Vertical control in orthodontics and utility arches

Vertical control in
SWA, Intrusion
Mechanics
and
Utility arches
www.indiandentalacademy.com

Introduction
Overbite – mm measurement / % - overlap of
the mandibular incisors by the max. incisors.
50% overbite – deep overbite.
Overbite control – closely related to arch
leveling process.
Occurs after levelling & aligning of
individual teeth.

Vertical control – management of
Deep Bite &
Open Bite.
Deep bite – 2 types:
True.
Pseudo.
True – infra eruption of post. teeth.
Pseudo – supra eruption of ant. teeth.

Development of Deep bite:
Ant. teeth – erupt – until contact made with –
Opposing ant. teeth.
Soft tissue of the palate.
Tongue inhibits – eruption.
Class II or III MO – facilitates - / reversed overjet
 over eruption of ant. teeth.
Unrestricted eruption – lower 2nd
molars – Cl II
deepening of curve of spee in post. part.

Correction – various tooth movts:
Eruption or extrusion of post. teeth.
Distal tipping of post.teeth.
Proclination of incisors.
Intrusion of incisors.
Combination

Eruption / extrusion of post. teeth.
Stable process – accompanies vert. facial dev.
Contributing factor – bite opening – deep bite patients.
vertical facial ht. – growing patients –
accommodates extrusion of post. teeth during ortho trt.
Not stable – adults – low mand. plane angles.
Musculature – resists extrusion.
High angle cases – weak musculature – stable results.
Permanent opening of mand. plane - undesired

Distal tipping of post. teeth.
Stable process – growing patients.
Low angle adult cases – not stable.
High angle cases – stable – to be avoided.
Proclination of incisors.
Proclination – retroclined incisors  in ant. region.
Lower arch – LI crowns – proclined.
Upper arch – crown proclination & root torque
control.

Intrusion of anterior teeth.
Not normally reqd in growing patients.
Face grows vertically – restricting the normal
eruption of ant. teeth – allow bite to open.
Adult cases – musculature resists post. changes.
:. bite opening in adults –
proclination of incisors
Intrusion.

Advantages:
Controlling VD – by preventing post. eruption –
mandible rotate closed / prevented opening.
No encroachment – inter occlusal space – Stability.
Prevention of post. eruption during growth – AB to
OP reln. Improved.
Eg. Sk Cl II not worsened by post. extrsn & rotn.

Principles of ant. intrusion.
Use of optimal magnitude of forces & delivery
with low LDR springs.
Use of point contacts in ant. region ( statically
determinant system)
Position of force – selection of the point of
application of force with respect to CR.
Selective intrusion based on ant. tooth geometry.
Control – reactive units – post. Anchorage unit.
Inhibition – erupn. of post. teeth.

Controlling force magnitude & constancy:
Lowest force – capable of intrsn. – used.
Heavy forces – 2 effects.
 in rate of root resorption.
On the anchorage unit –
Maxilla – Extrusion & steepening of the occl. plane.
Mandible – flattening.
Moment – intrsn arch - anchorage unit. Due to dist from
incisors to molars.

 Force constancy – low load defln. rate spring.
Lose less force / mm deactivation.
More accurate upon activation than high LDR spring.
 Ant. single point contact.
Intrusion arch – not directly placed into brackets.
Tied to ant. segments – 2 points of contact.
.

Advantages.
If placed into br.  torque to ant. segment.
Labial root torque -  intr. force.
Lingual root torque -  intr. force on ant. segment.
Force system statically determinant.
Clinician precisely know the force system involved.
Telescoping of trt.
Br. – used for initial alignment segments + intrusion.

Point of force application.
Intrusive force  CR  intrusion ,
no labial or lingual rotn. of the tooth.
Patients with procumbent incisors – intrusive force
–
farther from CR –
 moment   lingual root movt.
Management:
Retract ant. – upright axial incln.- intrude.
Apply vertical force – lingual to CR.

Selective intrusion.
Indescriminate levelling –
continous arch or sectional wire – undesirable side
effects.
Decision which teeth to intrude – Intelligent trt.
planning & accomplishing – creative use of mech.
In Cl II div. 2 – CI intruded > LI.

Indiscriminate levelling –
LI extrusion.
Moments – roots – converge
mesially.
Proper mech. – intrude CI to
proper reln. with LI, then include
LI & continue intrusion.

Control of reactive units.
Best method – control of anchorage unit - 
forces.
Effect – moment produced – intrusive force.
Large due to long moment arm.
2 side effects:
Plane of occln. of buccal segment altered.
Due to equal & opp. extrusive force – buccal
segments.

