Segmented arch technique

SEGMENTED ARCH
TECHNIQUE
www.indiandentalacademy.com


IntroductionIntroduction

Rationale of SATRationale of SAT

Preliminary Bracket AlignmentPreliminary Bracket Alignment

Deep overbite correctionDeep overbite correction

Open bite correctionOpen bite correction

Space ClosureSpace Closure

Root correctionRoot correction

 Designed to deliver light continuous forces.
 “continuous” arch wire.
 Segmented arch consists of multiple wire cross
sections.
 SA does not connect brackets & tubes on adjacent
teeth.
Introduction:

RationaleRationale
Consolidation of teeth into units:Consolidation of teeth into units:

Segmentation allows the treatment to proceed by consolidationSegmentation allows the treatment to proceed by consolidation
of teeth into units.of teeth into units.

Few teeth are considered for each segment.Few teeth are considered for each segment.

Continuous arch-forces are distributed to the adjacent teeth.Continuous arch-forces are distributed to the adjacent teeth.

Rationale
Varying Cross-section of Arch wire:

Active units

Reactive units

Wires used to displace the teeth should have low LDR.

Increasing the Inter bracket distance:
 Forces used during intersegmental mechanics are applied at
large distances.
 Continuous arch – Active & Reactive forces occur on the
adjacent teeth.

 Increases the space available for
longer activations.

Prefabrication & Precalibration:
• Continuous arch –Difficult to determine the forces.
• Segmentation allows the use of precalibrated springs
to deliver the desired forces.

Clinical Efficiency:
 No. of arches are made during treatment in continuousNo. of arches are made during treatment in continuous
arch therapy.arch therapy.
 In segmental approach continual replacement of archIn segmental approach continual replacement of arch
wires are not requiredwires are not required

Preliminary Bracket Alignment
• Initial stage of treatment.
• Brackets of the teeth are ideally aligned.
• Goal : Consolidated segments

Attachments & Placement
Attachments:-
- Slot - 0.022 x 0.028
-Hooks, auxiliary tubes, Head gear tubes.
-Cuspid bracket- 0.175 X 0.025
vertical/horizontal tube.

Molar attachments
Lingual hinge cap
(0.032 X 0.032)

• Attachments with 1st, 2nd, 3rd
order angulations are
available.
• Help clinician to get good occlusion.
• Second order angulations can be individualized during
banding.

Burstone OrthosBurstone OrthosTMTM
AttachmentAttachment
PrescriptionPrescription

Placement of Attachments
Objectives:

No 2nd
order steps

Minimal 1st
order bends

All slots are parallel to the occlusal plane.

Variations in the tooth position & morphology.

Second order level:-
Criteria:
-Occluso-gingival level
-Angulation with respect to ‘z’ or faciolingual axis.

 Level of attachments is established first for the
posteriors.
-Maxillary arch: centrals, laterals, canines,1st &2nd molars.
-Mandibular arch: centrals, laterals, canines,1st &2nd
molars.

Second order Angulation:
- OPG
Objectives:-Proper root dispersion, & occlusion.

 Angulations of anterior teeth are
assessed
 Using PA cephalograms &
assessed to the treatment occlusal
plane.
 All slots should lie in the same line
& roots should have proper root
dispersion.

First order placement:
-Attachments are centered mesiodistally on the crown
-Parallel to the incisal edges/buccal cusp tip.


Objectives of PBA:-Objectives of PBA:-

Normalize the teeth Intrasegmentally.Normalize the teeth Intrasegmentally.
-Rotations, B-L positions-Rotations, B-L positions
-Occlusogingival discrepancies.-Occlusogingival discrepancies.
-Teeth torqued-Teeth torqued..

Improve the Intersegmental relationship.Improve the Intersegmental relationship.

Improve the Intermaxillary relationship.Improve the Intermaxillary relationship.

Basic lingual arches:

Upper horse shoe shape

Lingual Arch Wires:Lingual Arch Wires:
 Establishing & maintaining the upper and lower arch widths.
 Correcting intra-arch rotations or inter-segmental rotations.
 A-P asymmetries.
 Difference in the occlusal planes.
 Buccolingual & M-D axial inclinations of the post. teeth.
 Reducing the undesirable side effects.

