Edgewise Technique 1 /certified fixed orthodontic courses by Indian dental academy

EDGEWISE APPLIANCE

INDIAN DENTAL ACADEMY
Leader in continuing dental education
www.indiandentalacademy.com

Contents :Evolution / Historical perspective
1) Bandelette appliance
2) Angle’s E–arch
3) Pin &Tube appliance
4)Ribbon arch appliance
5) Edgewise appliance
Attachments
Modification of edgewise brackets
Evolution of buccal tube


Bracket placement &angulation
Evolution of the technique
-Primary edgewise
-Secondary edgewise
-Tertiary edgewise
Ideal arch form
Three orders of tooth movement
Tweed’s philosophy of treatment
Anchorage preparation
Aims & goals of treatment
Diagnostic facial triangle
Growth trends
General plan of treatment
Merrifield’s modification


Evolution of appliance
First attempt at tooth movement in1728 by a French
physician Pierre Fauchard
Bandalette appliance-crude alignment of teeth by
expansion of the dental arches
Disadvantage : lacked stability
no effective means of firmly fixing it in position


1849-Dwinelle developed jack screw
1871-Magil introduced dental cements to attach
bands on teeth
1866-Kingsley advocated the use of extraoral
forces
No attempt was made to correct malocclusion by
placing teeth in a stable soft tissue environment
Angle believed that teeth when moved into their correct
occlusal relationship,stability would be assumed


The E arch
appliance(1880)
First typical orthodontic fixed
appliance
Rigid framework –Molar bands with
heavy labial arch wire soldered
to them,
Teeth tied to it by means of brass
ligature wire
Crown movement & simple
anchorage
Teeth were expanded into normal
occlusion


4 different designs:
 Basic E-arch
 Ribbed E-arch
 E-arch without threaded ends that fit into molar
sheaths ,used with an attached ball for high pull head
gear in the incisor area
 E-arch with hooks for intermaxillary elastics
Also had a maxillo mandibular growth
guidance
Disadvantages :1) correction of axial inclination could
not be accomplished
2)long term retention was required


The Pin &Tube
appliance(1912)
Ideal arch of E-arch was not
there
Arches were altered as tooth
movement carried out
progressing towards ideal
archform
Bands with tubes soldered on it
Pins soldered on the archwire &
made to fit into tube perfectly
Change position of pin ,solder it
again on archwire to a
different position & fit into the
tube again
Disadvantage:difficult to solder
& unsolder pins
time consuming


Ribbon arch appliance

(1915)

To overcome disadvantage of
pin & tube
Brackets with vertical slot
introduced
Archwire initially confirmed to
malocclusion ,held in place
by brass pins
Rectangular wire with longer
dimension vertical
Overcame 2 major problems:
1) archwire placement
2) M-D movement of
teeth
Teeth were free to move along
the archwire like strings of
beads

Teeth could tip M-D ,even with lockpins
Angle devised cleats to be soldered to archwire to
contact the sides of the bracket
Held the teeth upright ,but necessitates soldering new
cleats at different locations
Disadvantage:-relatively poor root control
-mesial & distal tipping bends could not
be incorporated
- enmass movement of teeth in an anteroposterior direction was not easy


The Edgewise
appliance(1925)
Solution to all problems –latest &
best in orthodontic mechanism
Changed the form of bracket
located the slot in the center
& placed it in a horizontal
plane instead of a vertical
Bracket wide mesio-distally
Rectangular slot for rectangular
archwire
.022x.028 slot size ,Same size wire
Archwire inserted in narrowest
dimension -EDGEWISE
Initially called open face or tie
brackets
Archwire held with brass ligature &
S-S ligature later


Accessories used in edgewise


Types of headgear used:High pull :- intrusion of maxillary incisors
increase the lingual root torque
used with cl.II elastics
Intermediate pull headgear :- distalise maxillary
dentition when bite is not deep
hold the maxilla during anchorage
preparation
Low pull headgear :- open bite case
support mandibular dental arch in
older patients
The Kloehn cervical gear:- growth trend is type A or C
restricting the maxillary growth so that
mandible can catch up

