extraction in orthodontics by almuzian

UNIVERSITY OF GLASGOW

Extractions in orthodontics

Personal notes

Mohammed Almuzian

1/1/2013

.

Table of Contents

Why we take teeth out..................................................................................................1

History...............................................................................................................................1

Angle time........................................................................................................................1

Case....................................................................................................................................2

Tweed.................................................................................................................................2

Begg....................................................................................................................................2

Advantages of non-extraction approach..................................................................2

Advantages of extraction approach...........................................................................3

Prevalence of extractions in orthodontics...............................................................3

Evidences about the detrimental effects of extraction........................................4

How we can measure crowding.................................................................................8

Factors affecting the choice of extractions in orthodontics...............................8

Types of extraction in orthodontics........................................................................10

Serial Extractions

Definition:.......................................................................................................................11

Extraction Sequence:...................................................................................................11

Indications:.....................................................................................................................12

Advantages of Serial Extractions............................................................................12

Disadvantages of Serial Extractions.......................................................................12

Mohammed Almuzian, University of Glasgow, 2013 1

Lower Incisors...............................................................................................................13

Indication:.......................................................................................................................13

Contraindication............................................................................................................14

Disadvantages................................................................................................................15

If a lower incisor is to be removed, it would be wise to..................................15

Upper central incisors.................................................................................................16

Upper lateral incisor....................................................................................................16

Indication........................................................................................................................16


Canines............................................................................................................................17

Indication:.......................................................................................................................17

Disadvantages................................................................................................................18

First Premolars..............................................................................................................18

Indication........................................................................................................................18

Advantages.....................................................................................................................18

Second premolars.........................................................................................................19

Indication........................................................................................................................19

Disadvantages:..............................................................................................................19

First Molars....................................................................................................................19

1.....................................................................Enforced extraction of the first molar 20


Incidence.........................................................................................................................20

Indications.......................................................................................................................20

Consequences of forced extraction of the first molar (Gill, 2001)................21

Guidelines for forced first molar extraction (RCSEng. By Cobourne 2009)22

Class I cases with minimal crowding (3mm)......................................................22

Class I cases with crowding......................................................................................22

Class II case with crowding......................................................................................24

Class III cases................................................................................................................25

2............................................Interceptive extractions of the 6's, Wilkinson 1940 25

Ideal Wilkinson criteria..............................................................................................25

Complication of Wilkinson extractions.................................................................25

3.. Elective first molar extractions to provide space for orthodontic purpose 26

Potential problem with first molar extractions to provide space for orthodontic

purpose.............................................................................................................................26

Second Molars...............................................................................................................28

Indications.......................................................................................................................28


Advantages.....................................................................................................................29

Disadvantages................................................................................................................29

Third molars...................................................................................................................30


Indication........................................................................................................................30

Early loss of primary teeth.........................................................................................30

RCSEng guidelines and Recommendations.........................................................30

BOS guideline for extraction letter.........................................................................31

summary of the evidences


Extractions in orthodontics

Why we take teeth out

1.General factors like caries, periodontal problems or sever malposition

2.Correction of incisor relationships and OJ

3.Relief of crowding

4.OB (flattening of curve of Spee requires space)

5.Correction of CL problems

6.Facial aesthetic by reducing fullness of the lip eg. Bimax protrusion

7.To allow distalization

8.Tooth size anomalies

9.Provision of anchorage provision of anchorage and allow the use of intermaxillary

elastic

10.Interceptive treatment

11.Stability

History

Angle time

Angle was convinced that

The human jaw could accommodate a full complement of teeth in an ideal occlusion.

Wollf, the physiologist maintained that bone formation was related to the stress


applied to it and from this Angle assumed that bone would surround teeth and

stabilising them in their new functional position.

Angle was also very preoccupied with facial aesthetics, maintaining that an ideal

profile would be gained from the ideal positioning of a full complement of teeth.

Case

Criticise Angle for non-extraction since it influence the profile

Tweed

Around the 1930’s Charles Tweed and Raymond Begg, both ex pupils of Angle,

were simultaneously revising their therapies to include extractions after being

dissatisfied with the extent of relapse noted in previous non extraction cases.

Begg

Abandon non extraction due to high relapse and accused the loss of IP abrasion to

the high need of extraction

Advantages of non-extraction approach

1.Less trauma to the child

2.Ease of treatment

3.Consumer demand

4.Short duration

5.Facial fullness to give young full profile

6.Less effect on TMJ


7.Less effect on the vertical relationship

8.Less effect on smile width

Advantages of extraction approach

1.Stability

2.Less protrusive facial appearance

3.Controllable outcomes

4.Begg philosophy (tooth size reduction required to compensate for dietary change)

5.Little gingival recession

Prevalence of extractions in orthodontics

A. McCaul 2001, found that extraction for orthodontics represents 10% of overall

extraction in dentistry.

