1. science
2. medicine
3. surgery

Wisdom Tooth Wisdom
Demystifying the Past
And
Planning for the Future
Ted Fields, DDS, PhD
Course Outline
Part I: To Remove or Not to Remove
1. Development
2. Wisdom teeth as an asset
3. Wisdom teeth as a liability
4. Alternatives to removal
5. Timing of removal
Course Outline
Part II: Treatment Approach
1. Assessing the difficulty of removal
2. Patient counseling and preparation
3. Anesthesia
4. Instrumentation
5. Technique
Course Outline
Part III:
Management of Infected Teeth
Course Outline
Part IV: It Ain’t Over Till It’s Over
1. Complications
2. Post-operative care
3. Documentation
The Difficulty in
Understanding 3rd Molars
1. European third molar surgery is much
different than that in the U.S.
 Lingual fracture technique
 Different instrumentation
 Different economic influences on dental
care
The Difficulty in
Understanding 3rd Molars
2. Many research papers of the past 20 years
set out to prove or disprove old ideas –
many of which themselves are outdated.
 Will the 3rd molar erupt?
 Is there enough arch length for eruption?
 Does removal of the 3rd molar compromise
the 2nd molar?
The Difficulty in
Understanding 3rd Molars
3. Much of the developmental literature is
written from an orthodontic viewpoint.
 There is an outcome bias towards younger
individuals (what is the result in a 16-yrold?)
 The 3rd molar is judged in relation to
orthodontic needs, rather than the patient’s
overall needs.
The Difficulty in
Understanding 3rd Molars
4. Many changes in technology have been
totally neglected.
 Implants
 Electric handpieces
 Antibiotics
 Hemostatic agents
 Bone augmentation materials
The Difficulty in
Understanding 3rd Molars
5. The topic is not covered in any depth in
most dental schools.
 Knowing when it is in the patient’s best
interest to remove 3rd molars is a judgment
that requires detailed knowledge of the
risks and benefits associated with tooth
retention and with tooth removal.
Development
Initial calcification
 Occurs as early as 7yrs, more typically age 9.
Crown Mineralization
 Usually completed by age 12 to 14.
Root Formation
 Usually half-formed by age 16.
Root Completion
 Fully formed roots with open apices are usually
present by age 18.
Eruption
 Most teeth that will erupt are erupted by age
20.
 95% of all teeth that will erupt are erupted by
age 24.
 A limited number of third molars appear to
erupt, at least to some degree, in young
adults.
Predicting Eruption –
Who Cares?
 Does it matter if a wisdom tooth erupts?
 Does it matter when
wisdom tooth erupts?
a
The Key Issue
Does it affect the
Risk:Benefit Ratio?
Evaluating Risk:Benefit
Evaluating Risk:Benefit
 Since “Risk of retention” and “Benefit of
removal” are essentially the same concept,
these terms may be combined.
 Since “Benefit of retention” essentially = 0,
the equation may be simplified:
Evaluating Risk:Benefit
You must consider 2 separate assets of each
risk and each benefit:
1. Magnitude of risk or benefit
2. Probability of risk or benefit
Magnitude
 Is it major or minor?
 Does it require hospitalization?
 Is it permanent?
 Does it affect your daily routine? If so, for
how long?
Probability
 The most overlooked aspect of most
consultations.
 Fortunately most real bad outcomes are real
uncommon
 What is the likelihood of certain problems?
How much does treatment alter this
likelihood?
The Difficulty of Accurate
Risk:Benefit Assessment
1. The literature is not very complete or very
helpful. Complication rates vary widely. Different
people view these complications very differently
(complication doesn’t always equal perception of
the complication)
Ogden GR, Bissias E, Ruta DA, Ogston S: Quality of life following third
molar removal: a patient versus professional perspective. Br Dent J
1998;185:407410.
The Difficulty of Accurate
Risk:Benefit Assessment
2. The wide variety of different complications
and the wide range in the incidences of each
potential complication result in a complex
body of data to assimilate.
Risk:Benefit
 Are erupted 3rds more or less subject to
disease?
 Are erupted 3rds more or less beneficial?
Wisdom Teeth as an Asset
What Impacts Treatment?
 Eruption into occlusion should not be
the sole criterion of usefulness.
 The issue is not “can you save it” but
“should you save it.”
Benefits of 3rds
 “Functional occlusion” – what is this?
 Is it any different than just “occlusion”?
 Is all occlusion functional?
 Is all functional occlusion important? If so, is it all
equally important?
 Without evaluating questions such as these, how
can you determine the true benefit of 3rds?
Benefits of 3rds – Part II
 Orthodontic repositioning to replace missing
or grossly compromised 1st molars
 Transplantation – poor long-term survival
 With dental implants, these are rarely
reasonable treatment alternatives.
Tooth Transplantation
 Under ideal conditions, 27 oral surgeons
transplanted 291 teeth:
 5-yr survival rate: 76.2%
 10-yr survival rate 59.6%
Schwartz O, Bergman P, Klausen B: Resorption of
autotransplanted teeth. A retrospective study of 291
transplantations over a period of 25 years. Int J Oral Surg
1985;14:245-258.
