Concepts of bracket positioning techniques

Concepts of bracketConcepts of bracket
positioning techniquespositioning techniques
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Andrew’s Bracket siting proceduresAndrew’s Bracket siting procedures
Andrews emphasized that the accurate placement of the
brackets was an integral part of the straight wire appliance.
He suggested a bracket siting procedure, which was aimed
at targeting the slot within 2 degrees and 0.5 mm of the
precise placement over the slot site. (This is the area on a
tooth that would accept the bracket such that the bracket slot
would receive a ‘straight’ arch wire passively when the tooth
gets optimally positioned).

FACCFACC
For all teeth except molars, it is located at the
mid-developmental ridge that runs vertically and is the most
prominent portion in the central area of the labial or buccal
Surface.

Hence he reasoned that it should be possible for anyone with
average skill to draw with a pencil the FACC of crowns of all
the teeth, mark their midpoints and align the midpoint of the
base of each bracket with the FA point in such a way that the
sides of the brackets are parallel with the FACC.
He demonstrated that most of the people are able to
mark the midpoint of a line about 10mm in length (a
figure close to the length of FACC of a maxillary
central incisor) to the accuracy of within 0.5 mm.
Further, they can also judge the parallelism of two or
more lines within the accuracy of 2 degrees

Vari simplex disciplineVari simplex discipline
It is one of the pre adjusted edge wise system. It was introduced
in 1978 by Dr. R. G . Wick Alexander.
The name vari – simplex discipline was chosen after very much
thought
“VARI” means the variety of bracket types used ( twin, lewis an
lang)
Simplex refers to the KISS principle.
Discipline instead of appliance.

Bracket height :-
each bracket is placed at a predetermined position on each tooth
relative to the other teeth.
Bicuspid bracket height is the key because its clinical crown height
is so variable. Its normal bracket slot height is 4.5mm
Maxillary arch:-
Centrals – x
Laterals – x – 0.5
Cuspids – x+0.5
Bicuspids – x
First molars – x-0.5
Second molars – x-1
Mandibular arch
Centrals – x-0.5
Laterals – x-0.5
Cuspids – x+ 0.5
Bicuspids – x
First molars – x- 0.5

Roth’s prescriptionRoth’s prescription
In 1968, R . H ROTH was introduced to Dr. L.F.
ANDREWS.
He started designing his own prescription as a clinical
trial and error evaluation that lasted severed years.
Cases were evaluated by the use of
Intra oral photographs and
Mounted models for tooth positions
During treatment and at the end of
appliance therapy
( the straight wire appliance – 17 yrs later – Ronald H Roth Jco vol 1987sep(632-42)

Bracket placementBracket placement
standardstandard
MaxillaryMaxillary
1/11/1
2/22/2
3/33/3
4/44/4
5/55/5
6/66/6
4.54.5
4.54.5
4.754.75
4.54.5
4.54.5
3.753.75
21/1221/12
3/33/3
4/44/4
5/55/5
6/66/6
4.04.0
4.254.25
4.04.0
3.753.75
3.53.5www.indiandentalacademy.comwww.indiandentalacademy.com

MBT PHILOSOPHYMBT PHILOSOPHY
The MBT philosophy of orthodontic treatment has been
developed over a twenty yr period of time and has involved
the combined efforts of its three principle clinicians, Dr. Mc
Laughlin, Dr. Bennett, Dr. Trevisi
Their philosophy places emphasis on
1. Treatment mechanics
2. The preadjusted appliance
3. Bracket placement technique
4. Arch form and arch wire sequencing.
(Systemized orthodontic treatment mechanics McLaughin Bennet . Trevisi)

The use of a bracket placement chart was developed in 1994,
as well as Dougherty gauges, dramatically reduces bracket
placement errors in the vertical dimension.

Use of Bracket Placement Chart:-
1. Measure the clinical crown heights of as many fully erupted
teeth as possible from the patient's study casts, using dividers
and a millimeter ruler.
2. Divide each measurement in half and round to the nearest .5mm
to obtain the distance from the incisal or occlusal edge to the
center of the clinical crown.
3. Select the row in the Bracket Placement Chart that contains the
greatest number of equal values. Measurements for teeth that
are disproportionately large or small will differ from those in the
selected row, but will thereby be automatically adjusted.

