OD 25

Question 1

Function of orthognathic surgery?

Answer 1

Corrects underlying skeletal discrepancies

Question 2

Name some local and systemic causes of impacted teeth?

Answer 2

Local causes

1) Irregular position of adjacent teeth
2) Lack of space due to underdeveloped jaws
3) Premature/ delayed loss of deciduous teeth
4) Infection/ inflammation – trauma normally predisposes to abnormalities within the developing dentition
5) Greater density of overlying bone or soft tissue – teeth hindered by quality/ quantity
6) Fibrosis of overlying mucous membrane

Systemic causes
Prenatal causes = heredity
CLP; cleidocranial dysplasia

Malnutrition
Irradiation

Question 3

Are impacted canines more likely to be palatally or buccally impacted?

Answer 3

Palatally impacted more common

Question 4

Sequalae of impacted teeth?

Answer 4

• Malpositioning of tooth – erupts buccally or palatally
• If it doesn’t erupt – other teeth may move forward/ backward – ARCH SHORTENING
• Internal resorption of teeth that haven’t erupted
• Resorption of adjacent/ impacted roots
• Dentigerous cyst formation – follicular cover of unerupted tooth can become cystic
• Infection – difficult to keep clean if partially erupted/ abnormal angle

Question 5

If planning to leave an impacted tooth, how should you monitor it?

Answer 5

Only leave if no pathology clinically/ radiographically.

Must be no symptoms/ no planned ortho or implants.

Radiograph yearly until no longer a teenager.

Question 6

What’s the mnemonic used to identify the position of impacted teeth?

Answer 6

SLOB
•	Same way
•	Lingual
•	Opposite way
•	Buccal
When tube is moved, lingual moves same way but the buccal moves the opposite

Question 7

A tooth that is magnified on a DPT is palatally or buccally impacted?

Answer 7

Palatally impacted

Question 8

Cone moves down, tooth moves up compared to previous radiograph. Buccally or palatally impacted?

Answer 8

Buccally impacted

Question 9

What tooth is the most common for primary failure of eruption?

Answer 9

Lower 6

Question 10

Why must a tooth erupt through keratinized gingivae?

Answer 10

To establish a MGJ

Not a problem in palatally positioned tooth.

Question 11

3 methods of exposing an impacted tooth?

Answer 11

Open
Apically repositioned flap
Closed

Question 12

Describe open exposure?

Answer 12

A window of mucosa is removed rather than a flap.
Palatal mucosa – fastest healing part of body – need to maintain hole that has been cut in the palate to allow tooth to come through

Question 13

Describe an apically repositioned flap?

Answer 13

3 sided flap

Cant take any higher as would be attaching free gingivae to attached gingivae

Question 14

Describe closed exposure?

Answer 14

Gold chains
Used for buccal impacted tooth where there is insufficient attached mucosa for an apically repositioned flap
Chain is bonded to tooth and then flap sutured over tooth.

Question 15

What can be used for anchorage if there is not enough teeth (for example in hypodontia)?

Answer 15

Orthodontic implants.
Bone micro screws.
Can sometimes osseo-integrate.

Question 16

Indications for a labial frenectomy?

Answer 16

• Facilitate closure of a diastema
• Reduce chance of the diastema relapse
• To eliminate tension on the gingiva
• Aid tooth brushing
• Lip lengthening- can reduce high smile line

Question 17

1 reason to do a lingual frenectomy?

Answer 17

Aid tongue mobility

Question 18

What else can cause a diastema?

Answer 18

Mesiodens