Conclusion
 3rd molars provide no proven functional
benefit and no obvious esthetic benefit.
 Rarely, they may provide a treatment option
that, at best, is third-line treatment.
Wisdom Teeth as a Liability
What Impacts Treatment?
 Failure of eruption should not be the sole criterion
for removal.
 Successful eruption should not be the sole criterion
for retention.
 Eruption is not always a “yes” or “no” proposition.
Problem #1 – Soft Tissue
 Even with adequate arch length and full eruption,
3rd molars are often surrounded by thin,
unkeratinized, highly distensible lining mucosa of
the buccal vestibule.
 Encourages pathogenic bacteria retention
 Poorly withstands hygiene measures
Problem #2 – Periodontal
Compromise
 Bone loss distal to the 2rd molar after
removal of the 3rd molar is controversial, at
best. Even with some loss of bone, the result
is stable and cleansable – the goal of
periodontal therapy.
Bone Loss Distal
to the 2nd Molar
 A reduction in pocket depth with no change
in bone height on the distal of the 2nd molar.
Szmyd and Hester
Groves and Moore
Grondahl and Lekholm
Bone Loss Distal
to the 2nd Molar
 Alveolar bone crest healing distal to the 2nd
molar is enhanced in younger patients with
incompletely developed 3rd molar roots.
Ash, Costich, and Hayward
Ziegler
Augmentation with FreezeDried Bone or Bone Substitutes





Why?
There is no independent evidence of benefit
Why graft a contaminated site?
Why graft a site you can’t close primarily?
Your goal is to maintain bone height on the distal of
the 2nd molar without pocket formation, not to
augment potential defects more posteriorly.
Augmentation: Conclusion
 It won’t improve your outcome.
 It will undoubtedly increase your infection
rate
 Why would you want to augment this area
anyway?
Measuring Bone Height
Problem #2 – Periodontal
Compromise
 The role of pathogenic bacteria retention in
3rd molar pockets is unknown. How does this
affect the rest of the dentition?
 Hygenic compromise of the 2nd molar can
result in a difficult to restore situation if this
tooth is lost.
How Do You Treat Missing
2nd Molars?
 If the entire dentition is healthy and a mandibular
2nd molar needs extraction, what is the
recommended treatment?





Cantilevered abutment?
Implant?
Partial denture?
Remove opposing tooth at same time?
Nothing. Allow opposing tooth to supererupt.
The Missing 2nd Molar
Dilemma
 Your treatment plan for this scenario
illustrates the value you place on 2nd molars.
 Most people will subconsciously do a
cost:benefit analysis and conclude
that restoration is not necessary.
Problem #3 –
rd
3
Molar Caries
Problem #3 –
rd
3
Molar Caries
Problem #4 –
nd
2
Molar Caries
Problem #5 - Infection
 Can turn an elective procedure into an urgent
or emergent situation
 Unscheduled loss of work
 Increased pain and healing time
 Compromise of adjacent teeth
 Compromise of patient’s systemic health
Infection
Types of Infection
1.
Simple dental caries and
5. Abscess spread to distant
periodontal disease
2.
Pericoronitis
3.
Abscess
4.
Cellulitis
5.
Abscess extension into
adjacent fascial spaces
sites
6.
Recurrent infections
7.
Infections resistant to
initial local and systemic
treatment measures
Pericoronitis
The most
common cause
of therapeutic
3rd molar
removal.
Pericoronitis
 A failure of preventive measures
 A failure of early recognition, or a failure to
seek proper treatment
 A step along the pathway of infection
 Pericoronitis should be a warning sign that
initiates immediate and aggressive treatment
with careful observation.
Problem #6 - Resorption
Problem #7 - Supereruption
Problem #8 - Cysts
Dentigerous
Cyst
Dentigerous
Cyst
Supernumerary
4th Molar
Dentigerous Cyst
Types of Cysts
 Follicular cyst (Dentigerous Cyst)
 OKC (Odontogenic Keratocyst)
 Ameloblastoma (several varieties)
 Not all radiolucencies are cysts!
- Lymphoma
- Myeloma
- Metastatic carcinoma
Without the
radiolucency, would
you have
recommended
removal?
Is the removal of
this better or worse
with the
radiolucency?
When would you
recommend removal
of this 3rd molar?
Cysts – A Few Facts
 May be prevented by early removal – when
normal dental follicle is still evident.
 The pericoronal pocket, or residual follicle, is
responsible for most cystic pathology.
 All cystic tissues should be removed and
biopsied.
Cysts
 Cysts themselves are not catastrophic – the
problem is that we don’t know exactly what
they are until they are histopathologically
examined – which necessitates removal.
 All cysts result in bone loss.
 Some cysts recur more than others.
Treatment of Large Cysts
 Aspirate first – rule out vascular lesions
 Consider decompression (only after biospy
confirmed diagnosis)
 Consider marsupialization
 Consider bone grafting
 Consider possibility of mandible fracture
 Consider extensive followup
Problem #9 - Tumors
 Benign vs. malignant
 Odontogenic vs. non-odontogenic
 Primary vs. secondary
 Each of these factors has important treatment
implications.
