3rd Molar Surgery

Question 1

Indications of 3rd molar surgery

Answer 1

• Dental caries
• Periodontal disease
• Pericoronitis
• Root resorption
• Supra-erupted tooth impinging on ramus
• Mesioangular impaction damaging adjacent tooth
• Pathology - odontogenic cysts or tumours
• Swelling with risk of orofacial infection spreading
  o e.g. Ludwig’s angina from an impacted wisdom tooth

Question 2

What is pericoronitis

Answer 2

• Pericoronitis refers to inflammation of the operculum, which is the soft tissue surrounding the crown of a partially erupted tooth
• It occurs most often in the mandibular third molar region

Question 3

Pericoronitis (clinical presentation)

Answer 3

• Oedema
• Tenderness
• Erythema
• Ulceration
• Purulence (pericoronal abscess)
• Halitosis (from bacterial putrefaction)
• Loss of appetite
• Pain - may be throbbing and radiating, may also occur on biting
• Rare sequelae - trismus (due to inflammation/infection of the masticatory muscles), lymphadenopathy, pyrexia (fever), peritonsillar abscess, facial cellulitis, Ludwig’s angina

Question 4

Classification of pericoronitis

Answer 4

I. Acute - involving trismus and radiating pain
II. Subacute - not involving trismus or radiating pain
III. Chronic - history of temporary dull aching low-grade pain with long periods of remission

Question 5

Gregory and Pell Classification

Answer 5

Amount of tooth covered by anterior border of ramus:
* Class I = crown is situated anterior to the anterior border of the ramus
* Class II = crown 1/2 covered by anterior border of the ramus
* Class III = crown fully covered by anterior border of the ramus

Depth of impaction relative to adjacent tooth:
* Class A = occlusal plane of crown is on the same occlusal plane as the adjacent tooth
* Class B = occlusal plane of crown is between the occlusal plane and CEJ of the adjacent tooth
* Class C = occlusal plane of crown is apical to the CEJ of the adjacent tooth

Question 6

Radiographic features of IAN proximity

Answer 6

1. Diversion of the IAN canal (below tip of tooth roots)
2. Darkening of the third molar root (due to canal passing over tooth roots)
3. Interruption of the cortical white line
4. Narrowing of the root
5. Bifid apex

Question 7

When to give prophylactic streroids

Answer 7

o When given in doses exceeding normal physiological levels, steroids are effective at minimizing post-operative oedema

Question 8

Complications of 3rd molar surgery

Answer 8

IAN damage
Lingual nerve damage
Fracture of the mandible
Haemorrhage - due to many nutrient canals in proximity to the 3rd molars
Displacement of whole tooth or roots into lingual and infratemporal fossa
Pain and swelling