The document discusses impacted third molars, including their classification, surgical removal procedure, and potential complications. It begins with definitions of tooth impaction and discusses causes such as insufficient jaw space. It then covers classification systems involving angulation, depth, and relationship to surrounding structures. Indications for removal include recurrent infections, cysts/tumors, and facilitating other procedures. The surgical procedure is outlined in steps including incisions, bone removal, tooth sectioning and extraction. Risks like nerve injury are also addressed based on radiographic findings. In summary, the document provides an overview of impacted third molar diagnosis, treatment planning, surgical techniques and considerations.

1. MANDIBULAR 3RD MOLAR IMPACTION-
Classification, Surgical procedure &
Complication
BY- RESHA GHOSH,( FINAL YEAR)

2. INTRODUCTION
 The term “impaction” originates from a Latin word “impactus”(wedged)
 Prevalence of tooth impaction is a common dental anomaly.
 The 3rd molar is the most frequently impacted tooth,with a frequency of
occurrence generally reported to be from 16.7% to 68.9%(Queck et al.
2003)
 They are retained for the patient’s lifetime,unless surgically removed or
exposed &brought into alignment by orthodontics.
 The early detection of tooth impaction is very important from a
therapeutic point of view,as the presence of impacted tooth may cause
many complications.
 Frequency of impaction is more in mandible than maxilla.with significantly
higher frequency in females than males.

3. DEFINITIONS
A. According to WHO:
“An impacted tooth is the one that is unable to fully erupt in its normal functional
occlusion/location by its expected age of eruption because it is blocked by overlying soft tissue or
bone or another tooth.”
B. According to Archer(1975):
“An impacted tooth or an embedded tooth is the tooth that has failed to erupt
cpmpletely to its correct normal position in the dental arch,and its eruption potential has been lost.”
Fully impacted tooth is completely encased in the jaw bone.
Partialy impacted tooth is the one, which is not completely encased in the jaw
bone and has communication in thhe oral cavity.

4. Causes of Impaction of Teeth
 3rd molar tooth impactionThe causes of impaction of teeth are still not clearly
understood.They appear to be multifactorial.Currently,insufficient amount of space in
the jaw distal to the second molar is considered to be the most significant
reason.The incidence of mandibular is nearly(17-32)%.
 1.Durbeck orthodontic theory(inadequate space in the dental arch for eruption):
Growth of the jaw&teeth occurs in forward direction,any interference in growth pattern will
cause impaction because of small jaw with decreasd space.
 2.Phylogenic theory(Nodine1943):Due to the evolution over centuries,the human jaw size
is becoming smaller than our ape like ancestors,& since the 3rd molar tooth is last to
erupt,there may not be room for it to emerge in the oral cavity.The modern food habits are
changed frpm earlier raw,fibrous diet to cooked/processed food,which does not require
forceful mastication,which offers less stimulation for jaw growth( disuse theory).
 3.Mendelian theory: Here genetic variations/genetics play a major role.If the
individual genetically receives a small jaw from one of the patient and/or large teeth
from the other parent,then impacted teeth can be seen,because of “lack of space.”

5. Factors responsible for impaction of a tooth (Archer1975)

6. Indications for removal/extraction of impacted 3rd molar teeth
1.Recurrent pericoronitis/pain:Pericoronitis is an infection with associated inflammation of gingival&contiguous soft tissue,covering the
crown of the partially erupted impacted mandibular 3rd molar and its associated follicle.It is reported to be common in vertical(23%) type of
impactions in case of 27 to 34% of patient.3rd molars with peticoronitis are removed to prevent recurrent episodes of it.
2.Impacted 3rd molar may decrease the amount of bone on the distal aspect of 2nd molar & may lead to periodontal defect.25% of patients
with aymptomatic 3rd molars were found to have deep periodontal pocket&attachment loss. Deep periodontal pocket more than or equal to 5mm
depth,distal to 2ndmolar associated with partialy erupted 3rd molar is often difficult to manage.
3.Prevention of root resorption and caries: Caries of the impacted tooth crown&the adjacent tooth at cervical area(3-28%) can be
seen due to the accumulation of biofilm& an inability to access and clean the aera.Root resorption of the distal root of the adjacent 2nd molar is
seen usually in 21-30 years of age group(7-24%) due to pressure from the eruptive 3rd molar&chemical mediators secreted by reduced enamel
epithelium.Prophylactic removal of impacted tooth is indicated here.

