UNIVERSITY OF GLASGOW
Extractions in orthodontics
Personal notes
Mohammed Almuzian
1/1/2013
.
Table of Contents
Why we take teeth out......................................................................................
Canines......................................................................................................................
Advantages ..................................................................................................................
Extractions in orthodontics
Why we take teeth out
1.General factors like caries, periodontal problems or sever malposition...
applied to it and from this Angle assumed that bone would surround teeth and
stabilising them in their new functional posi...
7.Less effect on the vertical relationship
8.Less effect on smile width
Advantages of extraction approach
1.Stability
2.Le...
2.Smile width
3.Vertical Dimension
4.TMD
5.Effect on PD
6.Relapse
7.The outcome of treatment
8.General problems
9.Intra-or...
difference between the groups.
Extractions
and smile
width
Orthodontic treatment involving
extractions has been accused in...
susceptible to recession than
thick attached gingivae.
lead to gingival recession after
orthodontic tipping and/or
transla...
It was a retrospective study. He
found the outcome measured on
the PAR basis was better in
non-extraction gp.
General
prob...
• Johal 1997 found that microscopic is better, visual over estimate and bras wire under
estimate.
Factors affecting the ch...
5. The degree of crowding.
• Mild , 1 to 4mm, Non extraction or second premolars
• Moderate, 5 to 8 mm, First premolars or...
1.Extraction of lower deciduous canines has been suggested for the correction of mild
lower incisor crowding. Houston and ...
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% r...
Disadvantages of Serial Extractions
1.Exposed to multiple extractions (12 teeth)
2.No guarantee, extractions of D`s can le...
Lower Incisors
Indication
1.Hypoplasia
2.Severe displacement
3.Heavily restored or poor prognosis
4.Impaction or abnormal ...
14.Removal of lower incisor to compensate for the loss of an upper lateral incisor may
be considered.
Contraindication
1. ...
If a lower incisor is to be removed, it would be wise to
1.First carry out a Bolton tooth-size analysis and Kesling diagno...
Upper lateral incisor
Indication
1.Hypoplasia
2.Severe displacement. If lateral incisor is severely crowded and the centra...
3. Heavily restored or poor prognosis
4. Impaction or abnormal shape.
5. if the lateral and the first premolar are in good...
12.Correction of incisor inclination
Advantages
1.their proximity to the labial and Buccal segments
2.5`s adequately repla...
Disadvantages:
1.fixed appliance almost always
2.spontaneous alignment of incisors is less satisfactory
3.mesial tipping o...
children, which can significantly affect the long-term prognosis of first permanent
molars in more severe cases
3.Heavily ...
• Necking of alveolus can make space closure difficult
• Tendency for lower second molar to tilt mesially and roll lingual...
2.Alternatively, first molars can be extracted at the optimum time and the crowding
treated once in the permanent dentitio...
Upper first molar extraction
•In the upper arch, space will often be required to correct the incisor relationship: If
the ...
•Space requirements in the upper arch can be significant. The upper first permanent
molars should be temporised or restore...
2.Incomplete closure
3.Rotation
3. Elective first molar extractions to provide space for orthodontic purpose
Indication
1....
Potential problem with first molar extractions to provide space for orthodontic
purpose, Sandler 2000
1. Anchorage • 7s pr...
Rolling • Add buccal crown torque in later wires
• Expand lower archform
• Class II or cross elastics from lingual surface...
• Miniscrew anchorage
Second Molars
Indications
1.Hypoplasia
2.Severe displacement
3.Heavily restored or poor prognosis
4....
• Third molars should be of 15 – 30 degrees with the long axis of the second molar and
its root not developed yet.
Contrai...
Third molars
1. Approximately 15% of patients never develop mandibular 3rd
molars (Robinson and
Vasir, 1993)
2. Approximat...
1. Loss of primary incisors – Early loss of primary incisors has little effect upon
the permanent dentition although it do...
Summary of the evidences
• Why we take teeth out: Provision of anchorage provision of anchorage and allow the
use of inter...
• Extractions and Mandibular Dysfunction, Farrar et al.(1983) suggested that removal of
four premolar teeth prior to ortho...
width.
