buccinator muscle, the most
posterior zone of the alveolar process, and the mandibular third molar.
Mucoperiosteal Flap Elevation
Insufficient Anesthesia
Surgical Procedure Complications
Excessive Bleeding
Autologous Bone Graft
Spread of Infection or Tumors

Most prevalent types of retromolar triangles,according to
Suazo et al.,2007
• A. Tapering form 9.16% B. Drop form 10.83%;
• C. Triangular form 80%.

MUSCLES
• TEMPORALIS
• BUCCINATOR
• MASSETER
• MEDIAL PTERYGOID
• MYLOHYOID

NEUROVASCULAR BUNDLE
• INFERIOR ALVEOLAR NERVES AND VESSELS
• BLOOD VESSELS-facial artery and anterior facial vein
• Long buccal nerve
• Mylohyoid nerve

LINGUAL NERVE
 Lingual nerve lies inferior and medial to the crest of the
lingual plate of mandible with a mean position of
2.28mm(+/-0.9) below the crest & 0.58mm(+/-0.9) medial
to crest - KIESSELBACH& CHAMBERLAIN
 In 17% of cases it lies superior to the lingual plate

• EXTERNAL OBLIQUE RIDGE
• LINGUAL POUCH
• SUBMANDIBULAR FOSSA

CLASSIFICATIONS OF
MANDIBULAR THIRD
MOLAR IMPACTION

CLASSIFICATION OF IMPACTED
THIRD MOLAR
WINTER’S CLASSIFICATION (1926)
According to the position of the impacted third molar to the long axis
of second molar
Mesioangular
Horizontal
Vertical
Distoangular
These may occur simultaneously in:
Buccal version
Lingual version
Torsoversion

MODIFIED WINTERS CLASSIFICATION
Vertical impaction (10° to -10°)
Mesioangular impaction(11° to 79°)
Horizontal impaction (80° to 100°)
Distoangular impaction ( -11° to -79°)
Others (111° to -80°)
Buccolingual impaction (any tooth oriented in a buccolingual
direction with crown overlapping the roots)
Sadeta Šeèiæ et al. Journal of Health Sciences 2013;3(2):151-
158

CLASSIFICATION BY ARCHER (1975) AND KRUGER
(1984)
Based on angulation of 3rd molar
Mesioangular
Distoangular
Vertical
Horizontal
Buccoamgular
Lingoangular
Inverted

BASED ON NATURE OF OVER LYING TISSUE
According to contemporary oral and maxillofacial
surgery-Peterson
The three types of impactions are:
(1) Soft tissue impaction
(2) Partial bony impaction
(3) Full bony impaction

PELLAND GREGORY CLASSIFICATION:
1. Relation of tooth to the ramus of the mandible

2. Relative depth of the third molar in the bone

COMBINED ADA & AAOMS CLASSIFICATION
07220- Soft tissue impaction that requires incision of overlying
soft tissue and the removal of the tooth.
07230- Partially bony impaction that requires incision of
overlying soft tissue, elevation of a flap, and either removal of
bone and the tooth or sectioning and removal of tooth.

07240- Complete bony impaction that requires incision of
overlying soft tissue, elevation of a flap, removal of bone, and
sectioning of tooth for removal
07241- Complete bony impaction with unusual surgical
complication that requires incision of overlying soft tissue,
elevation of a flap, removal of bone , sectioning of the tooth for
removal, and /or presents unusual difficulties and
circumstances.

KILLEY & KAY'S CLASSIFICATION
Based on angulation and position
Vertical
Mesioangular
Distoangular
Horizontal
Transverse
Buccoangular
Linguoangular
Inverted
Aberrant positions

Based on state of eruption
Erupted
Partially erupted
Unerupted
Soft tissue impaction
Complete bony impaction
Based on number of roots
Unfavorable impaction-
 Mesial curvature of roots
 Multiple roots
Favorable impaction-
 Fused roots
 Distal curvature of roots

PRE- OPERATIVEASSESSMENT
CLINICAL ASSESSMENT
General assessment
Age/ sex
Systemic condition
Drug history
Anesthesia history
General physical examination

Extra oral examination
Facial form & profile
Ramus flare
Cheek bulk
Swelling
Presence of Sinus/ fistula
Lymph node
Trismus

Intra oral examination
Soft tissues
Size of rima oris(mouth opening)
Position of mandible
Tongue size
Extensibility of lips & cheeks
Soft tissue trauma
Hard tissues
Dentition status
External oblique ridge

Assessment of impacted teeth
Status of eruption
Periodontal status
External and internal oblique ridge
Relationship with adjacent teeth
Soft tissue covering
Occlusal relationship with opposing tooth