Angle "malocclusion must be treated s.t.the
denture is a self-sustaining ,self maintaining
unit and all parts of denture exerting or
sustaining forces must be perfectly balanced”
1) fully normal proximal contact relations of
teeth
2) normal cusp & inclined plane relation
3) normal upright axial position & relation of
teeth
this is essential if the teeth are to balance
with the muscles & sustain the forces of
occlusion

Angle introduced the bracket 2 yrs.before his
death
Proposed nonextraction treatment for all
malocclusion
Expansion of the dentition –method of teeth
alignment
Muscular balance was upset,teeth were moved
to an unstable positions-------high frequency
of relapse
Little attention to establishment of anchorage


Graduated from an Angle
course given by George
Hahn in 1928
Tweed diagnosed & treated
cases under Angle’s
guidance
He held to Angle’s firm
conviction that one must
never extract - for 3 yrs.
High frequency of relapse –
discouraging
Important observation1) facial balance &post
treatment success related to
upright mandibular incisors
2) to get lower incisors
upright ,one must prepare
anchorage & extract teeth


His technique can be summarised as an anchorage
technique
While most operators were concentrating on how best
to move teeth ,he focused himself on how not to
move teeth
To a great extent “cart has been placed before the
horse”,Dr Tweed placed the horse where he
belongs ,in front of the cart
Angle gave orthodontics the edgewise bracket ,but
Tweed gave the speciality the appliance


Among his other contributions :a)Emphasized the four objective of orthodontic treatment with
emphasis & concern for facial esthetics
b)Developed the concept of up righting teeth over basal bone
esp.lower incisors
c)Made the extraction of teeth for treatment acceptable
d)Enhanced the clinical application of cephalometrics
e)Developed the diagnostic facial triangle to make cephalometrics
a diagnostic tool & a guide in treatment & evaluation of results
f)He developed the concepts of orderly treatment procedures
&introduced anchorage preparation as a major step in
treatment
g)He developed a fundamentally sound & consistent preorthodontic
guidance program using & popularizing serial extraction of
primary & permanent teeth

Over the years several modifications in the appliance
Angle advocated Non–extraction treatment
Basic concepts which are cornerstones of modern
edgewise orthodontics:1)Ability to obtain tooth movement in all 3 planes of
space with a single archwire
2)The philosophy of treating to an ideal arch or to
Angle’s concept of ‘Line of Occlusion’
The line with which ,in form and position according to type,the teeth
must be in harmony if in normal occlusion.

3)The use of rectangular or square edgewise arches
which if properly employed can control arch
width ,arch form ,B-L crown inclinations,axial root
inclinations & incisor crown-root torque

Types of head gears
High pull:- Intrusion of maxillary incisors
Increase lingual root torque
Used with cl. II elastics
Intermediate pull:-Distalize maxillary denture when bite
is not deep.
Hold the maxillary arch when using
cl.III elastics during anch.preparation
Low pull:- In open bite cases
To augment anchorage in mandibular arch in
adult patients
The Kloehn cervical gear:-restricting maxillary growth to allow
mandibular growth in growing patients

ATTACHMENTS
Evolution of edgewise brackets
Original bracket – soft gold , .
022 x .028 inch slot
1)Single width brackets
original bracket .050 inch
wide & soldered to the gold
band material
archwire rests on bottom of
bracket slot instead of the band
ineffective for tooth rotation
because of the narrow width
Angle devised gold eyelets to
be soldered on bands

2)Twin brackets
- two brackets on one base
-“Siamese twin brackets” by Swain
- space between two brackets was
.050 inch (equal to width of one
bracket )
Main advantage :
- ability to effect tooth
rotations without using
auxiliaries
Available in different widths:
Extra wide

Standard

Intermediate

Junior


3)Curved base twin
bracket
curved bases to confirm to
the curvatures of the canines
& premolars
Advantages of twin brackets :
Offers a positive control
Disadvantages:
increased width decreases
the inter bracket span ,thus
decrease the resiliency


4)Lewis bracket
Developed by Lewis in 1950.
To overcome the problem of
efficient tooth rotation.
He soldered auxillary rotation
arms that abutted against
the bracket itself thus,
offered a lever arm to deflect
the archwire & rotate the
tooth.
One piece bracket with integral
rotation wings
These wings do not interfere
with occlusogingival
deflections of archwire & do
not decrease the
interbracket span

