Bracket position jc

JOURNAL CLUB ON A COMPARISON OF ACCURACY IN
BRACKET POSITIONING BETWEEN TWO TECHNIQUES
LOCALIZING THE CENTRE OF THE CLINICAL CROWN AND
MEASURING THE DISTANCE FROM THE INCISAL EDGE
David Armstrong, Gang Shen, Peter Petocz and M. Ali Darendeliler:
European J. Orthodontics 2007;29: 430-436
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Content
• Introduction
• Using the bracket positioning chart
• Recommendations for using the bracket positioning
• Individualized bracket positioning system for each teeth
• Vertical positioning
• Horizontal positioning
• Axial positioning
• Errors in bracket positioning
• Gingival concern during vertical bracket positioning
• Incisal or occlusal concern during vertical bracket positioning
• Advantages of using recommended chart
• Material and method
• Results
• Discussion
• Conclusion
• Bibliography www.indiandentalacademy.comwww.indiandentalacademy.com

INTRODUCTION
• The pre-adjusted appliance has provided great benefits to orthodontics with a
gradual progression towards finishing, rather than an abrupt stage of wire bending
as in the standard edgewise technique (McLaughlin and Bennett, 2003). Good
finishing begins at the commencement of treatment with positioning of the brackets.
If the brackets are positioned correctly and the tip, torque, and in-out compensations
built into the appliance are suited to the patient's dentition, only minimal wire
bending will be required (Mc Laughlin and Bennett, 1991).
• Angle (1928) recommended that the ideal position to place the bracket should be at
the centre of the labial surface of the tooth.
• Later, placement of the anterior bands at the junction of the middle and mesial thirds
has been recommended (Balut et al., 1992).
• These authors suggest that with the Tweed and Begg techniques the brackets be
placed by measuring the distance from the incisal edge for anterior teeth and from
the cusp tip for posterior teeth.

• Holdaway in 1952 suggested bracket over-angulation for teeth on either
side of an extraction site, to re-duce the second-order wire bends
otherwise needed to promote both translation and angulation
overcorrection
• 'In 1957 Jarabak incorporated slot inclination to reduce the need for
third-order archwire bends, so he is credited for being first to actually
build guidance into the bracket. Jarabak also recommended bracket
angulation.
• In 1958 John J. Stifter was granted a U.S. patent for an edgewise bracket
comprising a male and a female component. This was the first edge-wise
bracket designed to build guidance into all three planes of space. Its lack
of acceptance may be partly because it did not address optimal tooth
position and because too many separate parts were needed

• Andrews (1976, 1979) developed the straight-wire appliance and
proposed that the brackets should be placed at the midpoint of the facial
axis (FA) point, as the midpoints of all the clinical crowns are located on
the same plane (the Andrews plane); it was felt that the FA point was
readily and consistently located.
• Ricketts ( 1976), and later Kalange (1999), advocated the use of marginal
ridges to guide the vertical positioning of brackets and bands.
• Dellinger, 1978; McLaughlin and Bennett, I995 have shown that the FA
points between the teeth are not necessarily on the same plane and this
led to other recommendations for ideal bracket placement.
• McLaughlin and Bennett (1995) advocated the positioning of brackets at
a measured distance from the incisal edge, with different vertical
positions recommended for different sized teeth. They felt that the use of
a bracket placement chart with the use of a Dougherty gauge
dramatically reduced the bracket placement errors in the vertical
dimension, with a 50--60 percent reduction in the need to reposition
brackets.

• Regardless of which method is used for positioning brackets, there
seems to be some margin of deviation from the ideal location and this is
before operator error is taken into account. Measuring from the incisal
edge and positioning at the FA point have been shown to be inaccurate
for premolars and can lead to marginal ridge discrepancies between the
premolars and molars and a lack of occlusal contacts with the opposing
dentition (Eliades et al., 2005).
• Fukuyo et al. (2004) digitized the models of 40 patients with normal
occlusion and compared three methods of bracket placement (FA,
height, and marginal ridge methods). The bracket positions relative to a
constructed virtual bracket plane were determined- They found that
even if the brackets were positioned ideally in each technique, vertical
errors will still occur and, therefore, suggested modifications to bracket
positions for each technique.

• There are a number of prescription available, with the manufacturers
recommending an optimum position to maximize the efficiency of
prescriptions for tooth movement. It would be beneficial to know if
there is a difference in the accuracy between the recommendations, as
the less accurate the positioning of the brackets, the more poorly they
perform. Incorrectly positioned brackets can render even the most
customized prescription ineffective and increase treatment time and the
number of archwire adjustments necessary (Carlson and Johnson, 2001).

• Carlson and Johnson described 5 steps for achieving crown and root
alignment. They recommended that each step be performed on every
patient undergoing fully banded therapy. Once integrated into the
treatment protocol, it can decrease treatment time and improve final
results.
• 5 STEPS:
• INITIAL BRACKET POSITIONING
• PRIMARY EXPRESSION OF BRACKET PRESCRIPTION AND POSITION
• RESET EVALUATION
• RESET APPOINTMENT
• SECONDARY EXPRESSION AND FINISHING

• Andrews plane: The surface or plane on which the midtransverse plane
of every crown in an arch will fall when the teeth are optimally
positioned .
When a crown is optimally positioned, its mid-transverse
plane (A) falls on the Andrews plane
• Clinical crown: Normally, the amount of crown that can be seen intraorally or with a
study cast
Orban has defined the clinical crown as the anatomical crown height minus 1.8 mm . In
young patients or those with hypertrophied or receding gingiva, the clinical-crown
height can be found by measuring the distance from the incisal edge or cusp tip of the
crown to the cemento-enamel junction, and then subtracting 1.8 mm
anatomical
crown
, Clinical & anatomical crown

• Crown angulation: The angle formed by the facial axis of the clinical
crown (FACC) and a line perpendicular to the occlusal plane
• Crown angulation is considered positive when the occlusal portion of
the FACC is mesial to the gingival portion negative when distal .
The exact degree of crown angulation cannot be judged, but the nature of
the angulation (positive or negative) and whether it is excessive can be .
Examples of crown angulation for each tooth : A, maxillary positive (a) and negative (b); B, mandibular
positive (a), and negative.

• Crown inclination: The angle between a line perpendicular to the
occlusal plane and a line that is parallel and tangent to the FACC at its
midpoint (the FA point).
• Crown inclination is determined from the mesial or distal perspective.
It is sometimes incorrectly called torque, which means a twisting force.
"Tangent to" means that the line representing the inclination of the
FACC should be equidistant from each end of the clinical crown, while
touching the FACC.
• Crown inclination is considered positive if the occlusal portion of the
crown, tangent line, or FACC is facial to its gingival portion, negative if
lingual .
• The exact degree, of crown inclination cannot be judged, but the nature
of the inclination (positive or negative) and whether it is excessive can
be .