B. Weintraub et al (1989) the actual extraction rates is 54% in all orthodontic

treatment.

C. There is a wide variation in the use of extractions which had no association with the

year of graduation of the dental school from which the orthodontist graduated from.

D. Bradbury (1985) carried out a survey of the types of teeth extracted by hospital

service orthodontists. The first premolars were the teeth most commonly extracted

(59%) followed by the second premolars (13%), first permanent molars (12%),

second permanent molars (7%), permanent canines (4%), permanent lateral incisors

(3%) and the permanent central incisors (1%).


Evidences about the detrimental effects of extraction

1.Profile

2.Smile width

3.Vertical Dimension

4.TMD

5.Effect on PD

6.Relapse

7.The outcome of treatment

8.General problems

9.Intra-oral detrimental effect

In details………………..

Effects on

profile

Angle believed that the best

facial appearance for a patient

would be achieved when the

dental arches had been

expanded so that all of the teeth

were in an ideal occlusion.

The upper lip to upper incisor

retraction approximately 1 :0.3

lower lip to lower incisor

relation approximately 1 : 0.59.

(Talass, 1987)

(Bowman and Johnston 1993).

extractions have a minimal

effect on the facial profile, but

that the effect is not deleterious

and should not influence the

extraction pattern prior to

orthodontic treatment

Paquette et al (1992) found the

soft tissue changes has no

detectable aesthetic effects.

Various assessments of the

patients' opinion of the

aesthetic changes in their


silhouettes and facial

photographs both before and

after treatment revealed no

difference between the groups.

Extractions

and smile

width

Orthodontic treatment involving

extractions has been accused in

causing larger “dark buccal

corridor”.

However, the study by Johnson

and Smith (1995) found no

evidence of this and also no

evidence that extractions

produced less attractive smiles

in the opinions of lay judges.

The Effect

on Vertical

Dimension

Dewel (1967) expressed worries

that premolar extraction may

tend to deepen the bite and

cause lower incisors to tip

lingually as well as developing

TMD.

Paquett et al (1992) there are

no convincing studies which

suggest that vertical dimension

is influenced by extraction or

non extraction treatment.

Extractions

and

Mandibular

Dysfunction

Farrar et al.(1983) suggested

that removal of four premolar

teeth prior to orthodontic

treatment can be detrimental to

the stability of the

temporomandibular joint as a

result of “over retraction” of the

maxillary incisors during space

closure, which displaces the

mandible posteriorly.

Plaquette 1992 found that

extraction has no influence on

TMJ.


Effect of

expansion

and

proclination

on PD

Artun 1987, excessive

proclination of mandibular

incisors may lead to dehiscence

and the overlying gingiva will

become very thin and more

susceptible to recession than

thick attached gingivae.

Aziz 2011, no association

between appliance induced

labial movement of mandibular

incisors and gingival recession

was found. Factors that may

lead to gingival recession after

orthodontic tipping and/or

translation movement were

identified as

a reduced thickness of the free

gingival margin,

a narrow mandibular symphysis,

inadequate plaque control

Aggressive tooth brushing.

The Effect

on Relapse

Some clinicians argue that

extractions are required to

prevent such relapse.

However, it has been shown

that relapse can happen in both

extraction and non-extraction

and there is no prediction for

relapse. (Little et al 1990).

Paquette et al (1992) Regarding

stability, the Little index in the

lower labial segment at recall

was 2.9 mm in the extraction

group and 3.4 mm in the non-

extraction group. This

difference was again not


significant

The

outcome of

treatment

Ileri 2011 compares the

outcome in treating class I with

extraction of 4s, non-extraction

or extraction of single incisors.

It was a retrospective study. He

found the outcome measured

on the PAR basis was better in

non-extraction gp.

General

problems

Cost

Pain,

Bleeding

Infection

Prolong treatment

Difficulty to close space

Intra-oral

detrimental

effect of

tooth

extraction

Loss of tooth substance

Reduction in the arch length

Reduction in the arch width

TSD

Reduction in the tooth inclination

However some of these could

be advantageous in certain

cases. Eg increase in the OB is

beneficial in case of high angle

class II D1

How we can measure crowding

1.Brass wire


2.Microscopic

3.Segemental measurement

4.Visual using clear ruler

Johal 1997 found that microscopic is better, visual over estimate and bras wire under

estimate.

Factors affecting the choice of extractions in orthodontics

A. General Factors

1.Medical condition

2.Age of patient - more difficult to close space in older pts. Also in young patient other

method of space provision can be used

3.Patient cooperation where other method of space provision can be used

4.Pathology

5.Gross Displacement

6.Abnormal morphology.

