Anchorage in orthodontics


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Anchorage in orthodontics

  2. 2. NEWTON’S third law of motion :“ Every action has an equal and opposite reaction.”
  3. 3. DEFINITIONS :Moyers :• “ Resistance to displacement.”• Active elements and reactive elements.T.M. Graber :• “The nature and degree of resistance to displacement offered by an anatomic unit when used for the purpose of effecting tooth movement.”
  4. 4. DEFINITIONS :Proffit :• “Resistance to unwanted tooth movement.”• “Resistance to reaction forces that is provided (usually) by other teeth, or (sometimes) by the palate, head or neck (via extraoral force), or implants in bone.”Nanda :• “The amount of movement of posterior teeth (molars, premolars) to close the extraction space in order to achieve selected treatment goals.”
  5. 5. CLASSIFICATIONS:Moyers :• According to the site of anchorage:1. Intra oral : Anchorage established within the mouth.2. Extraoral3. Muscular
  6. 6. CLASSIFICATIONS:2. Extra oral : Anchorage obtained outside the oral cavity. a.) Cervical : eg. neck straps b.) Occipital : eg. Head gears c.) Cranial : eg. High pull headgears d.) Facial : eg. Face masks
  8. 8. CLASSIFICATIONS:3. Muscular : Anchorage derived from action of muscles. eg. Vestibular shields.
  9. 9. CLASSIFICATIONS:Moyers :• According to the number of anchorage units : simple/primary compound reinforced one tooth two/more teeth non-dental sitesMucosa,head, muscles
  10. 10. CLASSIFICATIONS:Burstone :• Group A arches• Group B arches• Group C arches
  12. 12. BIOLOGICAL ASPECTS OFANCHORAGE :Factors affecting anchorage:• Number of roots• Shape, size and length of each root• multirooted > single rooted longer rooted > shorter rooted triangular shaped root > conical or ovoid root larger surface area > smaller surface area
  13. 13. BIOLOGICAL ASPECTS OFANCHORAGE :• Cortical anchorage: Cortical bone vs. medullary bone• Muscular forces: Horizontal growers vs. vertical growers• Relation of contiguous teeth• Forces of occlusion• Age of the patient• Individual tissue response
  14. 14. BIOLOGICAL ASPECTS OF ANCHORAGE :• Pressure in the PDL= Force applied to a tooth Area of distribution in PDL• Tooth movement increases as pressure increases upto a point, remains at same level over a broad range and then may gradually decline with extremely heavy pressure.• Anchorage control : Concentration of desired force and dissipation of reactionary force
  16. 16. BIOLOGICAL ASPECTS OFANCHORAGE :Anchorage situations :• Reciprocal tooth movement : Equal force distribution over the PDL eg. Midline diastema, First premolar extraction site Anchorage value depends on the root surface area
  17. 17. BIOLOGICAL ASPECTS OFANCHORAGE :• Reinforced anchorage: Distribution of force over a larger surface area Light forces vs. heavy forces eg. Addition of extra teeth, Extra oral anchorage• Stationary anchorage: Bodily movement of anchor teeth vs. tipping of teeth to be moved
  18. 18. BIOLOGICAL ASPECTS OFANCHORAGE : Anchorage situations : • Differential effect of very large forces: More movement of arch segment with the larger PDL area. Questionable response.
