Wisdom Tooth Wisdom Demystifying the Past And Planning for the Future Ted Fields, DDS, PhD

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 Many research papers of the past 20 years set out to prove or disprove old ideas – many of which themselves are outdated.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-yr-old?)

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 a wisdom tooth erupts?

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 Distalto 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 Distalto 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 Freeze-Dried 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 Missing2nd 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 – 3rd Molar Caries

Problem #3 – 3rd Molar Caries

Problem #4 – 2nd 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

periodontal disease

2. Pericoronitis

3. Abscess

4. Cellulitis

5. Abscess extension into

adjacent fascial spaces

5. Abscess spread to distant

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

DentigerousCyst

DentigerousCyst

Dentigerous Cyst

Supernumerary4th Molar

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 post-retention stability

Allow distalization of 2nd molars

These are controversial indications

Alternatives to Removal

1. Restoration

2. Periodontal therapy

3. Operculectomy

4. Removal of another tooth

5. 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 3rd 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: 3rd Molars

Age 7-11: 3rd Molars

Age 7-11: 3rd 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