RADIOGRAPHIC INVESTIGATIONS
A good radiograph helps to plan out the surgical procedure, rule
out and pathologies like cystic changes,eruption predilection &
also helps to visualize the proximity of vital structures.
Routine radiographs include:
• Intraoral –IOPAR, Bite wing , Occlusal radiograph
• Extra oral –OPG, Lateral cephelometric
• Digital imaging –CT, CBCT

INTRA ORAL RADIOGRAPHS
Indications-
Tooth in alveolus
Adequate mouth opening
Tube shift
Relationship with IAN
Bisecting angle technique
 X- ray film stabilized against the teeth and supporting
lingual alveolar mucosa

BITEWING RADIOGRAPH
For visualising class1 and class2 impacted mandibular 3rd molar.
Central rays are directed through the crown of 2nd molar with zero
degree vertical angulation.

FRANK’S TUBE SHIFT TECHNIQUE

EXTRAORAL RADIOGRAPHS
Panoramic radiographs
Lateral cephalometric skull projection
Lateral oblique view of mandible
Indications
 Restricted mouth opening
 Impacted tooth in aberrant position
 Rule out pathology
 Study the relationship to inferior alveolar nerve, inferior border of
mandible

Specialized techniques
COMPUTED TOMOGRAPHY
 Impacted tooth in ectopic position-
distant from oral cavity
 Associated with neoplastic or
inflammatory process with
morbidity in contigious tissues

RADIOGRAPHIC ASSESSMENT
• State of eruption of level of tooth
• Angulation of tooth
• Relationship with second molar
• Distance between ascending ramus and distal surface of
second molar
• Condition of second molar and impacted tooth
• The existing pathology
• Root shape
• Bone removal to permit application of elevators
• The relationship with inferior alveolar canal
• WHARFE assessment with OPG
• WAR lines/winters lines with IOPA

WHARFE ASSESMENT
• MACGREGOR 1985
• SCORING FOR DIFFICULTY LEVEL OF THIRD MOLAR.

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 2nd molar 1° - 59°
60° - 69°
70° -79°
80° - 89°
90°+
0
1
2
3
4
4. Root shape Complex
Favourable curvature
Unfavourable curvature
3
1
2
5. Follicles Normal
Possibly enlarged
Enlarged
Impaction relieved
0
-1
-2
-3
6. Path of exit Space available
Distal cusp covered
Mesial cusp covered
Both cusp covered
0
1
2
3

Winters “WAR” lines
• White line: Line joining the occlusal surfaces/highest cusps tips of all erupted molars,
extending up to the ramus. It indicates the difference in occlusal level of second and
third molars.
• Amber line: Represents the bone level distal to the 3rd molar, extended anteriorly
along the crest of interdental septum. This line denotes the alveolar bone covering the
impacted tooth and the portion of the tooth not covered.
• Red Line: Drawn perpendicular from Amber line to the imaginary point of application
of elevator on the 3rd molar. It indicates the amount that will have to be removed
before elevation i.e. the depth of the tooth in bone and the difficulty encountered in
removing the tooth. Length more than 5mm - extraction is difficult.
Every additional millimeter renders the removal of the Impacted tooth 3 times more
difficult.

THE ‘RED LINE’ CONUNDRUM:CONCEPT
BEYOND ITS EXPIRY DATE
Change of angulation of the film causes the ‘‘red-line’’ to change in length
significantly. The red-line in B is shorter by ( 30 % ) than in A with a 15
change in angulation of the film.
The ‘‘Red Line’’ Conundrum: A Concept Beyond Its Expiry Date? Sanjeev Kumar •
Mahendra P. Reddy • Lokesh Chandra • Alok Bhatnagar : JMOS 02 aug 2013

PEDERSON’S DIFFICULTY INDEX
• Very difficult: 7 to 10
• Moderataly difficult: 5 to 7
• Minimally difficult: 3 to 4
Scoring
Mesio angular 1
Horizontal 2
Vertical 3
Distoangular 4
Level A 1
Level B 2
Level C 3
Class I 1
Class II 2
Class III 3
Large bulbous crown increases the difficulty

RELATIONSHIPOF INFERIORALVEOLAR NERVE TO THE
ROOTS OF THE THIRD MOLAR.
Darkening of root Deflection of root Narrowing of root Dark & Bifid apex
Rood JP , Shehbab BA-BJOMS 1998:28:20

Interruption of white Narrowing of canal Diversion of canal
line of canal
Rood JP , Shehbab BA-BJOMS 1998:28:20

