2. CONTENTS
INTRODUCTION
FACC
FA POINT
ANDREW’S PLANE
BRACKETS
PARTS
BASE OF THE BRACKET
MESIODITAL POSITIONING OF
BRACKETS
MODIFICATIONS
3. AXIAL POSITIONING OF BRACKETS
MODIFICATIONS
VERTICAL POSITIONING OF BRACKETS
DIFFERENT GUIDELINES
ANDREWS
ROTH
ALEXANDER
MBT
VIAZIS
MODIFICATIONS
BRACKET POSITIONING GAUGES
BRACKET PLACEMENT ERRORS
CONCLUSION
4. INTRODUCTION:
In the past, the best results were achieved
by orthodontists who were the the best wire
benders.
The emphasis has changed since the
development of the pre-adjusted appliance
by Andrews.
The best results in the future will be achieved
by those orthodontists who are best at
accurate bracket positioning.
5. Orthodontic treatment is based upon specific
force applications to the dentition, the maxilla
and the mandible.
In order to obtain these forces in a fixed
appliance, orthodontic brackets are attached
to the teeth.
6. The brackets themselves produce no force. They are merely
handles for attachment of the force producing agents.
However, brackets can effect the directions of the force vectors
when torque, angulations, and in/out are built in to the brackets.
The accurately placed brackets will give better control on three
dimension position of the teeth during treatment.
An accurately placed bracket will also result in better
expression of its built in prescription and orthodontist will need
less wire bending and complex mechanics during the course of
treatment.
7. FACIAL AXIS OF THE CLINICAL
CROWN (FACC).
The most prominent portion of
the central lobe on each
crown’s facial surface. For
molars, the buccal groove that
separates the two facial cusps
8. The point on the facial axis that separates the gingival
half of the clinical crown from the occlusal half.
FACIAL AXIS POINT (FAPOINT ):
9. The surface or plane on which the mid-transverse plane
of every crown in an arch will fall when the teeth are
optimally positioned. This plane virtually connects the
appliance through the FApoint.
ANDREWS® PLANE:
12. BRACKETS
DEFINITION:
Raymond C. Thurow has defined bracket as
an orthodontic attachment secured to a tooth
for the purpose of engaging on arch wire and
to transmit the adjacent force to the tooth in
proper , precise and effective manner.
13. Bracket base
Slot base
Slot Point
Slot axis
Bracket stem
Base point
PARTS OF A BRACKET
14. Welding tab, solder or a bonding mesh
Curved to conform tooth structure
Mode of retention of bracket base may be:
Mechanical
Micromechanical
Chemical
Mechanical and chemical retention
BASE OF BRACKET
15. Mesh type
The sizes of the wire mesh used in the
manufacturing of the various single mesh
type bases were 40, 60, 80 and 100 meshes.
(dickinson 1980)
Non mesh type
BRACKET BASE TYPES
19. It is a general saying in orthodontics that
brackets should be placed at mesiodistal
center of the teeth.
This statement is partially correct as this rule
can't be applied to all the teeth.
20. A MORE CLEAR DESCRIPTION FOR RIGHT MESIODISTAL POSITION OF
BRACKETS WAS GIVEN BY ANDREW THAT BRACKETS SHOULD IDEALLY BE
PLACED AT THE MID DEVELOPMENTAL RIDGE OF THE TEETH.
21. MAXILLARY AND MANDIBULAR INCISORS
Bracket should ideally be placed at mesiodistal center of
maxillary and mandibular incisors. The mid developmental
ridge of these teeth is also present at their mesiodistal
center of the labial surface
.
23. VERTICAL LINES SHOWING MESIODISTAL CENTER OF THE
UPPER AND LOWER INCISORS. BRACKETS SHOULD BE
PLACED AT THE RECOMMENDED HEIGHT ON THIS LINE.
