Intrusion in orthodontics /certified fixed orthodontic courses by Indian dental academy

….post prandial stupor….
INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com

INTRODUCTION
Overbite
Deep bite
Problems with deep bite

Overbite . . .
Vertical overlap of the incisors
Ref: W.R.Profitt & H.W.Fields; Contemporary Orthodontics;chap 1;pg 10
Lower incisors contact uppers
at / above cingulum
1-2 mm
Excessive overbite is deep overbite/deep bite

Deepbite . . .
Skeletal Dental
True
Pseudo
maxilla
mandible
Both
Infraerupted molars
Supraerupted incisors

Intrusion Arches
Guided by
Prof.Dr.K.Rajasigamani
The Head
Presented by
anisha manjeni
PG Student
26.04.2006 www.indiandentalacademy.com

Features Of Pseudo Deep Bite
Small interocclusal space
Excessive curve of spee
Fully erupted molars
Incisal margins of incisors
beyond functional occlusal plane

Problems with Deepbite . . .
trauma to soft tissues
lower anterior attrition
palatal – deep bite + excessive overjet
lower labial – deep bite + reduced overjet
lack of incisal guidance
sensitivity

INTRUTION

apical movement of the geometric
center of the root in respect to the
occlusal plane / a plane based on
the long axis of the tooth

Factors considered for Intrusion . . .
Natural plane of occlusion
Anterior esthetics
Amount of attached gingiva in
lower incisor region
A-B discrepancy
clinical crown height

Biomechanics involved . . .
Intrusion force levels
Control reactions of posteriors

INTRUSION FORCE
MAX INCISOR
MAND INCISOR
CANINE
5 – 10 g
10 – 15 g
15 – 25 g
Ref : Dermaut LR Vanden Bulcke MM AJO 89; 251-263;1986

The III law of Newton action = reactionwww.indiandentalacademy.com

…just to warm up
Mulligan’s illustrations

Ref: Thomas.F.Mulligan ; Common Sense Mechanics :chapter 1 ;CSM1982
Short
long
equal

Ref: Thomas.F.Mulligan ; Common Sense Mechanics :chapter 1 ;CSM1982
Short long
equal

Intrusion arches

Intrusion arch gamut . . .
Begg & its modifications
Burstone’s 3 piece
Ricketts’ utility arch
Mulligan intrusion arch
Connecticut
KSIR

Begg

BEG
G
Arch wire material
Delivers light force
Heat treated SS
Developed by A.J.Wilcock
Round wire
High resiliency with toughness
Ref: Begg&Kesling ; Begg Orthodontic Theory & Technique;1977;W.B.Saunders;3rd
edt

Arch Design
Stage I archwire (0.016”) with intermaxillary hooks
Anchorage bends are formed in the buccal segments
First distal ends of arch wire are placed in molar tube
The labial segments of the arch wire press against the
mucolabial sulci
edt

Arch Design
The forces are not great enough to tip the crowns of
molars distally & are optimal for depressing
the six anterior teeth in their socket
But it can resist the forward pull of the class II elastics
- “tip back” action of anchor bend offers “toe hold” to
molars
edt

Begg stage I arch
Anchor bend

Modifications of Begg

Jayad
eShortcomings of conventional Begg
Molar extrusion & little incisor intrusion
Questionable efficacy in upper incisor intrusion
Stereotype approach for all types of cases
-Insufficient force from 0.016” upper archwire
-45g from archwire ( intrusive component )
-30g from Cl II elastics ( extrusive component)
-Net force is 15g for 3 teeth i.e.,5g for one tooth
-Upper incisor inclination was not considered
Ref: Vijay P.Jayade ; Refined Begg For Modern Times;Sep.2001;1st edt

Jayad
eBite opening
Excess proclination is corrected in substage I
This is done to orient the forces close to CRES
Proclined-intrusive force 45g;Cl II force 60g
Improved inclination –intrusive force 60g;Cl II force 30g
Upright –elastic force oblique with anterior downwards
- achieves controlled tipping & active intrusion