Plane of occln.
maxilla – steepens.
mandible – flattens.
To minimize –
 Intrsn forces.
 Teeth in the anchorage unit.
Retract as much as possible initially -  length of
moment arm
Occipital head gear – force directed ant. to C.R –
post. anchorage unit.

Equal & Opp. extrusive force.
Force – acting at aux. tube of molar –
Buccal to CR of molar/ buccal segment.
Moment  tip buccal segments lingually
roots moving buccally.
Prevented by
Lingual arch – maintains axial inclins. & arch width.
Fabricated width of intrn. arch less critical.

Avoiding extrusive mechanics.
Patients – genuine intrusion -
Cl II or Cl III elastics,
Cervical headgear – high outer bows to max. arch –
to be avoided.
Canine root – mesioangular incln.
Placement of continuous archwires – extrude incisors –
canine root moves distally.
Solution:
Bypass the canine with continuous arch &
Perform separate canine movement.

Methods to correct deep bite.
Bite plates.
Utility arches.
Reverse curve Niti / SS.
Burstone intrusive arch.
Kalra SIR, appliance.

Utility Arches.
Designed – Robert M. Ricketts – early 1950’s.
Originally designed for enhancing anchorage during
canine retraction.
History:
Continuous archwires ( flat or reverse curve of spee)
- Levelling & aligning –
Ant. flared out
PM overerupted.
Molars uprighted or tipped back.
Class III elastics & head gear used to prevent.

Canine retraction with sectional wires –
Molars & PM’s tipped mesially.
Canines tipped distally & extruded.
1950's Robert Ricketts - counteract the tipping in
the buccal segments - utilizing - immutable lower
incisors as an anchor unit,
Round arch segments - laced from the lower molars
and PM’s to the lower incisors.

Buccal segments maintained in an upright
position,
lower incisors intruded with this light, continuous
pressure.
Development - Step-down base arch, or Ricketts'
Lower Utility Arch.
Double tube with no torque – designed.
Sp. Blue Elgiloy wires – 0.016” x 0.016”
Force generated – 100 gms –four incisors.

Design And Function:
Extremely functional design.
Molar section – 2-3 mm beyond the molar tube
Stepped down 3- 5mm – bypass the PM & Canine.
Stepped up 2-3 mm distal to the LI br.
Follows the contour of the ant. segment.

Ant. segment – labial root torque – 10 - 15°.
Molar segment – buccal root torque.
- tip back of 30 - 45°.
Toe in – molar segment – extraction cases.
Expansion – 2 cm – on each side.

Effect on Molars.
Tends to upright the molars.
Crowns tip distally, rots move mesially
Tip back bend – straight distalizing force –
distolingual rotn.
Effect on Incisors.
Continous arch – flaring of the anteriors.
Crowns – mesially, roots – lingualy, hit against
cortical bone. Labial root torque – prevents this.
Most effective force - intrusion - // to long axis.

Function & roles of the Utility arch.
Used to position the lower molars – snable them
to use cortical anchorage.
Loss of proprioception – incisal occlsn. –
mandible relocates – Cl II corrections.
Torque placed – incisors & molars – helps to
define ideal archform.
Possible to treat ant. & post. segemnts
simultaneously to overcorrection.

It helps to maintain arch length, increase/
decrease it
Uprighting the molars.
Advancement of the lower incisors
Expansion of the buccal segments.
Saving “E” spce.

Fabrication
0.016x 0.016 Blue Elgiloy wire used.
Wire not heat trtd. When arch is formed.
Step 1. vertical step down – 10 mm from the end
– 3 – 5mm height. Horizontal section – 3mm
distal to the LI br.- step up bend
Step 2. bent horizontally. Slight inward angle –
10 - 15°. Ant. arch form swept into the wire.
Step 3. opp side completed. Buccal segment
gently contoured & buccal bridges flared

1 cm expansion on each side.
Distal leg twisted buccally. Places
labial root torque & prevents gingival
impingement of the distal vertical legs.
Incisors intruded - 45° tip back – molar
section.
Final arch form –
Well contoured ant. segment with labial root
torque.
Flared buccal segments.
Post. legs // to each other, 45° buccal root
torque.
Tip back – uprights molars & gains space.

Classification:
Passive utility arch:
Stabilisation or space maintainence.
Mixedentition – hold space – transitional period.
Permanent den.- maintain anchorage.
Intrusive utility arch.
Sizes of wire used in max. arch
0.018 slot – 0.016 x0.022
0.022 slot – 0.018 or 0.019 square wires.

