Class II DIV I

Question 1

Class II Div I

Answer 1

Lower incisor edges are palatal to the cingulum plateau of the upper incisors and the upper incisors are proclined or of average inclination, with an increased overjet.”

Question 2

Increased overjet

Answer 2

Horizontal relationship between upper and lower incisors
Normally 2-4mm

Question 3

Incidence

Answer 3

Most common malocclusion
20-30%. of all malocclusions
3/4 have a skeletal II base

Question 4

Significance

Answer 4

Poor dental appearance
Facial profile is poor
Inc risk of upper incisor trauma (over 40% risk with overjets 9mm +)
often associated with deep overbite and possible palatal trauma

Question 5

Aetiology

Answer 5

Growth - AP Skeletal Discrepancy (>70% of cases)
- Mandibular retrognathia
Habits eg thumb sucking
Soft tissues eg lower lips maintains proclination
Dental factors - maxillary crowding

Question 6

E/O Features

Answer 6

Mandible is behind the maxilla
Severity of discrepancy can be disguised by a prominent chin point
Lower vertical facial proportions often reduced

Question 7

Cephalometric analysis

Answer 7

Upper incisors are proclined >109 degrees
ANB > 4 degrees

Question 8

I/O Features

Answer 8

Proclined or average upper incisors
Overjet increased
Overbite increased
Buccal segments usually Class II
Crowding present

Question 9

Treatment

Answer 9

Improved dentofacial appearance
Improved self-esteem –> reduced teasing
Improved psychosocial wellbeing
Reduction in trauma
Improved function/reduce lip incompetence
Improved speech

Question 10

Aims of treatment

Answer 10

Improve facial profile
Reduce overjet
Reduce overbite
Relieve crowding and align arches
Correct centre-lines
Deal with impacted/ectopic/supernumerary/ missing teeth
Produce a stable result

Question 11

Treatment options

Answer 11

Functional appliances
- Andresen/CTB
URA
- Facilitates transition between functional and fixed phase
FA
- Used in conjunction with functional appliances +/- extractions
Headgear
Ortho mini-implants
- to improve anchorage balance
Surgical ortho tx
- Non-growing pts

Question 12

Overbite reduction

Answer 12

Anterior biteplane incorporated into URAs
Start overbite reduction early, during canine retraction

Question 13

Palatal Finger Spring Retractor

Answer 13

Retract canines or premolars
Crib 6s
0.5mm springs
Activate by 1/2 width of the canine or premolar

Question 14

Buccal canine retractor

Answer 14

Retracting canines to relieve crowding or reduce overjet
Crib 6s
0.7mm springs
Activate by 1/3 width of the canine

Question 15

Roberts Retractor

Answer 15

Retracting incisors (Class II Div I)
Crib 6s
0.5mm labial bow supported by SS tube
Should lie just behind the incisal edges when passive

Question 16

Fixed appliances

Answer 16

Excellent tooth control
Mild skeletal discrepancies
Crowded upper/lower arches
Extract upper premolars to provide space for overjet reduction/ if lower crowding then consider upper 4s and lower 5s to improve anchorage balance
may need headgear/ortho mini implants

Question 17

Anchorage in Class II Div I

Answer 17

Bodily retraction of upper incisors when fixed appliances is anchorage demanding
Usually extract upper 4s, providing a better anchorage balance than upper 5s
Consider banding/bonding upper 7s to improve anchorage balance
headgear may be required to help anchorage.

Question 18

Orthognathic Surgery

Answer 18

Moderate to severe Class II skeletal discrepancies in patients too old for functional appliances
FA to align and coordinate individual arches
Mandibular advancement