Impacted third molar management

Peri-operative Management

of Impacted Third Molars

Dr Chamara Atukorala MDConsultant Oral and Maxillofacial Surgeon

Definition Prevalence Indications for Surgical removal,

/Guidelines Investigations and Diagnosis Classification Surgical management

AssessmentPlanningExecution

Post op Management Complications and their Management Medico-legal Background

Impacted tooth is a one that has not erupted to its functional position in the occlusion and

does not show clinical or radiological features indicating that it may erupt.

Causes

• Angulation• Hard or soft tissue obstruction• Pathological lesions• Lack of space

The management of asymptomatic, disease-free

ITM is controversial, the best evidence currently

available neither supports nor refutes extraction

.

(Symptomatic ITM?)

Available GuidelinesLocal- NoneForeign

NICEAAOMS

What is a Guideline ?

Guidance

1.1 The practice of prophylactic removal of pathology-free ITM should be discontinued .1.2 The standard routine programme of dental need be no different.

1.3 Surgical removal of ITM should be limited to patients with evidence of pathology. Such pathology includes unrestorable caries, non-treatable pulpal and/or periapical pathology, cellulitis, abcess and osteomyelitis, internal/external resorption of the tooth or adjacent teeth, fracture of tooth, disease of follicle including cyst/tumour, tooth/teeth impeding surgery or reconstructive jaw surgery, and when a tooth is involved in or within the field of tumour resection.

1.4 The evidence suggests that a first episode of pericoronitis, unless particularly severe, should not be considered an indication for surgery.

The Guidelines boil down to waiting for some pathology to develop, (such as decay in the wisdom tooth or the adjacent tooth, gum disease around the wisdom tooth,infection around the tooth crown, cellulitis, abscess and

including cyst / tumour,tooth / teeth impeding surgery or reconstructive jaw surgery )

Why Do British Practice This ?

This is regarded by some as supervised neglect.

The American Association of Oral & Maxillofacial Surgeons (AAOMS), the professional organization representing more than 8,500 OMF surgeons in the USA .

• “Asymptomatic” does not mean “Disease Free ” Pathology is always present before symptoms appear. Once damage has occurred, it is not always treatable

• 25% of wisdom teeth patients who perceive themselves as asymptomatic actually already have inflammatory periodontal disease. Blakey GH, Marciani RD, Haug RH, et.al: Periodontal pathology associated with asymptomatic third molars; Journal of Oral and Maxillofacial Surgery. 2001;60:1227-1233

• The risk of future disease requiring removal of retained wisdom teeth in asymptomatic patients who retain their wisdom teeth, exceeds 70% after 18 years of follow-up. Venta I, Ylipaavalniemi P, Turtola L: Clinical outcome of third molars in adults followed during 18 years. J Oral Maxillofac Surg. 62:182, 2004

• 20 years after UK adopts the “National Institute of Clinical Excellence” (NICE) guidelines, volume of third molar surgeries decrease, with a corresponding increase in mean age for surgical admissions and an increase in “caries” and “pericoronitis” as etiologic factors. Renton T, Al-Haboubi M, Pau A, Shepherd J, Gallagher JE: What has been the United Kingdom’s experience with retention of third molars? J Oral Maxillofac Surg. 70:48-57, 2012, Suppl 1

• Retention of third molars is associated with increased risk of second molar pathology in middle-aged and older adult men. Nunn, ME, et al. Retained Asymptomatic Third Molars and Risk for Second Molar Pathology. Nunn et al. J DENT RES published online 16 October 2013.

AAOMS firmly supports the surgical management of erupted and impacted third molar teeth, even if the teeth are asymptomatic, if there is presence or reasonable potential that pathology may occur

caused by or related to the third molar teeth. November 10, 2011

Indications for removal of ITM identified in the Parameters and Pathways published by the

AAOMS include

1. Pain , 2. Carious tooth , 3. Pericoronitis

4. Facilitation of the management of progression of periodontal

disease

5. Nontreatable pulpal or periapical lesion

6. Acute and/or chronic infection (e.g., cellulitis, abscess)

7. Ectopic position (malposition, supraeruption, traumatic

occlusion)

8. Abnormalities of tooth size or shape precluding normal function

9. Facilitation of prosthetic rehabilitation

10. Facilitation of orthodontic tooth movement and promotion of

stability of the dental occlusion

11. Tooth in the line of fracture complicating fracture

management

12. Tooth involved in surgical treatment of associated cysts and

tumors

13. Tooth interfering with orthognathic /or reconstructive surgery

14. Preventive or prophylactic removal, when indicated, for patients with

medical or surgical conditions or treatments (e.g., organ transplants, alloplastic

implants, bisphosphonate therapy, chemotherapy, radiation therapy)

15. Clinical findings of pulp exposure by dental caries

16. Clinical findings of fractured tooth or teeth Impacted tooth

18. Internal or external resorption of tooth or adjacent teeth

19. Patient’s informed refusal of nonsurgical treatment options

20. Anatomic position causing potential damage to adjacent teeth

21. Use of the third molar as a donor tooth for tooth transplant

22. Tooth impeding the normal eruption of an adjacent tooth

23. Resorption of an adjacent tooth

24. Pathology associated with the tooth follicle

25. Abnormality of size or shape precluding normal function

When managing a patient with asymptomatic, disease-free ITM, one must carefully review the risks and

benefits of extraction or retention, and heavily weight the patient’s treatment

preference.