  19. 19. MECHANICAL ASPECTS OFANCHORAGE : • Tooth movement is brought about after overcoming the frictional resistance during sliding of wire in the bracket. • Frictional force is proportional to the force with which the contacting surfaces are pressed together • Affected by the nature of the surface • Independent of the area of contact
  20. 20. MECHANICAL ASPECTS OFANCHORAGE : • Asperities : Peaks of surface irregularities. • Local pressure at asperities causes plastic deformation • At low sliding speeds, ‘stick slip’ phenomenon occurs • Anchor teeth feel reaction to both friction and tooth moving forces
  21. 21. ANCHORAGE LOSS:Anchor loss in all 3 planes of space :• Sagittal plane: - Mesial movement of molars, - Proclination of anteriors
  22. 22. ANCHORAGE LOSS:• Vertical plane: - Extrusion of molars, - Bite deepening due to anterior extrusion
  23. 23. ANCHORAGE LOSS:• Transverse plane: - Buccal flaring due to over expanded arch form and unintentional lingual root torque, - Lingual dumping of molars,
  24. 24. ANCHORAGE IN REMOVABLEAPPLIANCES: Early removable appliances: • Completely tooth borne • Partly cast, partly wrought wire • Bimler appliance
  25. 25. ANCHORAGE IN REMOVABLEAPPLIANCES: Early removable appliances:• Crozat appliance- Lingual extensions- Heavy palatal bar- High labial base wire- Rest on molar clasp
  26. 26. ANCHORAGE IN REMOVABLEAPPLIANCES: CLASPED REMOVABLE APPLIANCES: - Active part, - Clasps, - Baseplate.• Baseplate : - Point of attachment for the active components, - Distribution of the reactionary forces to the teeth and tissues.
  27. 27. ANCHORAGE IN REMOVABLEAPPLIANCES: • To ensure adequate anchorage from baseplates: - Extension as far as possible, also for stability, - Close fit to the tissues, - Contouring along the lingual gum margins, - Adequate bulk of acrylic. - Eg. Schwartz expansion plate
  28. 28. ANCHORAGE IN REMOVABLEAPPLIANCES:• Wire components: - Labial bow: Prevents proclination of incisors Stationary anchorage.• Intermaxillary anchorage: - Elastics• Headgears
  29. 29. ANCHORAGE IN REMOVABLEAPPLIANCES: REMOVABLE FUNCTIONAL APPLIANCES:• Reactionary forces: - Sagittal - Vertical - Transverse
  30. 30. ANCHORAGE IN REMOVABLEAPPLIANCES: REMOVABLE FUNCTIONAL APPLIANCES:• Tooth borne appliances: - Sved bite plane:stationary anchorage
  31. 31. ANCHORAGE IN REMOVABLEAPPLIANCES: REMOVABLE FUNCTIONAL APPLIANCES:• Tooth borne appliances: Activator, bionator, twin block
  32. 32. ANCHORAGE IN REMOVABLEAPPLIANCES: REMOVABLE FUNCTIONAL APPLIANCES:• Anchorage obtained by:- capping of incisal margins of lower incisors- proper fit of cuspsof teeth into the acrylic- deciduous molarsused as anchor teeth
  33. 33. ANCHORAGE IN REMOVABLEAPPLIANCES: REMOVABLE FUNCTIONAL APPLIANCES: - edentulous areas after loss of deciduous molars - noses in upperand lower interdental spaces - labial bow preventsanterior flaring and posteriordisplacement of appliance
  34. 34. ANCHORAGE IN REMOVABLEAPPLIANCES: REMOVABLE FUNCTIONAL APPLIANCES:• Tissue borne appliances: - Vestibular screen, Frankel’s function regulator• Anchorage by acrylic extending into vestibule• Headgears
  35. 35. ANCHORAGE IN FIXEDAPPIANCES:• Historical perspective• Edgewise: Angle, Tweed, Andrews, Ricketts, Alexander, Roth, Burstone, Bennett and Mclaughlin• Methods to reinforce anchorage• Begg: conventional and refined• Tipedge• Studies in anchorage• Newer methods in anchorage conservation
  36. 36. HISTORICAL PERSPECTIVE:ANGLE;E arch : - tipping tooth movements - first to utilise stationaryanchorage of 1st permanentmolars with clamp bands
  37. 37. • Long clamp band: crown tipping resistance of posterior teeth pitted against crown tipping resistance of cuspid. - simple anchorage vs. simple anchorage
  38. 38. • Pin and tube appliance: root control by pins soldered to labial archwire• Ribbon arch appliance: size of archwire itself did not provide anchorage of posterior teeth