Tumors
Problem #10 – Risk of Fracture
Immediate Pre-extraction
Immediate Post-extraction
3 Days Post-extraction
8 Days Post-extraction
Problem #11 - Fracture
Problem #12 - Orthodontics
 Prevent loss of postretention stability
 Allow distalization of
2nd molars
 These are controversial
indications
Alternatives to Removal
1.
2.
3.
4.
5.
Restoration
Periodontal therapy
Operculectomy
Removal of another tooth
No treatment
Timing Removal of 3rds
When is the best time for
prophylactic removal?
Age 7-11: Mandibular 3rds
1. Germs are first visible during this time
2. They usually appear in a superficial
location close to the alveolar crest
3. After age 11, they are located deeper in the
mandible
Age 7-11: Mandibular 3rds
Very close to ridge
crest. Minimal if
any bone removal
will be needed.
Age 7-11: Mandibular 3rds
1. Mineralization is either not present or only
mineralized cusps are evident
2. Remove requires a flap and minimal, if any,
bone removal
3. Psychological factors and parental support
should be carefully evaluated on a case by
case basis
Age 7-11: Mandibular 3rds
Close to, but not at,
ridge crest. Some bone
removal will be
needed.
Age 7-11: Mandibular 3rds
Bone removal will
be necessary. Is it
better to remove
this 3rd molar or
wait?
Age 7-11: Mandibular 3rds
 There has been less published about removal
of thirds at this age than at other ages, so
intervention at this time tends to be more
controversial
 Much of the controversy has traditionally
revolved around the difficulty in predicting
eruption and arch length – probably not valid
Removing
rd
3
Molar Germs
 Bjornland T, Haanaes HR, Lind PO, Zachrisson B:
Removal of third molar tooth germs: study of
complications. Int J Oral Maxillofac Surg
1987;16:385-390.
 Half as much postop pain medication was required
 One third quicker procedure
 Well-tolerated with local anesthesia
Age 7-11: Maxillary 3rds
 These teeth tend to be high in the maxilla
 Their small size can make them difficult to
locate
 Their size and location can increase the risk
of injury to the developing 2nd molar
 Increased operating time and frustration
 Increased postop edema and discomfort
Age 7-11: Maxillary 3rds
Age 7-11:
rd
3
Molars
Age 7-11:
rd
3
Molars
Age 7-11:
rd
3
Molars
Age 7-11: Conclusion
1. Lower 3rds are often very simple, upper 3rd are
almost always very difficult and pose risk to the
2nd molars
2. In older individuals, 90% of the morbidity is from
removal of the lower 3rds
3. Early removal may obviate the need for any
sedation at any time
4. Psychological evaluation is critical
Age 12 -14
 Crown mineralization progresses
 Distance of lower 3rds from ridge crest increases
 Lower 3rds become more difficult to remove
 Upper 3rds may still be quite difficult
 Psychologically, many patients may be less
prepared at this age.
Age 12 -14
Age 12 -14
Age 12 -14
Age 15-18
 Root formation has begun and may progress
to near completion.
 Most patients are psychologically accepting
of surgery at this age.
 Most studies agree that complication rates
are least in this age range.
Age 15-18
Age 15-18
 The follicle allows for relatively easy
removal once the tooth is accessed.
 No PDL is present – there is no attachment of
the tooth to bone.
 The portion of the follicle deep to the
forming roots acts as a safety zone between
the tooth and the nerve.
Age 15-18
 The periphery of the deepest mineralized
tooth surface may be quite sharp, allowing
laceration of the neurovascular bundle if it
too is housed within the follicular space.
 The tooth may spin and be difficult to
stabilize while sectioning and elevating.
Age 15-18
Age 15-18
Age 15-18
Age 19-22
 Root development is not always complete
during this period, making it still a favorable
time for 3rd molar removal.
Age 22-35
 Nearly all patients in this age group will have fully
developed 3rd molar roots – this potential advantage
is lost.
 The bone still has a good ratio of elastic collagen
matrix to mineral content, usually simplifying
removal and even more frequently improving most
parameters of healing.
 Most of these patients are healthy.
Age 35-45
 Most patients are still ASA I or II
 The mineral content of the mandible
increases during this time.
 Many 3rd molars must be removed during
this time for therapeutic reasons.
Over Age 45
 The complication rate is highest in this
group.
 The incidence of nerve injury is highest in
this group – and recovery is the poorest.
 Even routine healing tends to be prolonged
and associated with increased morbidity.
 Patient health may be compromised.
With Increasing Age
 Narrowing of PDL and pericoronal space
 Thickening of cortical bone
 Increased risk of infection, bone loss, and
other pathoses
Advantages of Early Removal
 Wide pericoronal space
 Incomplete root
development
 Straight roots
 Away from IAN
 Away from sinus
 Less risk of infection
 Less risk of fracture
 Patient more likely in
good health
 Better chance for
primary closure
 Smaller teeth require
less bone removal