The document discusses the causes, development, classification, and surgical removal of impacted mandibular third molars. It includes information on indications and contraindications for their removal, as well as perioperative and postoperative management. Key considerations include the frequency of impaction, reasons for extraction, surgical techniques, and the importance of professional judgment in the decision-making process.

1. IMPACTED MANDIBULAR
THIRD MOLARS
DDS

2. outline
• Introduction
• Causes of impaction
• Development of third mandibular molar
• Indications and contra-indications for removal of impacted 3rd
molars
• Classification of impacted 3rd molars
• Removal of 3rd molar surgically
• Conclusion
• References

3. introduction
• Impaction is the cessation of eruption of a tooth caused by a physical
barrier or ectopic positioning of a tooth.
• unerupted tooth is a tooth lying within the jaw bone, entirely
covered by soft tissue, and partially or completely covered by bone.
• A partially erupted tooth is a tooth that has failed to erupt fully into a
normal position

4. Frequency of impaction(incidence)
• Mandibular 3rdmolar- >Maxillary 3rd
molar->Maxillary canine->Mandibular
premolar-> Maxillary premolar-
>Mandible canine->Maxillary central
incisor->Maxillary later incisor

5. Why impaction
• Inadequate Space in the Dental Arch for Eruption
>can be explained by the following theories
- The phylogenic theory
>Due to evolution, the human jaw size is becoming smaller and smaller
>there may be no be room for the 3rd molar to emerge in the oral cavity
,since it is the last tooth to erupt
- Mendelian theory
>Based on genetic variations
> If the individual genetically receives a small jaw from one of the parents
and/or large teeth from the other parent, then impacted teeth can be seen,
because of ‘lack of space’.

6. Development of mand 3rd molar
• The mandibular third molar tooth germ is usually visible radiographically by
age 9 years
• cusp mineralization is completed at age 11 years
• tooth located within the anterior border of the ramus with its occlusal
surface facing anteriorly ,at the level of occlusal plane of erupted dentition
• Crown formation is complete at age of 14 years,
• Roots are approximately 50% formed by age 16 years.
• During this time the body of the mandible grows in length at the expense
of resorption of the anterior border of the ramus.
• Roots completed at age of 18 and by age of 24 years 95% full erupted

7. Development cont….
• During root formation there is change in orientation from straight
anterior inclination into straight vertical inclination
• These changes needs sufficient space, which if absent causes
impaction

8. Reasons for removing impacted 3rd molars
• Pericoronitis and pericoronal abscess
- This is the most common cause for extraction of mandibular third
(25 to 30%)
-Pericoronitis is commonly associated with distoangular and vertical
impaction.
- If improperly treated or left untreated infection may extent
posteriorly resulting in sub masseteric abscess

9. • Dental caries
- Incidence of caries of the 2nd molar or 3rd molar is about 15%
- high incidence is due to difficulty to perform oral hygiene measures
in the third molar and second molar areas

10. • Prevention of odontogenic cysts
-in impacted tooth ,the associated follicular sac is retained within the
bone
-follicular sac may undergo cystic degeneration to form dentigerous
cyst or keratocyst
-these cysts may attain large sizes if left untreated and cause facial
asymmetry
-ameloblastoma may arise from the epithelial lining of the
cycts(mural ameloblastoma)

11. • Prevention of root resorption
- impacted tooth causes sufficient pressure on the root of an
adjacent tooth to cause root resorption
-this process is not well understood , it appears to be similar to
resorption process during eruption
-primary teeth do undergo resorption to allow eruption of
permanent tooth
-Removal of impacted tooth may save the adjacent tooth through
cemental repair

13. • Impacted tooth under dental prosthesis
-assessment to be done before planning for surgery
- superficial impacted teeth should be removed before prosthetic
appliance is constructed.
- because alveolar process slowly undergoes resorption
-tooth will come closer to the surface giving appearance of erupting
-denture may compress the soft tissues onto the impacted tooth which
is no longer covered by bone
-the result is ulceration and initiation of odontogenic infection
-if extraction is done after prosthesis has been made ,it will become non
functional an unattractive bse alveolar ridge may be so altered by extraction

14. • Prevention of jaw fractures
-Prophylactic removal of impacted third molars should be
considered for those engaged in contact games
- An impacted third molar presents an area of lowered resistance to
fracture
-Also presence of impacted tooth in the line of fracture may cause
increased complications in the treatment of fracture

15. • To facilitate orthognathic surgery
-In presurgical preparation for orthognathic surgery, removal of third
molars at the planned osteotomy must be done
-the removal brings better results eg in bilateral sagittal split osteotomies
(BSSO) can be better performed when third molars are not present at the
site of osteotomy.
-Third molars (both erupted and unerupted should be removed
preferably one year before the planned osteotomy to ensure the formation
of adequate bone
-Rigid fixation of the osteotomized segments needs adequate sound
bone to secure plates and screws

16. • Facilitation of orthodontic treatment
-Third molars can produce an anterior component of force leading to
crowding of mandibular incisors
- removal of third molars is recommended during or after
orthodontic treatment
- Some orthodontic approaches to a malocclusion might benefit
from the placement of retromolar implants to provide distal anchorage
-When this is planned, removal of impacted lower third molars is
necessary.

