MANDIBULAR IMPACTION ,EVIDENCED BASED PPT

MANDIBULAR
IMPACTIONS
PRESENTER
DR . PRATEEKSHA DAS

Contents:
Introduction
Glossary of Terms
Causes
Theories of Impaction
Classification
Rationale for Removal
Clinical & Radiological Assessment
Armamentarium
Surgical Procedure
Complication
Recent Advances
Conclusion
references

INTRODUCTION
• The management of impacted teeth is the most common treatment
done by oral and maxillofacial surgeons in day to day practice.
• The tooth becomes impacted due to prevention of eruption by
adjacent teeth, excessive soft tissue etc..
• Extensive training, skill, and experience are necessary to perform
this procedure with minimal trauma.

Glossary of terms:
•Impaction occurs where there is prevention of complete
eruption of one tooth by another into a normal
functional position , due to lack of space (in the dental
arch), obstruction by another tooth or development in
an abnormal position.
•An impacted tooth may be:
•Completely impacted: when entirely covered by soft
tissue and partially or completely covered by bone
within the bony alveolus.
•Partially erupted: when it has failed to erupt into a
normal functional position.

• American society of oral surgeons 1971
• IMPACTED TOOTH : 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.
• MALPOSED TOOTH : A tooth, unerupted or erupted, which is in
an abnormal position in the maxilla or mandible.
• UNERUPTED TOOTH : A tooth not having perforated the oral
mucosa.

Archer:
 Maxillary 3rd molars.
 Mandibular 3rd molars.
 Maxillary cuspids.
 Mandibular bicuspids.
 Mandibular cuspids.
 Maxillary lateral incisors
 Maxillary bicuspids.
 Maxillary central incisors.
ORDER OF IMPACTION

According to Laskin
Mandibular Third molars
Maxillary Third molars
Maxillary canines

Causes of impaction:
Local causes:
• Irregularity in the position and pressure of an adjacent tooth.
• The density of overlying or surrounding bone.
• Long continued chronic inflammation with the resultant increase in
density of the overlying mucous membrane.
• Lack of space due to under developed jaws.
• Prolong retention of the primary teeth.
• Premature loss of primary teeth.
• Acquired diseases – such as Necrosis due to infection or abscess and
inflammatory changes in the bone due to exanthematous diseases in
child.
• Dilaceration.

Systemic causes:
a) Prenatal causes:– Hereditary
- Miscegenation
b) Post natal causes:– All the conditions that may interfere with
development of child.
- Ricketts. - Anemia
- Congenital syphilis - Tuberculosis
- Endocrinal dysfunction
c) Rare conditions:
- Cleidocranial dysostosis - Oxycephaly
- Cleft palate - Achondroplasia
-Syndrome associates with micrognathia.
•

THEORIES OF IMPACTION
By Durbeck
1) Orthodontic theory:
• Growth of the jaw occurs in downward and forward direction and
movement of teeth occurs in forward direction.
2) Phylogenic theory:
• Nature tries to eliminate the disused organs
3) Mendelian theory: Heredity is most common cause
4) Pathological theory
5) Endocrinal theory:

Classification suggested by Pell & Gregory(1933), which includes portion of
George B Winter’s classification(1926):
A. Availability of space between 2nd
molar and ramus of the
mandible (horizontal plane):
Class I
There is sufficient space
between the ramus of the
mandible & the distal side of
the second molar for the
accommodation of the
mesiodistal diameter of the
crown of the third molar.

Class II
The space between the ramus of the mandible & the
distal side of the second molar is less than the
mesiodistal diameter of the crown of the third molar.

Class III
Complete or most of the third molar is located within
the ramus.

•B. Relative depth of the 3rd molar in bone (vertical
plane):
Position A:
The highest portion of the tooth is on a level with or
above the occlusal plane.
Position B:
The highest portion of the tooth is below the occlusal plane,
but above the cervical line of the second molar.
Position C:
The highest portion of the tooth is below the cervical line
of the second molar.