  39. 39. • Edgewise appliance: 0.022” slot Utilised by Tweed
  40. 40. TWEED TECHNIQUE:“ When teeth are tipped distally as they are in anchorage preparation, osteoid tissue appears to be laid down adjacent to the mesial surface of the tooth being moved distally.” - Kaare Reitan
  41. 41. Anchorage preparation:• First degree: ANB = 0 – 4 - mandibular molars must be uprighted and maintained - direction of pull of intermaxillary elastics should be perpendicular to long axis of the tooth• Second degree: ANB > 4.5 - mandibular molars must be distally tipped till distal marginal ridges are at gum level - direction of pull of Cl II elastics should be greater than 90 to the long axis of the tooth
  42. 42. • Third degree: ANB =5, - total discrepancy = 14- 20 mm. - mandibular molars must be distally tipped till distal marginal ridgesare below gum level - jigs are requiredfor anchorage
  43. 43. • Mandibular anchorage prepared first by distal tipping of the canines, premolars and first and second molars.• Resist displacementby Cl II elastic force• Stabilizing archwire: .0215 by .0275
  44. 44. • Hooks soldered for intermaxillary elastics and/ or headgear on the wires• High pull headgear: b/w centrals and laterals• Intermediate pull headgear and elastics: b/w laterals and canines
  45. 45. TWEED MERRIFIELD TECHNIQUE:• Sequential directional force edgewise technique – 1965• .022 slot• 20 degree tip back achieved• J hook headgear used to upright cuspids and apply distal force to terminal molars
  46. 46. Denture preparation:Mandible:• 20 degree tip back achieved• Straight pull J hook headgear used to upright cuspids and apply distal force to terminal molars
  47. 47. Maxilla:• 10 degree distal tip achieved• High pull J hook headgear used
  48. 48. • Class III elastics not used• Tip backs used instead of second order bends: better incisor control• Maxillary third order bends applied sequentially ( anterior lingual root torque, posterior buccal root torque)
  49. 49. • Sequential anchorage: the 10-2 systemMANDIBLE:• .0215 by .028 continuous archwire used• Ten teeth anterior to the second molars are stabilised while the two terminal molars receive the active force• High pull headgear used• Second molars: +10 to +15• First molars: 0 to –3 tip• Second premolars: 0 to –5
  50. 50. • Distal tip of 10 degree in first molars with compensation bends in 2nd molars• High pull headgear• End of 1 month: second molars: +10 to +15 first molars: +5 to +8 second premolars: 0 to -3
  51. 51. • 10 degree tip in second premolar region with compensating bend just mesial to first molar bracket• High pull headgear only at night• Second premolars: 0 to 5 degree tip
  52. 52. MAXILLA:• Sequential force from first molar onwards• 10 degree tip placed
  53. 53. • High pull headgear used for enhancing molar effect and incisor intrusion• Next appointment: additional 5 degree tip placed on 1st molar• Second molar : 20 first molar : 15 second premolar: 10
  54. 54. RICKETTS’ BIOPROGRESSIVE TECHNIQUE: 1978• Quad helix: holding appliance
  55. 55. ANCHORAGE IN FIXEDAPPIANCES:RICKETTS’ BIOPROGRESSIVE TECHNIQUE:• Adverse effects of light continuous round wires with reverse curve of Spee and tieback: lower incisors thrown against the lingual cortical plate causing forward movement of lower molars• Class III elastics with high pull headgear: extrusive effect on lower incisors and upper molars
  56. 56. • Lower utility arch: late 1950s• Position of lower molar to allow for cortical anchorage: - tooth movement through dense cortical bone is retarded because of reduced blood supply, which diminishes resorption - buccal root torque of lower molars• Tip back: gain in arch length – 4mm• Headgears: cervical, combination and high pull