17. • Periodontal diseases
-Blakey et al (2002) reported that the prevalence of increased
periodontal probing depths (PD) in the third molar region is higher than
that is expected in asymptomatic third molars.
- They noted that in inceassesd PD –> 5 mm in the third molar
associates with gingivitis and periodontitis
- Increased periodontal probing depths and attachment loss leads to
increased periodontal pathogen colonization and increased levels of
inflammatory mediators which causes periodontal diseases

18. • Treatment of Pain of Unexplained Origin
-Occasionally, patients may complain of pain in the retromolar region
of the mandible for no obvious reasons.
-removal of third molar may result in resolution of pain
-but conditions such as myofacil pain dysfunctionsyndrome and
other pain disorders should be excluded

19. Contraindications of removal of 3rd molars
• extreme of ages
-The third molar tooth bud can be radiographically visualized by age 6
-Some surgeons think that removal of the tooth bud at age 7 to 9 can be
accomplished with minimal surgical morbidity
-However, it is not possible to predict accurately if the forming third molar will be
impacted
-early removal of third molars should be deferred until an accurate diagnosis of
impaction can be made
-Also it is contraindicated in advanced age because the bone becomes highly
calcified and therefore not flexible and unlikely to bend under the forces of tooth
extraction.
-so more bone must be surgically removed to displace the tooth from its socket.

20. -if impacted tooth is discovered at older age and with no periodontal
disease, caries or cystic degeneration,then its unlikely for these sequela
to occur
-so older pt (>35)shows no signs of disease and radiographyicaly
there is enough bone overlying is not removed

21. • Compromised medical status
-more often compromised medical status and advancing age go
hand in hand.
- If the impacted tooth is asymptomatic, its surgical removal must
be viewed as elective.
-in conditions such as immunocompromised ,cardiovascular or
respiratory serious illneses, coagulopathy surgery is to be avoided

22. • Probable excessive damage to surrounding structures
-it is advised to leave the tooth in the alveolar bone if its removal will
jeopardize adjacent nerves ,teeth , crowns bridges etc
-decision to not remove the impacted tooth should be weighed
against possible future complications
- for younger patients its wise to remove the impacted tooth while
taking great measures to avoid damage to adjacent structures

23. Classification of impacted mandibular 3rd
molars
• Angulation(winters classification)
-most commonly used system in relation to treatment plan
-uses a determination of the angulation of the long axis of the
impacted third molar with respect to the long axis of the adjacent
second molar
-it gives an initial useful evaluation of the difficulty of extractions
but is not sufficient by itself to define difficulty of molar removal fully.
-generally the least difficult impaction to remove is the
mesioangular, particularly when only partially impacted

24. a)Mesioangular impaction
-Long axis of the impacted tooth is mesially tilted

25. b)Horizontal impaction
-uncommon and more difficult to remove than mesioangular
impaction.
- The crown of impacted tooth is usually adjacent to second molar and
it produces early periodontal disease

26. c)Vertical impaction
- Long axis of the impacted tooth is vertical
- second most common impaction and second most difficult to remove.
- Vertical impaction is frequently covered on its posterior aspect with
bone of anterior ramus of mandible.

27. d)Distal impaction
-uncommon and most difficult of the four types to remove
-Occlusal surface of distoangular impaction is usually embedded in
ramus of mandible and requires significant bone removal for extraction

28. • Relationship to anterior body of mandible
-aka pell and Gregory classification classes 1,2 and 3
-based on the amount of impacted tooth that is covered with the bone of
the mandibular ramus
a)Class I - Space between anterior border of ramus and distal side of 2nd
molar is enough to accommodate the mesiodistal diameter of the 3rd molar.
b)Class II - Space between distal aspect of 2nd molar and anterior border of
ramus is less than the mesiodistal diameter of 3rd molar and hence partial
buried in ramus.
C) Class III - 3rd molar is totally embedded in bone from ascending ramus
because of absolute lack of space.

30. • Relationship to occlusal plane
-pell and Gregory classes A,B ad C
-The depth of the impacted tooth compared with the height of the
adjacent second molar
a)Class A
-Occlusal plane of impacted tooth is at same level as occlusal plane of
second molar
b)Class B
- Occlusal plane of impacted tooth is between occlusal plane and
cervical line of second molar.

31. c)Class C
-Impacted tooth is below cervical line of second molar.