Lingual Hinge Cap -0.032 X 0.032
-Ligation of the lingual arch

 Buccal Stabilizing Segment:
-To connect the individual teeth into one unit
- For Alignment
-To act as stop anteriorly.
-Point of connection.
-0.018 TMA welded to the molar.

Deep Overbite Correction
Differential diagnosis & Treatment plan.
3 basic ways -
Intrusion of Ant. teeth Extrusion of post. teeth


Intermaxillary growth space

Skeletal vertical dimension

AB Relationship

Occlusal plane cant

Esthetics

Intermaxillary Growth Space:Intermaxillary Growth Space:

 Skeletal Vertical DimensionSkeletal Vertical Dimension

 Occlusal Plane cant desired after the treatmentOcclusal Plane cant desired after the treatment
 EstheticsEsthetics

 Principles of Anterior Intrusion
-Controlling force magnitude & constancy
-Anterior single point contact
-Point of force application
-Selective Intrusion
-Control of reactive units
-Avoiding Extrusive mechanics

 Controlling force Magnitude:Controlling force Magnitude:
-Magnitude of forces used for intrusion should as low-Magnitude of forces used for intrusion should as low
as possible.as possible.
--Side EffectsSide Effects: Root resorption: Root resorption
Extrusion of buccal segmentsExtrusion of buccal segments

TOOTH MOVEMENT FORCE (gm)
INTRUSION PER SIDE TOTAL IN MIDLINE
2 UPPER CENTRAL INCISORS 15 – 20 30 –40
4 UPPER INCISORS 30 – 40 60 – 80
6 UPPER ANTERIORS 60 120
2 LOWER CENTRAL INCISORS 12.5 25
4 LOWER INCISORS 25 50
6 LOWER ANTERIORS 50 100
2 UPPER CANINES 25 -
2 LOWER CANINES 25 -
MOLAR EXTRUSION 60 – 100 120 – 200
FORCE VALUES FOR INTRUSION

 Force constancy is obtained by using low LDRForce constancy is obtained by using low LDR
springs.springs.
 Intrusive Arch-0.018 x 0.025 with 3mm helixIntrusive Arch-0.018 x 0.025 with 3mm helix

 Anterior Single Point Contact:Anterior Single Point Contact:
-Intrusion arch is not placed in the anterior brackets.-Intrusion arch is not placed in the anterior brackets.
-Torque-Torque
-Allows the clinician to know the force systems involved.-Allows the clinician to know the force systems involved.
(Statically Determinant)(Statically Determinant)
-Anterior alignment arch wires can be placed.-Anterior alignment arch wires can be placed.

Point of Force Application:Point of Force Application:
 Force applied to the CresForce applied to the Cres
will not produce any labialwill not produce any labial
/lingual rotation./lingual rotation.
 Intrusion arch is placedIntrusion arch is placed
anterior to the labial surface.anterior to the labial surface.

 Selective Intrusion:Selective Intrusion:

 Control of the Reactive Units:Control of the Reactive Units:
-Minimization of force magnitudes.
Side Effects: Plane of occlusion in the buccal segments is altered.
• Forces of intrusion should be kept low.
• More no.of teeth should be incorporated.
• Retraction is done initially.
• Occipital HG

• Equal & opposite extrusive effectEqual & opposite extrusive effect

 Avoiding Extrusive Mechanics:Avoiding Extrusive Mechanics:
-CL-II elastics
-CL-III elastics
-Cervical HG
Pts requiring true intrusion.

Principles of Anterior IntrusionPrinciples of Anterior Intrusion

Use of optimal magnitudes of forceUse of optimal magnitudes of force

Point contact in the anterior regionPoint contact in the anterior region

Selection of the point of force application with respectSelection of the point of force application with respect
to the Cres.to the Cres.

Selective intrusionSelective intrusion

Control over the reactive unitsControl over the reactive units

Avoidance of undesirable eruptive mechanicsAvoidance of undesirable eruptive mechanics..

Continuous Intrusion ArchContinuous Intrusion Arch
• Post.Anchorage unitPost.Anchorage unit
• Ant.segmentAnt.segment
• Intrusion arch(0.017x0.025 TMA).Intrusion arch(0.017x0.025 TMA).

0.018 round TMA stops are welded – to serve as tie0.018 round TMA stops are welded – to serve as tie
backs.backs.