By NORTJE et al.,1977
Type I: Bilaterally single high mandibular canals-single high canals either
touching or within 2 mm of the apices of 1st and 2nd permanentmolars.
Type II: Bilaterally single intermediate canals-single canals not fulfilling the
criteria for either high or low canals
Type III: Bilateral single low canals-single canals either touching or within
2mm of the cortical plate of the lower border of the mandible
Type IV: Variations including-asymmetry,duplications and absence of
mandibular canals
CLASSIFICATION OF MANDIBULAR
CANAL

RELATIONSHIP TO LINGUAL
NERVE
Pogrel et al ,J oral maxillofac Surg 1995:53:1178

Surgical procedure
The surgical procedure for the extraction of impacted teeth
includes the following steps:
1. Asepsis and isolation
2. Local anesthesia/ general anesthesia
3. Incision-flap design
4. Reflection of mucoperiosteal flap
5. Bone removal
6. Sectioning (division) of tooth
7. Elevation and tooth removal
8. Debridement and smoothening of bone
10. Closure-suturing

SEQUENCE OFPROCEDURE
1) Isolation
2) Anaesthesia
3) Incision - Flap design
4) Removal of overlying bone
5) Sectioning of tooth.
6) Delivery of sectioned tooth.
7) Smoothening & debridement of socket
8) Arrest of haemorrhage
9) Closure of wound
10) Follow up

ISOLATIONANDASEPSIS
SCRUBBING
• Cetrimide+ absolute alcohol
• Cetrimide+povidone iodine
• Cetrimide+abs. Alcohol+chlorhexidine
CLEANING
• Normal saline
• Alcohol- spirit
PAINTING
• Povidone iodine (5% skin, 1% oral mucosa)
• Chlorhexidine (7.5% skin, 0.2% oral cavity)

ANESTHESIA
Choice of anesthesia
Apprehension level
The patient’s acceptance of the procedure
The length and technical difficulty of the procedure
Patient’s preference and risk to benefit ratio

Indications for general anesthesia
Fear of pain during the procedure
Emotionally unstable patient
Anticipated lengthy procedures
Removal of all four impacted molars in one sitting
Uncooperative patients
Allergy to LA
Tooth in aberrant position

DIFFERENT TYPES OF INCISION
AND FLAP DESIGN

• SHORT ENVELOPE
• LONG ENVELOPE
• L-SHAPED INCISON
• BAYONET SHAPED INCISION
• TRAINGULAR FLAP
• WARDS INCISION
• MODIFIED WARDS INCISION
• GROOVE AND MOORE INCISION
• S SHAPED INCISION
• COMMA SHAPED INCISION
• SZMYD FLAP
• MODIFIED SZMYD
• BERWICKS TONGUE FLAP
• GURALNIK HORIZONTAL INCISION
• DONLON TRINTA
• MOTAMEDI

Incision-flap design
3. Ward’s incision
4. Modified ward’s incision

COMMASHAPED INCISION
Starting from a point , posterior to the distal
aspect of the preceding second molar, the
incision is made in an anterior direction.
Incision is made to a point below the
second molar, from where it is smoothly
curved up to meet the gingival crest at the
distobuccal line angle of the second molar.
The incision is continued as a crevicular
incision around the distal aspect of the
second molar (a distolingually based flap).

S SHAPED INCISION
Incision was made from the
retromolar fossa across the external
oblique ridge curving down
through the attached
mucoperiosteum to run along the
reflection of the mucous
membrane to the anterior border of
the first permanent molar.

VESTIBULAR TONGUE SHAPED FLAP
 Berwick in 1986 designed a vestibular tongue shaped flap.
Extended into the buccal shelf of the mandible.
 For the pedicle flap an incision distal to the third molar was extended
approximately 1 cm and then curved towards the buccal sulcus
allowing for rotation of the flap and primary closure over sound bone.
Prior to closure, the gingival papilla distal to the second molar was
removed and the apex of the pedicle de-epithelialised

MUCOPERIOSTEAL FLAP
• A surgical flap may be defined as a piece of tissue which
has been detached from its underlying support but which
remains partially connected with its original site and
receives nourishment from this attachment.

Principles of flap design
 Incisions should avoid anatomical structures, such as major nerves or
blood vessels.
 Incisions far enough away from the surgical
area-The wound margins should rests on sound
bone
 The base of the flap should be wider than the apex to ensure adequate
blood supply.
 A firm pressure upon a sharp scalpel should be used so that both the
mucosa and periosteal layers of the gingiva are incised down to bone.
MUCOPERIOSTEAL FLAP

Incisions are made in one operation, as extensions.
Cut the soft tissues at right angles to the surface of underlying bone.
The Flap should be made large enough to provide for visibility,
accessibility and adequate room for instrumentation.
The vertical releasing (relaxing) incision should be avoided if the
horizontal incision will provide adequate access. This is because the
vertical releasing cut reduces the blood supply to the flap and cause
added discomfort.
The vertical releasing incision, if needed, should be made at a line
angle to maintain the integrity of the interdental papilla.
Schow(1974) –Extending flap beyond EOR increases the chances of
dry socket formation.