32. REMOVAL OF IMPACTED TEETH

33. PREOPERATIVE ASSESMENT
• CLINICAL EXAMINATION
-History taking
>chief complaint and HPI
>medical and dental history
-Extra oral and intraoral examination
• RADIOGRAPHIC ASSESSMENT
-complement the clinical examination by providing additional
information about the third molar, the related teeth and anatomical
features, and the surrounding bone

34. -periapical
-lateral view
-OPG(panoramic view )
• Radiographs will provide the following-
- Access
-Position and depth of impacted tooth
-Root pattern of impacted tooth
–Shape of crown
-Texture of investing bone
-Relation to inferior alveolar canal
-Position and root pattern of second molar

35. • Surgical removal(Kelsey Fry)
-Step 1: Reflection of adequate flap for accessibility
- Step 2: Removal of overlying bone
-Step 3: Sectioning of the tooth
-Step 4: Delivery of the sectioned tooth with elevator
- Step 5: Wound debridement and closure (suturing).

36. • Reflection of adequate flap for accessibility:
- Overlying tissue must be removed for accessibility and visibility
- mucoperiosteum flap is reflected for easy placement and stabilization of
instruments
a)Envelop flap
-The most commonly used
-incision extends from just posterior to the position of the impacted tooth
anteriorly to the level of the first molar.
- The posterior end of the incision is directed buccally along the external
oblique ridge.
- Its associated with fewer compications and healing is fast

37. b)Triangular flap
-if greater accessibility is required a releasing incision is made anterior
to the envelop flap to form a triangular flap
-It begins at a point approximately 6 mm down in the buccal sulcus and
then extended obliquely upwards to the gingival margin to a point at
the junction of the posterior and middle thirds of the second molar

39. • Removal of overlying bone
- The bone covering the impacted tooth is removed
- Removal can be accomplished by bur or chisel and mallet or
combination of the two methods
- First of all, the bone covering the occlusal part is removed to expose
the tooth
- followed by removal of the Buccal aspect of the bone till the cervical
margin of the tooth
- Then bone between the tooth and the cortical bone should be
removed to provide better access. This process is known as 'Ditching'.

40. -The depth of bone removal depends on depth of impaction
,morphology of roots and angulation of tooth
-lingual bone is not removed to prevent severe of the lingual nerve

41. • Sectioning of the tooth;
- Sectioning indicated if the tooth has been sufficiently exposed,and
still resistant to the use of elevator
- Reduces operating time and avoids removal of excessive amount of
bone
- Sectioning of tooth will depend on the angulations of tooth , depth
of impaction and root morphology
- Bur is used to section the tooth ,straight elevator is used to deliver
the tooth.

42. • Mesioangular impaction:
-section the distal part from the tooth and remove it
-followed by the mesial portion
• Horizontal impaction:
The distal portion of the crown is sectioned first then the distal part of
the root, followed by the mesial portion of the tooth

43. • Vertical impaction
- The tooth is sectioned into mesial and distal .
- Mesial half is removed followed by the distal half
• Distoangular impaction
- The crown of the tooth is removed first, followed by either of the
roots

47. • Delivery of the sectioned tooth with elevator
-The sectioned tooth is removed from the bone by using elevator
- Excess force should not be applied by the elevator but just enough to
lift the tooth
- Most commonly used elevators are
• Straight elevator
• Paired Cryer elevator
• Crane pick elevator

48. • Debridement of wound and wound closure
- Debridement of the wound is done by:
> Removing the bone chip and debris from the wound
> Periapical curettage
> smoothening of the sharp bony edges using bone file
>Irrigating with normal saline
>Control of bleeding
- Wound closure done by placing 3-4 sutures for envelop flap and
additional 1 suture for triangular flap

49. Postoperative management
• Post operative instruction should be given
• Medications
>antipain and antiflamatory -NSAIDS and steroids
>antibiotics-metronidazole and penicilins or erythromycin for
penicillin allergic pts
• suture removal
>done after 5-7 days

50. conclusion
• The surgical removal of third molars has been, and still is, the most
frequent operation performed by oral and maxillofacial surgeons both
in private practice and in hospital setting
• Extensive training, skill, and experience are necessary to perform this
procedure with minimal trauma
• When the surgeon is untrained and/or inexperienced, the incidence
of complications rises significantly
• Determining the need for removal of asymptomatic teeth is made
based on clinical experience and professional judgment.

51. references
• Petersons PRINCIPLES OF ORAL AND MAXILLOFACIAL SURGERY
Second edition chapter 8 pg 140
• ORAL AND MAXILLOFACIAL SURGERY by lars Andersson pg 235
• COTEMPORARY ORAL AND MAXILLOFACIAL SURGERY 5TH EDITION PG
180
• PRACTICAL GUIDE TO THE MANAGEMENT OF IMPATED TEETH by K
George
• A CONCISE TEXTBOOK OF ORAL AND MAXILLOFACIAL SURGERY PG
127

52. THANK YOU!!!