• Facial axis of the clinical crown {FACC). For all teeth except molars, the
most prominent portion of the central lobe on each crown's facial
surface, for molars the buccal groove that separates the two large facial
cusps.
• Clinically, the FACC for all teeth except molars can be high-lighted with
the side of a pencil lead for molars, it can be highlighted with the point
of pencil. From the facial perspective the FACC is observed as a straight
line . From the mesial or distal perspective this landmark is used to
judge inclination by visualizing a straight line that is parallel to the
FACC and tangent to a point on the FACC that separates the gingival
half of the crown from the occlusal half.

• Facial-axis point (FA point): The point on the facial axis that separates
the gingival half of the clinical crown from the occlusal half.
• The distances between the occlusal and gingival extremities of the facial
surfaces are not equal for all crowns within an arch, but for each crown
they are equidistance from the FA point.

• Bracket Siting
• Siting the brackets of an appliance designed for use with unbent
archwires is critical. Reliable bracket siting depends on a
• suitable bracket site,
• dependable landmarks for locating the site,
• features for locating the bracket on that site,
• and a reliable technique.
• Bracket Site
• A suitable bracket site has three criteria.
• First, a bracket located there will not interfere with either the gingiva or
with the opposing teeth during occlusion.
• Second, the angulation and inclination of the crown at the site will have
a consistent angular relationship to the plane of each tooth's occlusal
surface at all times and to the occlusal plane of the arch when the teeth
are optimally positioned.
• Finally, the middle of each bracket site must share the same plane or
surface when the teeth in an arch are optimally positioned.
• The site that meets these requirements is the area in immediate
proximity to the crown's FA point.www.indiandentalacademy.comwww.indiandentalacademy.com

• The area around the FA point is neutral enough in location so that
properly designed brackets positioned there are generally free of
occlusal and gingival interference.
• The angulation and inclination of the site are consistently related to the
plane of the Crown's occlusal surface at all times, and to the occlusal
plane of the arch when the teeth are optimally positioned. The center of
the site, the FA point, always falls on the Andrews plane when the teeth
are optimally positioned
FACC
FA point
Andrews plane
FACC
FA point
Andrews
plane

• Landmarks
• The criteria for the landmarks used to locate the bracket site and to
position the bracket are that the landmarks be accurately and readily
visible by all orthodontists, and that the same landmarks be valid for
both the anterior and posterior teeth.
• Bracket area
• Crown angulation
• Crown inclination
• FACC
• FA
• Bracket siting is an important link in the chain of requirements for
accurate slot siting. Accuracy in this matter requires a technique
for siting the bracket to within 2° of the FACC, and the base point of the
bracket to within 0.5 mm of the FA point.

VERTICAL BRACKET POSITIONINGVERTICAL BRACKET POSITIONING
• When developing the Straight-Wire Appliance- the first preadjusted
appliance- Andrews stated that the human eye is capable of locating
the center of the clinical crown of a normally erupted tooth; with
precision. As a result, the existing devices for bracket positioning in
the edgewise technique, such as the Boone gauge, were no longer
used.
• Vertical bracket positioning is important in terms of the functional
aspects of occlusion. To ensure accurate positioning of brackets, it is
advisable to use positioning instruments (gauges) and bracket
positioning charts for reference during both direct and indirect
bonding techniques. Clinicians should be careful and very precise with
the appliance set-up. Accuracy in vertical bracket positioning will
facilitate the final stage of orthodontic treatment, because the ultimate
goal is alignment of the slots of the upper brackets with the slots of the
lower brackets. Overbite in the anterior region and good
intercuspation of the premolars and molars are facilitated by correct
vertical bracket positioning, providing good functional occlusion.www.indiandentalacademy.comwww.indiandentalacademy.com

• VERTICAL BRACKET POSITIONING CHART
• In the early 1990s, to overcome the challenges faced during vertical
bracket positioning when using the Straight-Wire technique.
McLaughlin and Bennett developed a chart for positioning brackets
• The goal was to establish a positioning system that would improve
intercuspation of the posterior teeth and define the overbite for the
anterior teeth.
• The vertical bracket positioning chart can be used as a reference for the
set-up of both conventional fixed appliances and the SmartClip '" Self-
Ligating Appliance.

• Bracket positioning system
• for non-extraction cases,
• cases with extraction of the first premolars,
• cases with extraction of the second premolars, and
• atypical cases with extensive vertical discrepancy, such as open bite.
• Use of the vertical bracket positioning system for the posterior teeth can
lead to occlusal interferences between the upper buccal cusps and the
bracket wings of the lower premolars and molars. Therefore the use of
low-profile tubes for the lower molars and special tubes for the lower
second premolars in deep overbite cases is recommended. Such tubes
allow an additional 2 mm space in the vertical plane, thus avoiding
occlusal interferences during maximum intercuspation of the posterior
teeth. www.indiandentalacademy.comwww.indiandentalacademy.com

• USING THE BRACKET POSITIONING CHART
• There are two systems for vertical bracket positioning.
• System 1
• This system as recommended for the MBT philosophy, can be applied to
all orthodontic eases. The clinician measures the height of the clinical
crowns of all the teeth with calipers. These measurements are then
divided by two to locate, with accuracy the center of the clinical crown.
With these numbers in hand, the clinician can decide which row on the
bracket positioning chart best corresponds to the crown heights of the
individual patient. This row is then used as a reference for the vertical
positioning of the brackets in that patient.

• System 2
• This system is recommended for orthodontic patients who have upper
and lower incisors with normal clinical crowns. The clinician should
measure the height of the clinical crown of the upper central and lateral
incisors and divide the values by two to locate, with accuracy, the center
of the clinical crown. With these numbers in hand, the clinician can
decide which row in the bracket positioning chart best corresponds to
the height of the remaining teeth. The same procedure should be used
for the lower teeth.
• In both systems, the clinician should be aware of the possible need for
some individualization due to anatomical differences in the clinical
crowns of the teeth.

• Recommendations for using the bracket positioning chart
• Orthodontic treatment without extractions
• In non-extraction cases, the average bracket positioning is recommended
'

• Orthodontic treatment with extraction of first premolars
• When treatment require extraction of the first premolars. the height of
the brackets of the second premolars and the molar tubes will need to be
varied to avoid a vertical step between the canine and the second
premolar. This occurs due to the absence of the first premolar and can
lead to a lack of intercuspation in this area. The height of the canines
should be maintained and the brackets of the second premolars and the
molar tubes should be positioned 0.5 mm more towards the gingival

• Orthodontic treatment with extraction of second premolars
• When the treatment requires extraction of the second premolars, there
will be a need to vary the height of the buccal tubes on the molar to
avoid the occurrence of a vertical step between the first premolar and
the first molar. This can occur due to the absence of the second
premolar. and can lead to a lack of intercuspation in this area.