The incision having 3 parts-
LIMB A: The anterior incision started from buccal
sulcus approx. at the junction of posterior and
middle third of 2nd molar, passes upwards extended
upto the distobuccal angle of the 2nd molar at the
gingival margin approx 6mm.
LIMB B:It was carried along the gingival crevise of
third molar extending upto the middle of exposed
distal surface of the tooth
LIMB C: Started from a point where intermediate
gingival incision ended and was carried
laterally.This arm should be approx 19mm long.
Total length of incision should be approx 25.4mm.or
1inch
PARTS OF INCISION

LIMB C - not to be extended too distally
Bleeding from buccal vessels & other vessels
 Postoperative trismus – temporalis muscle damage
 Herniation of buccal fat pad
 Damage to lingual nerve (lingual extension)
In case of unerupted tooth ,intermediate incision is not
needed.The limb A is extended upto the middle of the distal
surface of the 2nd molar.

REFLECTION OF MUCOPERIOSTEAL
FLAP

• Periosteal elevator or Minnesota or Austin retractors
• Howarth retractor
• Austin retractor
• Ward killner retractor
• Dyson’s Malleable copper retractor
• Mac gregor periosteal elevator
• Fickling periosteal elevator
• Read periosteal elevator

BONE REMOVAL
• BUR TECHNIQUE
 Postage stamp technique
 Moore and Gillbe’s technique
 Guttering technique
 Bowdler Henry’s( Lateral trephination(1969))
• CHIESELAND MALLET
 Window technique
 Lingual split technique
Shaving technique
Distal lingual split technique

BUCCALGUTTERING TECHNIQUE
Once the soft tissue is elevated and retracted, the surgeon must make a
judgment concerning the amount of bone to be removed.
Bone must be removed in an atraumatic, aseptic, and non heat
producing technique, with as little bone removed and damaged as
possible.
 The amount of bone that must be removed varies with the depth of
impaction, the morphology of roots, and the angulation of tooth.
The speed of micromotor should be 12000- 20000 rpm.
Ideal length of the bur used is 7mm & diameter of 1.5mm.
(#702-diameter-1.6mm length-4.5mm)
(#703-diameter- 2.1mm length-4.8mm)

REMOVALOFOVERLYING BONE
A large round bur ( No. 8 ) is desirable, because it is an end cutting bur
and can be effectively used for drilling with a pushing motion.
The tip of a fissure bur ( No. 703 ) does not cut well, but the edge
rapidly removes bone and quickly sections teeth when used in lateral
direction.
The bone on the occlusal aspect of the tooth is removed first to expose
the crown of the tooth.
Then the cortical bone on the buccal aspect of the tooth is removed
down to cervical line.

Exposure of the crown of the tooth using a round bur.

Postage stamp technique
• In this technique a row of small holes is made(at 2-3mm
equidistance) with a small bur and then joined together either
with bur or chisel cuts.

Moore & Gillbe’s CollarTechnique
 Conventional technique 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 (mesial purchase point) is created with bur.
 Amount of bone sacrificed is less.
 Can be used in old patient.
 Convenient for patient.

• The surgeons should apply a handpiece load of approximately
300g and an irrigation rate of 15mL/mL to 24mL/min.
• For tooth sectioning – 300-550g
• Pressure applied for normal restorative dentistry-100-150g
(Sharon et al Oral SUR oral Med Oral Pathol Oral Radiol Endod 1999)

Lateral TrepanationTechnique
Bowlder Henry
 Employed to remove any partially formed unerupted 3rd molar that
has not breached the overlying hard & soft tissues.
 Age 9-18 yrs
 GA/LA with sedation.
 Excellent PDL healing on distal surface of 2nd molar.
 Bone healing is excellent as there is no loss of alveolar bone around
2nd molar.
 Disadvantage – increased buccal swelling

CHISEL TECHNIQUE THROUGH BUCCALAPPROACH
Elevation of mucoperiosteal flap
 Vertical limiting cut -5-6mm
 Oblique cut -45 deg
 Removal of triangular plate of bone
 Point of application of elevator
 Distolingual bone not fractured parallel to internal
oblique ridge due to the risk of fracture extending upto
the coronoid

SPLIT BONE TECHNIQUE
Sir William Kelsey Fry in 1933
Quick ,clean technique.
Reduces the size of the residual blood clot by means of
saucerization of the socket.
Suitable in young patients with elastic bone.
Increased incidence of post operative transient lingual
anesthesia.