  57. 57. THE STRAIGHT WIRE APPLIANCE:• Dr. Lawrence Andrews , mid 70s• Preadjusted bracket system• Extra torque added to incisor brackets to prevent bite deepening• Anti-tip and anti-rotation features in canine, premolar and molar brackets: extraction and non- extraction series• Same force levels and treatment mechanics as previous systems
  58. 58. LEVEL ANCHORAGE SYSTEM:• Terrell Root• Preadjusted appliance used with .018 slot• Anchorage: - inherent resistance of teeth to move - distance they can be allowed to move Orderly manipulation of need and availability of anchorage• High pull headgear to maxillary 1st molars or J hook headgear to anteriors: reduction in ANB by 1 degree (1mm) every 6 months
  59. 59. Anchorage savers:• Palatal bar: decreases vertical descent due to tongue pressure; reduction in space by 1mm• Delaying upper first molar extraction by one year: reduces mandibular anchorage space by 1mm• Class III elastics worn 24 hrs: flatten the curve of Spee and upright buccal segments at the rate of 1mm / month
  61. 61. ANCHORAGE IN FIXEDAPPIANCES: Anchorage conservation during treatment in level anchorage system: • Stabilization of upper arch: .018* .025 s.s. • Anchorage preparation in lower arch: Class III elastics: level curve of Spee • High pull headgear • Vertical loops in mandibular archwire to prevent space loss with class II elastics
  62. 62. ANCHORAGE IN FIXEDAPPIANCES: ALEXANDER DISCIPLINE: • Vari-Simplex discipline • -6 degrees angulation of lower first molar tubes for gain in arch length • ‘Retractors’ ( Dr. Fred Schudy) • Cervical, combination or high pull depending on growth pattern and control needed
  63. 63. ANCHORAGE IN FIXEDAPPIANCES:• Other intra oral appliances to control anchorage:1. Transpalatal arch inhigh angle cases withhigh pull headgear.2. Nance holding archin class I cases with crowding;preserves sagittal anchorageand retards vertical eruption
  64. 64. • Other intra oral appliances to control anchorage:4. Mandibular lingual arch: sagittal and transverse control5. Lip bumper: - uprighting of mandibular first molars - distal force on lower molars - muscular anchorage
  65. 65. BURSTONE’S SEGMENTAL ARCH TECHNIQUE:• Arch divided into 1 anterior and 2 posterior segments, treated as separate units• Frictionless mechanics using TMA springs; low load deflection rate• Differential space closure: anterior retraction or posterior protraction or both should be possible• Proper moment to force ratios
  66. 66. Anterior retraction: group A arches: (AJO 1982)• Buccal stabilizing segment with a transpalatal arch in maxilla and lingual arch in mandible: posterior anchorage unit• Anterior segment• Two tooth concept: large distance b/w canine and molar; low load- deflection rates
  67. 67. • En masse controlled tipping followed by en masse root movement• TMA 0.018 loop welded to 00.017 by 0.025 base arch• - magnitude of momenton molar increases dueto additional wirein the loop - low load deflection rate
  68. 68. ANCHORAGE IN FIXEDAPPLIANCES:• Heavy base arch withstands the higher moments without permanent deformation• Spring is positioned mesially• Posterior tipping of buccal segments along with TPA and consolidation of posterior teeth : anchorage reinforcement
  69. 69. ANCHORAGE IN FIXEDAPPLIANCES: Group B arches: • M/F ratio needed = 10:1 for translation • Spring placed centrally b/w the two tubes for same rate of change in M/F in both alpha and beta moments
  70. 70. ANCHORAGE IN FIXEDAPPLIANCES:Group C arches:• Loop is positioned at 1/3 rd interbracket distance from the molar tube or• Symmetrically placed spring with Cl II or Cl III elastics• Side effects: flaring of anteriors, vertical extrusion of anteriors• Can be eliminated by using headgear to upper arch
  71. 71. ANCHORAGE IN FIXEDAPPLIANCES:• Staggers and Germane (1991)Placement of gable bend near the beta moment to increase the M/F ratio• Kuhlberg and Burstone (1997)Use of a loop with symmetric angulation but asymmetric placement