• Orthodontic treatment for anterior open bite
• For anterior open bite cases, the height of the brackets of the anterior
teeth - incisors and canines - should be changed.
• The goal of orthodontic treatment is to level the planes of the slots of the
upper and lower brackets, in order to obtain an adequate anterior
overbite. In malocclusions with vertical discrepancies and open bites, the
planes of the slots are not always level, which in turn makes it difficult
to close the bite. Thus, the brackets of the-upper and lower incisors and
canines should be positioned more gingivally to compensate for the lack
of leveling of the planes. This will help to close the bite and reduce the
need for finishing elastics.
• Orthodontic treatment for deep overbite
• The severity of the overbite influences bracket positioning in the vertical
direction. Its evaluation is important for achieving leveling of the planes
of the upper and lower bracket slots. Generally there is no difficulty in
correcting overbites, especially when the second molars have already
erupted.

• INDIVIDUALIZED BRACKET POSITIONING SYSTEM
• Upper central incisors
• The clinical crowns of upper and lower central incisors show three
distinct anatomical shapes - ovoid, square and triangular. Special
attention should be given to the anatomical shape of the incisors to
achieve accurate bracket positioning.

• Andrews found that the upper incisors in normal occlusions of North
American individuals showed an average angulation of 3.590
. In a study
by Sebata on Japanese individuals, the average angulation was 4.25°,
whereas Watanabe et al found the average angulation in Japanese
individuals was 3.1 1 °. Trevisi Zanelato found the average angulation
was 2.2 1 ° in white Brazilian individuals. The average angulation based
on all the research mentioned above is 3.29° and shows huge variations
in angulation for the upper central incisors. Due to the anatomical shape
and the variation in angulation of the central incisors, clinicians should
pay particular attention to these teeth when setting up orthodontic
appliances.

• Triangular-shaped teeth requires less angulation than those that are ovoid or
square. The author recommends using an individualized bracket positioning
system for the incisors, canines, premolars and molars.
• Rhomboidal-shaped, medium-sized twin brackets with a .022 X 028 slot and a .
019 X.025 archwire are capable of transferring the angulation built into the
bracket prescription to the teeth. When positioning the bracket, the incisal edge
of the tooth should be parallel to the bracket slot. Thus, the facial vertical long
axis of the clinical crown is not the only reference used for the axial positioning
of brackets on the incisor teeth. It is important to recognize that this does not
apply to square and rectangular bracket designs, for example, the Straight-Wire'
brackets. In these brackets, the angulation is built in the bracket wings, and only
the facial vertical long axis of the clinical crown is used as the reference for axial
positioning. However, in the case of the incisors- this can result in the same
angulation being imparted to all teeth, depending on the bracket prescription
that has been used. Therefore, such brackets are being gradually replaced by
rhomboidal brackets that provide additional reference points for axial
positioning and coordinate the perspective lines into two planes along with
reduced bulk of each bracket.. The author recommends the use of
rhomboidal-shaped brackets with three reference points for positioning the
incisors. www.indiandentalacademy.comwww.indiandentalacademy.com

• Vertical positioning CI
• Brackets should be centered on the clinical crown when positioning the
bracket in the vertical plane, as recommended for the MBT philosophy
similarly even for Smart Clip self-ligating brackets. This positioning is
very important for correcting the overbite during the final stage of
orthodontic treatment to approximately 2-3 mm.

• Horizontal positioning CI
• The labial surface of the upper central incisors is flat, allowing good
horizontal positioning of the brackets. Minor mesiodistal positioning
errors will not cause rotational problems for these teeth. Horizontal
bracket positioning is achieved by clinical visualization, and the bracket
should be centered mesiodistally on the clinical crown

• Axial positioning CI
• As mentioned previously , the clinical crowns of the upper central
incisors have three distinct shapes – ovoid, square and triangular
• Triangular teeth should have less mesiodistal angulation than square and
ovoid teeth. The SmartClip self-ligating bracket for the upper central
incisor has 4° angulation. It can be used on ovoid, square or triangular
teeth to express the required angulation for each type of tooth when
applying the individualized bracket positioning system.
• Axial positioning is also achieved through clinical visualization, and if
the incisal edges of the teeth are parallel with the bracket slot, it
indicates that the axial positioning is correct.

• For individualized bracket positioning for the incisors, clinicians should
refer to the following:
• the facial vertical long axis,
• the mesial and distal edges, and
• the incisal edge of the clinical crown of these teeth.
• By adopting these references for the positioning of the rhomboidal-
shaped brackets, a great variety of angulations considered normal for
the upper central incisors are available to the clinician with a single
prescription.

• However some adjustments may be required if there are anatomical
variations or unevenness of the clinical edges, such issues should be
resolved before treatment.
• For eg: reshaping of the incisal edges to position the brackets accurately.
• Bracket angulation is fully expressed when full size archwire is engaged.
The slot should be parallel to the incisal edges, which should be parallel
to the lower incisal edges during protrusive functional movements.

• Upper LI
• Vertical positioning LI
• Upper LI brackets are more difficult to position than CI brackets.
• This is due to the anatomical variations typically shown by these teeth
• The size of the LI should also be considered when positioning the
brackets
• The MBT vertical bracket positioning chart indicates that the upper LI
brackets should be placed 0.5 mm more incisal than the CI brackets
• However in some cases this value can be higher
• The clinician should pay attention to the original step b/w the LI and CI
• During final vertical positioning of the LI it can vary b/w 0.5 and 1.0
mm
• In cases with small or peg laterals, bracket height should not be
compensated during bonding. The original step should be maintained
and later the crown should be anatomically built up with resin.

• Horizontal positioning LI
• For LI with normal anatomy, the horizontal bracket positioning is
guided by the M-D center of the clinical crown
• Sometimes these teeth show shape variations (labial surface slightly
rounded), thus making it difficult to place the bracket.
• In such cases, to achieve rotational overcorrection, it is helpful to
position the bracket slightly toward the mesial or the distal

• Axial positioning LI
• For upper lateral incisors with normal clinical crowns, bracket
positioning should be based on the facial vertical long axis and the
lateral and incisal edges of the teeth . Some teeth present shape
variation, making it difficult to accurately position the bracket on the
labial surface of the clinical crown. Sometimes, there is also root
dilacerations, which in turn results in a root with a different angle from
that of the clinical crown. This happens when, due to lack of space
during canine eruption, the canine puts pressure on the lateral incisor
root resulting in dilacerations in a mesial direction.
• To ensure good axial positioning of the bracket, it is sometimes helpful
to reshape the incisal edge of the tooth. It is also helpful to check the
pretreatment panoramic X-ray before bonding the brackets for any root
abnormalities. This will allow perfect crown and root positioning,
without compromising stability and esthetics. The incisal edges of the
lateral and central incisors should be parallel to the functional occlusal
plane, even when there is no protrusive contact with the lower incisors.
For teeth with root dilacerations the bracket should be slightly rotated.
This will position the root in the desired angulation.