24. MAXILLARY AND MANDIBULAR CANINES
Placing brackets at the mesiodistal center of the canines will result in contact
point error and slight rotation of the teeth as the mid developmental ridge of
upper and lower canines lies slightly mesial to the mesiodistal center of
the teeth and is more mesial in case of lower canines. So bracket is placed
slightly off center and toward mesial, in case of canines.
25. {
The vertical lines on maxillary and mandibular canines indicate the
mid developmental ridge of the canines and ideally the middle of
the brackets should coincide with this line.
26. MANDIBULAR PREMOLARS
Roth proposed that premolars brackets should
be placed at area of maximum convexity which is
usually the mesiodistal center of the teeth and
mid developmental ridge also lies in this area.
28. Sometimes the area of maximum convexity lies slightly
mesial to the mesiodistal center but degree of mesial
deviation is less than that of canines. The difference between
bracket placement on premolars and anterior teeth is
presence of a lingual cusp on premolars which must be taken
into consideration while placing
the brackets.
M D
29. Maximum convexity lies slightly mesial to the
mesiodistal center. The cast of the patient should
be examined to detect position of the maximum
convexity
30. In mandibular premolars the buccal and lingual
cusps lies at the same level in the mesiodistal
perspective. So when placing lower premolar
brackets the scribe line of the bracket should
coincide with line connecting the buccal and
lingual cusps.
31. IN MAXILLARY PREMOLARS, BRACKETS SHOULD BE PLACED SO THAT THE
SCRIBE LINE OF THE BRACKET IS SLIGHTLY MESIAL OF UP TO 0.5 MM TO
THE LINE CONNECTING THE BUCCAL AND LINGUAL CUSPS
MAXILLARY PREMOLARS
32. Bracket placement on maxillary premolars is different from mandibular
premolars as maxillary premolars should have slightly rotated position at
the end the treatment while the lingual cusps have cusp fossa
relationship with lower premolars in class I & II molarocclusion
33. ACCORDING TO ANDREW SIX KEYS OF NORMAL OCCLUSION
THE BUCCAL CUSPS OF UPPER PREMOLARS SHOULD HAVE
A CUSP EMBRASURE RELATIONSHIP WITH LOWER
PREMOLARS
34. ACCORDING TO ANDREW1 THE BUCCAL CUSPS OF
UPPER PREMOLARS SHOULD BE SLIGHTLY MORE
DISTAL THAN THE LINGUAL CUSPS IN THE
MESIODISTAL PERSPECTIVE
35. A. Keeping the buccal and lingual cusps of maxillary premolars in
the same mesiodistal perspective will cause poor occlusal results..
D. A bracket bonded slightly mesial to line connecting the buccal
and lingual cusp of maxillary 2nd premolar. Bonding the bracket in
this position will rotate the buccal cuspsdistally and lingual cusp
slightly mesial to get ideal relationship in a class I molar relationship
36. B&C. WHEN THE BUCCAL CUSP TIPS OF THE MAXILLARY
PREMOLARS ARE IN LINE WITH LOWER EMBRASURES THEIR
LINGUAL CUSPS LIES SLIGHTLY MESIAL TO EMBRASURES AND
REST AT THEIR CORRESPONDING TEETH FOSSA
37. Checking mesiodistal position of the brackets
The mesiodistal position of the bracket can be checked under
both direct and indirect vision. For indirect vision diagnostic
mirror is used . Generally mesiodistal position of upper
incisors, premolars and molars brackets is
checked under indirect vision
38. Modifications in mesiodistal position of the bracket
Alteration in mesiodistal position of the bracket will alter the
prescription of the bracket in terms of counter rotation.
Some situations where mesiodistal position of the bracket is
altered are given.
39. ROTATED TEETH
In case of rotated teeth the bracket should always be placed more
on side of rotation in the mesiodistal plane . This overcorrected
position of the bracket will result in early correction of the rotation
and will also accommodate the relapse factor after debonding.