• C. Long axis of the impacted tooth in relation to the long axis of
the 2nd molar (angulation ; Winter’s classification):
1. Mesioangular
2. Vertical.
3. Distoangular.
4. Horizontal.
5. Inverted.
6. Buccoangular [Laskin]
7. Linguoangular [Laskin]

Killey & Kay’s classification:
a) Based on angulation and position:
-Same as George Winters.
b) Based on the state of eruption:
- Completely erupted
- Partially erupted
- Unerupted
c) Based on pattern of roots:
1) - Fused roots.
- Two roots.
- Multiple roots
2) Root pattern may be –
- Surgical favourable
- Surgical unfavorable

•Indications:
1. Overt or previous history of infection including pericoronitis
This indication will generally exclude transient/self-limiting
‘inflammation’ that may be associated with normal eruption of
any tooth
Prevalence: It is the most common stated reason for removal.
• [BJOMS 2006 page 42-45]
Rationale for removing impacted tooth.

2. Unrestorable caries
• Prevalence: van der Linden et al
1995 in a review of 1001 patients
whose third molars were removed
aged 13-75 years reported caries in
7.1% of impacted third molars and
in 42.7% of adjacent molars (204
and 1227 of 2872 teeth
respectively). [Impacted
teeth & their influence on the Caries
Lesion Development 2012 page-6
3. Non-treatable pulpal and/or
periapical pathology.
4. Cellulitis, abscess and
osteomyelitis

5. Periodontal disease :
• Impacted third molars associated with periodontally
involved adjacent (usually second molar) teeth
should be removed early as the disease may be
irreversible by 30 years.
6. Orthodontic abnormalities
• However there is little rationale based on present
evidence for excision of lower third molars solely to
minimise present or future crowding of lower
anterior teeth.
7. Prophylactic removal in the presence of specific
medical and surgical conditions
8. Internal/external resorption of
tooth or adjacent teeth

9. Pain directly related to a third molar
• It is important to avoid an erroneous diagnosis
of third molar related pain which may in reality
be associated with the temporomandibular
joint and masticatory musculature.
• Prevalence: great variation has been reported
between 5 – 53%
10.Tooth in line of bony fracture or impeding
trauma management
• On occasions it is recommended that a third
molar be left in situ at the time of initial
fracture treatment.However in most cases
removal is required at a later time.
11. Fracture of tooth

12.Disease of follicle including cyst/tumour
• Prevalence: 2-11% for cyst and between 0.0003-2% for
odontogenic tumour.
13.Tooth/teeth impeding orthognathic surgery or
reconstructive jaw surgery.
14. Tooth involved in/ within field of tumour resection.
15. Satisfactory tooth for use as donor for transplantation .
16.An unerupted 3rd
molar in an atrophic mandible.
17.Contralateral tooth removal under GA.

Contraindications:
In patients whose 3rd
molar would be judged to erupt
successfully
Extremes of age.
Medically compromised patient.
Probable excessive damage to the adjacent structures.
In patients with deeply impacted 3rd
molar with no history or
evidence of systemic pathology.
In patients where risk of surgical complications is judged to
be unacceptably high.

ABSOLUTE CONTRAINDICATIONS
Acute pericoronitis.
Acute necrotising ulcerative gingivitis.
Haemangioma.
Thyrotoxicosis.

Clinical Examination
History:
 Most patients are symptomatic.
If so then associated with-
(Pericoronitis / pain / swelling of the face / trismus /
enlarged tender lymph nodes)
Intraoral examination-
 Size of oral cavity.
 Degree of mouth opening.
 Size of tongue.
 Palpation for external oblique & internal oblique ridge in
relation with 3rd
molar.

RADIOLOGICAL ASSESMENT
RADIOGRAPHS: IOPA,OCCLUSAL,OPG, SHIFT CONE TECH. LAT. OBLIQUE
•ACCESS
•POSITION & DEPTH
•ROOT PATTERN OF 3rd MOLAR
•SHAPE OF CROWN
•TEXTURE OF INVESTING BONE
•POSITION & ROOT PATTERN OF 2nd MOLAR
•INFERIOR ALVEOLER CANAL

Radiological assessment:
Orientation of the tooth.
Position and depth of the tooth
Winter lines.
 White line Amber line Red line:
less than 5mm long red line can conveniently be removed with
ease under local anesthesia.every additional mm renders the
removal of impacted teeth three times more difficult. If the line is
more than 9mm they can be safely removed under GA

MANDIBULAR IMPACTION ,EVIDENCED BASED PPT

Root pattern: Either Favourable
Unfavourable
Shape of the crown.
Texture of investing bone.
Position and root pattern of 2nd
molar.
Relationship of 3rd
molar to the inferior dental canal.
Darkening of
roots
Deflection of
roots
Narrowing of
roots
Dark & Bifid apex Interruption of white
line of canal
Diversion of canal Narrowing of canal

Radiographic assessment of inferior alveolar canal

FACTORS RESPONSIBLE FOR INCREASING THE
DIFFICULTY SCORE FOR REMOVAL OF IMPACTED 3rd
MOLARS
1. Difficult access to the operative field:
a. Small orbicularis oris muscle.
b. Inability to open mouth wide enough.
c. Trismus.
d. OSMF.
e. Macroglossia.