• Upper canines
• In a mutually protected occlusion at the end of orthodontic treatment,
the canines should guide the lateroprotrusive functional movement.
Accurate positioning of the bracket on the labial surface of the canine is
therefore important to establish the correct overbite and overjet for this
tooth.
• The anatomical characteristics of upper canines include rounded labial
surfaces in the gingivoincisal and mesiodislal directions. The reference
for bracket positioning on these teeth is the facial vertical long axis of the
clinical crown.

• Vertical positioning canine
• It is recommended to position the bracket at either the same height as
the upper CI or 0.5 mm more toward the gingival, using the upper
central incisors as reference. Upper canines should have adequate
overbite in relation to the lower canines to allow lateroprotrusive
functional movements to occur.
• The vertical positioning recommended in the MBT bracket positioning
chart for canines with undamaged anatomy allows disclusion of the
remaining teeth on the working and non-working sides.
• Special consideration should be given to canines that have an
accentuated cusp tip, because this could interfere with the brackets on
the lower teeth during orthodontic treatment, thus compromising
function and esthetics. When the canine cusp tip is very accentuated, it
should be reshaped to allow better positioning of the bracket.

• Canines showing minor cusp tip wear should have the bracket positioned
more gingivally to compensate for the wear, without compromising the
tooth's function. For canines with major cusp tip wear, bracket positioning
in the gingival direction will generate excessive extrusion, increasing the
labial-palatal thickness of the clinical crown occlusally, thus causing
interference with the lower canine during maximum intercuspation.
• For these teeth, the bracket should be bonded in the usual position and the
tooth built up with resin after leveling or at the end of treatment.
• Horizontal positioning Canines
• Upper canines feature rounded labial surfaces, and therefore errors in
bracket positioning toward the distal or mesial can result in rotation of these
teeth. The center of the clinical crown should be used for horizontal
positioning of the bracket- the center of the bracket should coincide with the
facial vertical long axis of the tooth. Some adjustments should he carried out
when there are anatomical abnormalities of the clinical crown.www.indiandentalacademy.comwww.indiandentalacademy.com

• Axial positioning Canine
• As the canine has a cusp tip and not an incisal edge, the anatomical
reference for axial bracket positioning is the facial vertical long axis of the
clinical crown
• The average angulation of upper canine crowns in normal occlusions as
found by
• The average angulation based on all the research mentioned above is 7.49°
• The SmartClip self-ligating bracket has 8° angulation, which is very close to
the universal average of 7.49°. and as the twin bracket angulation is fully
expressed, there is no need for additional angulation.
• The 80
angulation provided by the smart clip bracket for the canine is the
same as MBT bracket and allow minor rotational adjustments up to
approximately 2° in both directions (clockwise or counterclockwise). It is
emphasized that bonding on all teeth, especially the canines, should be
carried out using the panoramic X-ray, so positioning adjustments can be

• Upper premolars
• Due to the huge anatomical variation among premolars, special care is
required when positioning PM brackets. For these teeth, the facial
vertical long axis of the clinical crown should not be the only reference
used for positioning the brackets, because this could result in error
during axial and horizontal positioning.
• Vertical positioning PM
• The first premolar bracket is positioned 0. 5 mm more occlusally relative
to the canine bracket.
• For the second premolar, it is recommended to position the bracket
1.0mm more occlusally than the canine, and variations in placement may
be necessary due to the size of these teeth.
• The buccal surface of upper premolars is generally flat
occlusogingivally, and therefore vertical errors will not lead to
significant changes in torque. Ideal vertical positioning allows perfect
intercuspation with the lower premolars.www.indiandentalacademy.comwww.indiandentalacademy.com

• Horizontal positioning PM
• Correct horizontal positioning of premolar brackets is a very important
part of the set-up of an orthodontic appliance.
• The clinician should refer to the
• facial vertical long axis,
• the buccal and palatal cusp tips, and
• the mesial and distal contact points.
• An accurately positioned bracket should help correct rotations and
establish precise contact points between the premolars and the distal of
the canine .

• Axial positioning PM
• The facial vertical long axis of the clinical crowns of the upper premolars
does not provide a sufficient reference for axial bracket positioning and
could lead to errors. Therefore, the height of the mesial and distal
marginal ridges should also be used as a reference. The occlusal edge of
the bracket base should be positioned parallel to a line on the buccal
surface joining the mesial and distal marginal ridges - the buccal
intermarginal ridge line.
• Use of the references mentioned above for bracket positioning will avoid
a step between the contact points of the premolars and the first molars. It
is important to use the panoramic X-ray to check root parallelism. Due to
difficulty in visualization, second premolar brackets positioning errors
may occur when the direct bonding technique is used.

• Upper first molars
• First molars are very important for the occlusion, therefore three-
dimensional positioning of the buccal tubes should he perfect. In this
way the teeth can satisfactorily perform their function as part of the
masticatory apparatus.
• upper first molars should be perfectly related to the lower molars in
terms of their angular, vertical and rotational positioning. The
inclination of these teeth should also be taken into consideration. During
maximum intercuspation, the upper first molar should show the three
characteristics noted by Andrews when he described the first key to a
good occlusion
• 1. The mesiobuccal cusp of the upper first molar should occlude with the mesiobuccal
groove of the lower 1st
molar
• 2. The palatal cusp of the upper first molar should occlude with the center of the
mesiobuccal groove of the lower first molar.
• 3. The distal slope of the upper first molar distal marginal ridge should be in contact with
the mesial slope of the lower second molar mesial marginal ridge.