LINGUAL-SPLITTECHNIQUE
Described by Sir William Kelsey Fry (1933).
Later popularized by Terence G ward(1956)
Specially for lingually placed tooth.
Modified by Dr. Davis & Lewis in 1960
SURGICAL BASIS OF LINGUAL SPLIT TECHNIQUE
Whenever tooth is extracted
Lingual cortical plate is resorbed

Procedure :
• Ward’s or Modified Ward’s incision
• Reflection of mucoperiosteal flap
• Removal of buccal plate expose the crown chisel is used and section
the lingual cortex by planning 45˚angle to upper border and cutting
edge parallel to external oblique ridge
• 3rd molar elevated from mesial aspect.
• If it is firm crown it sectioned at cervical

INCISION VERTICALSTOP
CUT
HORIZONTAL
CUT
SPLIT OF
DISTOLINGUAL
BONE
REMOVALOF
BUCCAL
&
DISTOLINGUAL
BONE
ELEVATION
REMOVAL OF
DISTOLINGUAL
BONE
CLOSURE
LINGUAL SPLIT TECHNIQUE

Modified Lingual Split Technique For Removal Of
Mandibular Third Molar (Dr. Davis 1979)
Not to separate the mucoperiosteom from lingual area of bone
Kamanishi modification:
Do not raise the lingual flap
Advance to the lingual side under the bone only to the extent
which is necessary.
Lewis modification:
Flap was made lingual to second molar instead of third.
Vertical lingual step cut just distal to second molar.
Lingual plate was hinged like an osteoplastic flap.
It is considered as combination of both lingual and buccal
approach

TOOTH DIVISION TECHNIQUE
Kelsey Fry
To reduce the removal of large amount of bone
Avoid damage to adjacent structures
Decreases dead space
Allows portions of tooth to be removed separately with
elevators
Direction depends primarily on angulation of impacted
tooth
 With a bur, tooth is sectioned 3/4th toward lingual aspect

Criteria Buccal Lingual
Access Easy in conscious patient Difficult in conscious
patient
Instruments Chisel and mallet or bur Only Chisel and mallet
Procedure Tedious Easy
Operating time Time consuming Less time
Technique Tech. easy Tech.difficult
Bone removal Thick buccal plate Thin lingual plate
Post op pain Less More-due to damage to
lingual periosteum
Post op edema More Less
Dry socket Incidence high – due to
damage to ext. oblique
ridge
Negligible-socket
eliminated
Buccal vs. Lingual approach

A line is drawn from the mesiolingual cusp till the
distal root of the impacted
third molar.
Half the distance measured is taken as the radius and
an arc is drawn.
If the arc touches the 2nd molar indicates locking of
tooth.
Then sectioning is mandatory.
Mesio distal diameter of crown and mesiodistal width
of roots are more than the space for exit of the tooth.
CRITERIA FOR SECTIONING OF TOOTH

Arc of Rotation
Howe GH. The management of impacted mandibular third
molars. In: Howe GH. Minor Oral Surgery. 3rd ed. Ross J.
Bastiaan, Wright , Oxford, London. 1995: 109-144.

SECTIONING OFTOOTH
Reduces the amount of bone removal required prior to elevation of
tooth.
Reducing the risk of damage to the adjacent tooth.
Once sufficient amount of bone removed, the surgeon should access the
need to section the tooth.
The direction in which the impacted tooth should be divided depends
primarily on the angulation of the impacted tooth & root curvature.

SECTIONING OFTOOTH
The sectioning can be performed with a bur or chisel.
The bur is used by most surgeons, but if a chisel is used it
must be sharp.
When the bur is used, the tooth is sectioned three- fourth of
the way towards the lingual aspect.
A straight elevator is inserted into the slot made by the bur
and rotated to split the tooth.

Sectioning of the crown of an impacted tooth, in the buccolingual
direction, which extends as far as the intraradicular bone.