“A strong indication for removal of impacted third molar should be complemented with a strong contraindication to its retention”

– Mercier P., Precious D., Risk and benefits of removal of impacted third molars, IJOMS 21:17, 1992.

Radiological Investigations

Radiographs Intra Oral

IOPAOcclusal views

Extra OralDPT (OPG)Lateral Oblique Views

CTCone Beam CTConventional CT

Radiological Assessment Helps In

Classification of the ITM Localisation and orientation of the ITM Assessment of the crown and root

morphology of the ITM Assessment of the ramal bone cover Assessment of the second molar tooth and

its root morphology Relationship of the ID canal to the roots of ITM Associated pathological lesions with the ITM

Systematic classification of the position of

Impacted Third molar ( ITM) teeth helps in

– Assessing the best possible path of removal of the ITM

– Managing difficulties encountered during removal

Prediction of operative difficulty before the extraction of ITM allows a design of treatment that minimises the risk of complications.

Both radiological and clinical information must be taken into account.

Classification of Impacted Mandibular 3rd Molars

1. ADA-AAOMS Classification

2. Nature of the overlying tissues

3. Winter’s Classification

4. Pell & Gregory’s Classification

ADA-AAOMS Classification

Impacted tooth-with overlying soft tissue.

Impacted tooth-Partial bony impaction.

Impacted tooth-complete bony impaction .

Impacted tooth-complete bony impaction with unusual surgical complications.

Nature of the overlying tissues

Soft Tissue Impaction. is usually the easiest of type of impacted tooth to remove.

Hard Tissue ('Bony') Impaction.

– Partial Bony. The superficial portion of the tooth is covered only by soft tissue but the height of the tooth's contour is below the level of the surrounding alveolar bone.

– Complete Bony. The tooth is completely encased in bone so that when the gingiva is cut and reflected back, the tooth is not seen. These are often the most difficult tooth to remove

Winter's Classification

Mesioangular - 45% Vertical - 40% Horizontal - 10% Distoangular – 5% Inverted

• Bucco-version• Linguo-version• Transverse

Pell & Gregory's Classification

Based on the relationship between the ITM to the ramus of the mandible (lower jaw) and the 2nd molar (based on

the space available distal to the 2nd molar).

Class A. The highest portion of impacted 3rd molar is on a level with or above the occlusal plane.

Class B. The highest portion of impacted 3rd molar is below the occlusal plane but above the cervical line of the

of 2nd molar.

Class C. The highest portion of impacted 3rd molar is below the cervical line of the of 2nd molar.

Assessment

Case historyGeneral medical status of the patient ( Fitness to undergo ITM surgery)

Extra oral examinationMouth opening and TMJFacial form, mental nerve functioning

Intra oralSurgical site ITM in question

Assessment of the degree of difficulty of the ITM surgery

Assess the radiological features

Assessment of the degree of difficulty of the surgery

WAR (Winter’s) Lines

WHARFE’s ASSESSMENT by McGregor (1985)

PEDERSON’S DIFFICULTY INDEX

Category Score

1. Winters classification

HorizontalDistoangularMesioangular

Vertical

2210

2. Height of mandible

1-30mm31-34mm35-39mm

012

3. Angulation of 3rd molar

1° - 50°60° - 69°70° -79°80° - 89°

90°+

012344. Root shape Complex

Favourable curvatureUnfavourable

curvature

123

5. Follicles NormalPossibly enlarged

Enlarged

012

6. Exit (Path of exit)Space availableDistal cusp coveredMesial cusp coveredBoth cusp covered

0123

Total 33

WHARFE’s ASSESSMENT by McGregor (1985)

PEDERSON’S DIFFICULTY INDEX

• Very difficult : 7 to 10• Moderataly difficult: 5 to 7• Minimally difficult : 3 to 4

ScoringMesio angular1

Horizontal 2

Vertical 3

Distoangular 4

Level A 1

Level B 2

Level C 3

Class I 1

Class II 2

Class III 3

Radiological features indicating a close association between IAN and ITM

If the ID nerve is closely associated indicating a high risk of injury ; best is to assess using advanced imaging methods

Cone Beam CT Conventional CT

Important Anatomical Structures

ITM Management options

*Observation and periodic review

*Surgery

**Conventional

***Intra Oral

****Buccal Approach

****Lingual Split Technique

****BSSO

***Extra Oral Approach

• **Coronectomy

• ** Staged Removal

Planning

Observation and periodic review

For patients who elect retention, the frequency of follow ups should be designed

to match the symptoms or disease associated with ITM

( physical and radiographic examination every 12 to 24 months by a health care professional trained to evaluate third

molars.)