5)Curved base Lewis
bracket
Curved base confirms to
the canine ,premolar
surface
Wings lie close to the
tooth throughout their
length ,so less trapping
of food


5)Vertical slot Lewis bracket
Incorporation of .020 x .020 inch vertical slot
Possible to use uprighting spring to correct axial
inclinations if needed
Advantages of Lewis brackets:
1) complete rotational
control
2)do not reduce the
interbracket span


Steiner bracket
Given by Cecil C Steiner in 1931
Incorporated flexible rotation arms & so did not rely on
the resiliency of the archwire for tooth rotation
Introduced tie wings for ease of ligation

Broussard bracket
Designed by Garford Broussard
for use in the Broussard
technique
Addition of a 0.0185 x 0.046
inch vertical slot to accept a
doubled 0.018 inch auxillary
wire

Evolution of edgewise buccal tube
Original appliance had .022x .028 inch gold or nickel
silver tubing soldered to the molar band
Length –3/16 or ¼ inch
Notched distal ends- to facilitate a tie back ligature
Hook –gingival to buccal tubes ,soldered on the bands
for placement of elastics
Inconel tube- gold buccal tubes were discarded
Stamped buccal tube with welding flanges or
Inconel tube which could be soldered to the band

Combination buccal tubes
Incorporates a round tube for
insertion of a face bow
Fairly close tolerances must be
maintained between
archwire & tube for effective
transmission of torque to the
tooth

Triple buccal tube
additional rectangular tube for
auxillary sectional & base
archwire


Bracket & tube placement
Angle“goal of correct bracket & tube placement is to
produce an ideal occlusion at the end of treatment
with flat ,straight ,ideal archwires
Tweed advocates – millimeter measurement from
bracket slot to the incisal edge
UPPER ARCH
LOWER ARCH
Centrals –4.5
Laterals –4.0
Canines –5.0
Premolars-4.5
Molars –3.5

Anteriors-4.0
Canines-4.5
Premolars-5.0
Molars-4.0


Bracket angulation
Brackets –parallel to the long axis of the tooth
Holdaway (1952) described three uses for bracket
angulation
a) as an aid in paralleling roots adjacent to extraction
spaces
b) as a method of setting up posterior anchorage
units into tipped back or anchorage prepared
positions
c) as a means of obtaining correct axial inclinations or
artistic positioning


Evolution of technique
Primary edgewise
*as described by Angle in 1929
*fully banded technique-gold bands ,soldered soft
brackets
*flat ideal arch wire -to provide normal occlusion
*original arch was of .022 X .028 in.gold wire
*to be adapted passively to all malocclusion
*if space had to be made ,loops are soldered onto
main arch
*if space closure required , spurs & tie backs used
*involves all the teeth to be brought under control
so,treatment should be initiated after eruption of
canine & premolar

Secondary edgewise
*to avoid the making archwires passive
*use of round wires in the initial stages
*gold was replaced by a more rigid alloy
*frequency of extractions increased
*bands with prewelded brackets
*in 1940s round .045in.tubes were also soldered on
the upper molars for a face bow


Tertiary edgewise or Tweed’s edgewise
*stressed on the importance of anchorage
preparation
*advocated the use of cl. III elastics & extraoral
traction
*vigorous forces were now employed
*space closure was done by simple vertical or
horizontal open loops bent into the archwire or by
push coil tie -backs


Tweed’s philosophy
Based on the following :a)

Practically all malocclusions are characterized by a
forward adjustment of teeth in relation to their basal
bones --- this is due to deficiency between the
basal bone & tooth material

b)

The establishment & maintenance of a stable
anchorage should be the initial concern of the
operator & is a fundamental factor in successful
orthodontic treatment

c)