  72. 72. ROTH’S TECHNIQUE:• .022 slot• Double key hole loops used b/w lateral and canine, and canine and premolar - control canine rotation during extraction space closure
  73. 73. Things that tend to slip posterior anchorage forward:• Use of resilient wires and continuous wires to level a deep curve of Spee• Rapid bracket alignment with very resilient wires• Attempts to upright distally inclined canines• Attempts at moving maxillary incisor roots lingually• Attempts at expansion with a labial arch wire• Using a reciprocal force system to retract extremely proclined anteriors
  74. 74. Ways to avoid anchor loss:• Leveling with small flexible wire• Retraction of lower anteriors using a facebow• Band second molars in the beginning of treatment• Use of utility arch to level curve of Spee• Use of multiple short Cl II or Cl III elastics for intra-arch adjustment: do not extrude molars and do not change cant of occlusal plane
  75. 75. • Use of mandibularlingual arch with fingersprings to widen premolar areas• Transpalatal bar:intrusion of molars androtational control
  76. 76. • Critical anchorage cases: Asher facebow used to retract anteriors
  77. 77. BENNETT AND MCLAUGHLIN:Anchorage control: ‘The manoeuvres used to restrict undesirable changes during the opening phase of treatment, so that leveling and aligning is achieved without key features of the malocclusion becoming worse.’
  78. 78. Anchorage control in the horizontal plane:• Inbuilt tip: proclination of anteriors (especially uppers)• Elastic forces : anchorage loss, distal rotation of anteriors, bite deepening and increase in curve of Spee
  79. 79. Control of anterior segment:• Lacebacks from most distally banded molars to canines• Bending the archwire back immediately distal to the molar tube
  80. 80. • Robinson in 1989: - lower molars movedforward 1.76 mm on an averagewith lacebacks and 1.53mmwithout lacebacks - lower incisors moved distally1.0 mm with lacebacks and 1.47 mmwithout lacebacks
  81. 81. Control of the posterior segments:• Greater need in upper arch: - larger teeth - greater tip - more torque control and bodily movement - upper molars move mesially more readily - greater number of class II cases• Headgears : cervical, combination and high pull with long outer bow• Palatal bar
  82. 82. Control of posterior segments: lower arch Soldered lingual arch Severe anterior crowding cases: push coil springs with class III elastics; reinforced with upper palatal bar and high pull headgear
  84. 84. Anchorage assessment in the vertical plane:• Incisor vertical control: temporary increases in overbite
  85. 85. • Avoid bracketing incisors or avoid tying the wire in the incisor brackets• Avoid early engagement of highly placed canines
  86. 86. • Molar vertical control: prevent extrusion of posterior teeth and opening up of mandibular plane angle ( high angle cases)• Upper second molars not banded or archwire step placed distal to first molars• Avoid extrusion of palatal cusps during expansion : fixed expander with headgear
  87. 87. • Palatal bars lie away from palate by 2mm: vertical intrusive effect of the tongue• Avoid cervical pull headgear (combination pull or high pull)• Upper or lower posterior biteplatesAnchorage assessment in the lateral plane:• Intercanine width maintained: avoid uncontrolled expansion• Molar crossbites: bodily correction to avoid overhanging palatal cusps
  88. 88. INVERSE ANCHORAGE TECHNIQUE:Jose Carriere- 1991• Mandible is a preferred point of reference for diagnosis and treatment planning, while maxilla is better suited to adapting orthodontic correction• - maxilla is anatomically a more stable reference than mandible - functionally mandible is the center of convergence of force vectors, while maxilla is less influenced by forces