A rotated maxillary 2nd premolar,
As the tooth is distopalatally rotated
so the bracket is placed slightly
more distal than its required position
40. Clinical Notes
Sometimes due to severe rotation or
crowding the position of the tooth is such
that it's not possible to place bracket at the
correct mesiodistal center of the tooth
41. Rotated right upper central incisor.
Correct mesiodistal position of the bracket is not possible on
the first bonding visit due to rotation. The bracket should be
placed as far mesial as possible. The mesial side of the
bracket should not come in contact with left side incisor
because it will hinder the full insertion of the wire.
42. In such situations the bracket should be placed as far as
possible toward the mesiodistal center of the tooth or toward the
rotation. A flexible wire is passed and only the brackets wings
toward the rotation are ligated. At subsequent visit the tooth is
usually derotated enough to place bracket at the right
mesiodistal position
So the bracket is debonded and
either a recycled or new bracket is
rebonded at the correct mesiodistal
position
43. Clinical Notes
Sometimes the tooth is rotated 180° so that the lingual side is
on the facial side. Many times this form of rotation is
accepted. In such situation the bracket is bonded on the side
of the tooth which is facing labial or buccal .
Right lower lateral is rotated
180°.The rotation was
accepted and bracket placed
on lingual side of the tooth
which was facing labially
44. Another situation is maxillary lateral incisor substitution by canine. In
this situation the slightly convex labial surface
of canine is made flat to give it shape of lateral incisor and bracket is
bonded at mesiodistal center of reshaped canine
instead of slightly mesial.
45. Placing the bracket at the mid developmental ridge area
will cause poor contact point with the central incisor as canine is
also reshaped mesiodistally. On premolar tooth which
will become future canine the canine bracket is placed distal to
the mesiodistal center of the tooth.
46. •It is necessary to position these brackets
gingivally to permit the re-contouring of the
canines required for esthetics and function.
• The orthodontist should place the brackets
according to gingival margin height rather
than incisal edge or cusp tip.
51. Axial or long axis position of the bracket is related to the angulation or
tip of the teeth. In conventional edgewise system where there was no
built in tip, the brackets were placed angulated on the tooth. The amount
of bracket angulation on the tooth was equal to the amount of tip
required.
52. Standard edgewise brackets has no built in tip. Bracket
position didn't follow long axis of the crown or root and
were placed angular on the tooth equal to the amount of
tip required.
53. In pre adjusted edgewise system as the tip is already built
within the brackets so placing the bracket similar to standard
edgewise will result in increase or decrease of built in tip. In
pre adjusted edgewise system brackets are positioned on the
tooth so that their wings and scribe line are parallel to long axis
of the tooth .
54. A PRE ADJUSTED BRACKET OF MAXILLARY LEFT LATERAL INCISOR.
PLACING THE BRACKET PARALLEL TO LONG AXIS OF THE TOOTH
WILL CAUSE TOOTH TO ROTATE IN A CLOCKWISE DIRECTION AND
EXPRESS THE BUILT IN TIP.
55. BUT THERE IS ALWAYS SOME DIFFERENCE BETWEEN
THE ANGULATION OF LONG AXIS OF THE CROWN AND
LONG AXIS OF THE TOOTH IN THE MESIODISTAL PLANE .
There is always some
difference between long
axis of clinical crown and
long axis of the tooth
56. ALSO PLACING BRACKET ACCORDING TO LONG
AXIS OF TOOTH MAY RESULT IN WRONG
MESIODISTAL POSITION OF BRACKET ON THE
CROWN.
57. Andrew proposed that as the clinical crown is only visible in
the mouth so the angulation of the tooth should be taken by
taking the angulation of long axis of clinical crown (LACC)
and not the long axis of the entire tooth. But taking only
the long axis of clinical crown may result in poor root
parallelism and in some cases root resorption due to roots
approximation of adjacent teeth can occur.
58. A lateral incisor bracket placed with reference to long axis of
clinical crown.
