FIXED ORTHODONTIC APPLIANCES

FIXED ORTHODONTIC APPLIANCESAKINPELU A.J.

OUTLINEINTRODUCTIONDEFINITIONDEVELOPMENT OF FIXED APPLIANCE/HISTORICAL BACKGROUNDMECHANISM OF ACTIONINDICATIONS/CONTRAINDICATIONSADVANTAGES/DISADVANTAGESTYPES

OUTLINE CONTD.USESCOMPONENTSSTAGES OF FIXED APPLIANCE THERAPYINSTRUCTIONS TO PATIENTSCOMPLICATIONSREFERENCES

INTRODUCTIONEdward Hartley Angle introduced foundations of malocclusion treatment over 100years ago and since then numerous methods of efficient orthodontic tooth movement have been described in literature.The use of the fixed appliance in orthodontics is directly linked to the proposal and guides of Edward H. Angle to move the teeth to the occlusion line, defined as "the line, shape and position teeth must be if there is a normal occlusion".

INTRODUCTION CONTD.These recommendations required the designing of special devices for three-dimensional control of teeth in order to reach the occlusion line and allow teeth to be correctly aligned in both the maxilla and mandible.This was one of the main objectives to design the Angles devices; E-arch, Pin and tube, ribbon arch, and edgewise appliances.

DEFINITIONInclude all devices which have attachment to teeth surfaces and forces are exerted through these attachments using arch wire and other auxiliaries to bring about desirable tooth movement.A fixed orthodontic appliance is a device fixed to the teeth either by cementation or bonding to the etched teeth surface to bring about various types of tooth movement and can only be readily removed by the operator.

DEVELOPMENT OF FIXED APPLIANCEFauchards expansion archE-arch appliancePin and tube applianceRibbon arch applianceEdgewise appliance

DEVELOPMENT CONTD.Labiolingual twin wire applianceBegg applianceTip-edge appliancePre-adjusted Edgewise appliance

HISTORICAL BACKGROUNDFirst attempt to correct malocclusions was by Pierre Fauchard (1800s)Rigid framework to which teeth were tied called Fauchards expansion arch.

Fauchards expansion arch

E-ARCH APPLIANCEImprovement on first applianceBands were placed only on molars with heavy labial archwire End of arch wire threaded with a small nut at the end to allow arch expansionLigatures used to tie individual teeth to archwireOnly tipping movements were possibleDelivers heavy interrupted force with great relapse

E-ARCH

Basic designsBasic E-archRibbed E-archE-arch without threaded endsE-arch with hooks

HISTORY CONTD.PIN AND TUBE (EDWARD ANGLE, 1910)Improvement on E-archBands on other teeth with vertical tubes into which soldered pins were placedPins repositioned at each appointment to bring about tooth movementIt needed many small adjustmentsLimited mesiodistal movementsDifficult to use

Only angle and one of his students ever mastered the skill13

PIN AND TUBE

HISTORY CONTD.RIBBON ARCH (EDWARD ANGLE, 1915)Vertical rectangular slots behind the tubesRibbon arch of 10x20 gold wireGood spring propertiesPoor control of root position

Resiliency of the wire cldnt provide enough torque for root positioning15

RIBBON ARCH

HISTORY CONTD.EDGEWISE (EDWARD ANGLE, 1928)Slots rotated 90 degrees to the orientation in ribbon archEyelets placed in corners of the bands for rotational control of root positionDimensions of slot alteredControl of crown in all three planes of space possibleAppliance of choice till late 1970s

22x28mls17

STANDARD EDGEWISEDisadvantages Required many bends to be placed in the archwire for final detailingTime consumingSpace closure needed closing loopsTeeth movement is demanding upon anchorage

Standard edgewise brackets

Labiolingual twinwire appliance

Bands on first molars and incisorsCombination of heavy labial and lingual archwiresFinger springs soldered to archwire to move individual teeth

HISTORY CONTD.BEGG APPLIANCE (RAYMOND BEGG, 1956)Uses ribbon arch type of bracketsAccepts .016 round SS wire held in position with lockpinsModified type for rectangular wiresAlso known as light wire system