7.  4.Prior to orthodontic treatment: to control the tooth crowding in the mandible.
 5.Prevention or management of cysts and tumors associated with impacted 3rd molar of
odontogenic origin: 1 to 5% chances for cystic changes&tumors may range from 0.1-0.2% from dental
follicle.(seen under40 years of age group)
 6.Prevention of jaw angle fracture: Sinn et al. reported that impacted or submerged 3rd molar decreases the
amount of bone support & weakens the angle of the mandible.Patient engaged with sports like
football,rugby,martial arts etc. may get their impacted 3rd molars removed to prevent angle fracture.
 7.For the preparation of orthognathic surgery: prior to sagittal split osteotomy of ramus in oder to avoid
bad split/inadvertent fracture of mandible,lower 3rd molars extracted at least 1 to 2 months before majort
sugery.
 8.Management of preprosthetic concerns: Presene of impacted tooth in the residual ridge may cause
obstruction to the placement of a partial or complete denture.before the fabrication of the prosthesis,
impacted teeth should be removed.
 9.Impacted teeth in the line of fracture
 10.Buccoversion of partially reupted impacted molars may cause constant trauma to the cheek,leading to
ulceration,frictional keratosis or irritational fibroma.

8. Classification of impacted third molars
 Mandibular impacted 3rd molar are traditionaly classified radiographycally by angulation,depth&arch length or
by relationship to the anterior aspect of the ascendingmandibular ramus.
 1.Winter’s classification(1926):
A. Angulation: According to the position of the impacted 3rd molar to the long axix of the 2nd molar,this
classication is suugested for-

9.  B.Depth: As per the relationship to the occlusal surface of the adjoining 2nd molar of the impacted mandibular 3rd molar,the
depth can be judged:
• Position A: The highest position of the tooth is on a level with or above the occlusal line.
• Position B: The highest position of the tooth is below the occlusal plane,but above the cervical level of 2nd molar.
• Position C: The highest position of the tooth is below the cervical level of the 2nd molar.
 2.Pell and Gregory classification(1933):
• Relationship of the impacted lower 3rd molar to the ramus of the mandible &the 2nd molar[based on the space available distal
to the second molar]:
• CLASS 1:Sufficient space available between the anterior border of the ascending ramus &the distal side of the 2nd molar for
the eruption of the 3rd molar.
• CLASS 2: The space available between the anterior border of the ramus & the distal side of the second molar is less than
mesiodistal width of the crown of the 3rd molar,It denotes that,distal portion of the 3rd molar crown is covered by the bone
from the ascending ramus.

10. • CLASS 3: The 3rd molar is totally embedded in the bone from the ascending ramus,because of absolute lack
of space

11. 3.Quek et al.(2003)Introduced Measurment Of Angulation of Impaction:
 Here,the angle is measured by a protractor in degrees formed between the intersected long-axis of the 2nd and
3rd molar.
• Vertical(10-10º)
• Mesioangular(11-79º)2
• Horizontal(80-100º)
• Distoangular(-11º-79º)
• Others: Distoangular/mesioangular/
horizontally inverted(111ºto-80º)

12. RADIOLOGICAL EXAMINATION OF IMPACTED TEETH
1.Intraoral x-ray:
• Intraoral x-rays are possible,if tooth is in the alveolus &not in the ramus.
• Possible if oral opening is adequate.
• If there is no gagging.
• Useful to study the relation with adjoining tooth,configuration of the roots& status of the crown.
• Useful to record the relationship with inferior alveolar canal
• Tube shift or buccal object rule should be followed for periapical x-rays.
2.Extraoral x rays:
• Orthopantomogram(opg)
• Lateral oblique view
• Mandible
 Indicated in:
 Patients with restricted oral opening/treismus/excessive
Gagging.
 To study the relationship of the tooth to the inferior alveolar
Nerve(IAN).