A. buccal and distal bone are
removed to expose crown of
tooth to its cervical line.
B. The distal aspect of the
crown is then sectioned from
tooth. Occasionally it is
necessary to section the entire
tooth into two portions rather
than to section the distal
portion of crown only
C . A small straight
elevator is inserted into
the purchase point on
mesial aspect of 3rd
molar, & the tooth is
delivered with a
rotational and level
motion of elevator.
MESIOANGULAR IMPACTION

A. When removing a
vertical impaction, the
bone on the occlusal,
buccal, and distal aspects
of the crown is removed,
and the tooth is sectioned
into
mesial and distal portions.
B. The posterior aspect of
the crown is elevated first
with a Cryer elevator
inserted into a small
purchase point in the
distal portion of the tooth.
C. A small straight no.
301 elevator is then used
to lift the mesial aspect
of the tooth with a rotary
and levering motion.
VERTICAL IMPACTION

A.Removal of distal and
buccal underlying bone
B.The crown is sectioned
from the roots of the tooth and
is delivered from socket.
C, The roots are delivered
together or independently with a
Cryer elevator used with a
rotational motion. Saperation of
root into 2 parts - occasionally
the purchase point is made in the
root to allow the Cryer elevator
to engage it.
D, The mesial root of the
tooth is elevated in similar
fashion
HORIZONTAL IMPACTION

A.Removal of mesial & distal
boen. It is important to remember
that more distal bone must be
taken off than for a vertical or
mesioangular impaction.
B.The crown of the tooth is
sectioned off with a bur and is
delivered with straight
elevator
C, The purchase point is put into
the remaining root portion of the
tooth, and the roots are delivered by
a Cryer elevator with a wheel and-
axle
motion. If the roots diverge, it may
be necessary in some cases to split
them into independent portions
DISTOANGULAR IMPACTION

SMOOTHENING & DEBRIDEMENT OFSOCKET
Attention must be given to debriding the wound of all particulate bone
chips and debris.
Wound should be irrigated with sterile saline, taking special care to
irrigate thoroughly under the reflected soft tissue flap.
Remove any remaining dental follicle and epithelium.
The bone file is used to smooth any sharp, rough edges of bone.
A final irrigation and a thorough inspection should be performed before
the wound is closed.

SURGICAL CLOSURE
WEDGE REMOVAL
 Remove triangular wedge of soft tissue immediately posterior to
second molar- surgical drainage
 Excess tissue- elliptical incision

DEBRIDEMENT AND SMOOTHENING OF BONE
MARGINS
 Socket irrigation-saline, betadine
 Socket curettage
 Check for damage to adjacent tooth
 Smoothen socket margins
 Control heavy bleeding

Closure of soft tissue flap
 Return soft tissue flap to the original position
 Stabilize the flap to permit repair
 Resecure periodontal/ gingival attachments

IMPACTED MAXILLARY
THIRD MOLARS

• Classified according to the:
Position of long axis.
Relative depth.
Sinus approximation.

POSITION OF LONG AXIS
Mesioangular Distoangular
Vertical Horizontal
Can be
Buccally tilted
Palatally tilted

ACCORDING TO RELATIVE DEPTH
Class A Class B Class C
Sinus approximation No sinus approximation

Clinical examination
Inspection
Patient opens the mouth 25-30 mm
Partial eruption of crown
Pericoronitis
Periodontitis posterior to second molar
Palpation
Positioned buccally to second molar
Rounded bulge / sharp cusps of crown
Absence of these findings- third molar is directly posterior,
medial or extremely superior to second molar

RADIOGRAPHS
• Panoramic x- ray view
• Periapical views
• Bitewing view
• Occlusal radiographs

Intra Operative
1. During incision
a. Injury to facial artery
b. Injury to lingual nerve
c. Hemorrhage
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
COMPLICATIONS

Immediate
- Hemorrhage
- Pain
- Edema
- Drug reaction
Delayed
- Alveolitis
- Infection
- Trismus
POST OPERATIVE
COMPLICATIONS

HAEMORRHAGE
 The overall complication rate associated with the removal of third molars is
7% to 10%, and the risk of hemorrhage is 0.2% to 1.4%.
 Hemorrhage from the mandibular molars is more common than bleeding
from the maxillary molars (80% and 20%, respectively) because the floor
of the mouth is highly vascular.
 Furthermore, the distolingual aspect of the mandibular third molar region is
the most highly vascularized site, and this should be taken into
consideration when all third molars are to be removed.
 This area may encompass an accessory artery emanating
from the lingual aspect of the mandible, and bleeding may
be profuse if this vessel is cut.

Local hemostatic agents useful for controlling bleeding from
extraction socket

PAIN
Pain usually begins after the anesthesia from the procedure
wears off and reaches peak levels 6 to 12 hours
postoperatively. It is usually moderate and of short duration for
the first 24-48 hours .
 Pathophysiology of pain may be explained by facts that
following tissue injury or inflammation, there is a sequential
release of mediators from mast cells, the vasculature and other
cells.
Histamine and serotonin appear first, followed shortly after by
bradykinin and later prostaglandins.
The longer duration of the surgery leads a longer tissue injury.
In this way more mediators are released and therefore could be
a reflection of the severity of pain, swelling and trismus.