• Vertical positioning Molars
• Vertical positioning of upper first molar buccal tubes
is related to the vertical positioning of the remaining
teeth. Incorrect vertical positioning of the first molar
buccal tube will prevent adequate intercuspation of
the premolars and canines. The center of the clinical
crown is the reference for tube positioning, although it
may differ if there are anatomical variations present.
• www.indiandentalacademy.comwww.indiandentalacademy.com

• Horizontal positioning Molars
• The upper first molar buccal tubes of the SmartClip Appliance feature
10° rotation which is the same as for the MBT system brackets. Incorrect
mesiodistal positioning of the tube will result in unwanted rotations.
• Tube positioning toward the mesial will result in additional distal
rotation whereas tube positioning toward the distal will result in
additional mesial rotation.
• The reference for positioning upper first molar tubes is the buccal
groove and the center of the tube should coincide with this .
• Tubes prewelded to bands show this relationship, and correct
mesiodistal positioning will be achieved if the band fits well in the tooth.
Thus, when placing bands, the author recommends good separation of
the molars to avoid problems during tube positioning,

• Axial positioning Molars
• In a Class I normal occlusion, the upper first molar clinical crown is
distally angulated, with the distal slope of the marginal ridge in contact
with the mesial slope of the marginal ridge of the lower second molar.
This angulation should be approximately 5° and is obtained using the 0°
tube, which should be positioned parallel to the buccal intermarginal
ridge line .

• Upper second molars
• Tubes for the second molars feature the MBT prescription of 0°
angulation, 10° rotation and -19° torque. In some cases, the angulation in
these tubes will not be fully expressed, for example, due to a developing
third molar in contact with the root of the second molar
• Another point to be considered is the location of the second molar in the
dental arch. If the second molar is buccally or lingually displaced the
force exerted by the archwire will not be enough to bring it into the line
of the arch.
• Thus, the critical issue with regard to the upper second molars is the
expression of the -19° torque built in the buccal tube. This can be
neutralized by the factors mentioned above and by inappropriate
treatment mechanics that lead to buccal crown inclination (buccal
rolling), so that the lingual cusps become more prominent vertically.
• The SmartClip Self-ligating Appliance System bracket prescription does
not include tubes for upper second molars. Conventional tubes or
minitubes are used on these teeth.

• Vertical positioning 2nd
Molar
• According to the bracket positioning chart, the upper second molar
buccal tubes should be positioned 0.5-1.0 mm more occlusally than those
for the upper first molars. This difference is necessary due to the smaller
size of the clinical crowns of the second molars and the vertical
discrepancies presented by these teeth.
• For patients with open bite or a high angle growth pattern, the tubes
should be positioned more occlusally, thus avoiding the possibility of
extrusion, which can lead to occlusal interferences and further bite
opening

• Horizontal positioning 2nd
Molar
• The horizontal positioning recommended for upper
second molar buccal tubes is the same as for the first
molar buccal tubes. The center of the tube should
coincide with the buccal groove . An error in mesial
positioning will result in additional distal rotation;
conversely, incorrect distal positioning will result in
additional mesial rotation.

• Axial positioning 2nd
Molar
• Axial positioning of the upper second molar buccal tubes follows the
same protocol recommended for the upper first molar buccal tubes.
• The tube should be placed parallel to the buccal intermarginal ridge line
to provide 5° distal angulation. This 5° angulation is often compromised
by the Third molar if it is in contact with the root of the second molar.
However, the second molar can be ideally positioned after the extraction
of the third molar, or when enough space is available for the eruption of
the Third molar

The average angulation based on the research mentioned above
is 0.51° for the central incisors and-0.28° for the lateral incisor
• Lower central and lateral incisors
• The clinical crowns of the lower incisors, as those of the upper incisors
mentioned earlier, have three distinct shapes-ovoid, square, and
triangular. When evaluating the functional aspects of a normal occlusion
at the end of orthodontic treatment, the incisal edges of the lower
incisors should be parallel to the functional occlusal plane and to the
incisal edges of the upper incisors
• Andrews-found that the lower central incisors in normal occlusions
showed an average angulation

• Vertical positioning Lower Incisors
• For all four lower incisors, the bracket should be positioned vertically at
the center of the clinical crown.
• Alignment of these teeth is very sensitive to vertical positioning, and
even minor positioning errors will lead to steps between the teeth.
• In teeth with abnormalities of the incisal edge, these should be reshaped
before placing the brackets.
• The labial surfaces of these teeth are generally flat in the vertical
direction, allowing a good fit of the bracket base to the tooth, without
interfering with the torque.
• The overbite can often compromise the positioning of the brackets on
these teeth. In such cases, the author recommends correcting the
overbite first by starting the treatment' in the upper arch and after
correction of the overbite, proceed with bonding the lower arch.
• In anterior open bite cases, the lower incisor brackets should be
positioned more gingivally.www.indiandentalacademy.comwww.indiandentalacademy.com

• Horizontal positioning lower incisors
• Precise horizontal positioning of lower incisor brackets is important
due to the risk of rotations. The buccal surface of the incisor teeth has a
rounded shape in the mesiodislal direction, and bracket positioning
toward the distal or mesial will result in rotation of these teeth.
• The mesial and distal wings of the SmartClip bracket should be
centered on the labial surface of the clinical crown in the mesiodistal
direction
• The lateral incisors require special attention due to the possibility of
anatomical variations that can lead to rotational errors.

• Axial positioning lower incisors
• Twin brackets perform well in achieving the final axial positions of the
lower incisors. Brackets with 0° angulation are recommended to obtain
root parallelism of the lower incisors. To achieve this, the facial vertical
long axis, the incisal edges, and the lateral surfaces of the clinical crowns
of the incisors need to be taken into account .The panoramic X-ray is
important during bonding, especially for lateral incisors whose roots can
vary in shape due to lack of space during eruption.

• Lower canines
• Upper and lower canines are very important teeth for functional
occlusion, because they allow mutually protected occlusion during
lateroprotrusive movements. For the lower canines -6° torque allows
centering the roots in the mandibular alveolar bone, which results in
better occlusion between the upper and lower canines during
lateroprotrusive movements.

• Vertical positioning Lower Canine
• Lower canines have a rounded labial surface in the gingivoincisal
direction and bracket positioning errors in this direction result in
incorrect torque. For teeth with normal anatomy, the bracket should be
positioned in the center of the clinical crown.
• In the vertical plane, lower canine brackets should be positioned
approximately 0.5 mm more gingivally than the incisors.
• In cases of canines with worn cusp tips, the clinician should consider
either reshaping the enamel or positioning the bracket a little further
toward the gingival. It is important to recognize that positioning the
bracket more gingivally will result in an increase in negative torque,
tipping the clinical crown lingually.