13. A. Multiple impacted teeth
B. Kissing molars
C. Multiple impacted teeth
D. Multiple impacted teeth plus associated
keratocyst with impacted lower canine
E. OPG showing bilateral impacted lower
3rd molar:left 3rd molar associated with
cystic lesion
F. Deep impacted lower 3rd molar,almost
touching the lower border of the
mandible&associated with odontome
G. a rare case of impacted 4th molars;right
lower 4th molar is geminated with 3rd
molar.

14. FACTORS RESPONSIBLE FOR INCREASING THE DIFFICULTY SCORE FOR REMOVAL OF IMPACTED TEETH
1. As per depth
2. As per angulation
3. As per the space available for eruption
4. Crown size
5. Configuration of the roots of the impacted tooth:
-length of the roots
-root development
-curvature of the root
-root size
6.Bone texture and density
7.Size of follicular sac(non existent/narrow follicular sac around the crown will require bone cutting
Around the crown)
8.Space or contact in relation to mandibular second molar( if the impacted tooth is locked against
the crown of the second molar,then sectioning of the tooth should be planned)

15. Related,but non involving
the canal
Related to change in root Related with changes in
canal
Close proximity of the root
to canal but intervening
bone separates the both-
1.separated,2.adjacent,3.sup
erimposed.Trace the outline
of the root as well as
canal,which will show no
disturbance
1Darkening of the root
2.Dark and bifid root
3.Narrowing of the root
4. Deflected root
1. Interruption(loss of
lines)-the dense roof &
floor of the canal is
seen as 2 white
radiopaque lines(tram
lines)
2. Narrowing of canal
3. Diversion of canal
RADIOLOGICAL PREDICTION OF INJURY TO THE INFERIOR ALVEOLAR NERVE

16. A &B: Darkening of the root
C &D: Deflection of the root
E: Narrowing of root
F&G: Dark& bifid apex.
H&I: Interruption of white line
of the canal.
J,K&L: Diversion of canal.
M&N: Narrowing of canal

17.  Three imaginary lines which are known as George Winter’s lines can determine the position & depth of the impacted
mandibular 3rd molar.
1. WHITE LINE- corresponsed to the occlusal plane.The line is drawn touching the occlusal sufaces of 1st & 2nd molar
and is extended posteriorly over the 3rd molar region.It indicates the difference in the occlusal level of 2nd & 3rd
molars. eg: occlusal surface of the vertically impacted 3rd molar is parallel to the white line.
2. AMBER LINE – represents the bone level.The line is drawn from the crest of the interdental septum between the
molars & extended posteriorly distal to 3rd molar or to the ascending ramus.It denotes the alveolar bone covering
the impacted tooth& portion of tooth not covered by bone.
3. RED LINE- It is drawn perpendicular from the amber line to an
Imaginary point of application of an elevator.It indicates the
amount of bone that will have to be removed before elevation,
i.e. the depth of the tooth in bone & the difficulty encountered
in removing the tooth.
- If the length of the red line is more than the 5 mm, then the
Extraction is difficult. Every additional mm renders to removal of the
impacted tooth 3 times more difficult
WAR LINES

18. Difficulty Index
 A. Difficulty index for surgical extraction of impacted 3rd molar:
B.Difficulty index described by Pederson (1988):
Fig: Mesioangular Class 2 level A Mandibular
3rd molar impaction with difficulty index value
(slightly difficulty)