X ray showing that long axis of bracket not coinciding with
long axis of the root and because of this root of the lateral
incisor is in close contact with central incisor root
increasing chances of root resorption in this area.
59. TAKING THE LONG AXIS OF TOOTH CAN RESULTS IN POOR
PROPORTIONS OF CONNECTORS AND EMBRASURES . THESE
PROPORTIONS CAN BE CORRECTED AT END OF TREATMENT
EITHER BY COMPOSITE BUILD UP OR INTERPROXIMAL
REDUCTION.
60. A. Golden proportion of connectors that ideally should be
present in finished cases.
B. A case with dilacerated central incisor root. If there is
root dilacerations, placing bracket by following the clinical
crown will result in ideal connector areas but greater
chances of root approximation and so root resorption.
61. C. Bracket placed by following the long axis of the
roots. The golden proportion of connectors is
distorted. They can be restored by composite built
up or interproximal stripping at the end of
treatment
62. Clinical notes
Some clinicians also take incisor edge as
guideline for long axis positioning of brackets. But
incisor edge is mostly uneven due to trauma,
attrition and mamelons. So incisor edge shouldn't
be taken as a reference point for long axis
position of the bracket.
63. ALSO GINGIVAL ZENITH(TOP) SHOULDN'T BE TAKEN AS A
REFERENCE FOR LONG AXIS POSITION OF THE BRACKET AS IT
CAN BE EFFECTED BY UNEVEN PATTERN OF GINGIVAL
RECESSION.
64. A. Mamelons on central incisors. These mamelons will give a
different long axis position of the tooth if taken as reference for bracket
positioning.
B. Attrition of the incisor edge will also effect long axis position of the
teeth.
C. Gingival zenith shifted mesial from their ideal position due to gingival
recession. Taking gingival zenith as reference for axial position of the
bracket in these cases will result in wrong placement of the
brackets.
65. Importance of axial position of brackets
Correct axial position of the bracket is very important for
proper occlusal and esthetic relationship. As preadjusted
brackets have built in tip, a poor axial position of the
bracket will result in expression of increase or decrease
positive or negative tip. Increase in tip may increase space
requirement in the arch and also increase risk of adjacent
root approximation
66. Checking axial position of brackets
The axial position of the brackets is checked under both
direct and indirect vision. Usually maxillary anterior
brackets and mandibular brackets are checked under direct
vision from labial side of the tooth while maxillary posterior
brackets are checked under indirect vision using diagnostic
mouth mirrors.
67. IF THERE IS DOUBT IN POSITION OF MAXILLARY ANTERIOR BRACKETS
ESPECIALLY LATERAL INCISOR BRACKETS, SOME CLINICIANS FAVOR TO
USE INDIRECT VISION BY DIAGNOSTIC MIRROR AND USE GUIDANCE FROM
LINGUAL SIDE OF TOOTH.
68. MODIFICATIONS IN AXIAL POSITION OF
BRACKETS
Modifications are made in axial position in the
following circumstances
1.To avoid chances of root resorption due to adjacent
root approximation.
2.To avoid root resorption from orthodontic
implants.
69. .) .
3.To avoid root resorption from
impacted teeth in bones :-
canines or mesiodens
70. 5. In some surgical cases bracket position is modified to
move roots away from surgical site (Wassmound procedur
in maxilla, Subapical osteotomy).
4. TO ACCOMMODATE CROWN MORPHOLOGY FOR ACHIEVING
GOLDEN PROPORTIONS OF CONNECTORS AND EMBRASURES
72. Edgewise and Begg brackets were placed on
tooth with help of gauges using one standard
measurement for all the patients.
• The vertical positioning errors were
corrected by wire bending which was integral
part of the treatment.
73. With the advent of straight wire Appliance, vertical
position of the bracket gained more importance. As
morphology of tooth is not uniform throughout its
length, changing the vertical position of the bracket
will result in different expression of its built-in
prescription.
75. Andrew Guidelines for bracket placement
1) It should be free of occlusal and gingival
interference.
