Correction of deep bite

CORRECTION OF
DEEP BITE
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Deep Bite:
 The deep bite can be defined by the amountThe deep bite can be defined by the amount
and percentage of overlap of lower incisorsand percentage of overlap of lower incisors
by the upper incisors by the upper incisors.by the upper incisors by the upper incisors.
The overbite may be calculated as aThe overbite may be calculated as a
percentage of the clinical crown height ofpercentage of the clinical crown height of
one of the mandibular central incisors.one of the mandibular central incisors.

 Age related Changes Of Deep BiteAge related Changes Of Deep Bite::
 At age of 5 to 6 years this percentage variesAt age of 5 to 6 years this percentage varies
between 36.5 and 39.2. In adults it remains almostbetween 36.5 and 39.2. In adults it remains almost
unchanged, varying between 37.9 and 40.7%.unchanged, varying between 37.9 and 40.7%.
Fleming showed that between 9 and 12 years ofFleming showed that between 9 and 12 years of
age the overbite usually is increasing, whereas inage the overbite usually is increasing, whereas in
the period between 12 and adulthood it isthe period between 12 and adulthood it is
decreasing. No sex differences were noted.decreasing. No sex differences were noted.

Craniofacial Dimension and Deep Bite:
 Moorrees in 1959 determined that ramus length was one ofMoorrees in 1959 determined that ramus length was one of
the most important dimensions associated with the amountthe most important dimensions associated with the amount
of overbite. He further states that the reduction in theof overbite. He further states that the reduction in the
overbite after 12 years of age may be due to growth of theoverbite after 12 years of age may be due to growth of the
ramus of the mandible.ramus of the mandible.
 Nanda in 1988 Showed that fundamental differenceNanda in 1988 Showed that fundamental difference
between the open- and deepbite faces is found in thebetween the open- and deepbite faces is found in the
anterior segments of the face, rather than in variations ofanterior segments of the face, rather than in variations of
ramal height or total posterior face height. In the deep-biteramal height or total posterior face height. In the deep-bite
subjects, upper face height is increased.subjects, upper face height is increased.

Interocclusal space
 Interocclusal space is defined as space betweenInterocclusal space is defined as space between
the maxillary and mandibular dentition whenthe maxillary and mandibular dentition when
Patient is in CR. Normally interocclusal space isPatient is in CR. Normally interocclusal space is
about 2 mm. A large interocclusal space allowsabout 2 mm. A large interocclusal space allows
one toone to extrude the posterior teeth without hingingextrude the posterior teeth without hinging
the mandible open(eg class II divII)the mandible open(eg class II divII) . In a patient. In a patient
with little or no interocclusal space,with little or no interocclusal space, any eruptionany eruption
of the posterior teeth is accompanies by hinging ofof the posterior teeth is accompanies by hinging of
the mandible open.the mandible open.

Methods Of Correcting Deep Bite
 1.1. Extrusion of the posterior teethExtrusion of the posterior teeth
 2. Intrusion of the anterior teeth2. Intrusion of the anterior teeth
 A) Absolute IntrusionA) Absolute Intrusion
 B) Relative intrusionB) Relative intrusion
C) Pseudo intrusionC) Pseudo intrusion
 3.3. Combination of bothCombination of both
 4. Uprighting the Posterior Teeth4. Uprighting the Posterior Teeth
 5. Increasing the inclination of the anterior teeth5. Increasing the inclination of the anterior teeth

The method used to treat deep bite should be
determined by proper treatment planning with
consideration given to aesthetics, occlusal
plane ,lip incompetencey ,vertical
dimension,skeletal convexity and the stability
of the final results.

EXTRUSION OF THE POSTERIOR TEETH
 Correction of deep overbite by this method is oftenCorrection of deep overbite by this method is often
indicated in patients having a steep occlusal plane and inindicated in patients having a steep occlusal plane and in
growing children, in whom posterior eruption can begrowing children, in whom posterior eruption can be
tolerated without ultimately hinging the mandible open .tolerated without ultimately hinging the mandible open .
There may be a transitory hinging, but growth can beThere may be a transitory hinging, but growth can be
expected to overcome the hinging of the mandible .expected to overcome the hinging of the mandible .
 The use of these appliances is contraindicated, as inThe use of these appliances is contraindicated, as in
children with a backward growth rotation of the mandiblechildren with a backward growth rotation of the mandible
and non growing patients. It can also correct the lipand non growing patients. It can also correct the lip
redundancy.Stability of such correction is in question.redundancy.Stability of such correction is in question.