Three-Piece Intrusion Arch
 Intrude the flared incisors, control their axial
inclinations & retract with good anchorage control.
 Point contact of force application.
 Pt’s with proclined incisors have to be treated
differently.

 Post-Anchorage unitPost-Anchorage unit
 Ant.segment with a posterior extensionAnt.segment with a posterior extension
 Intrusion cantileversIntrusion cantilevers
 Chain elastic.Chain elastic.


Distal extensions end 2-3mm distal to the Cres of heDistal extensions end 2-3mm distal to the Cres of he
anterior segment.anterior segment.

Design of the appliance -low friction.Design of the appliance -low friction.


Anterior Segment & Direction of Intrusive forceAnterior Segment & Direction of Intrusive force

CANINE INTRUSION:
 A cantilever from the auxiliary tube of the molar tied to
the canine bracket.
 The cantilever is bent to the lingual to give a lingual
force.

CANINE INTRUSION:

Extrusion of Posterior SegmentsExtrusion of Posterior Segments

Higher forces promote posterior eruption.

Canting of the occlusal plane should be avoided.

Extrusion arch is similar to the intrusion arch.

Eruptive appliances should be used in growing children.

Extrusion occurs rapidly than intrusion.

 2 types of extrusion can be achieved
with extrusion arch.
Type-I Combines extrusion with rotation
of the buccal segment. Applied in the
lower arch.
Type-II Used in the upper arch when
parallel eruption of buccal segments is
required

Types of extrusive mechanicsTypes of extrusive mechanics
• Tip-back mechanism
• Base arch mechanism
• Parallel eruption of buccal segments

 Tip back mechanism:-Tip back mechanism:-
Indications:
Growing pt with a forward rotation.
Deep curve of spee in the lower arch.
Arch length inadequacy.

Tip back mechanism consists:Tip back mechanism consists:

0.036 inch lingual arch0.036 inch lingual arch

0.018x0.025 anterior segment0.018x0.025 anterior segment

Buccal stabilizing segment of 0.018x0.025.Buccal stabilizing segment of 0.018x0.025.

0.018x0.025 tip back spring0.018x0.025 tip back spring

 CCRotRot is placed around the root of the 2is placed around the root of the 2ndnd
molar.molar.
 Eruption & rotation of buccal segments.Eruption & rotation of buccal segments.
 Increase in the arch lengthIncrease in the arch length

Base Arch Mechanism:Base Arch Mechanism:
 Also called as Intrusive arch.
 Buccal and anterior arch wires are identical.
0.018x0.025 SS

• Ligature is tied to the helices to preventLigature is tied to the helices to prevent
flaring of anterior teeth.flaring of anterior teeth.
• Effects:Effects:
-Eruption & rotation of the buccal-Eruption & rotation of the buccal
segments.segments.
-Roots of the buccal segments move-Roots of the buccal segments move
forward.forward.
-No increase in the arch length.-No increase in the arch length.

Parallel Eruption of the Buccal Segment:Parallel Eruption of the Buccal Segment:
 Used in the upper jawUsed in the upper jaw
 Cervical HG with long outer bow .Cervical HG with long outer bow .


Natural plane of occlusion must be monitoredNatural plane of occlusion must be monitored

0.018x0.025 wire is placed as an indicator wire.0.018x0.025 wire is placed as an indicator wire.

Closing Anterior Open Bite : Extrusion Arch

Open bites occur less frequently.Open bites occur less frequently.

Treatment involves a wide variety of approaches.Treatment involves a wide variety of approaches.

Dental compensations – Vertical elastics.Dental compensations – Vertical elastics.
Extrusion ArchExtrusion Arch: reverse action of the intrusion arch.: reverse action of the intrusion arch.
 Effective way to close the open bite without Pt complianceEffective way to close the open bite without Pt compliance
 Choice of dental compensation is based on lip-tooth distance.Choice of dental compensation is based on lip-tooth distance.

Extrusion Arch

Action at the Molar:-Action at the Molar:-

Extrusion Arch
 TimingTiming: Undesirable actions at the: Undesirable actions at the
molars will be insignificant if themolars will be insignificant if the
EA is kept only for a minimumEA is kept only for a minimum
time. (time. (IsaacsonIsaacson))
 Segment of SS wire has to beSegment of SS wire has to be
placed in the posterior segment.placed in the posterior segment.