  89. 89. ANCHORAGE IN FIXEDAPPLIANCES: - histological difference between maxilla and mandible ; maxilla has more plasticity of response• Treatment starts from the distal segments and moves towards the mesial part sectionally ( distomesial sequence)
  90. 90. • Inverse anchorage equation: C - Dc/2 – R1 = 0 where,• C= horizontal distance b/w the vertical line passing through the cusp tip of the upper canine and the vertical line passing through the posterior end of the distal ridge of the lower canine• Dc= arch length discrepancy of the mandibular arch, measured from distal of both lower canines• R1= amount in mm which the anterior limit of the lower incisors should be moved in the ceph for the correction of a case
  91. 91. Stages:• Maxillary stage: treatment started in the maxilla with posterior leveling, canine retraction, anterior leveling and anterior retraction• Mandibular stage: same sequence
  92. 92. • Class II Div 1
  93. 93. • Other anchorage reinforcements used: - lingual arch, labial arch and transpalatal arch - extraoral anchorage with Cl III elastics
  94. 94. BEGG TECHNIQUE:• 1950s by Dr. Begg in Australia• Use of vertical slot• Use of light forces for tipping teeth• Use of optimal forces, so that extra oral forces are not required• No anchorage preparation necessary
  95. 95. Storey and Smith’s experiment on differential forces: 1954• Series of animal experiments• Bodily applied force will slow the rate of tooth movement through a bone compared with a tipping force• Optimal force concept by Storey: “ There is an optimum range of force which produces maximum amount of tooth movement through bone, and with forces above or below this range there is reduced tooth movement.”
  96. 96. • Experiment using cuspid retraction spring:• Free crown tipping retraction of cuspid and bodily movement anchorage resistance by molar and bicuspid
  97. 97. • Optimal force range for moving canines distally: 150-200 gm.• Further increase of force reduced the canine movement till it approached zero• Movement of molar unit occurred with force values of 300-500 gm.• Therefore, use of light differential forces in Begg technique
  98. 98. • Anchorage considerations in stage I:1. Sagittal: Upper molar anchorage: - upper Cl I elastics not used - TPA , when using power arms and palatal elastics ( also consolidating the first and second molars)
  99. 99. ANCHORAGE IN FIXEDAPPLIANCES: • Anchorage considerations in stage I: 1. Sagittal: lower molar anchorage: - stiff lower wire ( 0.018” P or P+) - light (yellow or road runner) elastics - molar stop in case of Cl II and lower Cl I elastics - lip bumper in critical anchorage cases
  100. 100. Causes of anchorage loss in sagittal direction in stage I:• Insufficient resistance from anchor bends due to inadequate anchor bends or use of flexible wires like NiTi and undersize or multilooped SS wire• Excessively heavyelastic pull
  101. 101. Causes of anchorage loss in sagittal direction in stage I:• Increased resistance from anterior teeth: - incisor and/ or canine roots touching labial cortical plate - abnormal tongue or lip function - overjet reduction before overbite reduction• High mandibular plane angle with reduced masticatory forces
  102. 102. Causes of anchorage loss in vertical direction in stage I:• Extrusion of molars dueto the anchor bends• Vertical component of Cl II elastics in lower arch
  103. 103. • Resistance to extrusion of upper molars by masticatory forces in normal or low angle cases• In high angle cases, reinforcement with TPA kept slightly away from palate• High pull headgear• Lower molars: light elastics with mild anchor bends; posterior acrylic bite blocks or EVAA appliance• Engagement of wire in first and second molars
  104. 104. Causes of anchorage loss in the transverse direction:• Anchor bends and Cl II elastics cause lingual rolling of lower molarsControl of anchor loss:• Sufficiently stiff wires kept expanded• TPA or expanded headgear facebow or lip bumper