• The Diagnostic line or A-P line(Williams., 1969): It was suggested that for a
harmonius facial profile and lip ba...
ICW  between 8-10yrs i.e. lower incisor crowding may resolve spontaneously
• If a lower incisor is to be removed, it woul...
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    Will like to correspond with you. Send me an email at paulmatondo@gmail.com. My name is Paul M. Matondo (Resident, Orthodontics department, University of Ghana School of Medicine and Dentistry, Accra, Ghana)
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  1. 1. UNIVERSITY OF GLASGOW Extractions in orthodontics Personal notes Mohammed Almuzian 1/1/2013 .
  2. 2. Table of Contents Why we take teeth out...........................................................................................................5 History .................................................................................................................................5 Angle time.............................................................................................................................5 Case......................................................................................................................................6 Tweed ..................................................................................................................................6 Begg.....................................................................................................................................6 Advantages of non-extraction approach .............................................................................6 Advantages of extraction approach ....................................................................................7 Prevalence of extractions in orthodontics..............................................................................7 Evidences about the detrimental effects of extraction............................................................7 How we can measure crowding...........................................................................................11 Factors affecting the choice of extractions in orthodontics..................................................12 Types of extraction in orthodontics ....................................................................................13 Definition: ..........................................................................................................................14 Extraction Sequence:...........................................................................................................14 Indications:.........................................................................................................................15 Advantages of Serial Extractions........................................................................................15 Disadvantages of Serial Extractions....................................................................................16 Lower Incisors....................................................................................................................17 Indication................................................................................................................................................17 Contraindication.....................................................................................................................................18 Disadvantages.........................................................................................................................................18 If a lower incisor is to be removed, it would be wise to..........................................................................19 Upper central incisors.........................................................................................................19 Upper lateral incisor............................................................................................................20 Indication................................................................................................................................................20 Contraindication.....................................................................................................................................20 Mohammed Almuzian, University of Glasgow, 2013 2
  3. 3. Canines...............................................................................................................................20 Indication:...............................................................................................................................................20 Disadvantages.........................................................................................................................................21 First Premolars...................................................................................................................21 Indication................................................................................................................................................21 Advantages ............................................................................................................................................22 Second premolars................................................................................................................22 Indication...............................................................................................................................................22 Disadvantages:........................................................................................................................................23 First Molars........................................................................................................................23 1.Enforced extraction of the first molar...............................................................................23 Incidence ................................................................................................................................................23 Indications .............................................................................................................................................23 Consequences of enforced extraction of the first molar (Gill, 2001)....................................24 Guidelines for forced first molar extraction (RCSEng. Cobourne 2009).............................25 Class I cases with minimal crowding (3mm)...........................................................................................25 Class I cases with crowding.....................................................................................................................25 Class II case with crowding.....................................................................................................................27 Class III cases.....................................................................................................................28 2.Interceptive extractions of the 6's, Wilkinson 1940..........................................................28 Ideal Wilkinson criteria...............................................................................................................................28 Complication of Wilkinson extractions...............................................................................28 3.Elective first molar extractions to provide space for orthodontic purpose.........................29 Indication............................................................................................................................29 Potential problem with first molar extractions to provide space for orthodontic purpose, Sandler 2000..30 Second Molars....................................................................................................................32 Indications..........................................................................................................................32 Contraindication..................................................................................................................33 Mohammed Almuzian, University of Glasgow, 2013 3