B. Factors specific to the malocclusion

1. Patient’s facial aesthetics and profile.

2. The A-P skeletal pattern

3. The vertical skeletal pattern. Extraction avoided in deep bite and vice versa.

4. The transverse relationship of the arches. Will Andrews and Larry Andrews' WALA

line is the band of soft tissue immediately superior to the mucogingival junction in

the mandible. It is at or nearly at the same superior-inferior level as the horizontal

centre-of-rotation of the teeth. Andrews' sees the WALA

Ridge as the primary landmark for arch width and form and for


archwire width and form. This is perhaps a better indicator of mandibular basal bone

position than the pretreatment mandibular arch width.

5. The degree of crowding.

Mild , 1 to 4mm, Non extraction or second premolars

Moderate, 5 to 8 mm, First premolars or second premolars

Severe, 9+ mm, First premolars

6. Site of crowding

7. Amount of overjet

8. Amount of overbite. Also space might be required to flatten the COS

9. The inclination of the canines.

10. Amount of space needed for correction of the molar relationship.

11. Amount of space for centreline correction.

12. Treatment plan and aim: surgical treatment plan or camoflagable.

13. Treatment mechanics: which determines the anchorage requirements of the proposed

tooth movements.

14. The Diagnostic line or A-P line (Williams., 1969): It was suggested that for a

harmonious facial profile and lip balance, the incisal edge of the lower incisor

should lie near or on the A-P line. It has been used as useful aids in Tip Edge and

Begg technique to determine the need for extraction (Cadman et al., 1975). If the

alignment, levelling, or the mandibular growth result in a potential anterior

positioning of the lower incisor edge in relation to the A-Po line, then it is likely that

extractions or tooth size reduction may be necessary.


Types of extraction in orthodontics A. Extraction of deciduous canines

1.Extraction of lower deciduous canines has been suggested for the correction of mild

lower incisor crowding. Houston and Tulley (1989) state that in general terms this

allows some correction of the incisor crowding. Stephens (1989), reported that the

ideal age group for this would be 9-10 years of age to allow full development of the

intercanine width. Proffit (1993) however warns that this may result in the lower

incisors tipping lingually further reducing arch length.

2.Provide space for palatally lateral incisors.

3.Provide space for incisors whose eruption is late due to supernumeries.

4.Serial extraction

5.Balance extraction for maintaining ML integrity

6.Extraction of lower C`s may help in treatment mandibular displacement.

7.Extraction of upper deciduous canines is often suggested in order to attempt to

encourage a palatally placed canine to erupt into a normal position. Research has

shown that this indeed is quite successful with 70% erupting into favourable

positions (Ericsson and Kurol, 1988).

B. Serial Extractions

Definition:

Timed extraction of 1o and 2o teeth for interceptive management of crowding

Originally advocated by Kjellgren 1947 to avoid the need for orthodontic treatment

but now modified and used as an adjunct to fixed appliance treatment


Extraction Sequence:

1. B`s as centrals erupt

2. C`s as laterals erupt (8½-9½ yrs) allows 1 & 2`s to align + move distally but 5 &

6`s drift mesially

3. D`s when 75% resorbed or 1st premolar roots are ½ to 2/3 formed, in order

encourage 4`s to erupt

too early extraction > bone formation over D`s hence delays eruption of 4`s

too late extraction >3`s will erupt before 4`s

4. 4s as the 3`s erupt

allows 3`s to align

any residual space will close with mesial drift of 5 & 6`s

Indications:

Sever crowding in:

1. 8-9 yrs old

2. skeletal Class I

3. normal OJ and OB

4. 4`s developmentally ahead of 3`s

5. First permanent molars of good prognosis

6. all permanent teeth present

Advantages of Serial Extractions

1.in theory no appliance treatment needed

2.appliance may be simpler and shorter 50% reduction in the treatment time (Little

1990)

3.Better stability and retention since tooth completes its formation in a site where it will

remain when treatment is completed (Graber, 2011)


Disadvantages of Serial Extractions

1.Exposed to multiple extractions (12 teeth)

2.No guarantee, extractions of D`s can lead to impaction of 4`s if the 3s erupt ahead of

the 4s. Removal of twelve teeth is a traumatic experience and there is no guarantee

that the lower premolar will erupt before the canine and as such the latter may be

impacted. If this occurs extraction of the second deciduous molars may be an option

with Holtz (1970) advocating the provision of a lingual arch retainer for space

maintenance. The latter author also recommends disking of the second deciduous

molars to provide space for premolar teeth.

3.Growth prediction problems: difficult to predict amount of incisor crowding because

ICW between 8-10yrs i.e. lower incisor crowding may resolve spontaneously

4.Space loss with extractions of C`s and especially D`s, by mesial drift of buccal

segments, lower incisors tip lingually, both of these reduces arch length

5.Tipping of teeth into extractions site especially anterior teeth causing OB increasing.