2. As per the angulation.
3. As per the depth.
4. As per the space available for the eruption.
5. Dilacerated roots.
6. Hypercementosis.
7. Extremely dense bone.
8. Proximity to mandibular canal.
9. Ankylosed impacted tooth.
10. Large bulbous crown.
11. Long slender roots.

A) Angulations Value
- Mesioangular 1
- Horizontal / transverse 2
- Vertical 3
- Distoangular 4
B) Depth
- Level A 1
- Level B 2
- Level C 3
C) Ramus relationship
- Class I 1
- Class II 2
- Class III 3
DIFFICULTY INDEX
Classification: Padersons Scale.
Difficulty scores:
Very difficult 7-10
Moderately 5-7
Minimally 3-4
Example: Mesioangular tooth 1 difficulty score is
Level B 2 5-7
Class III 3 Moderately difficult

•Although the Paderson scale can be used for predicting
operative difficulty, it is not widely used because it does not
take various relevant factors into account, such as bone
density, flexibility of the cheek and buccal opening.
•On the other hand, the modified Parant scale
was implemented to predict post-operative difficulties.

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° - 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’ASSESSMENT by McGregor (1985)

• The scoring by this system helps the beginners to anticipate problems and
to avoid difficult impactions.
• disadvantage of this method is that it is related only to radiological
features alone, the details of the surgical procedures are not considered.
• The total scoring is directly related corresponding difficulties in removing
that impacted teeth.

Armamentarium
(i) Local anesthesia (vi) needle holder (xi) cross bars
(ii) 15 no. blade (vii) suture material (xii) retractors
(iii) Tweezers (viii) scissors
(iv) Curette (ix) chisels
(v) Elevators (x) mallet

•Perioperative medication:
Drugs prescribed will vary according to local and/or
individual policies and also for specific patients.
However as a guide those in common use include:
1. Conventional sedative/antiemetic premedication.
2. Topical local anaesthetic cream at site of planned
injection .
3. Non steroidal anti-inflammatory drugs (NSAIDs) for
analgesia and to reduce oedema and trismus.
4. Steroids (eg: dexamethasone) to reduce oedema and
trismus.
5. Antibiotics to reduce incidence of local osteitis /infection
which may cause prolonged pain and swelling.

SURGICAL TECHNIQUE
GENERAL PRINCIPLES FOR SURGICAL TECHNIQUE OF
IMPACTION REMOVAL:
• Reflect mucoperiosteal flap to obtain good visual access.
• Remove labial bone with high speed surgical drill using round or cross-cut bur.
• Expose crown of impacted tooth upto CEJ and make room for elevator placement.
• Attempt to gently evaluate for mobility with elevator.
• Section the crown with high-speed surgical handpiece.
• Care should be taken to protect the lingual soft tissue and depth of surgical cut should not be
too much.

• Straight elevator should be used to separate
crown from adjacent tooth.
• Deliver roots with root tip elevators or crane
pick.
• Carefully remove the follicular soft tissue and
tease it out from surrounding mucosa.
• Inspect the bony crypt for loose debris or any
bleeding problems and smooth the bony
margins with bone file.
• Copious irrigation of socket and beneath soft
tissue should be done.

• Reapproximate soft tissue flap and close with 3-0 or 4-0
chromic or black silk sutures.
• Consider intraoral injection of steroids if extensive bone
surgery has been performed. 4mg of dexamethasone can be
injected into masseter muscle on each side.
• Evaluate for post surgical bleeding prior to discharge.

WARDS INCISION MODIFIED WARDS INCISION

INCISIONS AND FLAP DESIGNS
• Distal relieving incision
• Envelop flap
• Buccal extension flap
• Triangular flap

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.