  105. 105. Anchorage control in stage II:• Use of heavy arch wires ( 0.018 or 0.020) to maintain rotational correction, deep bite correction and arch form• Also resist distobuccal rotational tendency of molars due to Cl I elastics• Mild anchor bends to maintain over bite correction
  106. 106. Anchorage control in stage II:• Anterior anchorage for posterior protraction: - braking springs, - angulated T pins - combination wires withanterior rectangular ribbonmode and posterior round wire - torquing auxiliaries liketwo spur and four spur or MAA
  107. 107. Anchorage control in pre stage III:• Upper wire: Gable bend for holding the deep bite correction and uprighting distally tipped molars• Lower wire: gable and anchor bends• Inversion of segments to avoid canine extrusion due to gable bends• End of arch wires are bent back to prevent opening of extraction spaces
  108. 108. Causes of anchorage loss in stage III:• Torquing auxiliaries and uprighting springs cause reciprocal reactions in all three planes of space: - lingual root torquing and distal root uprighting:labial crown movements, extrusion of anteriors and intrusion of posteriors, buccal crown movement of posteriors - reverse effects for labial root torquing and mesial root movements
  109. 109. Control of anchorage in stage III:• Minimise need for root movements by: - careful diagnosis and planning of extractions - controlled tipping of incisors - use of brakes• Use of heavy base wires ( 0.020 P)• Lighter auxiliaries and uprighting springs• Light Cl II elastics
  110. 110. Control of anchorage in stage III:• Reinforcement of anchorage:1. Sagittal: - reverse torquing auxiliary on lower incisors - headgear or TPA on upper molars and lip bumper on lower molars2. Vertical: - high pull headgear, TPA or posterior bite blocks - molar uprighting springs in case of second premolar and first molar extraction cases
  111. 111. Control of anchorage in stage III:• Reinforcement of anchorage:3. Transverse: - contraction and toe-in in heavy base wires - TPA or overlay wires - molar torquing auxiliary for buccal root torque
  112. 112. Differences between conventional Begg and refined Begg:• Use of Special grade wire in conventional Begg as opposed to P and P+ and Supreme• Use of lighter elastic forces in refined Begg• Use of extraoral anchorage and other reinforcements• Use of lighter auxiliaries and springs ( 0.009, 0.010, 0.012 as opposed to 0.014 and 0.016)
  113. 113. DIFFERENTIAL STRAIGHT ARCH TECHNIQUE: TIP- EDGE• Peter Kesling• 0.022 by 0.028 slot size with increase to 0.028• Vertical slot for placement of auxiliaries• Finishing possible with rectangular wires
  114. 114. ANCHORAGE IN FIXED FUNCTIONAL APPLIANCES:• Herbst appliance: partial anchorage: maxilla: first permanent molars and first premolars are banded and connected with a lingual or buccal sectional wire mandible: first premolars are banded and connected with a lingual sectional wire touching anterior teeth
  115. 115. ANCHORAGE IN FIXEDAPPLIANCES:Partial anchorage
  116. 116. - total anchorage: maxilla:labial arch wire attached to brackets on premolars, canines and incisorsMandible: lingual sectional arch wire extended to permanent first molars• Bands are replaced by cast splints
  117. 117. ANCHORAGE IN FIXED APPLIANCES:total anchorage
  118. 118. Jasper jumper:• Preparation of anchorage: - full size arch wires cinched back at the ends; inclusion of second molars - anterior lingual crown torque in lower wire - TPA and lingual arch
  119. 119. Jasper jumper:• Expansion of molar area
  120. 120. IMPLANTS :• Boucher: Implants are alloplastic devices which are surgically inserted into or onto jaw bone.• Anchorage source:Orthopedic anchorage: - maxillary expansion - headgear like effectsDental anchorage: - space closure - intrusion ( anterior and posterior) - distalization
