Management of third molars

Question 1

When do third molars typically erupt? (3)

Answer 1

Last teeth to erupt
18-23 years
Often absent or fail to erupt into normal occlusion

Question 2

Definition of an impacted tooth (2)

Answer 2

Prevented from reaching normal position by presence of other structure - usually adjacent tooth, but may include ascending ramus or overlying soft tissues

Question 3

Problems associated with third molars (11)

Answer 3

Abnormal position - cheek biting upper 8s
Caries, pulp and periapical pathology in 2nd and 3rd molars
Periodontal problems
Pericorinitis
Resorption - internal, and external for 7s
Cyst formation
Difficulty with OH and food packing
Crowding of lower incisors
Often involved in line of mandibular fractures
In way of orthognathic surgery
Potential risk in future for vulnerable and medically compromised patients

Question 4

Late lower incisor imbrication - literature (5)

Answer 4

Richardson 1979 - mesial movement of 6s not different between groups
Linquest et al 1982 - alternative removal
Southard et al 1991 - no clinical difference (posture higher difference than third molars)
Harridine et all 1998 - no significant difference in outcome
Several ortho studies on long-term retention - no difference

Question 5

Describe pericoronitis (3)

Answer 5

Inflammation around the crown of a partially erupted tooth
Caused by bacterial infection and/ or traums
Most commonly cited reason for extraction of 8s

Question 6

Symptoms of pericoronitis (7)

Answer 6

Pain or discomfort
Soft tissue swelling in the region of the partially erupted tooth
Difficulty eating, swallowing or opening mouth
Tenderness on closing if opposing tooth in contact with inflamed soft tissues
Unpleasant taste or smell
May feel unwell with pyrexia
May be a recurring problem

Question 7

Signs of pericoronitis (6)

Answer 7

Inflammation in soft tissues around  crown of partially erupted tooth
Localised intra-oral swelling
Evidence of trauma from opposing tooth?
Pus	+/-
Local lymphadenopathy	+/-
Facial swelling	+/-

Question 8

`Management of pericoronitis (7)

Answer 8

Local measures:
Irrigation beneath gum flap with: Saline, Chlorhexidine mouthwash.
Remove upper 8 if traumatic occlusion
Advise HSMW / Chlorhexidine and analgesics +/-
Antibiotics if spreading infection or compromise (usually Metronidazole, 200mg t.d.s)
Drain pus if present
Formal review ?

Question 9

Management of pericoronitis: at review (3)

Answer 9

Assess outcome of treatment and manage appropriately
Assess 3rd molar(s)
-likely to erupt and be functional - monitor
-unlikely to erupt – if problematic - consider removal, if not then leave and monitor
-persistent, recurrent or severe problems –
consider removal

Question 10

NICE 2000 guidance on removal of wisdom teeth (2)

Answer 10

Routine practice of prophylactic removal of pathology- free impacted third molars should be discontinued in the NHS
Removal – limited to patients with evidence of pathology
Surgical removal of impacted third molars should be limited to patients with evidence of pathology
Plaque formation is a risk factor but is not in itself an indication for surgery…..
Adherence to guidelines should be audited
History and justification should be documented

Question 11

NICE - pericoronitis (3)

Answer 11

The degree to which the severity or recurrence rate of pericoronitis should influence the decision for surgical removal of a third molar remains unclear
A first episode, unless severe should not be an indication for surgery.
Second or subsequent episodes should be considered appropriate indications for surgery

Question 12

Rationale for trying to retain 3rd molars (3)

Answer 12

Potential saving of up to £5,000,000 per year if prophylactic removal of third molars discontinued
Numbers of patients on WL might reduce if these criteria applied
Not ethical to expose patients to unnecessary procedures

Question 13

Justification for prophylactic removal of third molars (4)

Answer 13

To prevent crowding
Reduce complications in older individuals
Better able to cope when young (American way!)
If a GA then do all at once – this happens – is it wrong?

Question 14

Cochrane review about prophylactic third molar removal 2008 (3)

Answer 14

NO – difference in clinical effectiveness between removal and retention
NO – difference in cost-effectiveness between removal and retention
CONCLUSION: No clear evidence to support or refute the benefits of prophylactic third molar removal other than prevention of late lower incisor crowding

Question 15

How many third molars surgically removed in 2014-2015 (1)

Answer 15

82,000

Question 16

`Radiographic assessment prior to removal of lower 3rd molars (8)

Answer 16

Diagnosis
Type of impaction
Depth of tooth within bone
Crown form
Root form and number
Coronal or root pathology
Other pathology (cyst, caries in 2nd molar)
Relationship with mandibular canal (IAN)

Question 17

What must be present in the radiographic assessment? (5)

Answer 17

Entire tooth
Adjacent 2nd molar
Surrounding bone
ID canal
Lower border

Question 18

Types of impaction (5)

Answer 18

Vertical - easiest to extract, risk of pericoronitis
Mesio-angular - more difficult, risk of food packing and caries in 2nd molar
Horizontal - even more difficult, risk of food packing and caries in 2nd molar
Disto-angular - very difficult, risk of pericoronitis
Transverse - tricky

Question 19

Treatment options for third molars (4)

Answer 19

Removal
Observation
Operculectomy
Coronectomy

Question 20

Treatment options for third molars: anaesthetic (4)

Answer 20

LA
LA + sedation
GA (day case)
GA (in-patient)

Question 21

Technique for coronectomy (4)

Answer 21

Raise buccal flap
Cut at 45 degrees to crown, passing completely through (minimises risk of mobilising roots) - dangerous
Use fissure bur to reduce root to 3mm below alveolar crest (grey shaded)
Periosteal release and primary closure

Question 22

Patient selection for coronectomy (3)

Answer 22

Close proximity to IAN

No evidence of :
Active infection
Tooth Mobility

Avoid horizontal/severe mesioangular - increased risk of IAN damage during sectioning

Question 23

Evidence for coronectomy (6)

Answer 23

Evidence unclear
Increasingly utilised with high risk cases
Appears to be a valid techique for reducing risk of IAN damage
Patient must be warned of potential for second procedure.
Mobility of roots appears to be predominant factor for success
Not indicated for co-morbidity patients e.g chemotherapy, diabetes, immunosupressed, (bisphosphonates?)