Teeth like inanimate objects ,best resist the force of
displacement when tipped to the angulation that
offers the most advantageous mechanical against
the pull of dislodging forces .they are best stabilized
when they overlie the basal bone

d)Teeth are most readily moved when their property &
power of mechanical resistance has been primarily
reduced
e) All forces emanating from an orthodontic appliance
must be synchronized if they are to be most effective
in the mass stabilization or the mass movement of
teeth
f) Nature being an expert mechanic herself ,offers
biologic compensations & adjustments when teeth
are placed in position of mechanical advantage for
force resistance
g) The dental units will best resist forward displacement
when the buccal teeth are in mild distal axial position
& the incisor teeth are in mild lingual axial inclination
& overlying a substantial bony foundation
“placing the incisors on the ridge”

Every malocclusion exemplifies a denture that is
stabilized by balanced muscular forces & this
muscular balance must be preserved in treatment if
stability in the end result is to be accomplished
( Strang & Thompson )


Facial types
Tweed divided the facial types into following
types:TYPE A :-Maxilla & mandible show forward &
downward growth
-ANB angle remains the same
-Prognosis is good
-Treatment not indicated during mixed
dentition if ANB angle does not exceed 4.5
TYPE A Subdivision:- ANB angle greater than 4.5


TYBE B :- Maxilla & mandible grow downward &
forward with maxilla growing more rapidly
than mandible
- When ANB angle is 4.5 or less
prognosis is favorable
- Extraoral appliances should be
used immediately after extraction
TYBE B Subdivision :- ANB is large & found to
be increasing
-Undesirable growth trend,
treatment long & difficult


TYPE C :- -Maxilla & mandible grow downward &
forward with mandible growing more than
maxilla
-ANB increasing
-Growth is favourable & treatment is
facilitated by growth
TYPE C Subdivision :- mandible grows more than
maxilla but only to a little extent


Tweed’s Diagnostic facial triangle
Basis for diagnosis & treatment planning
Consists of the following :1) FMA –the Frankfort mandibular plane
angle
2) IMPA –the incisor mandibular plane
angle
3) FMIA – the Frankfort mandibular incisor
angle


Angle
FMA
Visual
25
cephalometric 24.57
Range
15 – 36

IMPA
90
86.93
76 – 99

FMIA
65
68.20
56 – 80

For successful treatment triangle should be attainable
Aim should be to obtain:FMIA of 70° – 75° ( when FMA = 20 )
FMIA of 65°
( when FMA = 30)
When FMA is less than 20° FMIA should be more than 70° & IMPA should not
exceed 94°


He showed that in well balanced faces – IMPA was
90°±5°
For every degree that FMA was in excess of 25° .the
incisor mandibular angle IMPA would have to be
decreased by 1°
Treatment objectives :Facial balance & harmony
Stability of the post treatment dentition
Healthy oral tissues
Efficient mastication


Stable anchorage –important to prevent forward movement of
mandibular denture when cl.II intermaxillary force is applied
On histological basis Brodie (1937) believes that the strongest
anchorage is provided by stable fixation of teeth –to allow as
little movement as possible
Tweed – anchor teeth best resist the dislodging forces when their
vertical axes are parallel to the direction which offers the most
advantageous mechanical resistance against the pull of
dislodging forces


Strongest anchorage is provided by tipping back the crowns of the
teeth so that they will have a disto-axial inclination that will resist
a forward pull
First & most important step in treatment - Anchorage preparation
If anchorage preparation is not done -the action of intermaxillary
elastics cause elevation of terminal molars & depression of
mandibular incisors.
Thus,canting of occlusal plane,
increase in FMA ,
point B drops downward & backward ,
entire mandibular denture is tipped & displaced forward into
protrusion

Classification of anchorage preparation
First degree- minimal anchorage preparation,
-applicable to all malocclusion with ANB =0
to 4 ,
-total discrepancy does not exceed 10
mm,
-terminal molars must be uprighted & or
maintained in an upright position to
prevent their being elongated when cl. II
intermaxillary force is used .