2) The brackets siting site on a tooth should
have consistent angular relationship with
its occlusal plane and to the occlusal
plane of arch when all the teeth are ideally
placed.
76. 3) When the teeth are ideally positioned, the middle of each
bracket site must be at the Andrew plane, where Andrew
plane is a surface plane on which mid transverse plane of
every crown in an arch will fall when the teeth are optimally
positioned.
77. • In case gingival recession, Andrew quoted that “1.8 mm
should be subtracted from anatomical crown to find the
correct value of clinical crown. This measurement must be
adjusted while placing bracket at FA point in cases with
gingival recession”.
• Andrew proposed that bracket must be accurately placed
within 2° of FACC and base point or middle of the bracket
should be within 0.5 mm of FA point.
78. • Where FA point (facial axis point) is center
of facial axis of clinical crown (FACC) and it
virtually divides the clinical crown into
occlusal half and gingival half.
• The FACC on each tooth correspond to mid-
developmental ridge and in case of molar it is
dominant vertical buccal groove.
79. Andrew also proposed using LA point (long axis
point) for bracket positioning, where LA point is the
mid of long axis of clinical crown (LACC).Though
Andrew later disown LACC and LA point but
amazingly description of LACC or FACC remain the
same in Andrew writings that was mid developmental
ridge and dominant vertical buccal groove in case of
molars.
80. Limitations of Andrew's Recommendations
• Placing brackets with only guessing the
correct position will result in vertical positioning
errors. Not every orthodontist will place the
bracket at the same height. Even the same
orthodontist, after accidental debonding of
bracket will rebond the bracket at a slightly
different height
• Placing bracket is also troublesome in
gingival recession and gingival enlargement as
vertical adjustment in bracket height in
millimeters is again a matter of guesswork.
81. • Also no consideration was given for incisal and
occlusal edges which are functional and esthetic
units of teeth. Even an error of 0.5 mm in
anterior teeth is noticed by esthetic conscious
patients.
• Eliades found out that positioning bracket at
FA point results in marginal ridge discrepancy
and poor occlusal contacts.
82. • Roth like Andrew also proposed
center of clinical crown for ideal
bracket placement to be used with
his prescription.
• Roth advocated that for his
prescription anterior brackets should
be placed slightly more incisal than
Andrew proposed center of clinical
crown or FA point to level the curve
of spee.
Roth Guidelines
83. • According to Roth the upper central and lateral incisor
should either be at the same level or lateral incisor should be
0.5 mm less prominent than central incisor.
• The central incisors will elongate 0.5 mm to 1mm more than
the lateral incisor after settling. maxillary canine should be 1
to 1.5 mm below the occlusal plane while mandibular canine
should be 0.5 to 1 mm above the occlusal plane.
• The upper and lower canines also should be 1mm more
prominent than lateral incisors and bicuspid.
84. Most variation in bracket position are found in
bicuspids. In bicuspids the bracket should be placed
at area of maximum convexity which in most cases
is center of clinical crown.
In case of increase curve of spee the lower canine
brackets should be placed more occlusal than the
premolar brackets to avoid future wire bending to
level the curve of spee.
85. LIMITATIONS OF ROTH GUIDELINES
Roth recommendations are good to
attain a functional occlusion but merely
guessing the right height while placing
brackets with such accuracy in
millimeters is usually not possible.
According to Roth canine or premolar
teeth should be taken as reference while
placing brackets. A bracket positioning
chart advocated for speed brackets
having Roth prescription is given.
• No reference is found in literature
whether this chart is supported by Roth
or it's just manufacturer
recommendation.
86. Alexander Guidelines
Alexander advocated
individualizing bracket
positioning for each patient to
effectively use his bracket
prescription.
• According to Alexander , the
premolar clinical crown height is
the most variable in the arch so
premolar bracket height (X)
should be taken as reference. All
the other brackets are placed
with reference to premolar
bracket height (X).
