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F - ORAL SURGERY > Third Molars > Flashcards

Third Molars Flashcards

1
Q

Common consequences of impacted lower third molars?

A

Caries

Pericoronitis

Cyst formation

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2
Q

Nerves at risk during 3rd molar surgery

A

IAN

Lingual

Mylohyoid

Long buccal

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3
Q

What did the FDS, RCS 2020 document change about parameters for third molar surgery

A

Previously NICE and SIGN stated no need to extraction of third molars unless associated pathology

New document states it is often delaying inevitable surgery, and pathology such as carious or broken down tooth tissue can make surgery more difficult later down line.

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4
Q

Indications for extraction of lower 8s

A

Infection - pericoronitis, periodontal disease or local bone infection

Pulpal disease

Cysts

Tumours

Caries

External resorption of 7 or 8

Requirement to be dentally fit - bisphosphonates, cancer treatment etc….

Within surgical field e.g. radiotherapy

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5
Q

What is pericoronitis?

A

Inflammation around the crown of unerupted tooth due to build up of food/debris/plaque under the operculum, resulting in inflammation/infection

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6
Q

Signs + symptoms of pericoronitis

A

Pain

Swelling by operculum

Bad taste and pus

Ulceration or trauma to operculum

Malaise

Regional lymphadenopathy

Pyrexia

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7
Q

How treat pericoronitis

A

Incision of localised abscess?

Anaesthetics

Irrigation with warm saline with blunt needle and then use of periodontal scaler to clean below

Remove upper third molar to ease trauma of lower operculum

Rinse with warm saline pt at home

Metronidazole - only if required

Maintain home analgesia and keep eating even if in pain

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8
Q

Predisposing factors to pericoronitis

A

Partial eruption or abnormal angulation of third molars

Opposing 3rd molar contacting operculum

Upper respiratory tract infection

Poor oral hygiene

Poor space between ascending ramus and third molar

Caucasians

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9
Q

Why would radiographs of third molars be indicated? What would they be used to determine?

A

Only if surgical intervention being considered

Prescience or absence of disease
Anatomy of M3M
Depth / orientation of impaction
Periodontal status
Orientation with regards to maxillary antrum or IAN canal
Interruption of lamina dura
Darkening of root when crossed by canal
Deflection of root
Narrowing of IAN canal

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10
Q

What radiographic signs typically demonstrate a significantly higher risk to IAN damage?

A

Diversion of the canal

Darkening of root where crossed by canal

Interruption of white lines of canal

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11
Q

What % of lower 8s are vertical, mesial, distal or horizontal?

A

30-38% vertically impacted

40% mesially impacted

5-15% distally impacted

Horizontal 3-15% impacted

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12
Q

What are superficial, moderate and deep third molars?

A
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13
Q

What should be done for asymptomatic high risk of disease / diseased third molar?

A

Clinical and radiographic assessment

Surgical intervention should be considered.
If proximity is close to IAN with higher risks of complications then active surveillance is recommended

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14
Q

What to do for asymptomatic and low risk / non diseased mandibular third molar?

A

Clinical and radiographic assessment with risk assessment

Consider prophylactic removal
- are they going to undertake treatment that may make third molar removal difficulty e.g. immunosuppressive
- third molar lies within surgical field

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15
Q

What to do for symptomatic and diseased / high disease risk mandibular third molars?

A

Extraction to be considered when
- single severe acute or recurrent pericoronitis
- unrestorable caries in M3M
- compromising periodontal disease
- resorption of 3rd or 2nd molar
- Fractured 3 molar
- periapical abscess, irreversible pulpitis, cysts or tumours

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16
Q

What to do with symptomatic 3 molars with no disease / low disease risk?

A

Leave deeply impacted if no associated disease

Manage other diagnoses causing pain in region
- TMJD
- parotid disease
- skin lesions
- migraine / headaches
- referred pain from angina etc
- oropharyngeal oncology

17
Q

What nerve damage is possible from 3rd molar surgery?

A

IDN - lower lip and chin tongue etc numbness or tingling, hypersensitivity or neuralgia type pain

  • 10-20% temporary
  • <1% permanent

Lingual nerve damage - taste one side of tongue
- temp - 0.25 - 23%
- permanent - 0.14 - 2%

18
Q

Principles of REFLECTING a flap?

A

Commence relief at base of relieving incision

Undermine and free anterior papilla before proceeding with distal reflection

Reflect with periosteal reflector firmly on bone
- avoid dissection superficial to periosteum

19
Q

How does bone removal occur in third molar surgery?

A

Using straight electrical handpiece (avoid surgical emphysema)

Carried out on buccal aspect of tooth first, then mover to distal

Create deep narrow gutter around the crown of the tooth

20
Q

Where separate a tooth for horizontal sectioning?

A

Coronectomy = below CEJ

Removal of tooth = above CEJ
- for orientation and elevation

21
Q

When is vertical crown sectioning used?

A

When roots are very separate

Section vertically and first remove distal crown ands root

Allows mesial crown and root to be elevated

22
Q

How is debridement carried out below the mucoperiosteal flap raised for third molar extraction?

A

Physical
- straight handpiece
- Mitchell’s trimmer or Victoria curette for soft tissues

Irrigation
- saline into socket and under flap

Suction
- aspiration in socket and under flap
- check for retained apices

Must remove any granulation or inflammatory tissue

23
Q

What are the aims of suturing?

A

Compress blood vessels and reposition tissues

Cover bone and prevent wound breakdown

Achieve haemostasis of the area

Promote healing

24
Q

Why might a coronectomy be carried out?

A

When there is risk of damage to the IAN or other surrounding structures that can complicate surgery

25
Q

How is a coronectomy of a third molar carried out?

A

General flap design

Transaction of tooth 3-4mm below CEJ

Elevate and lever the crown off, without mobilising the roots

Pulp left in place - untreated

Further reduction of roots with rise bur 3-4mm below alveolar crest if needed

irrigation

26
Q

What warnings should be given to the pt regarding coronectomy?

A

If root mobilised, then then the whole tooth must be removed

Leaving roots behind can result in infection - however this is rare

Can have a slow healing socket

Roots may migrate later and begin to erupt through mucosa, requiring extraction down the line

F - ORAL SURGERY (25 decks)

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