Extrusion Arch

Action at the Incisor:-Action at the Incisor:-
Extrusion -Single toothExtrusion -Single tooth
-Groups of teeth.-Groups of teeth.
• Magnitude of extrusive forces used are100gms for 4 incisors
• 0.016X0.022 SS wire is used

Space ClosureSpace Closure
Biomechanical Basis of extraction space closureBiomechanical Basis of extraction space closure
 2 methods to close extraction sites
-Segmental springs
-Loops in the continuous wire

 Anchorage classification:-Anchorage classification:-

Single cuspid retraction Vs En-mass retractionSingle cuspid retraction Vs En-mass retraction
 Adequately designed appliances based on the desiredAdequately designed appliances based on the desired
biomechanics.biomechanics.
 En-mass space closure reduces the treatment time.En-mass space closure reduces the treatment time.
 Separate canine retraction is done in anterior crowdingSeparate canine retraction is done in anterior crowding
cases.cases.

Space closure –A Biomechanical PerspectiveSpace closure –A Biomechanical Perspective

 Force systems for Grp B space Closure.Force systems for Grp B space Closure.
 M/F-10/1 is needed for Translation.M/F-10/1 is needed for Translation.

Grp-A anchorageGrp-A anchorage:: Mesial force on the posterior teethMesial force on the posterior teeth
should be minimized.should be minimized.
-Forces & moments acting on the posterior teeth can be-Forces & moments acting on the posterior teeth can be
minimized by using extraoral force.minimized by using extraoral force.

 Differential tooth movement:

Grp-A anchorageGrp-A anchorage:: Space closure with differentialSpace closure with differential
moments.moments.
 Increasing the posterior M/F ratio encourages root movement &Increasing the posterior M/F ratio encourages root movement &
decreasing the M/F ratio causes tipping type of toothdecreasing the M/F ratio causes tipping type of tooth
movement.movement.
 Magnitude of the vertical force – difference between anterior &Magnitude of the vertical force – difference between anterior &
posterior moments.posterior moments.

Determinants of space closure:-Determinants of space closure:-

Amount of crowdingAmount of crowding

AnchorageAnchorage

Axial inclination of canines & incisors.Axial inclination of canines & incisors.

Midline discrepancies & Lft/Rht symmetryMidline discrepancies & Lft/Rht symmetry

Vertical dimensionVertical dimension

Space closureSpace closure
Considerations for anchorage control &
Differential tooth movement
 Size of the Anchorage units - No. of teeth .
 Differential force systems-Variable moments & Forces
-Forces act in 3 planes of space.

Segmental En-mass Extraction space closureSegmental En-mass Extraction space closure
• T-loop space closure springs are usedT-loop space closure springs are used
• Principle of SA-Ant & Post units are considered as onePrinciple of SA-Ant & Post units are considered as one
large tooth.large tooth.
• Rt & Lft buccal segments are connected by TPA.Rt & Lft buccal segments are connected by TPA.
• Design uses 0.0175x0.025 TMA wire.Design uses 0.0175x0.025 TMA wire.

General Concepts for Segmented T-loop useGeneral Concepts for Segmented T-loop use
 Passive form of a springPassive form of a spring
 Activation of the spring requiresActivation of the spring requires
application of forces & moments.application of forces & moments.
 Neutral positionNeutral position –Only moments–Only moments
are applied.are applied.

 Differential Anchorage: Unequal α & β moments.
 Higher moment is applied to the anchor teeth.
 Differential moments –Off-centered V-bend.
 Centering the T-loop -produces equal & opposite moments.
General Concepts for Segmented T-loop useGeneral Concepts for Segmented T-loop use

Symmetric Space Closure – Grp B AnchorageSymmetric Space Closure – Grp B Anchorage
 Simplest form of space closure.Simplest form of space closure.
 Equal translation of Ant & Post segments.Equal translation of Ant & Post segments.
 T-loop centeredT-loop centered
 Distance =Distance =Interbracket DistanceInterbracket Distance -- ActivationActivation
22

 Space closure is monitored periodically.Space closure is monitored periodically.
-amount of remaining space-amount of remaining space
-axial inclinations-axial inclinations

Space Closure – Grp A AnchorageSpace Closure – Grp A Anchorage
• T-loop is positioned closer to the post. Attachment.T-loop is positioned closer to the post. Attachment.