Little 1990

6.There was no difference between the serial extraction sample and a matched sample

extracted and treated after full eruption except shorter time for active orthodontic

treatment (Little 1990)

C. Modified serial extraction

1.Serial extraction has no real role in modern orthodontics

2.Modified form, by applying stage 3+4 only extraction of Ds and 4s and

D. Removal of the individual tooth types

Below will summarise the thoughts behind individual tooth extractions.


Lower Incisors

Indication

1.Hypoplasia

2.Severe displacement

3.Heavily restored or poor prognosis

4.Impaction or abnormal shape.

5.Traumatised, heavily restored or non-vital lower incisor (Kokich and Shapiro, 1984).

6.Periodontally involved tooth (Canut, 1996).

7.Ectopic eruption of lower lateral incisor or single lower incisor excluded from the

arch and remaining incisors will aligned.

8.Crowding of 5mm (equivalent to a lower incisor) localised in lower labial segment

with buccal segments well intercuspated. (Tuverson, 1980)

9.Excessive size of lower incisor teeth since it can relieve tooth-size discrepancy

caused by microdont 22

10.When reduction of the intercanine width is required

11.Distally tipped canines

12.Adult presenting with full unit class II in the buccal segment and 5mm crowding in

the lower arch (extraction of two premolars in the lower arch may be extremely

challenging).

13.The patient has had previous orthodontic treatment involving removal of upper

premolars producing a well-aligned upper arch, good buccal segment intercuspation

but leaving unacceptable lower incisor crowding


14.Removal of lower incisor to compensate for the loss of an upper lateral incisor may

be considered.

Contraindication

1. Deep overbite

2. Increased overjet (Hegarty and Hegarty, 1999)

3. Poor buccal segment relationship

4. Mesially inclined canines

5. Poor prognosis of posterior teeth

6. Mild (<3mm) or severe (>7mm) lower incisor crowding

Disadvantages

1. ML problems

2. Treatment must involve fixed appliances.

3. Reduction of the lower intercanine width

4. Increased overbite and overjet.

5. Loss of interdental papillae (Faerovig and Zachrisson, 1999)

6. TSD and poor occlusion.

7. Risk of space opening so fixed bonded lower retainer should be considered (Dacre,

1985)

However, the long term stability more favourable than with premolar extraction.

(Riedel et al., 1992)


If a lower incisor is to be removed, it would be wise to

1.First carry out a Bolton tooth-size analysis and Kesling diagnostic set-up.

2.If this confirms the proposed treatment plan, the majority of facial growth should be

complete before commencing treatment. If this is not possible, there is a greater

potential for relapse of crowding as a result of natural growth changes in this region.

3.Proximal enamel reduction should be carried out prophylactically to avoid black

triangle.

4.It is helpful to place the lower incisor brackets a little more gingivally such that the

incisal edges and canine tips are level.

5.It is also advisable to angulate the brackets of the incisors each side of the extraction

space by a few degrees so that the apices are a little closer together than usual.

6.It is occasionally necessary to remove a little enamel from mesial and distal 'ridges'

on the palatal surface of the upper incisors where the lower canine can contact

Upper central incisors

1.Again upper incisors are rarely the tooth of choice for extraction.

2.Hypoplasia




6.Again there are problems with reduction of the intercanine width and fitting the lower

labial segment around the upper labial segment.


Upper lateral incisor

Indication

1.Hypoplasia

2.Severe displacement. If lateral incisor is severely crowded and the central and the

canine are in acceptable contact.



5.If root is severely resorbed from ectopic canine.

6.If contralateral lateral incisor is congenitally absent (2% population).

7.Diminutive size with increased OJ or ML or crowding

Contraindication

1. aesthetic considerations:

If the canine crown is bulbous.

If the canine crown is different shade to the central.

If the canine gingival margin height differs significantly from the central

2. Class III Incisal relationship – unfavourable anchorage balance.

Canines

Indication:

1. Hypoplasia

2. Severe displacement. If lateral incisor is severely crowded and the lateral and the

premolar are in acceptable contact.


3. Heavily restored or poor prognosis

4. Impaction or abnormal shape.

5. if the lateral and the first premolar are in good contact

6. Patient unwilling a long procedure for aligning an impacted canine.

Disadvantages

1.Aesthetically: Loss of canine eminence & canine can be dark and big

2.Functionally: loss of canine guidance and improper buccal occlusion

First Premolars

Indication

1.Hypoplasia



4.Moderate to severe crowding,

5.Serial extraction

6.To relieve impaction of canines and second premolars,

7.To relieve moderate to severe crowding of the labial segements

8.To facilitate overjet reduction

9.Anchorage balance.