Adaptations: begg turned d brackets upside down so the slots faced gingivally rather than occlusally,he used 16 mil ss wireshe added auxillary springs for the control of root position

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BEGG APPLIANCEDisadvantages Precise finishing was difficultDifficult to control and time consuming

TIP EDGE APPLIANCE (PETER KESLING, 1980s)Allows later uprightingRigid three-dimensional controlRectangular archwires

COMBINATION OF BEGG AND STRAIGHTWIRE24

PRE-ADJUSTED EDGEWISE APPLIANCES

First designed by Lawrence F. Andrews(late 1960s)Alteration in bracket slot dimensionAutomatic rotational controlStraight wire prescriptions with customized bracketsVariable distance from base of slot to base of bracket for correct in/out position(1st order bends)Pre-angulated slots for correct mesiodistal angulation or tip(2nd order bends)Bracket bases inclined for correct inclination or torque(3rd order bends)

Alteration in bracket slot dimensions: 18 and 22Automatic rotational control: twin brackets or single bracket with extension wings(lewis or lang brackets)Straight-wire prescriptions: Building treatment into the appliance PrescriptionsRoth, hilgers, rickets, standard edgewise, alexander, mbt, sprint, orthos, damon, andrews

Angulation and torque value= appliance prescription25

First order bends

Made in horizontal directionIn and out bendsRequired to conform anatomically to labial and buccal contours of teeth

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Second order bends

Bends in vertical planeTip-backUsed for anchorage preparation or uprighting teethAlso for paralleling of rootsFailure to incorporate these bends results in improper interdigitation of molar cusps and positioning of premolars

Third order bends(Torqueing bends)Failure to place these bends meantanterior teeth will be too upright

Buccal cusps of posterior molars will be depressed while lingual cusps will be elevated

PREADJUSTED EDGEWISEAdvantages Allows groups of teeth to be moved in unison

DisadvantagesDeepening of anterior biteCreation of lateral open bite (roller coaster effect)Inventory problem

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Standard edgewise

Preadjusted edgewise

Roth(1975)Recommended a single appliance system to overcome inventory problemRecommended upright position and over-rotation of upper molars, upright position of upper premolars, upright position and distal rotation of lower buccal segment to overcome anchorage lossOvercorrection Use of articulators for diagnostic records

McLaughlin-Bennet-Trevisi (1993-2001)Bracket selection, accurate positioning and slot sizeLight continuous forceEarly anchorage control and group movementUse of three arch formsMethods of wire ligation and archwire hooksAwareness of tooth size discrepanciesPersistence in finishing

SWA

MBT

MECHANISM OF ACTIONForces are generated by the active components and transmitted to the tooth through the passive components to bring about tooth movementTipping movementSimplest Application of force to crown of toothGeneration of fulcrum within the root

Force-couple to the crown allows controlled apical movementMesiodistal movt of apices= uprightLabiopalatal movt= torque36

Uprighting and torqueing Controlled movement of apices of teethUprighting is mesiodistal movementTorqueing refers to labiopalatal movement

Bodily movementEqual movement of crown and apex in the same directionForce-couple is applied to the crownRotation of teethCorrect positioning of attachment on rotated toothMovement around the long axis of the tooth by applying force to the crown

Application of force to crown and prevention of tipping38

INDICATIONSGrossly misplaced teethRotated teethSpace closureCorrection of inter-incisal relationshipMultiple tooth movementLower arch treatment

Closure with removable is only by tipping and liable to relapse and to ensure parallel position of rootGrossly misplaced teeth which need occlusal movementLower removable is unsatisfactory due to bulkinessDerotation cos control of precise tooth position and abnormal root positionCorrection of incisor relationship improved by simultaneous overjet reduction

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CONTRAINDICATIONSPoorly motivated patientPoor dental healthLack of special skillsMalocclusion beyond scope of fixed appliance

ADVANTAGESProvides a wide range of tooth movementsThree-dimensional tooth controlMultiple tooth movements simultaneouslyMore precise tooth movement and detailing of occlusion is possibleBetter control over anchoragePatient factor Is reducedLittle disturbance of speech