METHODS OF POSTERIOR EXTRUSION
 The posterior teeth can usually be leveled about severalThe posterior teeth can usually be leveled about several
centers of rotation, depending on the amount of requiredcenters of rotation, depending on the amount of required
arch lengtharch length..
 1.1. Tip-back mechanism.Tip-back mechanism.
 2.2. Base arch mechanism.Base arch mechanism.
 3.3. 0.016-inch distal extension.0.016-inch distal extension.
 4.4. Parallel eruption of the buccal segmentParallel eruption of the buccal segment

Tip - Back Mechanism
 1.1. In growing patients with a forward growth rotation.In growing patients with a forward growth rotation.
 2.2. For a deep curve of Spee in the lower arch.For a deep curve of Spee in the lower arch.
 3.3. For a deep overbite.For a deep overbite.
 4.4. For slight arch length inadequacy (1 to 2 mm perFor slight arch length inadequacy (1 to 2 mm per
side).side).
 5.5. For a steepened natural plane of occlusion.For a steepened natural plane of occlusion.
INDICATIONS:

The tip-back mechanism consists of
1. 0.036-inch lingual arch.
2. 0.018 x 0.025 inch anterior segment, which can sometimes be
left long, distal to the cuspids.
3. Buccal stabilizing segments (BSS) of 0.018 x 0.025 inch from
(ideally) 7-4,
4. 0.018x0.025 inch tip back spring

With the correct use of this tip-back mechanism, one will notice that
1. The CRot
is placed distally, somewhere around the distal root of
the second molar.
2. There is eruption and rotation of the buccal segments.
3. There is increased arch length distal to the canines (1 to 2 mm).
4. The second molar is often buried.
5. With the hook placed distal to the CRes
of the anterior segment,
the roots of the lower anterior segment often come forward, which is
good, if one is flattening the plane of occlusion.
6. There is no flaring of the anterior teeth, because the hook is
made to slide freely along the anterior segment wire.

The force values used are calculated on the basis that between 3,500 and 4,000
g-mm is required to erupt and rotate the buccal segments optimally. This is a
moment of a force; the force can be calculated by knowing the distance from
the CRes
of the lower buccal segment (mesial to the lower first molar root for a
four -tooth segment ) to the point of attachment on the anterior segment:
3,500
____ = F
L
where L = the distance from the CRes
of the buccal segment to the point of
attachment on the anterior segment. The force can be adjusted using the
Dontrix tension gauge.

Base Arch Mechanism
The main difference between this applicance and the previous tip-back
mechanism is in the location of the center of rotations.
The force system is nearly identical to that of the tip-back
spring, except for the fact that there is no anterior hook free to
slide anteroposteriorly; with the base arch tied back securely as ,
the CRot
is moved mesially to somewhere close to the mesial root
of the first molar.
1. Eruption and a negative rotation of the buccal segment
(flattening of the plane of occlusion).
2. No increase in arch length.
3. That the roots of the buccal segment move forward.
4. That second molars sometimes appear to be buried (remember the
negative moment

0.016-inch Distal Extension
In order to use this appliance, there should be
Good growth increments remaining, since the
appliance is eruptive.
A significant second-order discrepancy
between
the canines and the incisors;
i.e., the incisors should be higher than the
canines.
Minimal arch length required (2 to 3 mm per
side).
A deep curve of Spee.
Extraction of teeth, usually the first premolars

The appliance itself consists of
0.018 x 0.025 inch base arch.
0.016-inch distal extension. Immediately mesial to the
canine bracket a vertical loop is placed and
immediately distal to the canine bracket a helix is
placed. The distal extension can be adjusted to lie over
the tie-wings of the second premolar bracket, or can be
hooked over the buccal segment wire.
.
0.036-inch lingual arch.

Parallel Eruption of the Buccal Segment
Parallel eruption of the buccal segment is used in the upper jaw
only. Using a cervical headgear with its long outer bow bent high
(about 60 degrees), a negative moment is provided by bringing
the outer bow down to the line of action of the headgear straps .
Once engaged, the line of action of the force times the
perpendicular distance away from the CRes
of the upper jaw
produces a positive moment. Both moments tend to cancel each
other out, and one is left with a purely extrusive force to the
buccal segments .

