Tx Class I Malocclusion

Question 1

What is class I incisor relationship?

Answer 1

Lower incisor occlude at or below the cingulum plateau of upper incisor

Question 2

What are problems in class I relationship?

Answer 2

Crowding, spacing, displaced teeth

Can’t have overbite

Question 3

How is crowding caused?

Answer 3

Imbalance jaw size and tooth size

Question 4

Tx of crowding?

Answer 4

Expansion, distal movement, enamel stripping, XLA

Question 5

What are problems with expanding?

Answer 5

Relapse, fenestration of labial plate, aesthetic

Don’t expand lower arch - prone relapse - get average 3.7mm expansion but 2mm relapse

Question 6

How expand upper arch?

Answer 6

Removable or fixed appliances

Question 7

What is quad helix?

Answer 7

URA
Bands on molars and arms on premolars
Quad sits roof of mouth
Activated out of mouth

Question 8

What is Damon system?

Answer 8

Expanded - self ligating

Question 9

What is the limits of expansion?

Answer 9

Buccal segments - stable up to 3mm

Question 10

What is fenestration?

Answer 10

Roots moved out of bone - risk of overexpansion

Question 11

Why use distal movements?

Answer 11

Use distal movement of buccal segments - retract 6s to help align anterior displacement

Question 12

How get distal movement in upper arch?

Answer 12

Headgear
Non-compliance appliances (e.g pendulum/ distal jet)
Temporary anchorage device - screwed into bone under LA

Question 13

How to get distal movement lower arch?

Answer 13

Lip bumper - doesn’t work - supposed to move via forces from soft tissue

Question 14

What pt are suitable for distal movement of upper buccal segments?

Answer 14

Co-operative pt
Half unit class II molars
Well aligned lower arch

Question 15

What is enamel stripping?

Answer 15

Interprxoimal reduction using abrasive metal strips/ air rotar
Remove up to 0.25mm enamel from contact point
Alignment after stripping

Question 16

What problems can spacing cause?

Answer 16

Upper midline diastema, generalised spacing

Question 17

Problem closing midline diastema?

Answer 17

Prone relapse - need bonded retainer

Question 18

How is generalised spacing causes and how would tx?

Answer 18

Jaw too big or teeth too small
Open space - restorative replacement (bridge/ implant)
Close space

Question 19

General rules for opening and closing space with incisors?

Answer 19

Class II - close space

Class III - open space (want to bring incisors forward)

Question 20

What is the most common displaced tooth?

Answer 20

Upper permanent canine (85% palatal impaction, 15% buccal impaction)

Question 21

How tx maxillary canine?

Answer 21

Buccal impaction - closed exposure/ open exposure

Palatal impaction - leave in situ, extract, expose and align or transplant

Question 22

Summary tx class I w/ crowding?

Answer 22

1. Expansion
2. Distal movement
3. Enamel stripping
4. XLA

Question 23

Summary tx class I w/ spacing

Answer 23

Open or close space

Question 24

Summary tx class I w/ displaced teeth?

Answer 24

1. Leave
2. Extract
3. Expose and align
4. Transplant