Orthodontic Extraction Patterns

Question 1

Reasons for extractions

Answer 1

Gain space to align crowded teeth
Reduce dental protrusion
Camouflage skeletal discrepancies
Correct midling discrepancies
Preparation for orthognathic surgery

Question 2

<4 mm of crowding

Answer 2

Ext rarely
Expand arch’s or IPR

Question 3

5-9 mm crowding

Answer 3

Either non ext or ext
Soft tissue profile
Gingival tissues

Question 4

> 10 mm crowding

Answer 4

Ext almost always indicated

Question 5

What limits the ability to protract or retract incisors

Answer 5

Soft tissue

Question 6

What creates fuller lips

Answer 6

Proclining the incisors

Question 7

Patients with thin lips, large nose and strong chin

Answer 7

Extracting teeth and retracting incisors can prematurely age the patient

Question 8

What is the first choice in borderline cases

Answer 8

Non - ext

Question 9

What does success depend on in borderline cases

Answer 9

Hard and soft tissues
Characteristics of the patient
Final incisor position

Question 10

Fixed lingual retainers

Answer 10

Can help in maintaining alignment in patients who may be a higher risk for relapse

Question 11

What should NOT be sacrificed to save premolars

Answer 11

Long term function and stability

Question 12

Alternative to extractions

Answer 12

Move incisors facially
Expansion of the arch to create space
Interproximal reduction (IPR)

Question 13

Potential problems of non ext treatment

Answer 13

Relapse potential
Periodontal concerns
Open bite tendency

Question 14

Relapse potential - non ext tx

Answer 14

Lip pressure increases if lower incisors move >3mm forward from original position
Expansion across lower canines is not as stable as expansion across premolars and molars

Question 15

Periodontal concerns - non ext tx

Answer 15

Recession
Fenestration of roots

Question 16

Class 1 profile

Answer 16

Straight

Question 17

Class 2 profile

Answer 17

Convex
Maxillary excess
Mandibular deficient
Combination

Question 18

Class 3 profile

Answer 18

Concave
Maxillary deficient
Mandibular excess
Combination

Question 19

Canine class I

Answer 19

Mesial incline of the maxillary canine occludes with the distal incline of the mandibular canine and the maxillary canine cusp tip occludes with the occlusal embrasure between the mandibular canine and 1st PM

Question 20

Class 2 Canine

Answer 20

Mesial incline of the maxillary canine occludes mesial to the distal incline of the mandibular canine

Question 21

Class 3 canine

Answer 21

Mesial incline of the maxillary canine occludes distal to the distal incline of the mandibular canine

Question 22

Class 1 crowding (moderate to severe) ext pattern

Answer 22

Generally - four 1st premolars - crowding is in ant, want to create space
OR- extract four 2nd premolars- reduce effect on soft tissue - ext 1st premolars bring back lips further

Question 23

Class 1 w dentoalveolar protrusion

Answer 23

Anterior teeth flare out during eruption
Lip fullness
Mentalis muscle strain
Lip incompetence

Question 24

Class 1 w dentoalveolar protrusion tx

Answer 24

Ext four 1st premolars
Retract anterior segments to reduce protrusion

Question 25

Class 1 crowding with retrusive lips tx

Answer 25

Extract four 2nd premolars Reciprocal closure of ext spaces - post teeth move ant, ant teeth move post Less of soft tissue effect

Question 26

Class 2 ext - dental etiology

Answer 26

There is crowding and ext are indicated

Question 27

Class 2 skeletal etiology - ext patterns

Answer 27

Severe case - surgery Mild to moderate case- functional appliances, surgery, ext to camo

Question 28

Class 2 dental crowding or class 2 skeletal camo tx

Answer 28

Extraction Max 1st premolars and mand 2nd premolars

Question 29

Class 2 ext pattern allows us to differentially move the molars and canines into what class relationship

Answer 29

Class I Retract max anterior segment Protract mand posterior segment

Question 30

Class 2 - pt non growing, good mandible/profile, little mandibular crowding, 5 -10 mm overjet -tx

Answer 30

Ext max 1st premolars only Retract maxillary anterior segment

Question 31

Overjet > 10 mm class 2 tx

Answer 31

Surgery

Question 32

Class 3 ext patterns - etiology

Answer 32

Usually skeletal Many surgery Mild - camo with ext

Question 33

Class 3 ext pattern tx

Answer 33

1 - max 2nd premolars and mand 1st premolars (primary ext pattern) (retract mand ant segment, reciprocal closure of max) 2- mand 1st premolars or single lower incisor (mild class 3, max arch not crowded, moderate to severe mandibular crowding)(reciprocal closure of ext space)

Question 34

Asymmetric ext

Answer 34

1-2 premolars may be extracted on one side only Helps shift the dental midline to center of face

Question 35

Ext 2nd molars

Answer 35

Helps correct class 2 and/or close an open bite Relies on third molars to erupt later and take second molars position Rare

Question 36

Class 2 ext vs class 3 ext (skeletal malocclusion)

Answer 36

Class 2 = extract lower 1st or 2nd premolars Class 3 = extract upper 1st or 2nd premolars Make surgical movements larger = more noticeable profile change

Question 37

The timed sequence of extraction of primary teeth and ultimately permanent teeth to relieve severe crowding (>10 mm) Increase available space for eruption permanent teeth by extraction of certain deciduous teeth Allows teeth to erupt over alveolus and through keratinized tissue

Answer 37

Serial extractions

Question 38

Indications for serial ext

Answer 38

Severe mesial tipping or ectopically erupting perm 1st molars Early loss mand deciduous canine Fanned out U/L perm incisors Abnormal resorption of prim teeth Permanent canines erupting buccally

Question 39

Serial ext pattern

Answer 39

1. Ext prim canines 2. Ext prim 1st molars 3. Ext 1st premolars