Anterior bite plane
Bonded biteplanes simultaneously accomplish:
• Intrusion of maxillary incisors and canines
• Intrusion of mandibular incisors and canines
• Extrusion of maxillary molars
Extrusion of mandibular molars

Bonded Acrylic Lingual Biteplanes
Technique developed by Ronald Madsen similar to lingual brackets
with built –in bite planes to open the bite. Acrylic extensions are
bonded to the lingual surfaces of the maxillary incisors producing an
intrusive or growth restraint on the incisors while allowing the
posteriors to erupt.they are called lingual bite steps because of their
stairstep form

Lingual Brackets in Deep Bite
This article will suggest a simple and effective method of intruding incisors in
deep-bite cases that fully respects the principles set out by Burstone. The
appliance for rapid incisor intrusion consists simply of four lingual brackets
(from Ormco* or American Orthodontics**), bonded directly or indirectly.
Precise placement is not necessary, because the brackets are used only as
fixed biteplanes.
For the mandibular incisors to occlude with the maxillary lingual brackets, the
initial overjet must be less than 4mm.

Intermaxillary Elastics

INTRUSION OF THE ANTERIOR TEETH
Bite opening in patients with a vertical growth pattern should be accomplished
by means of intrusion of incisors. The deep bite correction in these patients by
means of extrusion of molars may worsen their facial outlook. Most of these
patients already have lip incompetence and an increased lower anterior facial
height. Also in adults, where bite opening is aimed for, intrusion of incisors
should be our first choice. Increasing the lower anterior facial height by
extrusion of molars may not always be a stable situation in adult patients.

From the esthetic perspective, a serious mistake commonly made
in orthodontic practice is “overintrusion” of the maxillary incisors
in most deep overbite cases, this will tend to hide the maxillary
anterior teeth behind the upper lip in normal conversation. Such a
mistake can go undetected by the orthodontist unless the patient’s
toothdisplay and smile are analyzed from the front.The maxillary
incisors should be moved in the vertical direction that improves
their relationship to the resting lip position, and the tooth-to-lip
position should be monitored constantly throughout treatment.In
some deep overbite cases, this may actually mean extrusion rather
than intrusion of the maxillary teeth
The best treatment strategy in the majority of deep overbite cases is to actively
intrude the mandibularincisors.

Burstone intrusion arch
The intrusion arch, as described by Burstone, is significantly different in its
force deliver because it is not engaged in the incisor brackets.
Appliance design
The basic mechanism for intrusion consists of three parts: (1) a posterior
anchorage unit, (2) an anterior segment, and (3) an intrusive arch spring .
Early in treatment the posterior teeth are aligned and joined together with a
buccal stabilizing segment. Once a buccal stabilizing segment of at least
0.018 by 0.018 inch reached. Right and left posterior segments are joined
together across the arch by means of a transpalatal lingual arch in the maxilla
and a low lingual arch in the mandible.As many teeth as possible are joined
together to form the posterior anchorage unit. Whenever possible, at least the
first molars and second premolars should be used and the addition of other
teeth would further enhance the anchorage potential. All teeth are joined
together by means of a buccal wire to form a buccal unit. The buccal wires,
buccal stabilizing segments, are at least 0.018 inch square in cross section for
0.022 inch slotted brackets. www.indiandentalacademy.com

. Intrusive arch normally consists of an 0.018 by 0.025 inch by
edgewise wire with a 3 mm. helix wound 2½ times placed mesial
to the auxiliary tube. Curvature is placed in the intrusive arch, so
that the incisal portion lies gingival to the central incisor. When
the arch is tied to the level of the incisors, an intrusive force is
developed. In order that the arch does not increase its length
during the activation, a gentle curvature should be placed with
the amount of curvature increasing as one approaches the helix.
In this way the activated arch wire will appear relatively straight,
and as it works out during intrusion arch length will decrease and
no anterior flaring is produced

Principles of overbite control
Controlling the force magnitude and
constancy
If the magnitudes of force are too great, the rate of intrusion will
not increase and the rate of root resorption will increase. The
posterior teeth will feel a vertical force which will tend to extrude
the buccal segments and a moment or torque which in the upper
arch will steepen
Low load deflection mechanics
For eg Springs that deliver relatively constant force have low load-deflection
rates. An intrusive arch with a 30 mm. arm (perpendicular distance from the
incisor to the first molar) has a load-deflection rate of 6 Gm. per millimeter. If
this intrusive arch is activated 16.5 mm., 100 Gm. of force is produced in the
midline, 50 Gm per side. As the incisors intrude 1 mm., there is a change of
force magnitude of only 6 Gm.; hence, the delivery of force is relatively
constant.

Anterior single point contacts
intrusive arch is not placed directly into the brackets of the anterior teeth
anterior torque may be present in the arch. Even if no torque is present, as the
intrusive arch works out, torque can be introduced.