87. To find premolar bracket
height, premolar clinical
crown height is taken and
is divided into half.
• The premolar normal
bracket height (X) is usually
4.5 mm. The chart for
bracket height
measurement is given.
88. Limitation of Alexander
Guidelines
Premolars in upper and lower arch were
bonded at same height. As 1st premolars
cusps are longer than 2nd premolars
especially in lower arch. so bonding all the
premolar at the same height will result in
marginal ridges discrepancy and premature
occlusal contacts.
• Also no value was given for lower 2nd
molars. To correct these discrepancies ,
Alexander modified his bracket positioning
chart
89. Alexander modified his bracket positioning chart
X=4mm for small crown and 4.5
mm for average crown and 5
mm for large size crown. In case
of 1st premolar extraction 2nd
premolar is taken as reference
Alexander advocated specific
positioning gauges for bracket
placement. For ideal smile arc
relationship Alexander proposed
that maxillary lateral incisors
brackets should be placed 0.25
mm more incisal from central
incisor.
90. Limitations of modified Alexander Guidelines
Alexander bracket positioning chart
though help to level incisor edges and
give good anterior aesthetics but taking
premolar clinical crown height as a
reference mean, the clinician is denying all
the variations in other teeth clinical crown
heights and morphology.
• Taking half the height of clinical crowns
in premolars may result in marginal ridges
discrepancy and occlusal interferences.
• Wire bending is usually needed to
accommodate height differential and settle
down the occlusion
91. In modified chart the lateral incisor bracket position
was 0.25 mm more incisal than central incisor. It is
extremely difficult to place bracket with 0.25 mm
accuracy even with the help of gauge because of
the play between slot supporting part of the gauge
and slot of the bracket.
In modified Alexander bracket positioning chart
upper 2nd molar height is 1 mm greater than 1st
molar, this can create marginal ridge discrepancy
between the maxillary molars in many cases .
92. McLaughlin or MBT vertical bracket positioning
The method is given as follow:
1) Measure the clinical crown height of
fully erupted teeth on the upper and
lower study cast by dividers and
millimeter rulers.
2) To obtain middle of clinical crown
divide the measured height of each
crown into half and round the obtained
value to the nearest 0.5mm.For
example if crown height is
10.75mm.Half the crown height would
be 5.4 mm. Make this measurement to
5.5 mm
93. 3) Create separate rows of measurements for
maxillary and mandibular teeth. Now compare your
values of maxillary and mandibular teeth with that of
proposed charts. If your chart measurement don't
exactly tally with that of proposed MBT charts then
find a row on the chart which matches most of your
recorded measurement .
97. Versatility of MBT system:
1. Options for palatally displaced upper lateral incisors.(-10o).
2. Three torque options for the upper canines(-7o,0o, +7o).
3. Three torque options for the lower canines(-6o, 0o,+6o)
4. Interchangeable lower incisor brackets-same tip and torque
5. Interchangeable upper premolar brackets-same tip and
torque
6. Use of upper second molar tubes on first molars in non HG
cases.
7. Use of lower second molar tubes for the upper first and
second molars of the opposite side, when finishing the
cases to a class II molar relationship.
98. BONDING
MODIFICATIONS
VARIATION RATIONALE INDICATION
Invert Maxillary lateral Additional labial root torque Palatally placed lateral
Reverse lower canine additional distal crown tip Class III camouflage to
reduce arch length
Invert maxillary canine Additional palatal root
torque
Buccally placed canine
Maxillary 4 on maxillary 3 Limit mesial crown tip Finishing in class II
Invert mandibular anterior Additional lingual root
torque
In recession cases
Invert mandibular premolar Additional lingual root
torque
Scissor bite
Invert maxillary premolars Additional lingual root
torque
Posterior cross bite
99. Limitations of McLaughlin or MBT vertical bracket
positioning chart
Due to individual variation of cusps height in
premolar region, marginal ridges height
difference is seen in finished cases as
posterior bracketing is not optimum to level
marginal ridges.
