3rd molars

Question 1

Radiographic signs of possible increased risk to inferior alveolar nerve

Answer 1

Diversion/deflection of inferior alveolar canal
Darkening of root where crossed by canal
Interruption of white lines/lamina dura of canal
Deflection of root
Narrowing of inferior alveolar canal
Narrowing of root
Dark and bifid root
Juxta apical area

Question 2

What radiographs are taken before 3rd molar removal

Answer 2

Panoramic, periapical if more detail of root form required, if close relationship to IDC noted on panoramic CBCT (or periapical possibly) requested (can look in different planes and 3D construction to assess more accurately tooth/root position to IDC)

Question 3

What’s often the most difficult lower 8 to remove?

Answer 3

Disto-angular

Question 4

What does depth of impaction indicate about the surgery?

Answer 4

Amount of bone removal required

Question 5

What is

a) superficial impaction
b) moderate impaction
c) deep impaction

Answer 5

a) crown of 8 related to crown of 7
b) crown of 8 related to crown and root of 7
c) crown of 8 related to root of 7

Question 6

What should you warn pts of before removal of 3rd molar if the 3rd molar has caries?

Answer 6

Crown could fracture/crumble during extraction

Question 7

What are some reasons that upper 3rd molars specifically might need extracted?

Answer 7

Cheek biting/buccally erupted, overeruption, traumatizing lower operculum

Question 8

What is pericoronitis?

Answer 8

Inflammation in soft tissues around crown of a tooth

Question 9

What causes pericoronitis?

Answer 9

Food or debris gets trapped under operculum resulting in inflammation or infection

Question 10

Signs and symptoms of pericoronitis

Answer 10

• Pain
  
  • Swelling - intra or extraoral
  • Bad taste
  • Pus discharged
  • Occlusal trauma to operculum
  • Ulceration of operculum
  • Evidence of cheek biting
  • Foetor oris (bad smell)
  • Limited mouth opening
  • Dysphagia
  • Pyrexia (raised temperature)
  • Malaise
  • Regional lymphadenopathy (raised palpable lymph nodes usually in submandibular or upper cervical region)

Question 11

Where would extra-oral swelling from a lower third molar usually be?

Answer 11

Angle of mandible and may extend into submandibular region

Question 12

When should chlorhexidine not be used and why?

Answer 12

If have incised and drained area as should not be used on open wounds because of risk of anaphylaxis

Question 13

In what cases might there be a higher risk of jaw fracture?

Answer 13

Atrophic/edentulous mandible, aberrant lower 8 close to lower border of mandible, large cystic lesion associated with 3rd molar

Question 14

After how long would you not expect further recovery of damaged nerves?

Answer 14

18-24 months