Methods of gaining space -Extraction /certified fixed orthodontic courses by Indian dental academy


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  • Location in arch such that space gained by Xn utilized for correction of both anterior and posterior segments.
  • Bimaxillary dento alveolar protrusion.
  • Riedel- treatment time is reduced.
  • Methods of gaining space -Extraction /certified fixed orthodontic courses by Indian dental academy

    1. 1. Methods of gaining Space Extractions 1
    2. 2. INDIAN DENTAL ACADEMY Leader in continuing dental education 2
    3. 3.  Increased ability to move teeth under better control: everexpanding choice of extraction. Factors affecting choice of extraction 1. Treatment objectives 2. Type of malocclusion 3. Esthetics (large chin button, prominent nose) 4. Growth pattern. 5. Conditions of teeth.(caries, multifilled teeth, impacted, ectopic, severe rotation) 6. Health of supporting tissues. 3
    4. 4. Facial profile alteration:    Maxi retraction of U&L anteriors: 4s (laterals) Lesser retraction in lower face: U4s and L5s Less overall retraction: 5s or 6s. Deep anterior overbite:  Closer.( Mechanically easier to level, as spaces are closed). incisors – min time and effort. Open bite: 5 or 6 Xn. Accentuate the curve of Spee. GRABER: Removal of 5s in mandibular arch preferable. ‘.’ reduces the tendency of relapse of openbite &lingually inclined incisors seen occasionally with Xn of 4s.  4
    5. 5. Extraction of Ist premolars. ADVANTAGES :  Erupts before any other post teeth, after 6.  Eruptive sequence : Xn at proper time.  Strategically located close to the incisors.  Center of each half of arch .’. Ant & post crowding.  Protraction of molars not required.  4 Xn adequate anchorage for retraction of 6 teeth.  Contact b/w canine and 2nd premolar satisfactory. 5
    6. 6. Indications for I st premolar extraction: 1. Convex profile with severe crowding. 2. Class II div I with deep anterior bite. 3. Class I with severe crowding. 4. Class I with bimaxillary protrusion. 6
    7. 7. Indications for I st premolar extraction. 7
    8. 8. Extraction of 2nd premolars: History: Henry(1965) 1.mild degree of crowding & excellent profile. 2.No crowding and fullness of lips. Begg: unless carious or poorly formed. Nance: Ist person.Mild discrepancy. Avoids dished-in-face & less tendency for relapse. Carey: 2.5-5mm 8
    9. 9.    DEWEL: Xn creates more space in borderline cases, closed by reducing the anchorage value of buccal segments LOGAN:  U4 more esthetic than 5  Contact b/w 4 and 6 tended to stay closed.  Reduced possibility of buccal/lingual furrows in Xn site ‘.’ of rapid closure.  Closure of ant open bite, by reducing post vertical dimension. De CASTRO: 3 independent segments. • 5s Xed only post segment shortened. • 4s Xed, both segments shortened- functional integrity of the dentition. 9
    10. 10. INDICATIONS FOR 2ND PREMOLAR EXTRACTION 1.Good profile+mild crowding 2.flat profile+moderate crowding 3.Class II div 1 on skeletal class I +mild crowding. 4. Mild Class III inter-arch relation+mild crowding in U arch. 5.Congenitally missing,impacted. 6. Grossly destructed/heavy restn. 7. Abnormal root morphology. 8. Open bite. 10
    11. 11. ADVANTAGES: 1. Original facial contours retained without reduction of lip profile. Extraction of 2nd premolars: 11
    12. 12. ADVANTAGES:     U 4 more esthetic along side canine. Lesser tendency for extraction space to open in L arch. Less possibility of buccal/lingual furrow in Xn space. Easy correction of Class II molar correction to Class I molar relation. 12
    13. 13. Ist Molar Extraction:  Avoided: Not provide adequate space in the ant region. 5 & 7 may tip in the Xn space. Deepening of bite. Masticatory efficiency. 13
    14. 14. Indications: Carious- beyond restoration RCTreated, - than a perfectly good premolar. Multi filled teeth- crown. Premature Xn of 6, to preserve symmetry. Facial considerations: large chin buttons&/ prominent nose (4- dished-in) (rationale: farther back less facial change) Open bite cases. 14
    15. 15. Ist Molar Extraction:  Not to allow U7 locked behind L7. Horizontal elastics – until danger of locking has passed.  Mesially inclined 7, lesser degree of anchor bend. Wilkinson’s Extraction: 1942 8 ½ to 9 ½ yrs. Extraction of all Ist molars. Basis: •Additional space for eruption of 8s. •Crowding of lower arch minimized. •Disadvantages- 15
    16. 16. Single arch extraction – U 6 or what to do when non extraction treatment fails. Raleigh Williams. AJO 1979     Class II div 1 with perfect lower arch alignment but growth expectation inadequate. Class II div 1 active growth over. Pt non cooperative. Class II div 1 with good lower arch over basal bone, with some growth expectation. Class II div 1 with mild open bite. 16
    17. 17. Problems with Xn of 4s:  Tipping, opening of space (5 small to fill the space)  Mesial tipping of 6, hanging palatal cusp Avoided with 6 Xn.  Good molar relation.  U 4 occlude with L4  8s erupt normally.  Min patient cooperation  Stable results.  Tuberosity not crowded.  Results similar to nonext.  Rx duration is reduced.  Profile maintained.  17