Jayad
eBite opening
Methods of increasing intrusive force magnitude
Methods of reducing elastic force
Use of same elastics for a longer time
Shift to road runner elastics (5/16”)
Increase anchor bend of 0.016” from 30° to 50°
After 2-3 visits use 0.018” with anchor bends

Jayad
e
Palatal elastics
TPA fabricated with hooks
They lie in line with lat.incisor
Oval shaped wire soldered
in the center
This generates intrusive force by the tongue action
Four brackets bonded on palatal aspect of incisors
slots incisal – high hat pins on lat incisors
Light elastics applied from TPA to lat incisor
No elastics on buccal side

Jayad
eMechanics of palatal elastics
Neutralizes labially proclining component of the archwire
Augments intrusive force of the archwire
Cephalogram construction to estimate force levels

Construction of cephalogram
Arch wire
Palatal elastics
Intrusiveforce
Intrusive force magnitude
Elastic force magnitude

A line is drawn at right angle to the span of the archwire
at the bracket slot gives the direction of intrusive force
These two forms the two sides of the parallelogram
A line joining the bracket shadow to the CRES acts as
hypotenuses
This is extended to required length ( 1cm = 20g ) to
denote a resultant of 60g
The length of the 2 sides gives values of these 2 forces
These forces can be obtained in the mouth by selecting
a suitable elastic size and by manipulating the degree
of anchor bends
Construction of cephalogram
Ref: Vijay P.Jayade ; Refined Begg For Modern Times;

Jyothindra Kumar
Sections of rectangular wire of 0.018 X 0.025”
are bent in the form of hooks
Soldered on the buccal aspect of molars gingival
to tube
Elastics are engaged from these hooks to the
cuspid circles
Power arms
Direction from class II
to class I

Anchor bend modifications

Conventional anchor bend
Placed 3mm mesial to molar tube
Cause more intrusion of the upper canine &
less intrusion of the incisors
This is due to bowing of the arch wire in
canine area

Gable bend
Placed distal to canine
Cause extrusion of canine & more intrusion of
the incisors

Hocevar’s modification
Bend placed on either side of canine
Central incisors – intrusion
lateral incisor- less extrusion
canine – more extrusion

Kameda’s modification
Simultaneous anchor bend & Gable bend
Engaged on premolars
Extrusion of premolars & canine
Intrusion of canine

Jayade’s modification
Mild gingival curve in the anterior section from
mesial of cuspid circle on one side to the other
It should lift the arch wire at the midpoint by 3mm
over the brackets

The bend causes an inward tilting of the cuspid
circles and the posterior sections
Arch contouring plier is used to plane the cuspid
circles

A vertical step-up bend of 4-5 mm height is placed
2-3mm mesila to molar tube
Anchor bend is placed at the upper end of the step
Step-up bend converges occlusally to avoid trauma
to gingiva

The step-up bend applies intrusive force high
above the occlusal plane
The vertical step-up & the tip back intrude canine
Anterior gingival curvature intrude incisors

Burstone

Ref: Charles R.Burstone; Deep overbite correction by intrusion; AJO 1977;Jul;1-22
BURSTON
E
segmented arch mechanics
3 parts
a posterior anchorage unit
an anterior segment
an intrusive arch spring

Burstone’s intrusion arch
Posterior segment Anterior segment
Intrusion spring

BSS
Lingual
arch
High pull
Head gear
Posterior anchorage unit

Intrusive arch spring
0.018” x 0.022” / 0.018” x 0.025” SS
3mm helix wound 21/2 times & placed
mesial to the aux. tube
Incisal curvature lies gingival to
the central incisors
Gentle curvature increasing towards
helix
BURSTON
E

Six major principles of intrusion . . .
1.Force – less magnitude & constant
2.Anterior single point contacts
3.Point of force application & CRES
4.Selective intrusion based on anterior tooth
geometry
5.Control over reactive units with post.anch.unit
6.Avoid extrusive mechanics
BURSTON
E

Principle 1
Force – less magnitude & constant
Problems with increased force magnitude
Decreased rate of intrusion
Increased rate of root resorption
Increased reciprocal vertical force on molars
100g recommended

