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5. DR.EDWARD HARTLEY ANGLE
►
The edgewise arch
mechanism was the brain
child of this master
technician.
►
By the time of
Dr.Tweed,1930,with the
introduction of milled
brackets, S.S ligature
wires it had evolved into a
precision appliance, that
demanded accurate fitting
and placement of bands
and attachments on teeth.
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6. INTRODUCTION
► The edgewise arch mechanism/appliance was
Dr Angle’s last and greatest contribution to
orthodontics ,after almost a lifetime devoted to
improvement of orthodontic appliances.
► Edgewise mechanism was designed to place
teeth into 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.”
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7. ANGLE’S PHILOSOPHY OF
TREATMENT
►
Based on the then prevalent assumption that, if cuspal
interdigitation of teeth were made normal, stimulation by
function would result in growth of basal bone structures.
►
Little or no thought was given to the inclination of the
mandibular incisor teeth or to normal mesiodistal relation of
teeth and their respective jaw bases and head structures.
►
It was assumed that function would take care of such
matters.
►
Extraction of teeth for orthodontic therapy wasn’t even an
option .
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8. ►
E.H. Angle – Graduation 1878, experienced many
technical problems and frustrations in treatment which
irritated, motivated and inspired him to develop a
standard appliance. His obsession for order motivated
him to create the Angle System (1887)
►
This ultimately resulted in the multi banded edgewise
appliance 5yrs before his death.
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13. THE STANDARD APPLIANCE
USED BY ANGLE
►
Basic components of
the standard
appliance used by
Angle:
Traction screw,
jack screw,
attachment tubes,
band material
ligature wire,
arch wire,
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15. ► Unique feature rectangular wire
in
rectangular slot twisting / torquing forces
could be imparted to control the axial inclination
of teeth
► So possible to move teeth in all 3 planes of
space with a single arch wire.
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16. ►
For rectangular wire to move teeth into the “line of occlusion”,
it had to be shaped into normal arch form and given proper
twist or torque for individual teeth.
►
Angle recommended use of smaller diameter round archwires
in the early stages of treatment.
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18. EVOLUTION OF EDGEWISE
BRACKETS
Original bracket –
► soft gold ,
► .022 x .028 inch slot
► Slot was readily deformed by the forces of
occlusion.
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20. DISADVANTAGE
►
Repeated tying of the eyelets for rotation.
►
Necessary to continue tying eyelets throughout treatment
to prevent relapse.
►
Tying rotation eyelets is time consuming.
►
Ineffective.
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21. 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 )
- Available in different widths:►
Extra wide
►
Standard
►
Intermediate
►
Junior
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27. 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
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28. ADVANTAGE
► These
wings do not interfere with
occlusogingival deflections of archwire & do
not decrease the interbracket span
► 100% of the desired tooth rotation is
possible.
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29. 5)Curved base Lewis bracket:► Curved base confirms to the canine, premolar surface
► Types:- Long
Short
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30. ADVANTAGE
► Wings
lie close to the tooth throughout their
length ,so less trapping of food
► Increases the surface area
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31. 6)Vertical slot Lewis bracket :►
►
Incorporation of .020 x .020 inch vertical slot
Possible to use uprighting spring to correct axial
inclinations if needed
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33. 7) 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
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34. ADVANTAGE
► Easy to tie
► Quite efficient for tooth rotation
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35. DISADVANTAGE
► Once permanent deformation of the arms has
occurred, complete rotation will not be effective
unless the arms are adjusted to their original
positions.
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36. 8)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
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37. EVOLUTION OF EDGEWISE
BUCCAL TUBE
►
►
►
►
1)Original buccal tube was a piece of .022x .028 inch
gold or nickel silver tubing soldered to the molar band
Length –3/16 or ¼ inch
Buccal tube is for the insertion and stabilisation of the
archwire.
Notched distal ends - to facilitate a tie back ligature
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38. Hook – gingival to buccal tubes, soldered on the
bands for placement of elastics
Inconel tube - gold buccal tubes were discarded
- is preattatched to the curved and
contoured welding flange.
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39. 2)Combination buccal tubes
► Incorporates a round tube for insertion of a face bow
► Posses sufficient rigidity to resist deformation from the
forces of occlusion.
► Fairly close tolerances must be maintained between
archwire & tube for effective transmission of torque to the
tooth
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40. 3)Triple buccal tube
► additional rectangular tube for auxillary sectional & base
archwire
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41. LIGATURE TIE WIRE
► Used to attatch archwire to the bracket.
► Dead soft .009 or .010 inch stainless steel ligature
wire is used.
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42. 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
►
Brackets were soldered to band strips with the slot
parallel to the band strip.
►
General rule was to place band strip with the
brackets parallel to the long axis of the teeth.
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44. ►
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
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45. REFERENCES
Orthodontics Current Principles and Techniques
- Thomas Graber , Robert Vanarsdall
Contemporary Orthodontics - William R. Proffit
Orthodontics Principles and Practice T.M.Graber
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