• Horizontal positioning Lower canines
• Lower canines have a rounded labial surface in the mesiodislal direction.
To achieve the recommended mesiodislal position, the lower canine
bracket should be centered on the buccal surface of the tooth, using the
facial vertical long axis, to allow the contact point of the canine to make
correct contact with the distal contact point of the lateral incisor and
with the mesial contact point of the premolars

• Axial positioning lower canine
• The anatomical reference for axial positioning of lower canine brackets is
the facial vertical long axis of the clinical crown. The mesial and distal
wings should be parallel to the facial vertical long axis of the clinical
crown
• Andrews found that the average angulation for lower canine
• The overall average angulation based on the research mentioned above
is 2.950
• The SmartClip Appliance lower canine brackets have 3° angulation for
achieving correct axial positioning of the tooth. The brackets allow
adjustments from +2° to -2° in the axial direction. A panoramic X-ray iswww.indiandentalacademy.comwww.indiandentalacademy.com

• Lower premolars
• Lower premolars require extra care during bracket positioning. It is not
sufficient to rely on the facial vertical long axis. Anatomical
characteristics of the premolars need be considered to achieve good
three-dimensional positioning of the teeth.
• Vertical positioning lower PM
• The buccal surface of the clinical crown of the lower premolars is
rounded in the occlusogingival direction. Errors in the vertical direction
effectively change the torque built in the bracket. The recommended
vertical positioning for the first premolars is the same as that for the
lower incisors. For the second premolar it is correct to position the
bracket 0.5mm more toward the occlusal. Correct vertical positioning of
these teeth leads to better intercuspation with the upper premolars

• Horizontal positioning lower PM
• The buccal surface of the lower premolars is rounded in the mesiodistal
direction and accurate mesiodistal bracket positioning helps to avoid
rotation of these teeth. In most cases, the facial vertical long axis of the
clinical crown is not enough as a reference for good bracket positioning.
• The mesial and distal contact points of the tooth and the buccal and
lingual cusp tips should also be considered. Horizontal bracket
positioning should establish adequate contact points between the
premolars, as well as with the distal of the canine and the mesial of the
first molar

• Axial positioning lower PM
• Axial bracket positioning for premolars is difficult to accomplish
because of the difficulty in visualizing these teeth during direct
bonding.
• For correct bracket positioning of premolars the clinician should focus
on the facial vertical long axis and the mesial and distal marginal ridges.
A line connecting the two ridges (buccal intermarginal ridge line) should
be traced on the buccal surface, and this should be parallel to the
occlusal edge of the bracket base. This allows perfect contact between
the premolars, and with the distal of the canines, and the mesial of the
first molars. The panoramic X-ray should be checked to ensure root
parallelism during bracket positioning.

• Lower first molars
• Inadequate positioning of the lower first molar brackets can occur due to
failure to achieve correct horizontal positioning of the buccal tubes of the
preadjusted appliance.
• Vertical positioning lower 1st
Molar
• Vertical bracket positioning of first molars is often compromised by the
overbite or by the severe lingual inclination of these teeth in cases with a
steep curve of Wilson. Inaccurate tube positioning in the gingival
direction can result in negative torque, altering the first molar
relationship with the premolar. The occlusal wings of the tubes should
be ground down to allow ideal placement in the occlusogingival
direction in such cases.

• Horizontal positioning lower 1st
molar
• 1st
molars get badly rotated as a result of inaccurate horizontal
positioning of the tube
• Lower first molars should have 00
rotation, which provides good mesial
and distal contact points and helps establish good occlusion with the
upper first molars.
• Often the mesial cusp is not the correct reference for horizontal
positioning of the tube to maintain the molars in 0° rotation. In larger
teeth,-the first molars have a central buccal cusp which is very
prominent buccally: consequently, if the mesial cusp is used as the
reference for positioning the tube, there will be lingual rotation .
• To avoid the occurrence of this type of rotation, the tube should be
positioned in the center of the buccal surface of the tooth

• With regard to bands, the buccal tube should be welded toward the
distal, so that the opening of the tube and the lingual margin of the band
are parallel, depending on the tooth's anatomy
• Axial positioning1st molars
• Lower molars should show 20
mesial inclination and this achieved by
positioning the buccal tube parallel with the buccal intermarginal ridge
line
• When using convention tubes welded to bands, they should be welded
parallel to the occlusal edge of the bands. In the mouth, the bands
should then be placed parallel to the buccal intermarginal ridge line

• Lower second molars
• Lower second molars are important teeth in orthodontic biomechanics
and the final stage of orthodontic treatment. They normally have a well
defined anatomical shape with two buccal cusps, which facilitates the
positioning of the buccal tubes. The positioning challenge lies in the
difficult access to the buccal surface of these teeth during direct bonding
Minitubes, developed especially for the MBT technique, allow
positioning in relation to the mesial cusp. This in turn allows early
inclusion of the lower second molars in the orthodontic treatment

• Vertical positioning 2nd
Molar
• The lower second molar buccal tube should be centered vertically on the
clinical crown. Incorrect vertical positioning will result in a step between
the second molar and the first molar, resulting in occlusal interferences
during functional movements. Low-profile tubes or minitubes are a
good option in cases with deep over bite or severe inclination of the
curve of Wilson
• Horizontal positioning 2nd
molar
• Lower second molar buccal tubes have 0° rotation, which allows good
contact with the lower first molars and good occlusion with the upper
second molars.
• Lower second molars have two buccal cusps, and these are used to
locate the tube position in the mesiodistal direction. It is recommended
that the center of the tube should coincide with the buccal groove of the
clinical crown to avoid unwanted rotations

• Axial positioning 2nd
molar
• Tubes for lower second molars have 2° angulation and the axial
positioning protocol is similar to that used for the buccal tubes of the
first molars. The bands and/or buccal tubes should be placed parallel to
the buccal intermarginal ridge line

• Errors in bracket positioning
• Horizontal error
• If placed mesial or distal of the vertical long axis of the clinical crown,
improper tooth rotation can occur.
• Such errors can be avoided by visualizing the vertical long axis of the
crown directly from the facial surface as well as from the incisal or
occlusal surface with a mouth mirror
• Some orthodontist even consider drawing a pencil line along the vertical
long axis of the clinical crown, for more accurate visualization.

• Axial or paralleling errors
• These will occur if the bracket wings do not straddle the vertical long
axis of the crown in parallel manner
• Such errors lead to improper crown tip and can also be avoided by
viewing the crown directly from the facial surface, as well as from the
incisal or occlusal surface
• Special care is needed to avoid axial errors when positioning brackets on
cuspid
• Thickness error
• these can occur if there is excess adhesive under one side of the bracket
base or if the contour of the tooth is not the same as the contour of the
base of the bracket
• Such error can cause incorrect tooth torque or rotation, and can be
eliminated by pressing the bracket against the tooth during placement so
that excess adhesive flows from beneath the bracket, or by contouring
the bracket base to fit the tooth surface more accurately.

• Vertical error
• Theoretically bracket should be positioned at the vertical midpoint of the
long axis of the clinical crown
• However this has proven to be difficult to achieve clinically in some
cases and in past the authors have found that a high percentage of
bracket repositioning is for vertical reasons.