If Labial root torque is placed into the incisors, the intrusive
forces are increased on the anterior teeth and can produce
anchorage loss of the posterior teeth.
If lingual root torque is present, it will have the effect of
reducing the magnitude of intrusion on the incisors. if the
lingual root torque is large enough, the direction of the force
could reverse and the incisors could actually extrude.
An exception in which the intrusive arch may be placed in
the brackets of the incisors can be found in the example of
central incisor intrusion alone . If the intrusive arch is placed
into the incisors, it is necessary to round the wire so that no
torque is produced

Point of force application
An intrusive force placed through the center of resistance of the incisors will intrude
the center of resistance and not produce any labial or lingual rotation of the teeth.
In maxillary intrusion, the intrusive arch is normally placed slightly anterior to the
labial surface of the incisors as it is attached to the anterior segment.
This produces a moment which tends to flair the crown forward and move the root
distally

Right and left sectional intrusive arches are constructed with a hook
that catches on the posterior extension so that the force can be
directed through the center of resistance of the incisors .
An intrusive force on a flared tooth has a strong anterior component
which tends to translate the root of the incisors labially .
Since only a portion of the 'component force is directed along the
long axis of the tooth, rates of tooth movement are proportionately
low.
An anterior segment is made with a posterior
extension

Selective intrusion
Class II Div II
Indiscriminate leveling with a continuous arch
or with sections can produce undesirable side
effects in a patient with deep overbite
A straight arch wire placed through the brackets
produces vertical forces maxillary arch could be
leveled by not producing any intrusion but by
extrusion and steepening of the maxillary plane
of occlusion .
The undesirable moments will tend to converge
the roots toward the midline.
Intrude just the two central incisors to the level
of the lateral incisors before joining all four
incisors together for further intrusion

Class II, Division 1
patients may require intrusion of four incisors, both
maxillary and mandibular, to the level of the
canines.
Many times canines that appear in infraocclusion
should not be extruded, but the four anterior teeth
should be intruded to their level bypassing the
canines

Control of the reactive units
lateral view a moment is created which tends to alter the
plane of occlusion of the buccal segment; in the upper
arch the plane is steepened.
To minimize these changes, forces are kept as low as possible.
occipital headgear can be used in the upper arch, designed so that its force
is anterior to the center of resistance The headgear produces a moment
opposite to the moment produced by the intrusive arch and thus prevents
the steepening of the maxillary plane of occlusion

frontal view
With an intrusive force on the incisors, there is an equal and opposite
extrusive force on the molars.
Since the extrusive force is operating buccally at a tube a moment is
created that tends to tip the crowns lingually and the roots buccally.
lingual arch prevent any undesirable change in axial inclination of the
molars or change in width..

Avoiding extrusive mechanics
If the canine has a crown distal to the root. If the arch wire is placed into
the canine bracket, it will lie occlusal and hence will produce eruption of the
incisors. Incisors make very poor anchorage for distal root movement of a
canine, since eruption occurs so much more easily than distal root
movement. It is preferable to bypass the canines during canine root
movement, or in certain situations canine root movement should be
completed before the incisors are joined to the rest of the arch.
Inhibition of the eruption of posterior teeth in the growing patient can be
accomplished using.
Occipital headgear can be worn to the upper arch or cervical headgear with
high outer bows to the lower arch.
Chin caps can be useful in inhibiting the eruption of posterior teeth.

Canine intrusion
It is usually not possible to intrude all six anterior teeth at one time without
producing undesirable axial inclination change in the posterior segment.
100 Gm. of force on a side is required to intrude the incisors and the canines.
100 Gm. would produce a moment of 3,000 Gm.mm moment to the posterior
segment if the perpendicular distance from the incisors to the center of
resistance of the posterior segment was 30 mm.
moments of this magnitude are most effective, tipping of the posterior teeth
will occur more rapidly than the intrusion, on the posterior teeth.
canine-intrusion spring which is activated to produce 50 to 75 Gm. of force. It is
fabricated from 0.018 by 0.025 inch wire inserted into the auxiliary tube of the
first molar and into the vertical tube of a canine bracket. Since the intrusive force
lies lateral to the center of resistance of the canine, it is necessary to place a
slight constrictive force in the spring to keep the canine from flaring labially.

Rickets lower utility arch
Principles of overbite
control
The use of lighter
forces
A force of 300 grams is measured at the lower incisor bracket when a “reverse-
curved archwire” is tied in through the buccal occlusion to the cuspids.. These
heavier forces physically squeeze out the blood supply to the area and limit the
biological response so necessary to the physiological alteration of the bone and
the efficient movement of the teeth.