19. SURGICAL REMOVAL OF IMPACTED TEETH:
 Jhon Tomes in 1849, 1st described the surgical access for removal of impacted tooth
• Asepsis & isolation
• Local anesthesia or General anesthesia
• Incision: Flap disgn
• Reflection of mucoperiosteal flap
• Bone removal
• Sectioning(division) of tooth
• Elevation
• Extraction
• Debridement& smoothening of bone
• Control of bleeding
• Closure – Suturing
• Medications
• Follow up

20.  A. Isolation of surgical site:
-Scrubbing+painting of the skin& oral mucosa.
-scrubbing solution is 1st used on skin only: Cetrimide+absolute alcohol+chlorhexidine
-Cleaning solution used on skin only to remove residual soap: Normal saline, Alcohal,Spirit
-Painting solution act topically ton inhibit further growth of microbes: Providone iodine 5% for skin;1% for oral
mucosa.
-Drape the patient with sterile drapes
B.Local Anesthesia:
For mandibular molar: Inferior alveolar nerve block,Long buccal nerve block & Lingual nerve block
-Good infiltration is must to provide hemostasis & to define tissue plane.
-Plain saline in case of hypersensitive patient
-Saline adrenaline in conc. Of 1:400,000
C. Incision(Flap Design):
- Well mucoperiosteal flap design is required for adequate access,visualization of the tooth & for enough
placement of retractor,drilling equipment as well as for elimination of obstruction to the pathway of removal.

21.  -the incision for the mucoperiosteal flap will have an anterior
limb & a post. Limb connected with/without an intermediate limb.The incision made with no. 15 blade.
D.Reflection of mucoperiosteal flap for mandibular molars:
Ant. Releasing incision should begin from the vestibule upwards toward midway of the CEJ of 2nd at an angle.If
seated 3rd molar present,surgery requires more removal of bone,this incision should be placed ant. To the 2nd
-the incision is then continued to gingival sulcus up to the distal aspect of the 3rd molar.
-Distal releasing incision is started from distal most point of 3rd molar across external oblique ridge into the buccal
mucosa.
Fig A to C: Vertical periosteal flap
design.
Fig An envelope flap design.

22.  - this incision should not be taken on the lingual aspect of the ridge ,as the lingual nerve can be
found at or above the crest of the alveolar ridge.
- To protect lingual nerve trauma , careful elevation of a lingual flap with an appropriate sharp periosteal
elevator & placement of a suitable retractor is required.
- The length of this flap &the no. of the teeth included will br determind by the amount of exposure
necessary to gain the visibility of the region &the experience eof the clinician.

23.  The incision should not be extended too far upward disatally to avoid:
-Intraoprative brisk bleeding from the buccal vessels & anatomosing branches from lingual & facial arteries.
-postoperative trismus due to cutting through the fibers of temoral musle.
-Hernitation of buccal pad of fat into the surgical field.
-The sharp point of periosteal elevator is used to elevate,a mucoperiosteal flap carefully beginning at the point of
the incision behind the 2nd molar.
- The elevator is brought forward to elevate periosteum around the 2nd molar &down the releasing incision
- The other flatter end of the periosteal elevator used to elevate periosteum posteriorly to the ascending ramus
of the mandible.
- A Minnesota retractor is placed just lateral to the external oblique ridge and stabilized against the lateral
surface of the mandible.

24. BONE REMOVAL
 AIM: -To expose/uncover the crown by removing the bone overlying it.
-To remove the bone obstructing the pathway for removal of a tooth.
 2 ways of Bone removal: 1. High speed,high torque handpiece&bur technique
2.Chisel & mallet technique.
1.Bur technique: Either no. 7/8 round bur or a straight no. 702 or 703 carbide bus is used. Bur should be used
along with copious saline irrigation to avoid thermal trauma to the bone.
 1st step: the bur is used in a sweeping motion around the occlusal, buccal& distal aspect of mandibular 3rd
molar crown to expose it.
2nd Step: (Moore Gillbe Collar technique);
once the tooth crown is located ,the buccal suface of the tooth is exposed with the bur to the cervical level of
the crown contour & a buccal trough or gutter/ collar (made in cancellous bone)is created.