To achieve 100g of constant force . . .
Low load deflection wire
Helix - 2 ½ turns & 3m diameter
Activated 16.5mm delivers 100g
For 1mm intrusion change in force magnitude
is 6g – relatively constant force achieved
Long perpendicular distance from incisors to aux tube
- Intrusion spring of 30 mm LLD of 6g/mm

Force levels Upper Incisor 20 – 25 g
Lower Incisor 5 - 10 g
Canine 50 g
1mm deflection generates 6g force
100g needs 16.5 mm of deflection
25
25 25
25
100g

CRES
16.5 mm
1mm deflection generates 6g force

Arch wire engaged by considerable deflection

Principle 2
Anterior single point contacts
Disadvantages of engaging IA in brackets
Anterior torque
labial root torque – intrusive force increased →anchor loss
lingual root torque – intrusive force decreased/reversed
Unwanted curvatures forms during activation
Statically indeterminant force system

Advantages of single point contacts
Statically determinant force system
Allows placement of series of anterior alignment
arches
Principle 2
Anterior single point contacts

Principle 3
Point of force application (PFA) & CRES
Intrusive force through the CRES does not produce
any labial / lingual rotation of teeth.
The CRES of the anterior segments lie at geometric
centers of the roots of the incisors to be intruded

Proclined Normal
CRES
+ve
+ve
PFA thru’ CRES Tie IA back

Proclination Normal inclination
PFA thru’ CRES
Anterior segment with
distal extension
Sectional intrusive
springs (L&F)
IA tied back to
prevent protrusion

Principle 4
Selective intrusion
This has to be considered in class II DivII &
Div I cases with retroclined and extruded incisors
Arch leveling should not be by extrusion of
laterals but should rather be by intrusion of
centrals ( class II Div II )
Arch leveling should not be by extrusion of
canine but should rather be by intrusion of
incisors ( Class II Div I )www.indiandentalacademy.com

Principle 5
Control of reactive units
Reactive unit refers to the posterior unit
Minimization of the force magnitude offers
good control of posterior unit
A large moment arm b/w ant. & post. demands
additional control measures i.e,.max anchorage

Posterior unit
Why maximum anchorage?
Side effects due to intrusion
steepening of the occlusal plane
extrusion of molars

steepening of the occlusal plane
Intrusive
force
moment
M = F x D
Distal tipping
Exsisting OP
Steepened OP

extrusion of molars
Lingual tipping
TPA
Anchorage control
transverse plane
Strong consideration in vertical growth
-ve moment-ve moment -ve moment-ve moment
0.036” SS

Posterior anchorage unit
buccal stabilizing segment
0.018”x0.025” / 0.021”x0.025”
transpalatal / lingual arch
occipital headgear
Distal tipping
Extrusion
Distal tipping & Extrusion

Principle 6
Avoid extrusion mechanics
Class II & Class III intermaxillary elastics
Cervical head gear with outer bows placed high
applied to maxillary arch
Extrusive mechanics are . .
Reverse curve of spee in the lower arch wire to
extrude premolars
Ref: Charles R.Burstone; Deep overbite correction by intrusion; AJO 1977;Jul;1-22www.indiandentalacademy.com

Distally tipped canine…..to be bypassed
Extrusion
Principle 6
Avoid extrusion mechanics

Ricketts

Rickett
s
Utility arch . . .
0.016” X 0.016” / 0.022” blue elgiloy
in 0.018 slot
Design includes molar segment, posterior
vertical segment, vestibular segment & anteiror
vertical segment, incisal segment
Ref: Ricketts R.M ;Bioprogressive Therapy US:Rocky Mountain.1980:183-199

Rickett
s
Utility arch . . .
Molar segment extends into the tube on the 1st
/ 2nd
molar
30-45 degrees of molar rotation bend
45 degrees of buccal root torque
30-45 degrees of molar tipback bend
Molar segment

Rickett
s
Utility arch . . .
Formed perpendicular to molar bend
3- 4 mm length in mandible & 4-5 mm in maxilla
Posterior vertical segment

Rickett
s
Utility arch . . .
Formed by placing a right angled bend at the
inferior part of posterior vertical segment
Passes anteroinferiorly along the gingival margin
Vestibular segment