0.018 wire can excert 650gms of force between premolar
and molar
In order to lessen the force being delivered to a single tooth or group of
teeth the concept of a long lever arm is applied by placing more wire
between the teeth the applied force is lowered and the length of time of
activation is increased. Thus, the concept of lighter continuous forces

Treatment of overbite before overjet
It is found that cases finished in deep overbite can produce displacement of the
condyle.
Torque control
Problems in continious arch wire
Efficient lower incisor intrusion suggests that the roots be torqued buccally to
avoid the supporting lingual cortical bone, while the roots of the cuspids around
the corner of the arch also be torqued buccally to avoid the cortical bone on their
lingual surface. These movements are very difficult to effect by traditional full
arch round wire leveling

Segmented arch treatment allows us to torque the lower incisor roots away
from the lingual cortical bone which aids in their intrusion, and the cuspids
can then be intruded separately along a route of least resistance and still
maintain molar torque and rotational control for anchorage support.

Less friction and arch wire binding
The upper cuspids or other teeth are limited in their movement they first
must overcome the friction and binding force of the bracket in order to be
moved along an archwire.
Sectional arch treatment allows the cuspid to move more freely without the
binding effect of sliding around a continuous archwire.

Concept of Cortical Bone Anchorage
To anchor a tooth, its roots are placed in proximity to the dense
cortical bone under a heavy force that will further squeeze out the
already limited blood supply and thus anchor the tooth by
restricting the physiological activity in an area of dense laminated
bone. Because of its density and limited blood supply, the cortical
bone resists tooth movement. On the other hand, move a tooth, it
is necessary to route through the less dense trabecular bone where
under a light force a generous blood supply can be maintained
that will produce the physiological osteoclastic reaction of bone
resorption that is needed for the efficient movement of teeth

Upper and lower cuspid
During cuspid retraction the cuspid roots must avoid this denser
cortical bone on the lingual and be moved around the corner in the
initial stages of their retraction in order to stay in the trough of
trabecular bone .
When cuspid roots contact this lingual cortical bone they strain the
anchorage support and are more susceptible to tipping around this
denser bony fulcrum, tipping wherein the
crown is extended distally and the root tip comes forward often
into or through the labial cortical bone.
In extraction treatment the cuspids are first retracted on
sectional arches in order to keep the cuspid roots in the trough
of trabecular bone and thus round the corner by avoiding the
dense lingual alveolar or cortical bone

Round wire rolls the incisor crowns down and forward,
tipping their roots lingually against the denser cortical bone,
thus limiting their effective intrusion.
The cuspid roots around the corner on a continuous arch are
being tipped distally, which limits their intrusion and arch
leveling action.
The molars on round wire are often rolled mesially and
upright away from their buccal cortical bone anchorage
support.

Maxillary Incisors
If the root tips are forward, as in a Class II division 2 malocclusion, the
crowns must be advanced and the roots retracted before intrusion so that
they can avoid the cortical bone around Pt A in the maxilla Intrusion must
also respect the floor of the nasal cavity in those types with a low facial
height.

Maxillary Bicuspids and Molars
The maxillary molars with their three roots extend into
the cortical bone of the sinus floor and are located at the
base of the key ridge to the zygomatic process. They are
anchored by being expanded and rotated into the buccal
cortical bone

Appliance design
1) 30° to 45° Tip-back Applied to the Lower Molars
tip-back applied singularly to the lower molars will upright these teeth
bringing their roots mesially (the lower molar will tip around a center of
resistance near the top of its mesial root) and the crown distally.
Since the lower molar is supported on the buccal by a heavy cortical
plate and at the distal by the lower second molars, the most usual
movement of this tooth with a straight uprighting force is a distal
rotation.

2) 30° to 45° Buccal Root Torque and Expansion
Since the lower molar cannot differentiate between buccal root torque and
lingual crown torque when a 45° buccal root torque is placed on the distal legs
of the utility arch, the amount of movement of the root to the buccal is
proportionate to the amount of movement of the crown to the lingual. The only
way that buccal root torque can be expressed by buccal movement of the root
and stabilization of the crown is by expansion of the arch . it is important that
the distal legs of the utility arch be generously expanded prior to placement in
the mouth.