    18. 18. 2 nd MOLAR EXTRACTION:    David W.Liddle- AJO 1977  Malocclusion: potential force by developing 7,8.  Xn of 7s to intercept this forward force.  4 Xn: treating the effect and not the cause.  10-12mm of space :satisfies arch length problem, not apparent when patient smiles.  91% 7 Xn. 6 move distally in response to pressure. Over compressed CT fibers- move 3 &4 to a more normal occlusion. 18
    19. 19. 2nd MOLAR EXTRACTION: ADVANTAGES AND INDICATIONS           Disimpaction of 3rd molars, faster eruption Prevention of “dished-in” at the end of facial growth Prevention of late incisor imbrication Facilitation of 1st molar distalization Distal movement only as needed to correct the overjet Fewer “residual”spaces at the end of Rx Less likelihood of relapse Good functional occlusion Good mandibular arch form Overbite reduction. 19
    20. 20. Indications: Chipman:  Xn 7 - caries, ectopic, rotated.  Mild – moderate discrepancy with good profile.  Crowding in tuberosity area ,with a need for distal movement of 1st molar. Lehman - preconditions  8 in favorable angulation 15-30*angle to the long axis of the 1st molar.  Normal in size/shape & root area is sufficient w.r.t 2 nd molar.  No congenitally missing teeth. 20
    21. 21. Disadvantages:       Too much tooth substance removed in Cl I mal occlusion with mild crowding. Location far from area of concern. No help in correction of A-P discrepancy without patient cooperation . Possible impaction of 3rd molars even with 2nd molar Xn Unacceptable positions of erupted 3rd molars –second, late stage of fixed therapy. 9-20% missing 3rd molars. 21
    22. 22. Timing for mandibular 2nd molar extraction:  Kokich: 3rd molar crowns completely formed, Xn before roots begin to develop 2. 30*to the occlusal plane 3. 3rd molars in close proximity to 2nd molar-drift. Halderson, Huggins, Lehman and Smith. Before radiographic evidence of root formn.(12-14yrs) 1. Consensus opinion: as soon as 2nd molar erupts. angulation. 22
    23. 23. 3rd Molar Extraction:    Xn to prevent lower anterior crowding? Distal movement of 6,7– impaction of 8. Xn of 8 before retracting. Contraindications:  1st or 2nd molars are extracted. 23
    24. 24. Incisor Extraction:  Mandibular incisors- therapeutic value 1st sign of incipient malocclusion  Difficult to treat as they relapse easily.  Not a new idea.  Jackson (1904)  Riedel : Xn of 2 lower Incisors-arch form without Expn of intercanine width  Angle: Inexcusable.disharmony b/w Occlusal planes, abnormal overbite  24
    25. 25. Incisor extraction: Indications: For mandibular incisors:  Extreme crowding / protrusion. Gingival recession & loss of overlying bone on labial surface. Lateral incisors severely # in young children. Rarely-discrepancy in sizes of U & L incisors themselves, 1 incisor can be removed. Reidel- Rx time reduced. min facial change.      25
    26. 26. Incisor extraction: Advantages: 1. 2. 3. 4. 5. 6. 7. Maintains/ reduces intercanine width General arch form is maintained – greater stability Retention period- less Anterior segments can be retracted readily if need be. Immediate solid tooth support of entire buccal segments. Easy reduction of overbiteintrusion, reshaping Mechanotherapy is simplified. Space closure quick. 26
    27. 27. Incisor extraction: Disadvantages:     Reopening of space . Central Incisor. Danger of creating a tooth size discrepancy. Reidel- 2 mandi incisors Xed to maintain intercanine width. 1 incisor Xn- deepbite- if normal tooth size relationship is present before Xn. Color difference of canine. 27
    28. 28. Upper Incisor Extraction:  Rarely indicated.  Unfavorable impaction of U incisor. Bu/Li blocked out lateral, with good contact b/w central and canine. Congenital missing of 1 lateral incisor Dilacerated tooth. Gardiner et al: • U crowding, mesial displacement of root apices of U3 - Xn of lateral incisor.     28
    29. 29. Summarize: Incisor Xn rare.  Possibility must always be considered.  Careful planning with diagnostic setup  29
    30. 30. Extraction of Canines:   Not extracted. Profile. Long path of eruption.     Conditions where indicated: Impossible to bring in alignment. Gross displacement Bu/Li 4 in contact with 2 & does not show palatal cusp. Decision : position of apex. 30
    31. 31. The Effect of Different Extraction sites upon incisor retraction. Raliegh Williams et al AJO 1976     Relation b/w root surface area and Xn site selection upon incisor retraction. Efficient mechanotherapy. Diagnostic line. Larger the root surface area, greater the resistance to movement. 31
    32. 32. Non extraction 1.5mm 1st molars u&l 6.0mm U4 and L5 8.7mm 1st premolars 9.2mm 1st premolars &1st molars 16.9mm 32
    33. 33. Conclusion:   Location of the Xn site• Root surface area. • Predict incisor retraction. Should be considered in diagnosis, so that a desired Rx goal for the final position of incisors within the facial profile can be achieved. 33
    34. 34.   Orthodontic treatment may include extractions of any tooth in the arch. Based on sound diagnosis, treatment objectives. 34
    35. 35. Thank you Leader in continuing dental education 35