Rickett
s
Utility arch . . .
4-5mm height in mandible
This can vary with individuals
Anterior vertical segment
5-8mm height in mandible

Rickett
s
Utility arch . . .
A final 90 degree bend creates an incisal bend
Incisal segment
This lies passively in the brackets of anterior teeth

Rickett
s
Utility arch . . .
A final 90 degree bend creates an incisal bend
Activation
This lies passively in the brackets of anterior teeth

Why blue Elgiloy?
Elgiloy is a Co-Cr-Ni wire developed in 1950s by
the Elgiloy corporation ( USA )
They are color coded by the manufacturer :
Blue – soft
Yellow – ductile
Green – semi resilient
Red - resilient
Similar in composition but differ in wire processing
Blue elgiloy is popular among orthodontists
Rickett
s
Ref: WA.Brantley & Eliades ;Orhtodontic Materials;Thieme;Sttutgart NY 2001

Plus points of blue Elgiloy
Ease of manipulation – soft feel – low YS
Force delivery and joining characters similar
to SS
Modulus of elasticity similar to SS
Can be heat treated to increase its yield strength,
resilience & modulus of elasticity
Ref: WA.Brantley & Eliades ;Orhtodontic Materials;Thieme;Sttutgart NY 2001

Mulligan

Mulliga
n
Ref: Graber & Vanarsdall ; Orthodontics current principle & techniques;768-771
Employs the “cantilever principle”
Popularly described as “Diving Board Concept”
0.018” A.J.Wilcock SS wire
Design includes a helix mesial to molar tube
with an anchorage bend

How common sense avoids
molar distal tipping?
Arch wire tied securely to the molar tubes does not
allow tip back bend to tip molar crown distally
It brings out mesial root movement of molars
instead
This is advantageous as most of the class II
malocclusion requires molar uprighting
Crown movement precedes root movement
Ref: Thomas F.Mulligan ; common sense mechanics 6;JCO 1980;Feb;98-103

overlaywww.indiandentalacademy.com

KSIR

KSI
R
Introduced by Varun Kalra in 1998
Ref: Varun Kalra ; Simultaneous Intrusion & Retraction Of The Anterior Teeth;
JCO 1998;Sep;535-540
KSIR – Kalra Simultaneous Intrusion & Retraction
The mechanism is based on the space closure
mechanics advocated by Burstone
Easy fabrication,Easy adjustment,
& Patient comfort

KSI
R
Continuous 0.019” X 0.025” TMA
JCO 1998;Sep;535-540
7mm X 2mm U-loops incorporated at extr.
sites
3 bends
90° V-bend
60° V-bend
20° anti rotation bend

KSI
R
JCO 1998;Sep;535-540
Why TMA ?
Sufficient strength to resist distortion
Excellent formability
Titanium Molybdenum Alloy
Delivers low forces compared to SS & CrCo
Sufficient stiffness to generate moments
Activated twice of SS without permament
deformation

KSI
R
JCO 1998;Sep;535-540
Why Loop ?
Frictionless
mechanics
Space closure of extraction site
Increases the span of wire - LLD

KSI
R
Why bends ?
Placed at the level of each U- Loop
90° V-bend . . .
Centered b/w 1st
molar & canine creates 2 equal
and opposite moments
This counters tipping movements caused by
loop activation

90° V-bend . . .

KSI
R
Why bends ?
60° V-bend placed posterior to the center of
interbracket distance
60° V-bend . . .
Produces an increased clockwise moment on
first molar
This augments molar anchorage & incisor
intrusion

60° V-bend . . .