100. Central incisors brackets are
taken as reference.
maxillary central incisor bracket
(X)
mandibular central incisor bracket
(Y)
Both of them (x)(y) placed at FA
point which is center of clinical
crown.
VIAZIS GUIDELINES FOR BRACKET
PLACEMENT
101. The distance from the
incisor edge to FA point
is measured. Rest of
the brackets are placed
with reference to these
brackets at proposed
distance (Table 7.9) with
the help of bracket
positioning gauges
102. MODIFICATIONS IN VERTICAL POSITION OF
THE BRACKETS
Bracket placement needed recommended alteration
under certain situations as in.
:1. Open bite .
2. deep bite .
3. Irregular incisors edges.
4. Long canine tip .
5. Attrition of canine .
6. High buccally placed
teeth 7. Gingival recession
.
8. Premolar extraction
103. OPEN BITE
This is done by placing the
brackets more gingival on the
tooth which are in open bite. In
most case of open bite, only
maxillary anterior teeth are
contributing to open bite and so
bracket position alteration should
be done in maxillary arch only.
But if mandibular arch has a
reverse curve of spee then
bracket position alteration should
also be done in mandibular arch
too.
104. The Clinician advocate different rule for bracket
placement during treatment of open bite:
Alexander proposed that the teeth which are in
open bite should be bonded .5 mm more gingival
while teeth in occlusion should be .5 mm more
occlusal .
MBT proposed that teeth which are in open bite
should be bonded .5 mm more gingival than their
prescribed position, and the rests of brackets are
bonded at their normal height.
105. DEEP BITE
In deep bite cases the rules of bonding
brackets are opposite that of open bite
cases.
106. In MBT system teeth which are in deep
bite are bonded 0.5mm more incisal while
in Alexander discipline teeth which are in
deep bite are bonded 0.5 mm more incisal
while other teeth are bonded 0.5 mm more
gingival.
107. IRREGULAR INCISORS EDGES
Clinician suggest 3 options for manage long
cusp tip and irregular edges :
1. Recontouring of the incisor edges or
cusp tips before bracket placement.
2. Recontouring of the incisor edges or cusp
tips at end of treatment.
3. Composite filling of the incisor edges and
cusp tips.
108. Ideally teeth should be recontoured prior to bracket
placement.
If teeth are recontoured previous to orthodontic
treatment so there is no need to alter the bracket
height.
But if it is planned to recontour at the end of
orthodontic treatment or composite filling is needed
at the end of treatment , then height modification of
bracket is done at the start of treatment.
109. LONG CANINE TIP
In cases where canine tip is long, it's
better to place brackets 0.5mm more
gingival than standard values and
reshape canine tips at the end of
treatment. Another option is : to reshape
canine tip at the start of the treatment and
place bracket at its ideal position. Long
canine tips are usually found in impacted
canines or canine placed out of
occlusion.
buccally placed
canine lack of
function and attrition
110. ATTRITION OF THE CANINE.
In case of attrition of the canine the brackets are
placed 0.5-1 mm more gingival, depending upon
the severity of attrition. The canine tip is
reshaped at the end of treatment.
112. GINGIVAL RECESSION
Individual teeth with up to 1.5mm
gingival recession can be bonded
more gingival so that at end of
treatment their gingival margins
should be at the ideal height. But
incisor or occlusal edge needed to
be reshaped by equal amount.
In teeth with more than 1.5 mm of
gingival recession an expert
opinion from periodontist should
be taken and many a time gingival
grafting is a viable option than
bracket position alteration.
115. BRACKET POSITIONING
GAUGES
• Bracket positioning
gauges are used to ensure
vertical accuracy of
brackets on the teeth.
Many different instruments
have been recommended
to check for vertical
accuracy of seated
brackets ranging from
periodontal probes to rulers
but
116. In contemporary orthodontics
two types of gauges or their
variations are usually used.