SWELLING/OEDEMA
• The swelling or surgical edema usually reaches a
maximum level 2 to 3 days postoperatively and should
subside by 4 days and resolve by 7 days.
• Mucoperiosteal flap designs may play also an important
role in postoperative surgical edema development, thus
those flaps which ensure a secondary healing, because of
wound drainage, lead to lower incidence of swelling.

TRISMUS
• Trismus or difficulty opening the mouth, is often the result
of surgical trauma and is secondary to masticatory muscle
inflammation following lower third molar surgery. The
patient may feel jaw stiffness with difficulty to brush, talk,
or eat normally.
• If the mouth stays open for too long, trismus may be
expected. So, its development is correlated with operation
time. In most cases, the trismus is temporary.
• Preoperative use of steroids may be helpful in reduction
of trismus.

DEFINITION-
·
I.R. Blum: Contemporary views on dry socket (alveolar osteitis): a clinical appraisalof standardization, aetiopatho
genesis and management: a critical review. Int. J. Oral Maxillofac. Surg. 2002; 31: 309 3–17
DRY SOCKET
Postoperative pain in and around the
extraction site, which increases in severity
at any time between 1 and 3 days after the
extraction accompanied by a partially or
totally disintegrated blood clot within the
alveolar socket with or without halitosis.”

First described by CRAWFORD-1896
SYNONYMS
Alveolar osteitis(AO)
Alveolitis
Localized osteitis
Alveolitis sicca dolorosa
 Localized alveolar osteitis
 Fibrinolytic alveolitis
 Septic socket
 Necrotic socket
 Alveolalgia

Mostly 1-3 days after extraction
UnlikelyBeforefirst operative day Because the blood contains anti-
plasmin that mustbe
consumed before clot disintegration can take place.
The duration of AO varies dependingon the severity of disease ,but it
usually ranges from 5-10 days
The incidence of alveolitis was 2.7 times greater among females than
among males.
ONSET AND DURATION

SIGNS AND SYMPTOMS
The denuded alveolar bone ma be painful and tender
Some patients may also complain of intense continuous
pain radiating to the ipsilateral ear, temporal region or the
eye
 Regional lymphadenopathy(occasionally)
Unpleasant taste(occasionally)
Trismus

 Multifactorial in origin
Suggested factors include
 Oral micro organisms(Treponema denticola)
 Difficulty and trauma during surgery
 Roots or bone fragments remaining in the wound
 Excessive irrigation or curettage of the alveolous afterextraction
 Physical dislodgement of the clot
 Local blood perfusion and anaesthesia
 Oral contraceptives-estrogens, like pyrogens, will activate the
fibrinolytic system indirectly
 Smoking
ETIOLOGY

Previous experience ofAO
Deeply impacted mandibular third molar (risk factor is directly
proportional to increasing severity of impaction)
Poor oral hygiene of patient
Active or recent history of acute ulcerative gingivitis orpericoronitis
associated with the tooth to be extracted
Smoking (especially >20 cigarettes per
day)
Use of oral contraceptives
Immunocompromised individuals
RISK FACTORS

PATHOGENESIS-
BIRN’S HYPOTHESIS

Antibacterial agents
Antiseptic agents and lavage - Chlorhexidine
Antifibrinolytic agents- Para hydroxybenzoic acid(PHBA)
Steroid anti-inflammatory agents-polylactic acid
Obtundant dressings
Clot supporting agents
PHARMACOLOGICAL MEASURES

Under Local aneasthesia
The clot devoided socket is thoroughly curetted, both from the floor ofthe
socket as well as from the bony walls
The sharp margins were trimmed & rounded
Any foreign bodies if present were thoroughlyremoved
The detached gingival margins were also scraped
The desired medications and precautions
MANAGEMENT

NERVE INJURIES
Incidence
 > 20% in the first 24 hours postoperatively.
 0.3% to 5.3 % after six months.
 Inferior alveolar nerve-
Immediate disturbance-4-5% (1.3-7.8%)
Permanent disturbances -<1% (0-2.2%)
 The nerve damage depends of several factors such as type of anesthetic, state of
eruption, depth of impaction, patient age, experience of the surgeon and type of
lingual flap retraction.
Clinical symptoms of lingual nerve damage
 Pain,drooling, tongue biting
 Burning sensation of the tongue, burns on the tongue from hot food and drinks
 Change in speech pattern and change in taste perception of foods and drinks

• Neurosensory dysfunctions associated with nerve injuries
includes anesthesia or numbness (loss of sensation,
because of damage to a nerve or receptor)
• Paresthesia (abnormal touch sensation, such as burning,
prickling or formication, often in the absence of an
external stimulus), dysesthesia or hypoesthesia.
• Nerves can be damaged by traumatic, compressive or
toxic injuries, which usually result in neuropraxia;
however traumatic anatomic breakdown of the nerve may
occur leading to axonotmesis or neurotmesis.
.

