Extractions in Orthodontics

Question 1

Alternative to extraction orthodontics is

Answer 1

Non-extraction

Question 2

Expansion - 3 types/directions

Answer 2

Laterally
Anteriorly
Posteriorly

Question 3

Expansion - 3 types
Anteriorly
Leads to

Answer 3

Procline incisors
Bimaxillary proclination
Prognosis of teeth reduced

Question 4

Expansion - 3 types

Posteriorly - how is this achieved

Answer 4

Upper arch

With headgear

Question 5

Bimaxillary proclination features

Answer 5

Unaesthetic appearance

Stability affected - neutral zone is destroyed so lips start exerting opposing force –> relapse

Question 6

Complications with newly erupted teeth

Answer 6

7 and 8s can be impacted during late mixed dentition e.g if 6s are distally displaced

Question 7

Reasons/indications for extractions in orthodontics

Answer 7

Relieve crowding
Correct incisor relationship
- reduce overjet by extracting premolar so canine can move back
- camouflage in class III - removal of lower arch teeth only so that incisors move backwards
Overbite correction - reduced overbite
Correct centrelines - remove tooth asymmetrically
Anchorage - balancing molar relationship with need for space anteriorly

Question 8

Principles of extractions - what to consider

Answer 8

Condition of the teeth
Location of crowding
Position of teeth - crowns and apices
Appliance treatment proposed - patient attitude

Question 9

Extraction choice - anterior teeth - centrals and laterals

Answer 9

Central - rarely indicated

Laterals - poor prognosis - symmetry needs, severely displaced

Question 10

Extraction choice - premolars

What do they allow for

Answer 10

Most common
Good anchorage balance
retract anterior teeth
bring posterior teeth forward

Question 11

Principles of extractions - condition of the teeth

Answer 11

e.g no canines

Compromised extraction pattern - taking out teeth we have to take out when preference is another tooth

Question 12

Previous loss of upper central incisor

Answer 12

Preserve space as space maintainer OR

Close space i.e crown lateral incisor

Question 13

Problems with lower incisor extraction

Answer 13

Compromise occlusion buccally
Increased overjet or overbite
Increased upper crowding

Question 14

Problems with canine extractions

Answer 14

Harder to disguise other teeth as canines
Poor aesthetics due to space between two and four
Poor contact between 2+4 on lower

Question 15

Aims of treatment

Answer 15

Relief for crowding
Class I incisors
Class I buccal segments

Question 16

Problems with 1st premolar extractions

Answer 16

Too much space

Effect on patient profile (mechanics)

Question 17

Extraction of second premolars - what does it allow for

Answer 17

Changes anchorage balance due to more mesial movement of molars - closing space from behind

Question 18

Extraction of first molars - allows for

Answer 18

Removes teeth of poor prognosis

Extended treatment

Question 19

Extractions of 2nd molars is carried out when

Answer 19

3rd molar impaction
7s of poor prognosis
2nd molar extraction with mild crowding
Not to be used to resolve anterior crowding because if 7s are removed nothing to anchor 6s to to draw them distally

Question 20

Alternatives - asymmetric extractions

Answer 20

Within the arch
Between the arches
Depending on malocclusion
Class II patients have u4s and l5s removed as they have increased overjet - allows for retraction of anterior teeth on uppers to correct I+M relations

Question 21

Extraction also depends on

Answer 21

appliance treatment proposed