• Gingival concerns during vertical bracket positioning

• Teeth with palatally or lingually displaced roots
• With such cases gingiva covers a greater portion of the clinical crown
than normal, producing a shorter clinical crown.
• The tendency is to place the bracket too incisally or occlusally
• Teeth with facially displaced roots
• Such teeth show lengthened clinical crown, creating a tendency to place
bracket too gingivally
• This is common occurrence with cuspids.

• Incisal or occlusal concerns during vertical bracket positioning
• Incisal or occlusal crown fractures or tooth wear results in difficult to
visualize the size of the clinical crown before the fracture or tooth wear
occurred
• Correction of this problems can be made either by restoring the crown to
its appropriate length or by estimating the how long the crown was
before fracture or wear.
• Crowns with long tapered buccal cusps
• Occasionally the crowns of cuspid or PM will show an unusually long
and tapered buccal cusp
• If the bracket is placed in the center of the clinical crown, adjacent
marginal ridge will not be properly aligned. This can be corrected by
selectively reducing the height of the crown before bracket placement.

• Advantage of using chart
• Potential gingival errors are eliminated, because measurements are
made from incisal or occlusal edges.( because most vertical errors result
from the inability to visualize accurately the gingival half of the clinical
crown)
• Difficulties with proportionally large or small teeth within the dentition
are eliminated
• Errors can be avoided when bracketing teeth which have long, tapered
crowns or which show incisal fractures or attrition

Materials and methods
• Thirty-eight typodont models were simulated with a Class 1 molar
malocclusion with severe crowding, but no tooth was so severely displaced
that it prevented ideal bracket placement .
• The typodont was custom-made from a rapid set polyurethane resin with each
arch having two holes drilled posteriorly to allow them to be fitted to a
modified adjustable typodont mount. Prior to placement of the typodont on
the mount, the buccal surface of each tooth was prepared by sandblasting it
for 10 seconds with 50.µm aluminum particles were then fitted followed by a
cheek retractor placement . This was to ensure a realistic clinical situation
where the premolar teeth had to be bonded with the use of a mirror and not by
direct vision. The mount was attached to the side of a table so each operator
could modify its position to represent a patient in a supine position.

The operator and bracket bonding
• Nineteen experienced orthodontic specialists {12 -male, 7- females}
participated in this study. Their mean age was 40.6 years (range 29-
53} and their mean years of experience was 8.3 years (range 1—25).
They were asked to bond pre-adjusted straight-wire brackets (Victory
series, low profile, MBT, 3M, Unitek, Monrovia, California, USA) on
the simulated typodont models.
• All participants were given a prepared handout, with photographic
images, defining the exact position each bracket is to be placed.
• Each operator was asked to bond 20 brackets on one typodont with
the CC method and 20 brackets on another typodont with the ME
method.

• The FA point was perceived as the vertical midpoint along the long axis
of the CC. (Andrews. 1979), while the measured distances from the ME
of different teeth were adopted as those defined by McLaughlin and
Bennett (1995).
• The operators were given a selection of instruments{ mirror, probe,
periodontal probe, scaler , hollenbach , flat plastic, ruler, and height
gauges (4-5.5 mm, 3M Unitek )}. The teeth were then primed and
bonded with Transbond (3M, Unitek). The time taken to place the
brackets for each technique was recorded. The brackets were set using
the available curing light. As the bond strength of the brackets were not
to be tested, standardization of the curing lights was not necessary.

Examination of the accuracy of bracket placement
The teeth were removed and placed in individually made jigs (Odontosil,
Dreve-Dentamid GmbH, Unna, Germany).
Twenty jigs were manufactured, one for each tooth. The jigs could be
positioned in two ways in a mount, which fitted on one end of a specially
constructed photographic jig (Figure 3).
A Nikon D1 with a Nikon 110 lens was fitted on the other end of the jig and
two digital photographs were taken (one buccal and one occlusal). The
images were saved as Joint Photographic Expert Group images and then
opened using an imaging system (Analysis Pro 3.1, Munich, Germany) and
calibrated using the ruler attached to the jig. The images were magnified
200 per cent and three measurements were made by one author (DA) to
identify the error of bracket positioning (Figure4).

Each measurement was repeated three times, 1week apart and an average
was taken. The three measurements were
• Vertical positioning error (Figure 4a):
• The vertical position of the bracket was measured from the incisal edge
to the vertical midpoint of the bracket archwire slot, which was located
by constructing two diagonal lines from the four comers of the slot. The
vertical positioning error was then calculated by subtracting this
measurement from
• (1) the actual distance between the CC and the ME or
• (2) the defined measured distance for that particular tooth (Table 1).
• Positive values indicated occlusal placement and negative values
gingival placement.

2. Mesiodistal positioning error :
• This was measured from the occlusal image with the midpoint of the
tooth being identified, and the horizontal distance from the midpoint
of the tooth to the midpoint of the bracket measured.
• Mesial placement was defined as a positive value and distal
placement as a negative value.
3. Angular/tip error :
This was identified by measuring the intersecting angle between the
vertical scribe line on the bracket and the long axis of the CC.
If the bracket was tipped mesially the value was recorded as positive
and if distally a negative value was recorded.
Positioning the bracket with a mesial tip would result in a final distal
tip of the crown.

• Results
• The mean time taken to bond the 20 brackets was 28.53 minutes (SD
9.51) for the CC placement and 28.2I minutes (SD 10.53) for the ME
method. There was no statistically significant difference between the two
technique:-
• Neither the age nor the years of experience of the orthodontists affected
the accuracy of bonding.
• Overall the vertical, mesiodistal, and tip errors were not statistically
significantly different with cither the CC or the ME method. When
assessing the arches independently, there was also no statistically
significant difference between the two methods of bracket placement.
The errors for the vertical dimension assessed relative to the mean and
for the arches independently and overall were not statistically different .

• An overall test of significance between the two method (CC and ME)
using all the measurements rather than comparing the means is more
likely to demonstrate small differences.
• The overall test demonstrated significant difference in the vertical
between the CC and ME methods, with the ME method more accurate
(mean CC = 1.19, mean ME =1.10, P = 0.002) but no significant
differences for mesiodistal (mean CC = -0.08, mean Ml= 0.05, P = 0.28)
or for tip (mean CC -= -1.61, mean ME = 1.35, P= 0.34) errors.

• The teeth were paired and a t-test was performed to identify if there
were any differences in accuracy comparing the right and left sides.
• For the CC method, there were significant error differences (P < 0.01) in
the vertical and mesiodistal error for teeth 15 -25, vertical for 13 -23.
vertical and mesiodistal for 12-22, mesiodistal for 41 31, and tip for 44--
34.
• For the ME method, there were significant error differences (P < 0.01) in
the vertical and mesiodistal for 15-25, vertical for 14-24, vertical for 13-
23, mesiodistal for 41-31, tip for 42- 32, vertical for 43- 33, and vertical
and tip for 44-34.
• Although there were no statistically significant differences in the tip
error b/w the two methods of bracket placement, the majority of the
errors were negative, which suggested a trend to bond the brackets with
a distal tip.