DISADVANTAGESTechnique sensitive and complexAesthetic implicationIncreased chair side time and clinic visitsAnchorage is difficultOral hygiene is difficult to maintainRequires special training of the operatorExpensive

Types of fixed appliance

Transpalatal archNance archBand and loop space maintainerFixed retainerLower lingual arch

Types

Fixed functional applianceMiniscrew implantsGold chain for the traction of impacted canineQuad-helix habit breaker

USESSpace maintenanceHabit breakerAnchorage Growth modificationCamouflage Pre and post surgical orthodonticsCorrection of skeletal discrepancy

Uses Levelling and alignmentCorrection of overjet and overbiteUprighting Creation of space for restorative workMaintenance of stability after orthodontic treatmentFor the traction of canine

Habit breaker

Fixed retainersHeavy intracoronal wire

Fixed lingual bar

COMPONENTS Attachments Bands, brackets, buttons, cleats, eyelets, tubesArchwires Maxillary and mandibularAuxillaries Elastics, separators, power chain, ligature wires, springs, hooks, extra oral appliances

COMPONENTSPassive BracketBands Buccal tubeLingual attachmentLock pinsLigature wire

Active Arch wireSpringElastomerics i.e. ligature elastics, separators and power chain

ATTACHMENTS

Brackets Width of bracketMesiodistally narrow e.g. Ribbon-arch bracket, Begg bracketMesiodiatally wide e.g. Edgewise bracket

Slot of bracketHorizontal slot e.g. Edgewise bracketVertical slot e.g. Begg bracketSize of slot e.g. 0.018x0.025 and 0.022x0.025

PrescriptionsRoth, hilgers, rickets, standard edgewise, alexander, mbt, sprint, orthos, damon, andrews52

Brackets contd.Material Metal : stainless steel, gold, titanium, nickel, chrome-cobaltPlastics Ceramics (laminated, zirconia based, mono/polycrystalline)Combination e.g. metal reinforced ceramics, metal reinforced plasticsMagnetic brackets (25%-30% chromium, 15-25% cobalt, 45-60% iron, samarium)Polycarbonate, polyurethane,

First goldPlastics in late 60sCeramics in mid 80sTitanium for nickel sensitivityChrome cobalt in Nu edge 1997Samarium is a rare earth metalPolycarbonate brackets were described and tested by Newman in 1969. Later, polyurethane, fiber-reinforced, and filler-reinforced brackets 53

Plastic bracketsNot durableDiscolorationFracture No strength Coating came off wiresUncoated wires didnt slideCeramic AestheticDoes not discolorBulkyEnamel damage

Ceramic brackets

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Brackets contd.Ligation of bracketConventional ligation e.g Edgewise and Begg bracketsSelf-ligating e.g. Edgelock and Speed brackets

Self ligating bracketsIntroduced in the 1970s with EdgelockSpringy latch(Speed), spring retaining walls(smart clip), rigid latching(Damon)Advantages Aesthetic and comfortableShortened chair timeSecure wire engagementLow friction

The most commonly used brackets are Mobil-Lok brackets, Insert bracket, SPEED brackets, Activa Brackets, Damon SL Brackets, Time Bracket etc.

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Self-ligating brackets

Brackets contd.Movement of teethTipping movement e.g. Begg bracketBodily movement e.g. EdgewiseTipping and bodily movement e.g. Tip-edge bracketBracket morphology Siamese e.g. Edgewise bracketSingle wing e.g. Lewis and Lang bracketsMini twin

Tip-edge bracket

Single wing bracketsLang bracket

Lewis bracket

Bracket baseMeshed, microlock, dynalockBracket techniqueBegg light-wireEdgewise Straight-wireTip-edgeLingual preadjusted

Others Weldable and bondable brackets

Bracket base

Lingual appliance

Kinya fujita 1979Lingual padsComputer controlled wire bendingVery technique sensitive66

Custom bracketsCustom labial brackets are cut using CAD-CAM technologyThe base of each bracket is contoured for a particular place on the surface of a particular toothThe slot of the bracket has appropriate thickness, inclination and torque Minimal number of archwires are usedTreatment period is reduced