3) Long Lever Arms Applied to the Lower Incisors
Long lever arm intrudes the incisor, it bye pass
the premolar and canine and acts on the
incisors.
Reverse curve of spee extrudes the premolar
and canine and increase the curve of speewww.indiandentalacademy.com

Cuspid Intrusion
This is normally accomplished by lightly tying these teeth to the
stabilizing utility arch with an elastic thread
small vertical loop is pinched into the wire (this can be done
intraorally with a large three-prong plier).
This elastic thread is brought around the vertical loop and tied
prior to encircling the cuspid bracket.

Parts of a utility arch

Modifications of the utility arches
One of the principles of the Bioprogressive Therapy is to correct the overbite
before the overjet
. In Class II, Division 2 malocclusion, this is generally not true. Due to the
original lingual version of the upper incisors, if these teeth are intruded
initially, they will be forced into labial cortical bone, thereby limiting
intrusion.
It is, therefore, necessary to create overjet first and then correct the overbite.
Many Class II, Division 2 malocclusions have the upper central incisors in
lingual version locked behind the lateral incisors

Three piece Intrusion Arches
Three piece intrusion arches can achieve deep overbite
correction and close extraction spaces simultaneously
Appliance design
Treatment is initiated by aligning the teeth included in the right and the left
posterior segments.. transpalatal arch placed between the first maxillary
molars..
The position of the center of resistance of the anterior teeth may be estimated
on a lateral cephalometric x-ray film..
A heavy stainless steel segment (0.018 ´ 0.025 or larger) with distal
extensions below the center of resistance of the anterior teeth is placed
passively in the anterior brackets.
The distal extensions end 2 to 3 mm distal to the center of resistance of the
anterior segment.
The intrusive force is applied with a 0.017 ´ 0.025 TMA tip-back spring
distal force delivered by a Class I elastic to the anterior segment is used to
alter the direction of the intrusive force on the anterior segment.

intrusive force applied through the center of resistance of the
anterior teeth will intrude the incisor segment.
It is possible to change the direction of the net intrusive force
by applying a small distal force.
The line of action of the resultant force will be lingual to the
center of resistance and a combination of intrusion and tip
back of the anterior teeth will occur..
To obtain a line of action of the intrusive force through the
center of resistance and parallel to the long axis of the incisors,
the point of force application must distal of the lateral incisor
bracket as possible.

If the intrusive force is placed farther distally and an appropriate small
distal force is applied intrusion and simultaneous retraction of the anterior
teeth occurs because of the tip back (clockwise) moment created around
the center of resistance of the anterior segment consisting of four
incisors.This can correct a class II buccal relationship Headgear is not
usually required for anchorage control,

K-SIR APPLIANCE
An appliance for simultaneous intrusion and retraction of the six anterior
teeth should ideally control:
• Magnitude of forces and moments
• Moment-to-force ratio
• Constancy of forces and moments
• Friction From a practical standpoint, the appliance should:
• Be easy to fabricate and adjust
• Be comfortable for the patient
• Require a minimal amount of patient cooperation
• Be cost-effective

Appliance Design
The K-SIR (Kalra Simultaneous Intrusion and Retraction)
archwire is a modification of the segmented loop mechanics of
Burstone and Nanda. It is a continuous .019” ´ .025” TMA
archwire with closed 7mm ´ 2mm U-loops at the extraction
sites

To obtain bodily movement and prevent tipping of the teeth into the
extraction spaces, a 90° V-bend is placed in the archwire at the level
of each U-loop . This V-bend, when centered between the first molar
and canine during space closure, creates two equal and opposite
moments to counter the moments caused by the activation forces of
the closing loops

A 60° V-bend located posterior to the center of the interbracket distance
produces an increased clockwise moment on the first molar, which
augments molar anchorage as well as the intrusion of the anterior teeth .

To prevent the buccal segments from rolling mesiolingually due to the
force produced by the loop activation, a 20° antirotation bend is placed in
the archwire just distal to each U-loop .

Activation
A trial activation of the archwire is performed outside the mouth . This
trial activation releases the stress built up from bending the wire and
thus reduces the severity of the V-bends . After the trial activation, the
neutral position of the each loop is determined with the legs extended
horizontally . In neutral position, the U-loop will be about 3.5mm wide.
The archwire is inserted into the auxiliary tubes of the first molars and
engaged in the six anterior brackets . It is activated about 3mm, so that
the mesial and distal legs of the loops are barely apart .

The second premolars are bypassed to increase the interbracket distance between the
two ends of attachment. This allows the clinician to utilize the mechanics of the off-
center V-bend.