Retraction Utility arch
To achieve retraction & intrusion.
Loops into archwire – ant. vertical step
Greater range of retrcn.
Mainly used in the maxilla.
Protraction Utility arch.
Proclining & intruding upper and lower incisors –
Class II div 2.
Post. step flush with molar tube. Loop distal to the
ant. vertical step & occlusal to the horizontal
segment.

Tip back Springs ( Intrusion Springs ).
Originally proposed – Burstone
Upper & lower arches –levelled & aligned – rigid
SS wire – 0.017 x 0.025.
Used when true intrusion requd.
Growing patients with forward growth rotation.
Deep curve of spee in the lower arch.
Deep overbite – extrusion of the incisors.
Steep natural plane of occln.

Anchor molars reinforced.
TPA – upper, Lingual arch – Lower.
Intrusion spring –
With helix –SS – 0.017 x 0.025
Without helix – TMA – 0.017 x 0.025.
Fabrication:
Wire bent gingivally mesial to the molar tube .
Helix formed.

Mesial end bent into a hook.
Engaged distal to the LI.
When passive – mesial end – height of muco-
buccal fold.
Three Piece Intrusion Arch.
Consists of the following parts.
Post. anchorage unit.
Ant. segment with post. extension.
Intrusion Cantilevers.

Fabrication:
Anterior segment – bent gingivally – distal to the
laterals.
Then bent horizontally – step of 3 mm.
Distal part – distal end of canine br. – formed
into a hook.
Ant. segment – 0.021 x 0.025 SS wire – prevent
side effects – bending the wire during force
aplcn.

Intrusion Cantilever – 0.017 x 0.025 TMA.
Bent gingivally mesial to the molar tube & helix
formed.
Mesial end of cantilever – bent into a hook.
Activation:
Bend mesial to the helix at the molar tube.
Passively – ant. end lies – vestibule.
End brought down and engaged – horizontal
portion of the ant. segment.

Further distal placement of the force – lateral to
the LI.
Resultant forces – CR of ant. teeth.
E chain – attached to hook – simultaneous
intrusion & retraction.

Canine Intrusion.
Difficult to intrude six ant. teeth.
High foce levels requd.- large moments –
undesirable changes in the axial incln. of
post.teeth.
Achieved in 2 ways:
Cantilever form aux. tube of molar tied to the canine br –
point contact.
0.017 x 0.025 TMA wire used.
Problem – labial flaring.
During cuspid retraction – applying more β moment
( post.) than α ( ant. ) moment.

K – SIR archwire.
Appliance for simultaneous intrusion & retrcn. Of
six teeth – should control:
Magnitude of forces & moments.
Moment to force ratio.
Constancy of forces & moments.
Friction.
Kalra Simultaneous intrusion & retraction
archwire – modifn. of segmented loop mech. of
Burstone & Nanda.

Continuous 0.019 x 0.025TMA wire with closed
7mm x 2 mm U loops at the extn. site.
For bodily movement & prevent tipping - 90° V
bend – at the level of each U loop.
V bend when centred – counter the moments –
activation forces of the clodong loops.
60° V bend – post to the center of inter br. dist. –
increased clockwise moment – molar-
Augments molar anchorage & intrsn. of ant. teeth.

Activation:
Trial activation – outside the mouth – releases
stress built on bending the wire.
Neutral position – U loop – 3.5 mm wide.
Activated – 3mm. Mesial & distal legs – barely
apart.
Control of Reactive forces:
Keep forces to a min.
Add teeth to the anchorage unit.
High pull head gear.

Intrusive force – 125 g.
Advantages:
Simplicity of design.
Easy to fabricate
Comfortable to the patient.
Low forces, Low LDR.
Activation – 8 week period.
Shortens trt. time.
Unsightly space distal to laterals avoided.

Open Bite:
Non extn. Trt. Preferred.
Some cases – extn. – to allow for eruption &
retroclination of incisors.
Upper & lower arches – crowding & protrusion –
upper & lower PM extn.
1st
PM extn. – molars > 3-4mm class II.
Br.placement – 0.5mm more gingival than normal.
Early second molar banding – avoided.
Class II or III elastics – to PM’s than Molars. Short
elastics minimize extrusion.

Vertical control in orthodontics and utility arches

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Viewers also liked

Viewers also liked (20)

Similar to Vertical control in orthodontics and utility arches

Similar to Vertical control in orthodontics and utility arches (20)

More from Indian dental academy

More from Indian dental academy (20)

Recently uploaded

Recently uploaded (20)

Vertical control in orthodontics and utility arches