Intro to Ortho

Question 1

Define orthodontics (3)

Answer 1

• Specialty concerned with:
• Growth + development of teeth, face + jaws
• Diagnosis, prevention + correction of dental and facial irregularities

Question 2

What is the maxilla attached to?

Answer 2

Anterior cranial base

Question 3

How do we determine anterior/posterior skeletal face relationship?

Answer 3

Class I II or III Skeletal relationships

Question 4

Class I skeletal relationship

Answer 4

Maxilla 2-3mm in front of mandible

Question 5

What do we use to get the patients orientation correct?

Answer 5

Frankfurt plane horizontal to the floor

Question 6

Class II skeletal relationship

Answer 6

Maxilla more than 3mm in front of mandible

Question 7

Class III skeletal relationship

Answer 7

Mandible in front of maxilla

Question 8

What can cause a class II skeletal relationship?

Answer 8

Mandibular hypoplasia

• V small mandible
• Mandible going back + up

Question 9

What is mandibular retronaphia?

Answer 9

Mandible is the right size but just further back in the skull base

Question 10

What is mandibular prognathism?

Answer 10

A big lower jaw

Question 11

What is Hemimandibular hypertrophy?

Answer 11

Facial asymmetry

- Tends to happen in females (late teens, early 20s)

Question 12

What does hemimandibular hypertrophy cause in terms of dental problems? (2)

Answer 12

1. Lack of eruption of max teeth on LHS

2. Over-eruption of max teeth on RHS

Question 13

Tx for facial asymmetries

Answer 13

Costacondral graft

• Piece of rib with cartilage strapped onto ramus
• Works in a 3rd of cases

Question 14

What skeletal classes are cephalograms taken for?

Answer 14

Class II or III

Question 15

TX options for skeletal discrepancies in growing patients? (3)

Answer 15

Growth modification techniques to promote/restrict growth of either jaw

1. Functional appliances
2. Headgear
3. Reverse pull facemask and RME

Question 16

TX options for skeletal discrepancies in adults who have completed growth? (2)

Answer 16

1. Orthognathic surgery

2. Single jaw/bimaxillary procedures

Question 17

Dangers of orthognathic surgery

Answer 17

10-15% cases associated with permanent nerve damage

- numb lip

Question 18

What tests do we use to reach an orthodontic diagnosis? (5)

Answer 18

1. Study models
2. Radiographs
   - OPG
   - Lateral Ceph
3. Photographs
4. Sensibility tests
5. Cone beam CT scan

Question 19

Function of removable appliances

Answer 19

Tip teeth
Open bites
Maintain space

Question 20

Function of functional appliances

Answer 20

Modify jaw growth

Question 21

Benefits of orthodontic tx (4)

Answer 21

1. Improve function
   - anterior xbites / AOBmake it difficult to incise food
2. Improve appearance
   - aesthetics
3. Improve dental health
   - Make teeth easier to clean
   - Reduce risk of trauma
4. Facilitate other dental tx
   - rearranges spaces in hypodontia cases prior to bridges or implants

Question 22

Risks of orthodontic tx (8)

Answer 22

1. Decalcification
2. Relapse
3. Root resorption
4. Pain/discomfort
5. Soft tissue trauma
6. Failure to complete tx
7. Loss of tooth vitality
8. Candidal infections