4. Position each bracket initially by visualizing the vertical long
axis of the clinical crown (or the buccal groove of the molar) as a
vertical reference and the estimated center of the clinical crown
as a horizontal reference.
5. Use a bracket placement gauge to adjust the bracket heights to
the exact values from the chart. A light-cured adhesive is
recommended for direct bonding because of its unlimited
positioning time

Combination anchorage techniqueCombination anchorage technique
- four stage light wire appliance- four stage light wire appliance
- 1988- 1988
(( combination anchorage technique – Thompson vol 1988 Ajo-do may 363-79combination anchorage technique – Thompson vol 1988 Ajo-do may 363-79))
CAT in its early structure was principally a four stage
Begg light wire system, the fourth stage being the straight
wire finally.
The concept was to use a light wire appliance system to
establish the early organization of the malocclusion and
to finish the treatment with more rigid and precise
straight wire appliances.
What was originally believed to be modernized Begg wasWhat was originally believed to be modernized Begg was
actually a true combination anchorage technique.actually a true combination anchorage technique.www.indiandentalacademy.comwww.indiandentalacademy.com

BRACKET AND TUBE PLACEMENT
similar to that of straight wire appliances like edge wise slot parallel and at
the same level as the interproximal contact point of the teeth in normal
occlusion.
Molar tube can be banded or bonded.
Remaining brackets are bonded on the anterior and premolars keeping the
molar tube as guide line.
Molar tube placement
rectangular tube 3.5 mm from the molar cusp tip.
Other teeth are at the same level except canine and lateral incisor
If maxillary molars are interfering in static of functional occlusion,
-position have to be altered.
Canines edge wise slot should be 4mm
Maxillary lateral incisors 3 mm from the incisal edge.
Non extraction case – mandibular I premolar – 4mm

BRACKET AND TUBE PLACEMENT

Level anchorage systemLevel anchorage system
ROOT began using the angulated appliances of Holdaway in
1954 and since that time, he included the anchorage needed to
reduce ANB angle, correct class II molar relationships, close
extraction space, and level curve of Spee.
In 1975 Root began using a completely preadjusted appliance,
varying the amount of angulation in the buccal segment by
severity of the malocclusion

BRACKET PLACEMENT

Bioefficient bracket systemBioefficient bracket system
It is a modification of preadjusted systemIt is a modification of preadjusted system
introduced byintroduced by Viazis.Viazis.
The bracket prescriptions were designed toThe bracket prescriptions were designed to
overcorrect malocclusion and to make it possibleovercorrect malocclusion and to make it possible
to work with the largest possible wires from theto work with the largest possible wires from the
start of the treatment .start of the treatment .
(Atlas of advanced orthodontics: a guide to clinical efficiency - Anthony D. Viazis)

The Next Generation :StraightThe Next Generation :Straight
Wire ApplianceWire Appliance
 This concept was introduced by Creekmore andThis concept was introduced by Creekmore and
Randy in 1993 AJORandy in 1993 AJO
 Frequently anticipated results are not achievedFrequently anticipated results are not achieved
by using a preadjusted appliance and straightby using a preadjusted appliance and straight
wire .wire .

 There are atleast five reasons –There are atleast five reasons –
1.1. Inaccurate bracket placementsInaccurate bracket placements –a mean of .34–a mean of .34
mm error in vertical plane and 5.54mm error in vertical plane and 5.54˚ for˚ for
angular placement is observedangular placement is observed
- Balut et.al- Balut et.al
2.2. Variations in tooth structureVariations in tooth structure
3.3. Variations in ant –post and vertical jaw relationsVariations in ant –post and vertical jaw relations
require variations in the position of the max andrequire variations in the position of the max and
mand incisors.mand incisors.

4.4. Need for overcorrectionNeed for overcorrection
5.5. Mechanical deficiencies of the edgewise appliance –forceMechanical deficiencies of the edgewise appliance –force
application away from CRes.application away from CRes.
-play between arch wire and slot.-play between arch wire and slot.
-force diminution.-force diminution.

The Next Generation :StraightThe Next Generation :Straight
Wire ApplianceWire Appliance
THE SLOT MACHINETHE SLOT MACHINE

Advanced Preadjusted ApplianceAdvanced Preadjusted Appliance
FabricationFabrication
 TorqueTorque –with the use of an incisor Torque–with the use of an incisor Torque
Template (Creekmore Enterprises ).Template (Creekmore Enterprises ).
 TipTip -can be adjusted taking in consideration the-can be adjusted taking in consideration the
anchorage requirement .anchorage requirement .
 Rotations-Rotations- rotations can be accurately measuredrotations can be accurately measured
by using rotational guidesby using rotational guides

 HeightHeight – more precise height– more precise height measurements aremeasurements are
possiblepossible
All this requires proper planning of individual toothAll this requires proper planning of individual tooth
movement so as to determine exact amount of torque ,tipmovement so as to determine exact amount of torque ,tip
rotation and height parameter for eachrotation and height parameter for each
toothtooth

Concepts of bracket positioning techniques

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