TECHNIQUES FOR REMOVAL OF DIFFERENT TYPES OF MANDIBULAR 3rd
MOLAR IMPACTIONS

MOORE/GILLBE COLLAR TECHNIQUE
• A mucoperiosted flap of standard design is
elevated exposing the underlying bone.
• A rose-head bur (no.3) is used to create a
‘gutter’ along the buccal side and distal
surface of the tooth.
• The lingual soft tissue should protected
with a periosteal elevator during the
removal of the distolingual spur of bone

• A mesial point of application is created with the bur, and a straight elevator is
used to deliver the tooth.
• After delivery of the tooth has been effected, the sharp bone edges are smoothed
with a vulcanite bur, and the cavity is irrigated.
• The wound is closed with sutures or the buccal flap is tucked into the cavity and
held against the bone with a pom-pom soaked in Whitehead’s varnish.

Split bone technique - Sir William Kelsey
Fry
VERTICAL STOP
CUT
LINGUAL CUT
ELEVATION
CLOSURE
HORIZONTAL
CUT
REMOVAL OF
BUCCAL BONE
REMOVAL OF
# LINGUAL BONE
INCISION

ADVANTAGES:
Faster tooth removal.
Less risk of inferior alveolar nerve damage.
Reduces the size of residual blood clot by means of saucerization of the socket .
Decreased risk of damage to the periodontium of the second molar.
Decreased risk of socket healing problems.

•DRAWBACKS OF THIS TECHNIQUE ARE:
Risk of damage to the lingual nerve.
Increased risk of postoperative infection and greater danger of
spread.
Patient discomfort due to the use of a chisel and mallet for lingual
bone removal or fracturing.
Only suitable for young patients with elastic bone in which grain is prominent

MODIFIED LINGUAL SPLIT TECHNIQUE FOR
REMOVAL OF MANDIBULAR THIRD MOLAR (Dr.
DAVIS 1979)
DISTAL CUT
VERTICAL STOP CUT
INCISION

LATERAL TREPANATION TECHNIQUE
(BOWDLER HENRY).
Bone removal Tooth sectioning
Flap design

ADVANTAGE
• Partially formed unerupted 3rd molar can be
removed. (9-16yr.)
• Can be preformed under general or regional
anesthesia with sedation.
• Post-op pain is minimal.
• Bone healing is excellent and there is no loss
of alveolar bone around the 2nd molar.

DISADVANTAGE
• Virtually every patient has some post operative buccal swelling for 2-
3 days after surgery

BUCCAL VS LINGUAL APPROACH
Criteria Buccal Lingual
Access Relatively easy in the conscious patient Relatively difficult in the conscious
patient
Instruments Chisel and mallet or bur Only chisel and mallet
Procedure Tedious Easy
Operating time Time consuming Less time consuming
Technique Easy to perform, hence traditionally
popular
Technically difficult, hence not
popular among all dental surgeons
Bone removal Thick buccal plate Thin lingual plate
Postoperative
pain
Less More due to the damage of lingual
periosteum
Postoperative
edema
Obviously more Less
Dry socket Incidence is high due to the damage of Incidence is negligible since socket

CHISEL VS BUR
Sl.No Criteria. Chisel & Mallet Bur
1. Technique Difficult Easy.
2. Controll 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.

•Excision of impacted mandibular
molar from edentulous areas
• Careful radiographic studies made to prevent fracture of mandible.
• The radiographs will reveal the position, size and shape of
embedded tooth and the amount of overlying bone.

SURGICAL CLOSURE
1) Wedge removal
2) Debridement
3) Intra-alveolar dressings
4)Closure of soft tissue flap
5) Intraoral dressings

• Level A. The crown of the impacted canine
tooth is at the cervical line of the adjacent
teeth.
• Level B. The crown of the impacted canine
tooth is between the cervical line and root
apices of the adjacent teeth.
• Level C. The crown of the impacted canines
is
beneath the root apices of the adjacent teeth.
Depth classification of impacted canine

SURGICAL SIDE-EFFECTS AND
COMPLICATIONS
Intra operative complications:
1. During incision
a.Injury to facial artery.
b.Injury to lingual nerve.
2. During bone removal
a. Damage to second molar.
b. Slipping of bur into soft tissue & causing injury.
c. Fracture of the mandible when using chisel &
mallet.

a. Luxation of neighbouring tooth.
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 canal.
f. Breakage of instruments.
g. TMJ Dislocation.
3.DURING ELEVATION OR TOOTH REMOVAL

• Tooth segment displaced into the
submandibular/Pterygomandibular space.
• Tooth segment displaced through very thin cortex
of submandibular fossa may remain in
submandibular gland.
• 3 options:
1. Indefinite observation and treatment as
indicated if on inflammatory process should occur.
2. Delay of removal for 3/4 weeks to await
stabilizing fibrosis and then removal of segment.
3. Immediate/early removal.