When the loops are first activated, the tipping moments generated by the
retraction force will be greater than the opposing moments produced by
the V-bends in the archwire.
This will initially cause controlled tipping of the teeth into the extraction
sites.
As the loops deactivate and the force decreases, the moment-to-force
ratio will increase to cause first bodily and then root movement of the
teeth.
Control of Reactive Forces
Off-center V-bends will generate an extrusive force on the molars, which
is usually undesirable
The reactive extrusive force on the buccal segments is countered by the
forces of occlusion and mastication.
Reactive forces are counteracted by including the second molars

Advantage
The intrusion of the six anterior teeth occurs at the same time
as their retraction, and because the canines and incisors are
retracted as a unit, the K-SIR archwire shortens treatment time
compared to conventional edgewise mechanics.
In addition, the en masse retraction of the six anterior teeth
prevents the appearance of an unsightly space distal to the
incisors, which occurs if the canines are retracted separately

The Connecticut Intrusion Arch
Appliance Design
The CTA is fabricated from a nickel titanium.
The maxillary and mandibular versions have anterior
dimensions of 34mm and 28mm, respectively.

The CTA’s basic mechanism for force delivery is a V-bend calibrated to
deliver approximately 40-60g of force.
Upon insertion, the V-bend lies just anterior to the molar brackets.
When the arch is activated, a simple force system results, consisting of a
vertical force in the anterior region and a moment in the posterior region.

During intrusion of flared incisors, the CTA’s point of force application
is anterior to the center of resistance, which will flare the incisors even
more unless the length of wire between them and the molars is fixed.
A tight cinch-back—a sharp bend distal to the molar tube, preventing
forward slippage of the wire.)
Simultaneous Class II Molar Correction
The V-bend mesial to the molars corrects a Class II molar relationship by
tipping the molars distally. This tipback effect can be maximized if
posterior anchorage is reduced.

headgear is used to counteract these effects and correct
molar root positions as needed.
Flared incisors
CTA is not cinched back, it will slide forward through the molar
tube, and the incisors will flare

Modification of Lingual Arch For Deep
Bite
Developed by Winston Senior
Many mechanical systems have been described for intrusion of the
lower incisors

Appliance Design
An .036” lower lingual arch is soldered to first molar bands.
Distal extensions form occlusal rests on the second molars
to prevent distal tipping of the first molars as the incisors
are intruded
Four elastic chains are attached to the anterior bridge of the
lingual arch with a mosquito forceps

Equiplan Quad helix Combination
Appliance design
The palatal expander is inserted into the lingual tubes of the first
molar bands or welded directly to the molar bands.
The Planas Equiplan is attached to the anterior arms with acrylic
or directly to the anterior helices of the Quad Helix.

BEGG APPLIANCE
Conventional begg opens the bite by molar extrusion and
intrusion of lower incisors
Refined Begg has introduced many variation to overcome
these short comings.Intrusion with anchor bend causes labial
crown tipping .Such movements are desirable in classII
divII.This displacement is resisted by class2 elastics
Anchor bend in 0.016 arch wire is 45 gms on each
side,extrusive component of class elastic is 30gms .The net
intrusive force is 15 gms.In refined begg excessive proclination
or retroclination is controlled in sub stageIA.Then the
classIIelastic force are varied depending on the changing
inclination of the so that the resultant force pass through center
of resistance

1 In severely proclined teeth the intrusive force is
45 gms and classII force is60 gms.The resultant of
this force will pass behind the center of resistance.It
reduces the proclination but very little intrusion
2 As the inclination is improved the intrusive force
is increased to 60 gms while the classII force is
reduced to 30 gms.this produces more intrusion
along the long axis of the tooth
3 As the incisors become more upright the elastic
application is changed to an oblique direction
The gradual increase in the intrusive force is by
increasing the anchor bend from 30 degrees to 50
degrees

The elastic force is reduced by using class II elastics for longer
period (3-5) days and switching from yellow 5|16 to38
Palatal elastics attached to the TPA is used.This involve using
force in both the palatal and labial side giving better control over
the orientation of the resultant force.
TPA helps in the extrusive effect on the molar by constant tonque
pressure
For uniform intrusion of the anterior a mild gingival curve is
incorporated from the mesial of one cusp to the other
Vertical step-up bend 4-5 mm in height and placed 2-3mm mesial
to the molar tube .Tip back bend of required degree is placed in
the upper end of the step.This causes the intrusive force to be
applied above the occlusal plane .The vertical step and tip back
bend reduces the extrusive effect of the gingival curvature on the
canine