  121. 121. • Implant designs for orthodontic usage:- onplant- mini-implant- impacted titanium post- skeletal anchorage systemWhy implants?Limitations of fixed orthodontic therapy:• Headgear compliance and safety• Reactive forces from dental anchors
  122. 122. Implants for orthopedic anchorage:• Maxillary protraction: - Smalley (1988) - insertion of titaniumimplants into maxilla,zygoma, orbital and occipitalbones of monkeys-12-16mm widening of sutureswith 5-7mm increase in overjet
  123. 123. • Implants for skeletal expansion: -Guyman (1980) intentionally ankylosed maxillary permanent lateral incisors of monkeysNo movement oflaterals during expansion
  124. 124. • Parr, Roberts, et al (1997):Midnasal expansion using endosseous titanium screws; Rabbit studyStability of implants seen for 1N and 3N loading
  125. 125. Implants for intrusion of teeth:• Creekmore ( 1983) Vitallium implant foranchorage while intrudingupper anterior teeth6mm intrusion with25degrees torque
  126. 126. • Southard (1995) Comparison of intrusionpotential of titaniumimplants and that of teethTitanium implants placedin extracted 4th premolararea of dogsIntrusive force = 60gms
  127. 127. Implants for space closure:• Linkow ( 1970): implanto-orthodontics
  128. 128. IMPLANTS :
  129. 129. Implants for space closure:• Eugene Roberts: use of retromolar implants for anchorageSize of implant: 3.8mm width and 6.9mm length0.019 x 0.025 TMA wire from premolar to retromolar implant to prevent distal movement of premolar
  130. 130. IMPLANTS :
  131. 131. Other implant designs:• Onplant: Block and Hoffman (1995)“an absolute anchorage device”Titanium disc- coated with hydroxyapatite on one side and threaded hole on the otherInserted subperiosteally
  132. 132. • Impacted titanium posts:Bousquet and Mauran (1996)Post impacted between upperright first molar and secondpremolar extraction space onlabial surface of alveolar processPerpendicular to bone surface
  133. 133. • Molar connected toimplant with 0.040 sswire
  134. 134. • Mini-implant:Ryuzo Kanomi ( 1997)Small titanium screws 1.2mm diameter and 6mm lengthInitially used for incisor intrusion6mm intrusion of mandibular incisors
  135. 135. Incisor intrusion:
  136. 136. Incisor intrusion Cuspid retractionMolar intrusion
  137. 137. • Skeletal anchorage system (SAS):Sugawara and Umemori (1999)Titanium miniplates Placement in key ridge for upper molar and ramus for lower molar intrusionUses:- molar intrusion- Molar intrusion and distalisation- Incisor intrusion- Molar protraction
  138. 138. ANCHORAGE IN FIXEDAPPLIANCES:Zygoma ligatures: Melsen et al JCO ’98• Anchorage for intrusion and retraction of maxillary incisors in partially edentulous patients• Horizontal bony canal drilled 1cm lateral to alveolar process with entrance and exit holes in superior portion of infrazygomatic crest• Double twisted 0.012 ligature wire inserted through the canal
  143. 143. ANCHORAGE IN FIXED APPLIANCES:Methods of anchorage conservation:Transpalatal arch:• Introduced by Goshgarian• 0.036 SS wire• Anchorage reinforcement• Other uses: distalization,rotation, torque, expansionor contraction, vertical control
  144. 144. ANCHORAGE IN FIXEDAPPLIANCES:• Burstone : ( JCO ’88-’89)use of 0.032 by 0.032 SS or TMA in transpalatal arches depending on the passive or active
  145. 145. ANCHORAGE IN FIXEDAPPLIANCES:Lip bumper:• Alters equilibrium b/w cheeks, lips and tongue• Transmits forces from perioral muscles to the lower molars• Can be used for distalization of molars• Attachment of Cl III elastics
  146. 146. ANCHORAGE IN FIXED APPLIANCES:Lingual arch:Introduced by Hotz0.036 SS wireLoops mesial to the lower molarsPrevents mesial migration of molarsCan be used for gaining arch lengthSprings soldered to lingual archesfor premolar movements