Bonding techniquesDirect bondingIt is fasterEasier Less expensiveBracket guage

Indirect bondingIt is more accurateTwo-stage Working castBonding using candy waxSilicone rubber transfer trayRemoval with hot waterTransfer to teeth with base and catalyst

Other attachmentsHeadgear tubes Placed on maxillary first molarsUsed for insertion of facebow or auxillary labial archwireLabial hooksInsertion of inter and intra-arch elasticsLingual arch attachmentButtons , cleats, eyelets

Cleats and buttonsCross elasticsExtrusion of canineEyelets Rotation control

Bands Passive component that carries attachmentsAvailable in different sizes Made of soft stainless steelHas a smooth outer surface and rough inner surfaceCan be preformed or custom

Indications for bandingTeeth that will bear heavy forcesTeeth that will need facial and lingual attachmentsTeeth with short clinical crownsTeeth with extracoronal restorationsPosterior teeth Hypomineralized and flourosed teeth

Saliva control and occlusal force75

Steps in bandingSeparator applicationSelection of bandTooth preparationIsolation Cementation

Brasswire of .5/.6mmRing separatorDumbell separator76

ARCHWIRES

Archwires Preformed and custom Material ( stainless steel, Nickel-titanium, gold, alpha/beta titanium, chrome cobalt, elgiloy, composite coated)Posted and non-posted Arch forms (Catenary and Brader)Shape (round, square, rectangular)Function (passive and active)Size

Ss= chromium 18%, nickel 8%,Elgiloy= cobalt 4%, nickel 15%, chromium 20%, iron 10%Nitinol= cobalt 3%, nickel 52%, titanium 45%Copper nickel titanium for damon self ligating78

Basic Arch forms

Tapered Square Ovoid

Brader

Catenary

Ideal Properties of archwiresLarge spring-backLow stiffnessResistant to fatigueHigh formabilityLow surface frictionBiocompatibility and corrosion resistantCheap

AUXILLARIES

Elastomerics Made of latex elasticsThey deliver a normal force of about 150-300gmUses Separation for banding Closure of space i.e. power chainLigation of archwire i.e. ligature elasticsTreatment of crossbiteCorrection of interarch relationship e.g class II or III elasticsDerotation of teeth e.g. elastic thread

Springs Uprighting springs e.g. in Begg applianceRotation springs(Whips)Torquing springCoil spring Open : for opening spaceClosed: for closing spaces

Springs Coil spring

Uprighting spring

Extra-oral device

STAGES IN FIXED APPLIANCE THERAPYLeveling and alignment of teethWorking stageOverjet correctionOverbite controlFinishing Retention

Leveling and alignment

Alignment of archCorrection of crowdingCrossbite correctionExposure and alignment approach for impacted teethDiastema closureLeveling by extrusion and intrusion

Working stageCorrection of molar relationship using inter-arch elasticsOverbite controlOverjet correctionDecreasing curve of speeOpen bite correctionClosure of extraction spacesMaintenance of suitable arch form

Finishing stageAlignment of individual teeth positionsRoot parallelingTorque of incisorsCorrection of midline discrepanciesFinal settling of teethDebanding and debonding

INSTRUCTIONS TO PATIENTBrush teeth before and after every meal and before bedAvoid eating hard and sticky foodContact orthodontist in case of pain or loose applianceRoutine dental visits

COMPLICATIONSPeriodontal problemsDemineralization Traumatic injuriesIatrogenic injuriesTooth mobilityPain Tooth resorptionLoss of tooth vitalityCaries

THANK YOU

REFERENCESCONTEMPORARY ORTHODONTICS, William R. Proffit, DDS, PhD, 2007 A TO Z ORTHODONTICS, Dr Mohammad K. Alam, BDS, PGT, PhD(Japan) ,2012SYSTEMIZED ORTHODONTICS TREATMENT NEEDS, McLaughlin, Bennett, Trevisi, 2001ESSENTIALS OF ORTHODONTICS DIAGNOSIS AND TREATMENT, Robert N. Staley DDS, MA, MS, 2011MARCH 2011 WEST AFRICAN COLLEGE OF SURGEONS UPDATE COURSE