In severe deep bite cases there is heavy contact of the
incisal edge on the palatal surface, this prevent labial
movement of the incisors during initial bite
opening.The lower incisor brackets are boned as far
gingival and anchor bends are decreased than the one
used in the upper teeth.Both these measures reduces
tipping tendency of the lower incisors
MAA with labial root torque is used on the lower
incisors
The ends of the lower arch wire is bent distally to the
molar to minimizing the tipping of the lower incisors

Preadjusted Appliance Using Sliding Mechanics
Deep overbite can be effectively controlled with preadjusted appliance
when the following principles are observed
1.Avoid extraction in low-angled cases whenever possible
A non extraction approach seems to be the most effective for controlling
deep bite on low angled cases with a maxillomandibular angle of less than
25˚.overbite control is a result of leveling and aligning as a result of up
righting and slight extrusion of the posterior teeth.When the incisor are
inclined forward bite opening is enhanced and fascial esthetics is
improved.If the teeth are extracted overbite control becomes difficult
because of the strong muscle forces that impedes the ability of the posterior
teeth to move forward.

As the extraction sites are closed the anterior teeth tend to upright and
move posteriorly and bite will further deepen. Great care must be taken
to maintain the torque control during retraction. cases where extraction
are indicated such as severe proclination and crowding leveling and
aligning and space closure should be done with light forces to avoid bite
opening
3. Use bite planes at he beginning of treatment in moderate to low angle
cases
4.Band or bracket the second molar as early as possible. Complete
leveling of the curve of spee is not possible without banding the molars
5.Avoid elastic retraction of the cuspid with pre adjusted system the tip
built into the cuspid and incisor brackets causes the teeth to tip
anteriorly upon intial wire placement. When this tendency is
counteracted with by early application of even the lightest elastic forces
the cuspids are tipped distally the overbite deepens and the posterior
bite opens. this roller coaster effect invariably results in extended
treatment time. inorder to prevent this lace backs are given. if the
cuspids are unfavourably positioned incisors are not included in the
arch until the cuspid are retracted and a leveled cuspid slot is achieved

6.use of .022 slot with.019 x .025 working arch wires with bite opening curves
7.use class II elastics selectively. the premature use of class II elastics for instance
in round wire leveling stage can lead to bite deepening and to excessive
interference between the advancing lower incisors and the retracting upper
incisors and distal displacement of the condyle
Apical Root Resorption and Intrusive
Tooth
Movements
Costopoulos and Nanda in a study on the effect of intrusion on
root length showed that over a 4-month period of intrusion, root
resorption was 0.6mm versus 0.2mm for controls. The amount of
resorption was not found to be correlated with the amount of
intrusion.

FACTORS AFFECTING RELAPSE OF
DEEP BITE CORRECTION
In a study of 26 patients, Berg found relapse of 18.8% of the achieved
deep bite correction. He also found more relapse of the deep bite in
Class II, Division 2 cases. Hellekant and Lagerstrom reported a relapse
of the dental deep bite in 19% of the cases . Simons and Joondeph found
that proclanation of the incisors during orthodontics treatment may
cause relapse of the corrected deep bite in the postretention period.
They also found that clockwise rotation of the occlusal plane during
treatment will go back toward its original cant, thereby causing relapse
of the dental deep bite. Contrary to other authors who found more
deep bite relapse in extraction cases, Simons and Joondeph, as well as
Berg and Hellekant and Lagerstrom, could not find any difference
between extraction and nonextraction cases in this regard.

McAlpine found that relapse of the deep bite was correlated with the
interincisal angle and the lower anterior facial height. In case in
interincisal angle of 125 to 130o
was established, the chances of stable
correction of a dental deep bite were found to be highest. Brachycephalic
patients showed more relapse of the dental deep bite than others.
Gordon found that intrusion of lower incisors in an attempt to correct a
dental deep bite was prone to relapse in 33% of the cases
Bell and Hunt concluded that relapse of the overbite is primarily due to
continued lower incisor eruption, retroclination of these teeth, and forward
rotation of the mandible with continued growth.
Burzin and Nanda studied the stability of incisor intrusion in 26 patients 2.32
years post-treatment. The incisors were intruded an average of 2.30 mm and
relapse was only 0.15 mm. The study concluded that the overbite correction by
intrusion is a stable procedure.

In conclusion, changing the lower anterior facial height in adult
patients due to extrusion of molars is not an advisable clinical
procedure. According to some authors, intrusion of lower
incisors may not be the ideal treatment with respect to stability.
Some claim that the establishment of an appropriate interincisal
angle is advisable in an attempt to prevent deep bite relapse.

Correction of deep bite

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