Second degree-for malocclusions with ANB more than
0° to 4°
-facial esthetics requires to move point
B anteriorly & point A posteriorly i,e
cl. II cases
-usually accompanied by type A, type A
subdiv.,type B & type B subdiv.
-degree of distal tipping of mandibular
molars more severe than first degree
anch.prep. –they should be tipped so
that their distal marginal ridges are at
gum level

Third degree –severe discrepancy cases –14-20mm or
more
-ANB does not exceed 5°
-generally cl.I bimaxillary cases
-sliding jigs are necessary
-2nd ,1st molars & 2nd premolar must be
tipped to such an extent that the distal
marginal ridges are below the gum level
also called total anchorage preparation


Ideal arch form-

orthodontic arch is the form
which moulds the dental
arch with every bend
reflected in the position of
the teeth
Angle “ if an archwire is placed
in brackets with uniform slot
depths,it must take the form
of the outline of the buccal &
labial surfaces of the teeth”
Unique alignment of upper
lateral incisor –thinner labiolingually & short crown
length


Contact points lie on an ellipsoid curve
There is a straight line from canine to mesio buccal
cusp of first molar,but the beyond that it curves
inward progressively
Bonwill-Hawley diagram is widely used to decide arch
form


Bonwill-Hawley diagram is widely used to decide arch
form

General pattern –decided by studying the original
models & of the muscle behavior of the patient rather
than based upon widths of teeth themselves

Three orders of tooth movement
Movements necessary to bring the teeth into the line
of occlusion –first ,second ,third orders
First order bends-horizontal change relative to the line of occlusion
-also called in -out bends
-do not alter the horizontal plane of the wire
-the action & reaction of these bends affect
expansion or contraction
-used to move individual teeth
-the interaction of bends can affect the third order
position of the teeth if expansionary forces are used

Second order bends
-represent a vertical
change
-also called
tip/angulation
-used to tip posterior
teeth mesially or
distally-may be
tip back or tip forward
bends


Third order bends
-torsional change (with the line of occlusion
serving as axis)
-also called torque or inclination movement
-used to obtain axial changes in the buccolingual or
labio-lingual root & crown axis on one or
more teeth
There are two types of torque
1)passive
2)active

Tweed summarised his philosophy on which his
appliance therapy is based:i) Normal occlusion is best maintained with the mandibular
incisors in their normal axial inclination when related to the F-H
plane approx. 65°(FMIA)
ii) The ultimate in balance & harmony of facial esthetics is
achieved only when the mandibular incisors are positioned over
the basal bone
iii) The normal relationship of the mandibular incisors to their
basal bone is the most reliable guide in diagnosis & treatment
of cl. I ,cl. II &bimaxillary protrusion cases and also in
attainment of balance & harmony of facial profile & permanence
of tooth position


General plan of treatment
Treatment divided into 3 phases:a)Anchorage preparation
b)Distal enmasse movement of maxillary buccal
segments
c)Establishing correct denture form & completing
treatment objectives
Anchorage preparation involves:1) placing mandibular incisors upright
2) changing axial inclinations of the maxillary incisors,
to make them less resistance to distal movement
3) changing the axial inclinations of buccal teeth to a
more distal axial inclination

Extaction treatment
a)Leveling of arches
.o18 in. wire with molar
stops /tie back spurs at
the molar tube & distal tip
back bends in posteriors
cl. III elastics & headgear
Working arches U/L .019 X .
025 in. with mild second
order bends
Uprighting of canines-horizontal
loops soldered mesial to
second premolars


Uprighting of canines-horizontal loops soldered mesial
to second premolars
Canine bracket is not engaged in the wire


.021 X .028 stabilization wire
with mild second order
bends in upper arch
.019 X .028 in working wire in
lower arch with tip back
bends & sliding jigs to bear
pressure on 2nd premolar
bracket
cl. III elastics are worn
Once anchorage preparation
done – reverse the
mechanics
cl. II elastics are worn


Distal movements of canines & incisors
U/L .019 X .025 archwires with second order bends &
open coil springs compressed mesial to canines are
inserted
cl. III elastics aid in distal movement of mandibular canine
Headgear applied to upper arch aids in upper canine retraction


Incisor retraction
Using .019 X .025 archwire with closed Bull loop distal
to canine –activated 1mm every 3 wks.
Mandibular incisors are retracted to an FMIA of 65° in
cl.I cases & 70° in cl.II cases
Maxillary incisor retraction completed –heavier .021 X .
027 in.wire ,reduced posterior to lateral incisors &
passed free of canine
Strong lingual root torque in upper anteriors for bodily
retraction