10.Midline correction

11.Leveling COS


12.Correction of incisor inclination

Advantages

1.their proximity to the labial and Buccal segments

2.5`s adequately replaces 4`s both aesthetically + functionally

3.good contact point between 5 33 5

4.good anchorage balance

Second premolars

Indication

1.Hypoplasia



4.Impaction

5.Congenital absence of contralateral second premolars

6.Mild crowding (2-4mm per quadrant). Creekmore (1997), reviewing this subject

concludes that as a rule of thumb, extraction of first premolars provides

approximately 66% of the space for aligning/retracting the anterior teeth, whereas

extraction of second premolars provides approximately half of the space

7.Where space closure by forward movement of the molars rather than retraction of the

labial segments is indicated whilst taking into account the molar relationship.

8.anchorage consideration


Disadvantages:

1.fixed appliance almost always

2.spontaneous alignment of incisors is less satisfactory

3.mesial tipping of molar tooth

First Molars

1.Hypoplasia



4.Mild crowding (2-4mm per quadrant).

5.Impaction of the 5 or the 7 keeping in mind that these teeth should be in a favourable

angulation and the degree of their root formation favouring their eruption before

commencing 6 extraction.

6.For balancing or compensating purposes in enforced extraction.

7.Prophylactic treatment of crowding (Wilkinson extractions).

1. Enforced extraction of the first molar

Incidence

12% of Xtn cases referred to Consultant Orthodontists involve first permanent

molars

Indications

1.Extensively carious first molars


2.Hypoplastic first molars — linked with MIH (molar-incisor hypoplasia), is a

recognized condition of unknown aetiology seen in around 15% of Caucasian

children, which can significantly affect the long-term prognosis of first permanent

molars in more severe cases

3.Heavily filled first molars where premolars are healthy

4.Apical pathology or root treated first molars

5.Factors to consider when planning extraction of first permanent molars of poor

prognosis:

The restorative state of the tooth;

Age of the patient;

Amount of crowding

Inter arch relationship

Developmental status and the inclination of the 7s

Presence and condition of the other teeth.

Angulation of the 5s. if the 5s are distally angulated then extraction of the E might be

indicated to prevent distal tipping of the 5s.

Consequences of enforced extraction of the first molar (Gill, 2001)

A. Lower Arch

1. Correct extraction timing:

The lower labial segment can retroclined, resulting in an increased overbite and

relieving crowding;

OB increased

relieving crowding

successful third molar eruption

2. Early loss: Lower second premolar can become tipped distally or impacted against

second molar , so it is recommended to extract the E at the same time

3. Delayed loss: this results in:


Incomplete Space closure

Necking of alveolus can make space closure difficult

Tendency for lower second molar to tilt mesially and roll lingually.

Lingual rolling may result in the development of a scissor bite

Upper molar may over and may predispose to TMD

B. Upper Arch

1. Upper second molar rotates around the palatal

2. Faster space closure

3. However it is less critical than L6 extraction cases.

Guidelines for forced first molar extraction (RCSEng. Cobourne 2009)

A number of general guidelines on treatment planning first permanent molar

extraction cases for a number of malocclusions are available

As a general rule, if in doubt, get the patient out of pain, try and maintain the teeth

and refer for an orthodontic opinion.

Class I cases

Class I cases with minimal crowding (3mm)

Aim for extraction at the optimal time without balancing extraction

1.If the lower first molar is to be lost, compensating extraction of the upper first molar

should be considered to avoid overeruption of this tooth, unless the lower second

molar has already erupted and the upper first molar is in occlusal contact with it.

2.If the upper first molar is to be lost, do not compensate with extraction of the lower

first molar if it is healthy.

Class I cases with crowding

1.First molar extractions can be delayed until the second molars have erupted and then

the extraction space used for alignment with fixed appliances.


2.Alternatively, first molars can be extracted at the optimum time and the crowding

treated once in the permanent dentition. If premolar extractions are likely to be

required at this stage, the third molars should be present.

3.If the buccal segment crowding is bilateral, consider balancing extraction to provide

suitable relief and maintain the centreline. Sometime asymmetrical balanced

extraction (extraction of other poorer tooth than 6s) is indicated if there is sever

crowding and if extraction is decided at early age with a risk of CL shift.

Compensating extraction of upper first molars should be considered to prevent

overeruption or relieve premolar crowding

Class II cases

The main complicating factors often involve the upper arch because of the need for

space to correct the incisor relationship.

Class II cases with minimal crowding

Lower first molar extraction

It should be carried out at the ideal time for successful eruption of the second

permanent molar and control of the second premolar. Regarding compensating and

balancing extraction:

a)Compensating and balancing extraction of healthy lower first molars are not

indicated. So that, if the upper first molars are to be left unopposed, a simple

removable appliance may be required to prevent their over-eruption, whilst waiting

for the second molars to erupt. Alternatively, a functional appliance can be used

immediately to correct the incisor relationship prior to extraction of the first molars

and fixed appliances.

b) If the upper first permanent molar is sound, elective extraction may be indicated if it

is at risk of over-erupting; however, the third molars should ideally be present

radiographically.


c)If there is no sign of upper third molar development, an appliance to prevent the over-

eruption of sound upper first molars should be considered.

