Third Molars

Question 1

What is the best way to determine orientation of impaction?

Answer 1

Draw lien through long axis of 7 and 8

Question 2

What are the aspects of a ‘full marks’ radiographic report?

Answer 2

• Look for caries in crown
• Direction of impaction
• How impacted- moderately etc
• Roots- dilacerated, splaying, converging, divergent
• Interfering with canal- narrowing, darkening, interruption (anatomical or radiographic cause?)
• Is their a follicular/cystic change

-> Would you offer CBCT

Question 3

What are the causes of not being able to see the IDC?

Answer 3

Outwith focal trough (radiographic error)
- Prominent chin
- Alignment issue

Question 4

How much more radiation is given out by CBCT over OPT?

Answer 4

CBCT- 2.5 x times an OPT
- Consider whether it would change management- caries into the pulp (extract)

Question 5

What is neuralgic pain described as when consenting patient for third molar surgery?

Answer 5

electric shock, comes and goes, debilitating

Question 6

What are the percentage risks for different sensation alterations?

Answer 6

% for temporary altered sensation after wisdom teeth removal (low risk)
-> 5-10%
Permanent in low risk - <1%
High risk temporary- 25%
Permanent- 3-7%

Question 7

What instruments can be used to keep the flap under tension to making lifting of it easier?

Answer 7

Mitchell’s

Howarths

Question 8

What are the different types of retractors?

Answer 8

Rake (bowdler henry)- risk of macerating periosteum (more risk of bruising and swelling)

Minnesota- benign edge, reflects light into wound, gives cheek protection

Question 9

What can occur if distal relieving incision is too distal?

Answer 9

• Can affect lingual nerve- as these can sit above alveolus (have it more buccal to avoid)
• Difficult suture

Question 10

Why is lingual retraction not done routinely?

Answer 10

Lingual retraction- better access but risk to lingual nerve

Question 11

What is the risk if the relieving incision does not release the papillae?

Answer 11

Risk of recession
-> care in anterior region

Question 12

What is used for bone removal and why? What may be used in practice?

Answer 12

Electric handpiece with saline cooled tungsten carbide bur
-> air driven handpieces can cause surgical emphysema

In practice- slow speed with saline irrigation

Question 13

How is the crown taken off when decoronating?

Answer 13

 horizontal cut at ACJ (width of bur)
 Go 2/3 way through middle, avoids adjacent structures
 Compare size of bur to occlusal surface
 Coupland’s in between- crack (warn)

Question 14

What causes snapped tip in luxators?

Answer 14

Lateral forces

Question 15

How is a 3 sided flap sutured

Answer 15

• 3 sided- suture distal reliving incision and mesial relieving incision

Question 16

What is anatomical closure?

Answer 16

Leave defect (prevent fibrous scarring)
-> Primary closure- can cause tension resulting in scarring

Question 17

What is a juxtaposition-apical area?

Answer 17

Juxta-apical area- PA around root of tooth in otherwise sound wisdom tooth

Question 18

What is checked when examining Lower 8s?

Answer 18

• Caries
• Periodontal condition (check distal of 7 for communication even if tooth unerupted)
• Eruption status
• Angulation
• Depth of impaction
• Signs of infection
• Pericoronitis
• Relationship of tooth to IDC
• Relative position of upper 8s
• Working distance- distance from distal of 7 to ascending ramus (check on radiograph)

Question 19

When is it unlikely that the 8 is causing an issue?

Answer 19

If no communication to oral cavity
 Will be sent back if referred
 Be careful what you say to patient
 Double check for other pathology

Question 20

What commonly occurs to the bone as a result of pericoronitis?

Answer 20

Distal bone loss

Question 21

What can CBCT show us about relationship between 8 and IDC?

Answer 21

If there is compression of nerve by tooth

Nerve can perforate root- very rare
-> Coronectomy

If intervening bone present

Question 22

What is the benefits of no treatment of impacted 8s?

Answer 22

Benefits- no risks of surgery (pain bleeding etc)

Risks- subsequent episodes/future pain, caries in 7 (esp mesioangular impaction)

Question 23

What is the reoperation rate for coronectomy to remove roots?

Answer 23

4-5%
-> often easier procedure due to migration