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3. Introduction
•Andrews published his land mark article in 1972 and subsequently
designed an appliance based on his findings.
However , soon after the introduction of pea , it became clear that
the bracket required a whole new program of treatment mechanics
and force levels to fully realize its potential .
•Appliance design and treatment mechanics are closely interrelated .
to some extent ,bracket design can be scientific and based on
research and clinical experience.
• But devolpment of treatment mechanics takes years and have to
based on experience with numerous treated cases .
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5. THE WORK OF ANDREWS
Andrews is regarded as father of pea system
When original swa became available in 1972 , it was based on science
but included many features of siamese edgewise brackets .
Although swa was radically new , traditional heavy forces continued
to be used .
No anchorage control measures .This may have been due andrews
clinical experience as an edgewise orthodontist.
He also emphasiszed wagon wheel effect where tip is lost due to
addition of torgue . henc he chose to add tip to anterior brackets.
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6. The bracket positioning was based on centre of clinical crown
because less wire bending was needed , there was a trend to standardize
arch form ,
roth recommended broad or square arch form
Andrews continued to use basal bone of mandible as an arch form
reference
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8. Difficulties with increased tip and heavy forces
resulted in lateral open bite this became to
Known as - “ROLLER COASTER EFFECT”.
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10. These experience led andrews to introduce a series of modifications
For extraction cases ,canine bracket
anti tip ,anti rotation and power arm
Different incisor bracket for varying degree of torque
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12. THE WORK OF ROTH
Following his experience with original swa . Roth
Introduced measures to overcome day to day shortcomings .
Roth was anxious to avoid the inventory difficulties of a multiple
bracket system . he therefore recommended a single appliance system
Which will manage both extraction and non extraction cases .
he emphasized the use of articulators for diagnostic records , for early
Splint construction and use of gnathalogical positioners
to get correct condyle position.
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14. THE WORK OF MCLAUGLIN AND
BENNETT BETWEEN 1975 AND 1993
They worked mainly with standard swa
Instead of initially modifying the basic bracket design , for more
than 15 years they developed and refined treatment mechanics
based on sliding mechanics and continuous light forces .
These mechanics were published initially as series of papers in
early 1990 and then as a book in 1993.
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15. Also lace backs and bendbacks for early anchorage control
Sliding mechanics on .019 x .025 steel rectangular wires , with light .
014 finishing wires.
Unlike andrews non extraction cases , many patients were children
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16. THE WORK OF MCLAUGHLIN, BENNETT
AND TREVISI -1993 AND 1997
•Mclaughlin and bennett then worked with trevisi to re design the
entire bracket system to complement their proven philosophy.
•They re-examined andrews original findings and took into account
research input from japenese sources when designing mbt bracket
system.
•This is third generation bracket system , it is a pea specifically for
use with light ,continuous forces, lacebacks and bendbacks and it
was designed to work ideally with sliding mechanics .
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17. Additional anterior tip was a disadvantage
In roth and swa :
• it created a significant drain on anterio posterior anchorage
• it increased the tendancy to bite deepening during aligment stage
•It brought the upper canine root apex too close to first premolar in some
cases.
• As lighter forces were being used in all stages of treatment this anti tip
or second order compensation wasnot needed in mbt system
•A total of 10 deg less distal root tip in upper ant segment and 12 deg
less tip in lower ant segmentis needed.
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19. THE PEA SYSTEM IS A DEVELOPMENT OF EDGEWISE
BRACKET WHICH IS RELATIVELY INEFFIENCENT IN
DELIVERING TORGUE.
SO IN MBT SYSTEM IT WAS NECESSARY TO BUILD EXTRA
TORQUE IN INCISOR AND MOLAR REGION .
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20. UPPER CANINE BRACKET WOULD BE AVAILABLE WITH 7, 0
-7 DEG FOR LOWER CANINE 6, 0 AND –6 DEG .
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22. THE WORK OF MCLAUGHLIN ,BENNETT,AND
TREVISI BETWEEN -1997 AND 2001
It became nessecary to address the subjects of arch wire selection and
force levels
Although an ovoid arch form had proved useful in the early years
three basic arch form tapered , square and ovoid would be of use.
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23. OVERVIEW OF MBT TREATMENT PHILOSPHY
•BRACKET SELECTION
•VERSATILITY OF BRACKET SYSTEM
• ACCURACY OF BRACKET POSITIONING
• LIGHT CONTINOUS FORCES
• THE .022 VERSUS .018
•ANCHORAGE CONTROL EARLY IN TREATMENT
• GROUP MOVEMENT
•THE USE OF THREE ARCH FORMS
• ONE SIZE OF RECTANGULAR STEEL WIRE
• ARCHWIRE LIGATION
• AWARENESS OF TOOTH SIZE DISCREPANCIES
• PERSISTENCE IN FINISHING
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24. Bracket selection
Standard metal , mid sized and clear bracket
Versatility of bracket system
To control inventory costs and avoiding needless wire bending.
Accuracy of bracket positining
gauges and individual bracket reposition charts are recommended.
Light continous forces
No clear defination and quantification .
Use of active tie backs , and .014 finishing wires.
.022 vs .018 slot
.022 is better as allows more freedom of movement of wires with
sliding mechanics.
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25. A
A
A
A
ANCHORAGE CONTROL EARLY IN TREATMENT
-Reduced tip ,
-light wire forces.
LACEBACKS AND BENDBACKS
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26. GROUP MOVEMENT
Crowding is resolved and then anterior segment moved as enmasse as
group of six or eight anterior teeth
The use of three arch forms
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27. ONE SIZE OF RECTANGULAR STEEL WIRE
.019X.025
THEORETICALLY , THERE IS APPROX 10 DEG OF SLOP , BUT
CLINICALLY WIRE PERFORMS BETTER DUE TO THE
RESIDUAL TIP IN WIRE
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33. TORQUE IN BASE THE COMPUTER AIDED DESIGN
FULL SIZE AND CLEAR - TORQUE IN BASE
MID SIZE- TORQUE IN FACE AND IN BASE COMBINATION
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34. IN OUT SPECIFICATION
UPPER SECOND PREMOLARS HAVE SMALL CROWNS
A BRACKET WHICH IS 0.5mm THICK
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43. THE VERSATILITY OF BRACKET SYSTEM
SEVEN MAIN VERSATILITY FEATURES
• OPTIONS FOR PALATALLY DISPLACED LATERAL INCISOR
•THREE TORQUE OPTIONS FOR UPPPER CANINE
• THREE TORQUE OPTIONS FOR LOWER CANINE
• INTERCHANGEABLE LOWER INCISOR BRACKETS
• INTERCHANGEBLE UPPER PREMOLAR BRACKET
• USE OF UPPER SECOND MOLAR TUBES ON FIRST MOLAR
IN NON HG CASES
• USE OF LOWER SECOND MOLAR TUBES FOR UPPER FIRST
AND SECOND MOLARS OF OPPOSITE SIDE
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