Upper first molar extraction

In the upper arch, space will often be required to correct the incisor relationship: If

the upper first permanent molars require immediate extraction, orthodontic treatment

may be instituted to correct the incisor relationship. A functional appliance or

removable appliance and headgear can be used to correct the buccal segment

relationship, followed by fixed appliances if required.

If the upper first permanent molars can be temporised or restored, then their

extraction can be delayed until the second permanent molars have erupted. The

resultant extraction space can then be used to correct the malocclusion with fixed

appliances.

Alternatively, after extraction of the upper first permanent molars, the second

permanent molars can be allowed to erupt and the incisor relationship corrected then

by the loss of two upper premolars teeth. But as a condition, there should be a

radiographic evidence of third molar development.

Class II case with crowding.

Lower first molar extraction

Space will also be required in the lower arch for the relief of crowding. If the third

molars are present radiographically, lower first molars can be extracted at the

optimum time to allow second molar eruption and then premolars extracted at a later

stage for the correction of crowding. In these cases, fixed appliances will usually be

required.

Alternatively, first molars can be extracted after second molar eruption and the

space used directly for the correction of crowding with fixed appliances.

Balancing and compensating extraction of lower first molars are not generally

required.

Upper first molar extraction


Space requirements in the upper arch can be significant. The upper first permanent

molars should be temporised or restored and the child referred to a specialist

orthodontist whenever possible.

If the upper first permanent molar is unopposed, at risk of over-erupting and third

molars are present radiographically, then extraction of the upper first molar may be

indicated. The patient should be counselled that additional premolar extractions in

the upper arch may be required in the future to create sufficient space for crowding

relief and incisor correction.

Class III cases

As a general rule, extraction of maxillary molars should be avoided if at all possible,

whilst balancing and compensating extractions are not recommended in class III

cases.

2. Interceptive extractions of the 6's, Wilkinson 1940

Ideal Wilkinson criteria

1.Class I malocclusion seen at between 8.5 and 9.5 years

2.No increase in overbite.

3.Mild anterior segment crowding

4.Moderate posterior crowding

5.all successional teeth present and third molars present

6.lower second molar bifurcation beginning to form,

7.angle between long axis of crypts of 6 and 7 = 15-30 degree and

8.crypt of lower 7 overlaps the root of lower 6

Complication of Wilkinson extractions

1.Black triangle bet 5 and 7


2.Incomplete closure

3.Rotation

3. Elective first molar extractions to provide space for orthodontic purpose

Indication1. Extensively carious first molars

2. Hypoplastic first molars

3. Heavily filled first molars where premolars are perfectly healthy

4. Apical pathoses or root treated first molars

5. Crowding at the distal part of the arches and wisdom teeth reasonably positioned

6. High maxillary/mandibular planes angle

7. Anterior open bite cases

8. Extraction of first molars, if they are not restored, can be indicated if the patient

has previous orthodontic treatment with premolar extraction or the premolars are

missing.

“First permanent molar extractions doubling the treatment time and halving the

prognosis” was the phrase coined by Mills 1987.

Potential problem with first molar extractions to provide space for orthodontic

purpose, Sandler 2000

1. Anchorage 7s provide little

anchorage

Palatal arch with a button

Miniscrew anchorage


7s unsuitable for Kloehn

bow EOT

2. Overbite

Reduction

Bite opening curves less

effective

Less scope for class II

elastics

Anterior bite plane early in

treatment

Functional appliance pre SWA

Miniscrew anchorage

3. Mesial

Tipping

Space closure after

the extraction of the

first permanent

molar teeth has been

studied in some

detail and has led to

conclusions that

satisfactory closure

of spaces was best

achieved on children

and young adults

Mesial tipping

particularly in the lower

arch

Rotations particularly in

the upper arch

Do not over tighten lacebacks

Do not over loading the second

moalrs

Build up archwires quickly,

particularly in the lower arch,

even if not all anterior teeth

are fully engaged

4. Lower

Second Molar

Lingual

Rolling

Initial alignment with rectangular Niti wire

Add buccal crown torque in later wires

Expand lower archform

Class II or cross elastics from lingual surfaces


MBT molar tubes (and premolar brackets)

Nance or lingual arch on the 7s

5. Class II

second

molars

It is caused by the fast

migration of the U7s

than L7s causing a

class II molar

relationship

It can be a real problem

and can become

established in a matter

of weeks, even in cases

that are class I or 1/2

unit class II at the

outset. Prevention of

this complication is

highly recommended.

The solutions vary according to

whether the remainder of the

malocclusion is class I or II.