25.  -It is important that the adequate amount of trough is created to remove any bony obstruction
for exposure& the delivery of the tooth,especially aound the distal aspect of the crown.
2. Chisel& mallet technique:
- Less bone necrosis than bur technique
- Can cause inadvertent fracture of the bone
- The jaw bone is supported in this technique.
 First step: the placement of vertical stop cut,which made by placing a 3mm/5mm chisel
the distal aspect of the 2nd molar with bevel facing posteriorly (5-6mm height).

26.  Second step: At the base of the vertical stop(limiting) cut,the chiselm is placed at angle of 45º with
bevel facing upwards or occlusally & oblique cut is made till the distal most point of 3rd molar.
- Removal of triangular piece of buccal plate distal to 2nd molar
- Gain entry of the elevator tip

27. LINGUAL BONE SPLIT TECHNIQUE
 Described by Sir William Kelsey FRY.
 STEPS: - vertical stop cut is made by placing the chisel,distal to the 2nd molar with chisel bevel
downward, a horizontal stop cut is made backward the lower end of the vertical stop cut buccal
bone plate is removed distolingual bone is fractured inward by cutting edge held at 45º to the
bone surface remaining bone between the buccal & lingual cut is removed elevate the tooth by
a sharp straight elevator tooth moves upward & backward,then lingual plate gets fractured and
facillated the delivery of the tooth tooth is removed lingual plate is grasped with the hemostat
& freed from the soft tissue and removed smoothening of the edges is done with bone file.
Wound irrigated & sutured.

28.  A. soft tissue reflection by a standard incision
 B. vertical stop cut is made by chisel at anterior end of the
wound
 C. horizontal stop cut is made backwards from a point just
above the lower end of vertical cut.
 D.Excision of triangular piece of bone bounded ant. By the
lower end of stop cut.
 c. the distolingual bone fracture.
 d. Separation of lingual plate from rest of the alveolar bone.
 E.The peninsula of bone,between thwe lingual & buccal cut is
excised.
 F.displacement of tooth
 G.lingual plates are grasped in the fine haemostat & soft tissues
are freed from it.
 H. smoothening of the bone by bone file

29. TOOTH/ROOT SECTIONING:ODONTECTOMY
 Reduce amount of bone removal
 Reduce the risk of damage to the adjacent teeth
 Avoids inadvertent jaw fracture
 Reduces total surgery time
 Planned sectioning permits the parts of the tooth to be remove separately in an atrumatic manner by creating
a space into which it is displaced & the remaining crown or root segments.
 The direction of the root sectioning is dependent on angulation of the impacted tooth.
 Can be performed either with a bur or chisel.Bur use is preferable.
 The tooth is usually sectioned one-half to ¾ with the bur & then is is completely sectioned with the elevator.
 INDICATIONS:
-deep impacted tooth,with lot of bone coverage
-large bulbous crown,locked under 2nd molar
-unfavourable root anatomy

30.  -roots with close proximity to IAN
 -extencively carious tooth
 Bulbous root
 Narrow periodontal ligament space
 1.IN CASE OF VERTICAL AND MESIOANGULAR IMPACTION:
 PROCEDURE: distal half of the crown is sectioned off from the buccal groove, till the CEJ ; extended into
furcation → straight elevator is placed in to the cut & rotate to fracture the distal part of the crown which
removed → Straight elevator placed into the mesial aspect of 3rd molar below the cervical area→ elevate
tooth by a crane / cryer elevator , engaging the purchase point.

31.  2. IN CASE OF HORIZONTAL IMPACTION & DISTOANGULAR IMPACTION:
- Most difficult to remove
- Large amount of distal bone removal is required.
PROCEDURE:
-the crown is sectioned from the roots just avove the cervical line after sufficient bone removal from
occlusal & distobuccal aspect
-entire crown is removed to improved the visibility and access the root.
-if roots are divergent, they are further sectioned into 2 pieces and delivered individually.