• Neuropraxia is defined as physiological damage to the
myelin sheath after transient ischemia or metabolic
disturbance characterized by transient impossibility to
transmit action potentials.
• Axonotemesis is anatomic breakdown in the axon without
cutting the nerve trunk. It may be seen even in cases
where the irritating factor (for example displaced root
fragment near inferior alveolar nerve) is not removed.
• Complete breakdown of axons is defined as neurotmesis.
Axonotmesis and neurotmesis can lead to subsequent
paresthesia which may almost never resolve.

A method of removing the crown of a tooth but leaving the rootsuntouched,
which may be intimately related with the inferior alveolar nerve, so that the
possibility of nerve injury is reduced.
first proposed in 1984 by Ecuyer and Debien .
Also known as intentional partial odontoectomy, partial root removaland
deliberate vital root retention
BASIS FOR CORONECTOMY
It is common practice for broken fragments of the root of vital teeth to beleft
in place and most heal uneventfully.
Renton et al.and Leung et al. (randomised clinical trial), Hatano et al. (case
control study) and and O‟Riordan (retrospective study) provided evidence
that coronectomy decreases the risk of IDNI when compared to traditional
extraction of Mandibular Third molars.
CORONECTOMY

Coronectomy:A, cutting crown below cement-enamel junction (arrow);
B, trimming cutted surface to less than 3 to 4 mm below alveolar crest.
A B

The removal of the overlying bone to allow for the tooth to erupt away from the IAN,
in cases of incomplete root formation in younger patients 14 to 18years old
PERICORONAL OSTECTOMY

CAUSES
 Excessive apical force during the use of elevators.
 Incorrect surgical technique.
 Maxillary third molars have only a thin layer of bone posteriorly
separating them from the infratemporal space and anteriorly separating
them from the maxillary sinus.
 IN mandibular third molar, the thinness of the lingual cortical
bone predisposes to displacement in a lingual direction.
 Distolingual angulation of the tooth predisposes to the displacement.
ACCIDENTAL DISPLACEMENT OF THIRD
MOLARS
Displacement to maxillary sinus
Displacement to pterygopalatine fossa
Displacement to buccal space
Displacement to pterygomandibular space
Displacemnt to submandibular space

Mandible fracture
Alveolar Process Fracture
the lingual plate, alveolar plate, buccal cortical plate, palatal
cortical plate, and labial cortical plate(s) may fracture during
procedure.

REFRENCES
Oral and maxillofacial surgery – LASKIN volume
Oral and maxillofacial surgery - FONSECA volume I
Expert third molar extractions- Asanami Kasazaki
Killey and Kay's outline of oral surgery
Principles of oral & maxillofacial surgery-Peterson
Textbook of oral & maxillofacial surgery-Neelima Anil Malik
Textbook of oral & maxillofacial surgery-Gordon w Pedersen

• Textbook of oral & maxillofacial surgery-Harry Archer
• Impacted teeth – Alling and Helfrick
• Textbook of oral & maxillofacial surgery-Daniel M Laskin
• The impacted lower wisdom tooth –Macgregor
• Expert third molar extractions- Asanami Kasazaki
• Killey and Kay's outline of oral surgery
• Principles of oral & maxillofacial surgery-Peterson
• Textbook of oral & maxillofacial surgery-Neelima Anil Malik
• Textbook of oral & maxillofacial surgery-Gordon w Pedersen

• m. a. pogrel, j. s. lee, and d. f. muff, “coronectomy: a technique to
protect the inferior alveolar nerve,” journal of oral and maxillofacial
surgery, vol. 62, no. 12, pp. 1447–1452, 2004.
• t. renton, m. hankins, c. sproate, and m. mcgurk, “a randomised
controlled clinical trial to compare the incidence of injury to the inferior
alveolar nerve as a result of coronectomy and removal ofmandibular
thirdmolars,” british journal oforal and maxillofacial surgery, vol. 43,
no. 1, pp. 7–12, 2005.
• saravana kumar et al.,“study of comparison of flap designs – comma
incision versus standard incision in impacted third molar surgery.
• DISSECTION AND DETAILED ANATOMY OF AN IMPACTED
MANDIBULAR THIRD MOLAR Radu C. Ciuluvică, Mugurel C. Rusu

Impacted third molars

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