• Having carried out the procedures, it was confirmed that the sample size
of l9 orthodontists was adequate to determine clinically significant
differences between CC and ME if they occurred.
• For the vertical and mesiodistal errors, it was felt that differences of 0.25
mm for upper central and lower incisors (11, 21, 31, 32, 41, 42) and 0.50
mm for other teeth would be clinically important. On the basis of
observed variability, the present sample of 19 achieved 77 percent power
in the incisor teeth, and over 95 percent power for other linear
measurements. A sample of size 19 would also achieve 85 per cent
power to identify differences of 2 degrees in incisor teeth and 3 degrees
in other teeth.

• Discussion
• This study was designed to identify if there were any significant
differences in accuracy of positioning of orthodontic brackets between
the two methods (CC and ME).
• The time taken to position the brackets was 28.53 minutes (SD 9.51) for
the CC method and 28.21 minutes (SD 10.43) for ME method, indicating
that there is no advantage in terms of chair time between the two
techniques.
• The overall analysis and the assessment of the arches independently
showed that there were no statistically significant differences in
accuracy of bracket positioning between the two techniques (Table 3),
indicating that there appears to be no advantage in one technique over
the other. Conversely, an overall test of significance between the two
methods using all the measurements rather than comparing the means
demonstrated a significant difference in the vertical between the CC and
ME methods, with the ME method more accurate (mean CC = 1.19,
mean ME = 1.10,P = 0.002).

• However, this statistical method is more likely to show small differences
as significant with the difference between the means 0.09 mm. which
would not be clinically significant. However, analysis of the teeth
individually suggested that the ME method was more accurate in
vertical positioning for several upper and lower anterior teeth and less
accurate for the upper first premolars
• This may indicate that it is more accurate to bond these teeth a measured
distance from the incisal edge. However, the operators tended to
bond incisally and the correct bracket position for the ME method was
more incisal than that for the CC method. Therefore, possibly by
default, the brackets ended up closer to the correct position. The
majority of the operators did not use the height gauges available.
They either estimated the bracket positions for both techniques or used
the periodontal probe, and only one operator measured the teeth
to identify the centre of the CC. This possibly reflects the fact that as
specialists they are bonding brackets on a daily basis and feel that their
perception of distance is as accurate as measuring.www.indiandentalacademy.comwww.indiandentalacademy.com

• Koo et al. (1999) reported that the use of height gauges does not
necessarily reduce the range of error They found that there was a wide
range of variation in height measurements when bonding using boon
gauge (overall mean 0.35 mm. SD 0.26) They suggested that this could
be due to tilting of the gauge, which affects the accuracy of the height
measurement. Their investigation demonstrated less vertical error than
the present study (CC 1.19 ± 0.23 mm, ME I.IO ± 0.25 mm). Therefore, it
is possible that if operators measured the teeth and used the height
gauges the accuracy of bracket placement in the vertical dimension
could have been improved.

• Aguirre et al. (I9S2) found that for linear vertical measurements, there
was a trend for left-side bonds to more accurate in the upper arch, direct
or indirect, and right side bonds to be more accurate in the lower arch.
However in this study although there were statistical differences in both
techniques when comparing the right and left sides, there was no
specific pattern. This may indicate that it was no more difficult to place
brackets on either side.

• For both techniques, there appeared to be a trend for brackets to be
bonded with a distal tip. This may be due to the fact that the long axes of
the typodont teeth were hard to identify correctly, or that the scribe line
was difficult align with the long axis.
• In this study, the finding that the pattern of the error bracket positioning
was very similar between the techniques is in agreement with that of
Balut et al. (I992) who suggested that there was a basic human limitation
in the direct placement of brackets in the mouth.
• The evidence showed that neither technique proved perfect accuracy in
bracket positioning. This further requires the orthodontists to either add
compensating bends into the arch wires or reposition the brackets to
compensate for the bracket placement errors throughout the course of
treatment.

• On the other hand, more advanced techniques in locating the brackets
are required to secure reliable bracket positioning. Hopefully with the
introduction of three-dimensional compute:-generated models, it will
become more practical to place bracket in a more ideal position for
individual cases compensating for tooth size and shape, tooth
malposition in the arch, t operator skill. It is expected that these ideal
positions could be transferred by custom-made transfer jigs
manufactured by either a third party, or an in-house milling machine,
and then indirectly bonded to improve clinical efficiency and
potentially to reduce treatment time (Ciuffolo et at. 2006).

• Conclusions
• Placement of brackets in the positions determined measuring the
distance from the ME appears to be more accurate in the vertical
dimension for the upper ;lower anterior teeth.
• The extent of error of bracket placement, regardless which technique
was used, demonstrates that archwire bending adjustments or
repositioning of brackets will be necessary to achieve acceptable
treatment results.

• Bibliography
• Hugo Trevisi: SmartClip self ligating appliance system concept and
biomechanics
• Lawrence F Andrews: Straight wire The concept and appliance.
• John C Bennett & Richard P McLaughlin: Orthodontic management of
the dentition with the preadjusted appliance.
• John C Bennett , Richard P McLaughlin & Hugo Trevisi :Systemized
orthodontic treatment mechanics.
• Andrews LF. The straight wire appliance explained and compared. J
Clin Orthod 1976;10:174-95..
• Germane N, Bentley BE, Isaacson RJ. Three biologic variables modifying
faciolingual tooth angulation by straight-wire appliances. Am J Orthod
Dentofacial Orthop 1989;96:312-9.www.indiandentalacademy.comwww.indiandentalacademy.com

• Balut N, Klapper L, Sandrik J, Bowman D. Variations in bracket
placement in the preadjusted orthodontic appliance. Am J Orthod
Dentofacial Orthop 1992;102:62-7
• Creekmore TD, Kunik RL. Straight wire: the next generation. Am J
Orthod Dentofacial Orthop 1993;104:8-20
• Koo BC, Chung C-H, Vanarsdale RL. Comparison of the accuracy of
bracket placement between direct and indirect bonding techniques. Am J
Orthod Dentofacial Orthop 1999;116:346-51
• Sean K. Carlson and Earl Johnson. Bracket positioning and resets: Five
steps to align crowns and roots consistently. Am J Orthod Dentofacial
Orthop 2001;119:76-80.
• Hoffman BD. Indirect bonding with a diagnostic setup. J Clin Orthod
1988;22:509-11

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