Space Closure – Grp C AnchorageSpace Closure – Grp C Anchorage
 Post. Protraction is the difficult spacePost. Protraction is the difficult space
closure.closure.
 Extrusive effect on the anterior teeth.Extrusive effect on the anterior teeth.
 CL-III elasticsCL-III elastics – to augment the– to augment the
protractionprotraction

Separate Canine & Incisor RetractionSeparate Canine & Incisor Retraction

Anterior crowding

Midline disrepancies

Moment is produced on the canine during separate canine
retraction.


3 ways to counteract this moment:3 ways to counteract this moment:

Cuspid-Cuspid Bypass wire:-Cuspid-Cuspid Bypass wire:-

Prevent RotationPrevent Rotation

Alter arch widthAlter arch width

Eliminate side effects from vertical forces.Eliminate side effects from vertical forces.
0.017 X 0.025SS

Incisor RetractionIncisor Retraction

Canine & Incisor Root MovementCanine & Incisor Root Movement

Control of axial inclinations of teeth is important.Control of axial inclinations of teeth is important.

Good axial inclination & root parallelism-stable result.Good axial inclination & root parallelism-stable result.

Root correction involves-Individual/Groups of teeth.Root correction involves-Individual/Groups of teeth.

Enmass root movementEnmass root movement

Separate canine root following separate canine retraction.Separate canine root following separate canine retraction.

Separate incisor root correctionSeparate incisor root correction

Diagnosis & Evaluation of root correctionDiagnosis & Evaluation of root correction

Clinically-Inclination of canine & incisor brackets.Clinically-Inclination of canine & incisor brackets.

Lateral films-Axial inclinationsLateral films-Axial inclinations

Enmass Root MovementEnmass Root Movement

Second phase of space closure after tipping movement.Second phase of space closure after tipping movement.

Moments are delivered byMoments are delivered by Root springsRoot springs..

Moments generated cause the crowns to flare and rootsMoments generated cause the crowns to flare and roots
to retract.to retract.

Ligature tie –to prevent the space from opening.Ligature tie –to prevent the space from opening.

Selection of wire in the anterior segment:Selection of wire in the anterior segment:
• Rigid wire placed in the 6 anterior teeth.Rigid wire placed in the 6 anterior teeth.
• Undersized wire – rotation of the incisors.Undersized wire – rotation of the incisors.

3 major root springs for enmass root movement3 major root springs for enmass root movement

 Root springs:Root springs:

 Cuspid root movement:Cuspid root movement:

 Incisor root movement:Incisor root movement:
0.021 x 0.025 TMA root spring

References:-References:-
Biomechanics In Orthodontics –Biomechanics In Orthodontics – Marcotte.Marcotte.
Biomechanics In Clinical Orthodontics-Biomechanics In Clinical Orthodontics-Ravindra NandaRavindra Nanda..
 Rationale of the Segmented arch –Rationale of the Segmented arch –BurstoneBurstone AJO (1962).AJO (1962).
 Deep overbite correction by intrusion –Deep overbite correction by intrusion – BurstoneBurstone
AJO(1977).AJO(1977).
 Biomechanics of Deep Overbite Correction-Biomechanics of Deep Overbite Correction-BurstoneBurstone
(Semin Orthod 2001).(Semin Orthod 2001).


Segmented approach to simultaneous intrusion and spaceSegmented approach to simultaneous intrusion and space
closure: Biomechanics of the three-piece base archclosure: Biomechanics of the three-piece base arch
appliance-Bhavna Shroff AJODO-1995appliance-Bhavna Shroff AJODO-1995..

Closing Anterior Open bite :The Extrusion Arch –Closing Anterior Open bite :The Extrusion Arch –
Isaacson & Lindau Semin Orthod 2001.Isaacson & Lindau Semin Orthod 2001.

The Segmented arch approach to space closure – BurstoneThe Segmented arch approach to space closure – Burstone
1982 AJO1982 AJO

Segmented arch technique

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to Segmented arch technique

Similar to Segmented arch technique (20)

More from Indian dental academy

More from Indian dental academy (20)

Recently uploaded

Recently uploaded (20)

Segmented arch technique