These are:
1. Star shaped gauges
or Boone bracket
gauges.
118. PARTS OF GAUGES
All bracket positioning gauges have a holding
arm for holding the gauge with fingers during
bracket positioning, a tooth supporting arm
which rest on the incisor or occlusal surface of
the tooth and a slot supporting arm which is
seated in slot of the bracket.
The holding arm is the longest part of gauges
while the slot supporting arm is the shortest
part of the gauges.
Different slot supporting arms are available for
0.018” and 0.022” slots.
119. POSITION OF THE GAUGE DURING BRACKET
PLACEMENT
For correct positioning the gauge should
be held in hand at right angle so that the
orthodontist vision should also be at right
angel to the gauge.
The gauge should always be placed
perpendicular to the labial or buccal
surface of the teeth.
This makes the gauges parallel to the
occlusal surface in all the teeth except
incisors.
In lower arch if the incisors are
upright the gauge should be placed
parallel to the occlusal plane.
120. In case of upper incisors the gauge is placed
slightly upward angulated usually 15° to 20°
to the occlusal plane to make it perpendicular
to the labial surface of the tooth as the upper
incisor are slightly inclined forward over basal
bone.
But if the lower incisors are proclined the
gauge is placed below the occlusal plane and if
the lower incisors are retroclined the gauge is
directed from above the occlusal plane.
121. • In case class II div 1
incisor relationship where
the upper incisors are
proclined the gauge is
angulated more upward as
compared to normal incisor
inclination.
• In case of class II div 2
the gauge lies below the
occlusal plane angulated at
an angle depending upon
the severity of
malocclusion.
122. BRACKET PLACEMENT BY WIRE GUIDANCE
In this technique all the steps of conventional bonding are done in usual
way but before curing the bracket a heavy wire is passed through the
bracket slot and its bonded neighboring brackets and bands. The
mesiodistal position of the bracket is corrected manually while axial and
vertical positions are guided by the heavy wire.
Orthodontic brackets can be placed by wire guidance if brackets are
debonded when 0.016x0.022 inch or heavier wire is in place. If brackets
are placed in usual way then due to small human errors, mostly it is not
possible to place the existing working wire after bracket rebonding and
clinician need to move back on lighter wires.
123. Bracket Placement errors with the Preadjusted
Appliance
1. Horizontal errors. Placing the bracket to the
mesial or distal of the vertical long axis leads to
undesirable tooth rotation. Such errors can be avoided by
visualizing the vertical long axis—directly from the
facial surface, or with a mouth mirror from the incisal or
occlusal aspect. Some orthodontists even draw a line on
the tooth to indicate the correct vertical long axis.
Horizontal bracket placement errors can
be avoided with careful technique.
124. 2.Axial or paralleling errors. If the bracket wings
are not parallel to the long axis, the result will be
unwanted crown tipping. These errors can be
avoided in the same way as horizontal errors.
Axial or paralleling errors can be avoided
with careful placement technique.
125. 3. Thickness errors. Leaving excess adhesive under
a portion of the bracket base or failing to conform
the base accurately to the contour of the tooth can
cause improper torque or rotation. This problem is
overcome by expressing all excess adhesive from
beneath the bracket during placement and by more
accurate contouring.
Excess adhesive beneath bracket base can
cause thickness and rotational errors.
126. 4. Vertical errors. Improper vertical placement
can lead to extrusion or intrusion of teeth,
as well as to torque and in-out errors
Improper vertical placement can lead to extrusion
or intrusion and to torque and in-out errors.
127. POSITION OF CLINICIAN DURING BRACKETS
PLACEMENT
The clinician
position for bracket
placement given
here are for right
handed
orthodontist. For
left handed
orthodontist similar
positions would be
used from the left
side.
128. Conclusion
Accurate bracket positioning is
essential, so that the built in features
of the bracket system can be fully and
efficiently expressed.This helps in
treatment mechanics and improves the
consistency of the results.