Solutions if the occlusion is

Class I incisors at the start

Palatal arch with button

Miniscrew anchorage if

necessary

Laceback lower but not upper

Hold back 717 with stopped arch

Hold back 717 with coil spring

Solutions if the occlusion is

Class II incisors at the start

Functional appliance

URA with EOT to premolars if

717 unerupted

Miniscrew anchorage


Second Molars

Indications

1.Hypoplasia



4.Facilitate molar distalization to:

Correct incisors relationship

OJ reduction

Correct crowding of lower incisor by providing a mild amount of space after

distalising the first molar with little effect on OB and inclination of the incisors as

well as the profile.

Relief of premolar crowding in a vertically impacted premolar in the line of the arch

where early extraction indicated for spontaneous correction. Richardson 1992

5.Provide space for the third molars. Richardson 1983

6.Open bite treatment

7.Interceptive treatment of the existing or anticipated arch length deficiency. Extraction

in early permanent dentition may prevent or at least limit late lower arch crowding.

Richardson 1983. Requirements for second molar prophylactic extraction (Lehman,

1979):

All third molars are present and of normal size and shape.

Third molars should be of 15 – 30 degrees with the long axis of the second molar

and its root not developed yet.


Contraindication

1. Congenital absence or diminutive 3rd molar.

2. Lower anterior crowding more than 2 mm.

Advantages

1.May relieve mild ant. crowding 1-2 mm`s

2.May prevent late incisors crowding

3.Space provided with little effect on profile

4.Provides space for crowded 2nd premolar

5.Facilitates distal movement of buccal segments (6`s) + OB reduction

6.Eliminates 8`s surgery + its complication

7.facilitation of overbite reduction (unsubstantiated)

8.Reduction of treatment time (Lehman, 1979; Richardson and Burden ,1992)

Disadvantages

1. 3rd molars may erupt into an unsatisfactory position, rarely with proper angulation

and contact relationship in 4% Richardson and Richardson (1993)

2. Difficult to predict which 3rd molars will erupt unsatisfactory (Thomas and Sandy,

1995).

3. Second course of treatment to orthodontically upright the 3rd molar may be required

(Orton and Jones, 1987).


Third molars

1. Approximately 15% of patients never develop mandibular 3rd molars (Robinson and

Vasir, 1993)

2. Approximately 25% of third molars become impacted (Robinson and Vasir, 1993)

Indication

1.No orthodontic indication is present

2.Teeth that present with symptoms

3.Concealed caries in distal surface of second molar.

4.Resorption of the second molar.

5.Follicular cyst.

6.Bone loss due to repeated episode of chronic periodontitis.

7.Effects of early extraction of lower 3rd molar on late crowding; no significant

difference in incisor crowding between extraction and non-extraction groups

(Harradine et al., 1998; Robinson and Vasir, 1993; Ades etal., 1990). Late lower

incisor crowding is insufficient reason alone to remove mandibular third molars as

lingual nerve and inferior alveolar nerve may be damaged. (Ades, 190 and review

by Bishara, 1999)

Early loss of primary teeth

RCSEng guidelines and Recommendations

Radiographic screening is highly desirable before extracting primary molars to

check for the presence, position and correct formation of the crowns and roots of

successional teeth.


1. Loss of primary incisors – Early loss of primary incisors has little effect upon

the permanent dentition although it does detract from appearance. It is not necessary

to balance or compensate the loss of a primary incisor.

2. Loss of primary canines– Early loss of a primary canine in all but spaced

dentitions is likely to have most effect on centre lines. The more crowded the

dentition, the more the need for balance.

3. Loss of primary first molars –With regard to a primary first molar, a

balancing extraction may be needed in a crowded arch but compensation is not

needed.

4. Loss of primary second molars – There is no need to balance the loss of a

primary second molar because this will have no appreciable effect on centreline

coincidence. However when a primary second molar has to be extracted

consideration should be given to fitting a space

maintainer

BOS guideline for extraction letter

1.Request should be written

2.Two nomination technique should be used

3.Always rely on the record not the memory

4.In case of supplemental tooth a descriptive method should be used.

5.In case of confusion, better to fax a new letter or speak directly to the clinician. If

doubt then ask to delay the extraction and review the patient again

Summary of the evidences Why we take teeth out: Provision of anchorage provision of anchorage and allow the


use of intermaxillary elastic, Stability

Prevalence of extractions in orthodontics, McCaul 2001, found that extraction for

orthodontics represent 10% of overall extraction in dentistry.

Artun 1987, excessive proclination of mandibular incisors may lead to dehiscence

and the overlying gingiva will become very thin and more susceptible to recession

than thick attached gingivae.

Aziz 2011, no association between appliance induced labial movement of mandibular

incisors and gingival recession was found.

lower lip to lower incisor relation approximately 1 : 0.59.(Talass, 1987)The Effect on

Vertical Dimension

(Bowman and Johnston 1993). extractions have a minimal effect on the facial profile,

but that the effect is not deleterious and should not influence the extraction pattern

prior to orthodontic treatment

Paquette et al (1992) found the soft tissue changes has no detectable aesthetic effects.