Stops are soldered 3mm mesial
to 2nd premolar brackets
Coil springs compressed
against the stops


Correction of cl. II relationship
Now , mand.arch -.021 X .028 in.
max.arch -.019 X .025 in. with accentuated tip
back bends
Mand. arch tied back to receive cl. II elastics –continued
till normal cusp relation is achieved


Completion procedure
Final space closure & detailed tooth positioning -.019
X .026 in. max. & mand.ideal arches ,coil springs
compressed mesial to 2nd molar tubes until space
closure is completed
Vertical elastics are used for seating cusps if bite is
open


cl. II div.1 –non-extraction treatment
Preparation of anchorage in the lower arch
 Preparation of anchorage in the upper arch
 Distal enmasse movement of maxillary arch
 Detailed positioning of teeth
ANCHORAGE PREPARATION
Initial leveling & alignment - .016 or .018 round wires
Working arch wire .019 X .025 in. with coordinated tip
back bends
cl. III intermaxillary hooks soldered mesial to canine
Loop stops are made mesial to molar tubes but the
archwire not tied to molar anchor teeth



Upper arch is stabilized -.021 X .028 in.wire with mild tip
back bends
Intermediate pull headgear mesial to canine is used to
augment the anchorage - min. 14 hrs./day
Distal pull by headgear –twice as much as mesial pull
on the arch by cl. III elastics
During day – light cl. III
During night –heavy cl. III
Distal tip back bends increased slightly every 2-3 wks.


Stabilization arch -.021 X .028 in. wire with same
degree of tip back bends as in working archwire
Passive in mandibular incisor region
Total time required – aprrox. 4 mons.
Anchorage preparation in upper arch
Excessive inclination of the proclined upper incisors is
reduced by using .018 in. round wire
Important – this provides unfavorable stationary
anchorage & resist distal / lingual movement of the
teeth
Heavy stabilization wire with mild second order bends is
placed

Enmasse distal movement of maxillary arch
Upper arch wire -.021 X .028 in. reduced distal to
lateral incisors
Mild lingual crown torque if incisors are proclined
Intermaxillary hooks on archwire –patient put on cl. II
elastics
Watch out for mandibular anchorage –any signs of
mobility ,increase the tip back bends
After 3 wks. –tip back bends in the maxillary arch are
increased ,stronger elastic force is applied until
normal relation of teeth attained
Mild palatal root torque in anteriors
Continue till incisors in edge –edge relation & posteriors
in good occlusion

Detailed positioning of teeth
Proper seating of cusps is obtained by fitting correlated
U & L ideal arches carrying vertical spurs for vertical
elastics between them


Bimaxillary dentoalveolar protrusion
Two types of cases:1)Axial inclinations of all the teeth in the arch inclined
abnormally forward (both in cl.I & cl. II cases ),
Dental arches are more or less well aligned
2) Axial inclinations of teeth in buccal segments fairly
upright ,irregular & crowded
Steps in treatment: Anchorage preparation in lower arch
 Anchorage preparation in upper arch
 Extraction of four premolars
 Multiple loops .016 in. archwire U/L used for
alignment
 Space closure done using looped archwire

Treatment of cl.III malocclusion
Objective:1)To correct abnormal buccolingual inclination of all
posterior teeth in both arches
2)Constrict the mandibular arch which is too broad
3)Expand the maxillary arch which is too narrow
4)Move maxillary arch forward enmasse ,using
mandibular arch as stationary anchorage


Steps in treatment
Initial .016 in. round wires
After 2 wks. ,.021X .027 in. U/L ideal arches
Brass wire hooks mesial to canine
Mandibular archwire is bent considerably narrower than the ideal &
torque is placed in the buccal segment
Step forward 2nd order bends placed in maxillary posterior segment
(direct opp.of tip back bends)
Intermaxillary elastics from lingual of maxillary molar to hook
mesial to mandibular canine
When cross bite is corrected –archwires are reshaped to the ideal
Treatment continued until the maxillary teeth have moved forward
enmasse into occlusion with teeth in mandibular arch.


Leader in continuing dental education


Edgewise Technique 1 /certified fixed orthodontic courses by Indian dental academy

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