• TMJ pain
• During impacted tooth surgery, the jaw should be supported so that the
pressure required to remove the tooth are not transmitted to TM Joints.
• A rubber bite block, placed on the opposite side of the surgery, will
stabilize mandible and decrease TMJ strain.
• The rare postoperative TMJ pain can be managed by soft diets, restricted
activity of mandible.
• prescription of NSAIDS, orthodontic splints may also be indicated.

Soft Tissue injuries: can be minimized by
• Careful and controlled use of surgical instrument
• Contact of skin/mucous membrane with the shank
of burs avoided, can creates a deep abrasion/burn.
Similar injury may occurs if hand piece
overheats/hot.
• Puncture wound does not require special
management
• Skin abrasion allowed to repair by secondary
intension.

• . Fracture of Mandible
• Fracture may be occurs in the region
of angle of mandible.
• Predisposing factors
1. Injudicious force during removal of
deeply impacted tooth
2. Patients with osteoporosis and other
disorder of bone.
3. Mandible weakened by cysts or
tumors.
4. Severely atrophic mandible
5. Infection involving bone surrounding
the tooth.
• The patients with above conditions are
more likely to experience fracture of
mandible.

Postoperative Complication
Post operative Hemorrhage:
• Hemorrhage most of the time is due to local rather than systemic factor.
• Thorough History taken prior to impaction surgery.
(i) Patients taking NSAIDs on chronic basis may affect platelet function
causing prolonged BT
(ii) Patients taking anticoagulants.
(iii) Coagulopathy disorders.
• When the bleeding is local an aggressive approach is usually indicated.
• Vital signs should be obtained and recorded. IV infusion started.
• Pressure must be used.
• Status, local haemostatics, crushing the bone over bleeding site are used
whenever indicated.

• Ecchymosis
• The raising of Intraoral flaps may produce a normal postoperative
ecchymosis, creating subcutaneous discolorations in the facial tissue.
Usually it is seen in buccal facial space, between elderly patients
ecchymosis may dissect to distant sites.
• Trismus
• Infections
• Dry socket

• Neurological complications of surgery to impacted teeth
• Clinical evidence of nerve injury is reported in less than 0.5% to 5% of all
surgeries for impacted teeth.
• Inferior alveolar nerve is most frequently affected followed by lingual nerve.
• Majority of patient’s nerve injuries related to surgery for impacted teeth are
caused by benign nerve exposure, extra neural toxic metabolic factors, and
transient mild compression by nerve stretching. Usually of type I and type II
nerve injuries.
• Recovery occurs within 6 to 12 months
• These patients require physical, medical and behavioral support.

Use of Erbium (Er):YAG laser
[by M.Abu-Serriah / A.Ayoub : Bjoms 2004; 42:
203-208]
Adv:
Less stressful
Less unpleasant
No vibrations & sound
Sharp clean cut through the bone & tooth
Can be used in anxious patients
Disadv:
It is more technique sensitive.
more chances of Trismus.
Time consuming
Costly
Recent Advances:

Use of endoscopic approach for ectopic
mandibular 3rd molar
(BJOMS 2003; Oct. 41: 340-42)
Adv:
Less tissue damage
Good elimination
Clear magnified visualization of operative field
More conservative surgery with precise
dissection.
Disadv:
Costly
Needs basic equipments
Good eye coordination and training

REFERENCES
• Impacted teeth – Charles C. Alling
• Peterson’s Principles of oral and maxillofacial surgery, 2nd
edition, vol. 1.
• Atlas of oral & maxillofacial - Mcgowans
• Textbook of oral and maxillofacial surgery, vol. 2, Laskin.
• Textbook of oral and maxillofacial surgery-Kruger
• Surgery of the mouth and jaws-Moore
• The management of patients with third molar (syn: wisdom)
teeth- Faculty of Dental Surgery The Royal College of Surgeons
of England
• (Oral Surg Oral Med Oral Pathol Oral Radiol Endod
2000;90:140-3)
• Mohammad S Sulieman. Al–Rafidain Dent J Vol. 5, No. 1, 2005
• British Journal of Oral and Maxillofacial Surgery (2004) 42, 21
—27

THANK YOU
DR. PRATEEKSHA DAS ,MDS.

MANDIBULAR IMPACTION ,EVIDENCED BASED PPT

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