Surgery

Set up of careLA +/- sedation

GA

Steps In Surgical Removal(Buccal Access)

Anesthesia

Incision and mucoperiosteal flap design and flap reflection

Removal of bone

Sectioning of tooth/roots

Elevation/Extraction

Wound debridement and smoothening of bone

Achieve Haemostasis

Wound closure, Analgesics

Postoperative follow-up

Principles of flap design

Adaquate access

Viability of the flap ( Base> top)

Avoid vital structures

Plan ease of repositioning

Ability to extend if the need arises

Clean incisions

Types of flap designs

• Envelope flap• L- shaped incision• Bayonet shaped incision• Triangular shaped incision• Ward’s incision and Modified Ward’s incision.• Comma shaped incision.• S -shaped incision• Szmyd and modified Szmyd incision

• Berwick’s tongue shape flap.

Ward’s incision

Modified Ward’s

Envelop flapIncision Not to be extended too distally-

Bleeding from buccal vessels & other arteries

Postoperative trismus – temporalis muscle damage

Herniation of buccal fat pad Damage to lingual nerve

(lingual extention)

Triangular shaped Incision

Bone Removal

“Bone belongs to the patient and tooth belongs to the dentist”

Minimize the amount of bone removal as possible

Instead section the tooth and deliver in pieces Excessive bone removal results in poor healing

and bone defect. High risk of alveolar osteitis, post op pain and

trismus.

Once the soft tissue is elevated and retracted, the surgeon must make a judgment concerning the amount of bone to be removed.

Bone must be removed in an atraumatic, aseptic, and non–heat-producing technique, with as little bone removed and damaged as possible.

The amount of bone that must be removed varies with the depth of impaction, the morphology of roots, and the angulation of tooth.

No bone should be removed from lingual aspect so as to protect the lingual nerve from injury.

Bone removal - Moore & Gillbe’s Collar Technique

Tooth Division“Rationale of tooth sectioning is to create

a space into which impacted tooth can be

displaced & thence removed.”

Tooth is sectioned in various ways depending on the type & degree of impaction.

Tooth is sectioned ¾ of the way

towards the lingual aspect. A straight elevator is inserted into the slot made by the bur and rotated to split the tooth

Extra Oral Approach

Coronectomy

Coronectomy

What is it ?IndicationsTechniquePost op MxFollow up

Staged Removal

Debridement of Wound & Closure

• Thorough debridement of the socket by Periapical

curettage.

• Remove the follicle of the ITM.

• Smoothening of sharp bony margins by Bone file / burs.

• Thorough irrigation of the socket Betadine solution + Saline

.

• Initial wound closure is achieved by placing 1stsuture just

distal to 2ndmolar, sufficient number of sutures to get a

proper closure.

Post Operative Instructions

• Pressure pack , Ice application

• Soft diet –1st two days

• 1st dose of analgesic should be taken before

the anesthetic effect of LA wears off.

• Avoid strenuous exercises for 1st 24 hrs.

• Avoid gargling / spitting / smoking / drinking

with straw.

• Warm water saline gargling after 24 hrs +

mouth wash regularly thereafter.

• Suture removal on 5th POD.

Antibiotics ?

Steroids?

Complications and their Management

Intra Operative

1. During incision a. Injury to facial arteryb. Injury to lingual nervec. Hemorrhage – careful history

2. During bone removal a. Damage to second molar b. Slipping of bur into soft tissue & causing injury c. Extra oral/ mucosal burns d. Fracture of the mandible when using chisel & mallet e. Subcutaneous emphysema

3. During elevation or tooth removal

a. Luxation of neighbouring tooth/ fractured restoration

b. Soft tissue injury due to slipping of elevator

c. Injury to inferior alveolar neurovascular bundle

d. Fracture of mandiblee. Forcing tooth root into submandibular

space or inferior alveolar nerve canal

f. Breakage of instrumentsg. TMJ Dislocation – careful history

Post-operative complications

• Immediate

- Hemorrhage

- Pain

- Edema

- Drug reaction

• Delayed

- Alveolitis

- Infection

- Trismus

From Medico-legal point of view to avoid getting in to problems.

• Make correct decisions • Get patient actively involved in decision making• INFORMED CONSENT• Proper investigations• Correct treatment.• Manage complications• Communicate with the patient• Be nice to your patient

Impacted third molar management

Health & Medicine

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