32.  Coupland elevator: placed at the base of the crown
 Winter Cryer’s: may be used in buccal elevation/wedging action.
 PRECAUTIONS:
- Support the inferior border and lingual cortex of the bone in mandibular
impaction.
DEBRIDEMENT, DECONTAMINATION & SMOOTHENING OF BONE MARGINS:
- Irrigation of the socket
- Curreting to remove any remaining dental follicle and epithelium
- Look for pieces of coronal portion ( espceally for carious teeth), chek for remnant of the bone
/granulation tissue , bleedind point
- Inspection for fracture of lingual plate
- Round off margins of the socket with bone file / large vulcanite round bar.
- Irrigated the socket again & inspect again
- Control the bleeding before suturing
ELEVATION :

33. CLOSURE WITH PROPER APPROXIMATION
 A 3-0 black silk is used .
 Interrupted sutures given & maintained for 7 days.
 21mim or 23mm half circle or 1.25 mm 5/8 circle cutting needle is used.
 In case of molars, suture distal to 2nd molar should be placed first & should be
water tight to prevent pocket formation.
 Use as few suture as possible.

34. A. OPG showing horizontally
impacted lower right and left 3rd
molar
B. Intraoral clinical picture
C. Incision and mucoperiosteal flap
reflection
D. Sectioning of a tooth
E. Surgical extraction done
F. Suturing
G. Extracted tooth

35. EARLY REMOVAL OR
GERMECTOMY
• Described by Bowdler Henry
• Removal of unerupted wishdom tooth, with less than 1/3 root formation(9 to 16 years age)
• Advocated when prediction of interference with the proper development of the 2nd molar is
made.
LATERAL TREPHINATION
TECHNIQUE:
A modified S- shaped incision is used
from retromolar fossa, across external
oblique ridge to the 1st molar.
 Mucoperosteal flap reflection
Round bur is used to trephine the crypt
of the 3rd molar,

36. A. An extended s shaped incision is made from the
retromolar fossa,across the external oblique
ridge,curving down through the attached
mucoperiosteum along the mucous membrane to the
ant. Border of the permanent 1st molar.
B. Soft tissue elevation by Bowdler Henry retractor.
C. A second cut through the outer plate is made at the
posterior end of the crypt at an angle 45º from the row
of trephine holes.
D. Out fracture of buccal plate by chisel in vertical
direction, exposing the crown of the 3rd molar by curved
haemostat.
E. A warwick James elevator is applied to the occlusal
suface of the tooth to deliver it.
F. Suturing.

37. COMPLICATION
S
INTRA-OPERATIVE COMPLICATION:
DURING INCISION:
-For molars,facial vessels or buccal vessles may be cut.
-Injury to lingual nerve ,if not careful.
During Bone Removal-
1.Damage to the second molar.
2.Damage to the roots of overlying teeth.
3.Slipping of bur into the soft tissues.
4.Breakage of bur and getting embedded in the
bone.

38. During Elevation-
1.Luxation of neighbouring or overlying tooth.
2.Fracture of the adjoining bone.
3.Fracture of the tuberosity.
4.Fracture of mandible.
5.Soft-tissue injury.
6.Damage to nasal wall/ overlying teeth/ Lingual,
Inferior alveolar or mental nerve.
7.Slipping of the tooth into pterygomandibular, sub-
lingual pouch.
8.Breakage of elevator tip.
9.Temperomandibular joint dislocation.
During Debridement:
1.Damage to inferior alveolar nerve and lingual nerve.

39. Post Operative
ComplicationsPain due to dry socket.
Swelling due to oedema, hematoma
formation.
Trismus.
Hemorrhage.
Loss of vitality of neighbouring teeth.
Pocket formation.
Sinus tract formation.