Various assessments of the patients' opinion of the aesthetic changes in their

silhouettes and facial photographs both before and after treatment revealed no

difference between the groupsThe upper lip to upper incisor retraction

approximately 1 :0.3

Dewel (1967) expressed worries that premolar extraction may tend to deepen the bite

and cause lower incisors to tip

Paquett et al (1992) there are no convincing studies which suggest that vertical

dimension is influenced by extraction or non extraction treatment.

Extractions and Mandibular Dysfunction, Farrar et al.(1983) suggested that removal

of four premolar teeth prior to orthodontic treatment can be detrimental to the


stability of the temporomandibular joint as a result of “over retraction” of the

maxillary incisors during space closure, which displaces the mandible, Plaquette

1992 found that extraction has no influence on TMJ.

The Effect on Relapse, However, it has been shown that relapse can happen in both

extraction and non-extraction and there is no prediction for relapse. (Little et al

1990).

Paquett et al (1992) Regarding stability, the Little index in the lower labial segment at

recall was 2.9 mm in the extraction group and 3.4 mm in the non-extraction group.

This difference was again not

Extractions and smile width, However, the study by Johnson and Smith (1995) found

no evidence of this and also no evidence that extractions produced less attractive

smiles in the opinions of lay judges.

The outcome of treatment, Ileri 2011 compares the outcome in treating class I with

extraction of 4s, non-extraction or extraction of single incisors. It was a

retrospective study. He found the outcome measured on the PAR basis was better in

non-extraction gp.

Johal 1997 found that microscopic is better, visual over estimate and bras wire under

estimate.

The transverse relationship of the arches. Will Andrews and Larry Andrews' WALA

line is the band of soft tissue immediately superior to the mucogingival junction in

the mandible. It is at or nearly at the same superior-inferior level as the horizontal

centre-of-rotation of the teeth. Andrews' sees the WALA Ridge as the primary

landmark for arch width and form and for archwire width and form. This is perhaps

a better indicator of mandibular basal bone position than the pretreatment

mandibular arch width.


The Diagnostic line or A-P line(Williams., 1969): It was suggested that for a

harmonius facial profile and lip balance the incisal edge of the lower incisor should

lie near or on the A-P line. It has been used as useful aids in TE and Begg technique

by (Cadman., 1975) to determine the need for extraction. If the alignment, levelling ,

or the mandibular growth change the location of LLS incisor edge to the A-Po line,

it is likely that extractions or tooth size reduction may be necessary.

Extraction of lower deciduous canines has been suggested for the correction of mild

lower incisor crowding. Houston and Tulley (1989) state that in general terms this

allows some correction of the incisor crowding. Stephens (1989), reported that the

ideal age group for this would be 9-10 years of age to allow full development of the

intercanine width. Proffit (1993) however warns that this may result in the lower

incisors tipping lingually further reducing arch length.

Extraction of upper deciduous canines is often suggested in order to attempt to

encourage a palatally placed canine to erupt into a normal position. Research has

shown that this indeed is quite successful with 70% erupting into favourable

positions (Ericsson and Kurol, 1988).

Originally advocated by Kjellgren 1947 to avoid the need for orthodontic treatment

but now modified and used as an adjunct to fixed appliance treatment

Advantages of Serial Extractions, appliance may be simpler and shorter 50%

reduction in the treatment time (Little 1990), Better stability and retention since

tooth completes its formation in a site where it will remain when treatment is

completed (Graber, 2011)

Growth prediction problems: difficult to predict amount of incisor crowding because

ICW between 8-10yrs i.e. lower incisor crowding may resolve spontaneously


If a lower incisor is to be removed, it would be wise to First carry out a Bolton tooth-

size analysis and Kesling diagnostic set-up.

Second premolars, Indication, Congenital absence of contralateral second premolars ,

Mild crowding (2-4mm per quadrant). Creekmore (1997), reviewing this subject

concludes that as a rule of thumb, extraction of first premolars provides

approximately 66% of the space for aligning/retracting the anterior teeth, whereas

extraction of second premolars provides approximately half of the space

Hypoplastic first molars — linked with MIH (molar-incisor hypoplasia), is a

recognized condition of unknown aetiology seen in around 15% of Caucasian

children, which can significantly affect the long-term prognosis of first permanent

molars in more severe cases

Consequences of enforced extraction of the first molar (Gill, 2001)

Guidelines for forced first molar extraction (RCSEng. By Cobourne 2009)

Interceptive extractions of the 6's, Wilkinson 1940

Second Molars, Indications, Provide space for the third molars. Richardson 1983


extraction in orthodontics by almuzian

Health & Medicine

choice of extractions

prevalence of extractions

types of extraction

extraction sequence

lower incisors

upper central incisors

upper lateral incisor

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