  4. 4. Advantages ....................................................................................................................33 Disadvantages.........................................................................................................................................33 Third molars.......................................................................................................................34 Indication............................................................................................................................34 Early loss of primary teeth .......................................................................................................................34 RCSEng guidelines and Recommendations ............................................................................................34 BOS guideline for extraction letter......................................................................................35 Summary of the evidences...................................................................................................36 Mohammed Almuzian, University of Glasgow, 2013 4
  5. 5. 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 Mohammed Almuzian, University of Glasgow, 2013 5
  6. 6. 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 Mohammed Almuzian, University of Glasgow, 2013 6
  7. 7. 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 Mohammed Almuzian, University of Glasgow, 2013 7
  8. 8. 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 Mohammed Almuzian, University of Glasgow, 2013 8
  9. 9. 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 Aziz 2011, no association between appliance induced labial movement of mandibular incisors and gingival recession was found. Factors that may Mohammed Almuzian, University of Glasgow, 2013 9
  10. 10. susceptible to recession than thick attached gingivae. 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. Mohammed Almuzian, University of Glasgow, 2013 10
  11. 11. 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 Mohammed Almuzian, University of Glasgow, 2013 11
  12. 12. • 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. Mohammed Almuzian, University of Glasgow, 2013 12
  13. 13. 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 Mohammed Almuzian, University of Glasgow, 2013 13
  14. 14. 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 Mohammed Almuzian, University of Glasgow, 2013 14
  15. 15. 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) Mohammed Almuzian, University of Glasgow, 2013 15
  16. 16. 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. Mohammed Almuzian, University of Glasgow, 2013 16
  17. 17. 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 22 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 Mohammed Almuzian, University of Glasgow, 2013 17
  18. 18. 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) Mohammed Almuzian, University of Glasgow, 2013 18
  19. 19. 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 3.Severe displacement 4.Heavily restored or poor prognosis 5.Impaction or abnormal shape. 6.Again there are problems with reduction of the intercanine width and fitting the lower labial segment around the upper labial segment. Mohammed Almuzian, University of Glasgow, 2013 19
  20. 20. 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. 3.Heavily restored or poor prognosis 4.Impaction or abnormal shape. 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. Mohammed Almuzian, University of Glasgow, 2013 20
  21. 21. 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 2.Severe displacement 3.Heavily restored or poor prognosis 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 Mohammed Almuzian, University of Glasgow, 2013 21
  22. 22. 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 33 5 4.good anchorage balance Second premolars Indication 1.Hypoplasia 2.Severe displacement 3.Heavily restored or poor prognosis 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 Mohammed Almuzian, University of Glasgow, 2013 22
  23. 23. Disadvantages: 1.fixed appliance almost always 2.spontaneous alignment of incisors is less satisfactory 3.mesial tipping of molar tooth First Molars 1.Hypoplasia 2.Severe displacement 3.Heavily restored or poor prognosis 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 Mohammed Almuzian, University of Glasgow, 2013 23
  24. 24. 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 Mohammed Almuzian, University of Glasgow, 2013 24
  25. 25. • 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. Mohammed Almuzian, University of Glasgow, 2013 25
  26. 26. 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. Mohammed Almuzian, University of Glasgow, 2013 26
  27. 27. 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 Mohammed Almuzian, University of Glasgow, 2013 27
  28. 28. •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 Mohammed Almuzian, University of Glasgow, 2013 28
  29. 29. 2.Incomplete closure 3.Rotation 3. Elective first molar extractions to provide space for orthodontic purpose Indication 1. 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. Mohammed Almuzian, University of Glasgow, 2013 29
  30. 30. Potential problem with first molar extractions to provide space for orthodontic purpose, Sandler 2000 1. Anchorage • 7s provide little anchorage • 7s unsuitable for Kloehn bow EOT • Palatal arch with a button • Miniscrew anchorage 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 • Initial alignment with rectangular Niti wire Mohammed Almuzian, University of Glasgow, 2013 30
  31. 31. Rolling • 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 Mohammed Almuzian, University of Glasgow, 2013 31
  32. 32. • Miniscrew anchorage Second Molars Indications 1.Hypoplasia 2.Severe displacement 3.Heavily restored or poor prognosis 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. Mohammed Almuzian, University of Glasgow, 2013 32
  33. 33. • 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). Mohammed Almuzian, University of Glasgow, 2013 33
  34. 34. 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. Mohammed Almuzian, University of Glasgow, 2013 34
  35. 35. 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 Mohammed Almuzian, University of Glasgow, 2013 35
  36. 36. 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. Mohammed Almuzian, University of Glasgow, 2013 36
  37. 37. • 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 Mohammed Almuzian, University of Glasgow, 2013 37
  38. 38. 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 Mohammed Almuzian, University of Glasgow, 2013 38
  39. 39. 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 Mohammed Almuzian, University of Glasgow, 2013 39

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