KSI
R
JCO 1998;Sep;535-540
Why bends ?
To prevent the buccal segments rolling
mesillingually due to the force produced by the
activation
20° antirotation bend . . .
This bend is placed in the archwire just distal
to each U-loop
This augments molar anchorage & incisor
intrusion

20° antirotation bend . . .
JCO 1998;Sep;535-540

Fabrication . . .
JCO 1998;Sep;535-540

Done extraoral
releases built stress
severity of bends↓
Neutral position 3.5mm wide
After trial activation
Trial activation . . .
JCO 1998;Sep;535-540

Insertion . . .
Archwire is inserted in the auxillary tube of 1st
molars
Engaged in the six anterior brackets
Activated about 3mm so that mesial & distal legs of
loop are barely apart
Premolars are bypassed for biomechanical purpose
JCO 1998;Sep;535-540

When loops are first activated greater tipping moments
are generated
Mechanism of action . . .
This cause controlled tipping of the teeth into extraction
space
As loops deactivate and forces decreases moment –to-
force ratio will increase to cause bodily movement and
then root movement
Thus frequent reactivation not recommended
( once in 6-8 weeks until all space closed )
Arch wire left in place for 4-5 months
JCO 1998;Sep;535-540

From the author’s gallery . . .
JCO 1998;Sep;535-540www.indiandentalacademy.com

Connecticut

Designed by Ravindra Nanda, Robert.M
& Andrew.K
Inmates of university of Connecticut
health centre, Farmington
Ref: Ravindra Nanda et al. The Connecticut Intrusion Arch JCO 1998 Dec 708-715
Connectic
ut

Connectic
ut
Appliance design
0.016” X 0.022” / 0.017” x 0.022” NiTi
Anterior dimensions max-34mm;mand-28mm
UTLD molar tubes
Auxillary tube 0.018”x0.025”
TPA -added anchorage/maintain buccal width
Ref: Ravindra Nanda et al. The Connecticut Intrusion Arch JCO 1998 Dec 708-715www.indiandentalacademy.com

DIMENSION
Connectic
ut
Anterior dimension is the length of wire b/w bypasses
&distal to lateral incisors
Posterior dimension is the length of wire b/w each
bypass & the tipback bend on the same side

Connectic
ut
Why NiTI?
Shape memory
Spring back
Light continuous forces on large activations
Low load deflection
Reduced number of reactivations

Connectic
ut
Mechanics
Force is delivered from a calibrated V-bend
40-60g of force generated
V-bend lies just anterior to the molar tubes
Following activation intrusive force in the
anterior & moment in posterior is generated
V - BEND www.indiandentalacademy.com

Connectic
ut
Mechanics
1mm of intrusion / month is achieved
Molar side effects may be counteracted with
head gear
Single point contacts with incisors
Incisor flaring is avoided by tight cinch backs

Connectic
ut
Steps in use
CTA is tried in to determine length
Cut off excess wire protruding from the molar
tubes leaving 3mm/side for cinch backs
A section of wire is inserted into incisor barckets
Appropriated length of CTA is selected
Insert posterior legs & tie anterior part at lateral
incisor & between the central incisors

From the author’s gallery . . .

Comparison of intrusion arches
Compared five intrusion arches
Ref: DivakarKaranth & SurendraShetty;Comparative Study Of Various Intrusive Arches
JIOS 2001;34:82-91
Anchorage bends
Burstone’s intrusive arch without helix
Burstone’s intrusive arch with helix
Mulligan’s intrusive arch
Ricketts intrusive utility arch
1
2
3
4

Comparison of intrusion arches
Concluded that….
Ref: DivakarKaranth & SurendraShetty;Comparative Study Of Various Intrusive Arches
JIOS 2001;34:82-91
Anchorage bends exerted maximum force
Burstone’s intrusive arch without helix
Burstone’s intrusive arch with helix
Mulligan’s intrusive arch
Ricketts intrusive utility arch

Biologic hazards

Pulpal alterations like vacuolization of
odontoblasts layer
Nonvitality of pulp
Apical root resorption –continuous heavy forces
Adults
Dens invaginatus, blunt root
Risk factors
Endodontically treated
Incisors

Thank you.

MOLAR TRIPLE TUBE
HEAD GEAR T.
ARCH
WIRE T.
AUX.T.
.018” ×.025”
Connectic
ut

MAND MOLAR DOUBLE TUBE
ARCH
WIRE T.
AUX.T.
.018” ×.025”www.indiandentalacademy.com

Proclined Retroclined
CRES
+ve
-ve
PFA thru’ CRES PFA thru’ CRES

Thank you
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Intrusion in orthodontics /certified fixed orthodontic courses by Indian dental academy

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