MBT

ROTH PRESCRIPTION
DR. KAPIL SAROHA
BDS, MDS
ORTHODONTICS AND DENTOFACIAL
ORTHOPEDICS
Monday, July 31, 2017
WWW.DRDENTISTE.COM DR.DENTISTE DENTAL
ACADEMY

DR. Ronald Roth after using the
Straightwire appliance for many years,
raised a question:-
"If we were clever enough to get the
teeth into ideal position at the end of
the treatment using Straight wire
appliance, would the teeth remain in
those positions?“
Probably not!
Monday, July 31, 2017WWW.DRDENTISTE.COM DR.DENTISTE DENTAL ACADEMY

• He said
" I have never seen a case with fixed
appliance in which the teeth did not move or
settle into occlusion after appliance removal".

He noted that following changes occur after
appliance removal:
• Teeth will move after appliance removal, no
matter where they are placed.
• Curve of spee will return or deepen after
appliance removal.
• As the teeth in buccal segments settle they
will tip mesially.
• Teeth adjacent to an extraction site will tend
to rolate & tip towards extraction site.

• Because these factors seems to occur most of
the time, it seems only logical to plan for
these things to happen during treatment &
set up a goal that will overcome these
factors.
• The obvious choice is Overcorrection, which
he gave in the form of Roth prescription.

MBT
ACADEMY

After using the Straightwire appliance system by
Andrew and Roth prescription system for more
than 8 years and reviewing more recent
research on measurements of the dentition
Bennet, Mc.Laughlin and Trevisi determined
that further modifications were needed to
optimize treatment efficiency.
Together they developed the MBT Versatile +
appliance system.

Upper anterior tip:
• The anterior tip measurements for the
original SWA are all greater than those found
in Andrew research.
• This was done to control what Andrews
referred to as "Wagon wheel" effect that
torque places on the anterior crown tip.
• He said that as the palatal torque is added to
the anterior segment, the mesial crown tip is
reduced giving the wagon wheel effect.

• But MBT observed that with light continuous
force mechanics, tip is well controlled by the
PEA.
• By using lacebacks and bendbacks during
leveling and aligning and elastic module
tiebacks during space closure, very little
adverse tipping occurs during these stages of
treatment.
• So in the MBT Versatile+ appliance, the
anterior tip is reduced.
• `

Upper posterior tip:
• For the MBT Versatile appliance, 0
degree tip, as opposed to 2 degree tip
has been selected for all the premolar
brackets.
• This places the crowns of these teeth in
slightly more upright position, which is
more in the direction of class I.
• It also provides for slightly reduced
anchorage needs for these teeth.

• The reference for crown tip in
the upper molar is the buccal
groove.
• This buccal groove shows a 5
degree angulation to a line
drawn perpendicular to the
occlusal plane.
• Usually a 5 degree bracket is
used with the bands seated
more gingivally at the mesial
aspect.

• When this 5 degree bracket is placed parallel
to the occlusal plane, it actually provides 10
degree tip to the upper first molars which is
excessive.
• In MBT versatile+ appliance, the tip for the
upper molar is 0 degrees with the band and
bracket slot placed parallel to the occlusal
plane.
• This introduces the correct 5 degree tip in the
upper first and second molars as measured
from the buccal groove

Lower posterior tip:
• MBT prefers the same tip to that of the
Andrews in the premolars, since angling
these teeth slightly forward in this manner
moves them more into the class I direction.
• Zero degree tip is preferred in the lower first
and second molars.
• Similar to the upper molars, 2 degree tip is
derived when the band and bracket is placed
parallel to the occlusal plane.

Anterior torque:
The palatal torque in the upper incisors and
the labial torque in the lower incisors is
increased, since it is the most common
requirement in the orthodontic cases and
thereby reducing the need for wire bending.

While the upper canine torque is same to that of
the Andrews, lingual torque in the lower
canine is reduced. This is done so that the root
is placed more closer to the center of the
alveolar process.

Upper posterior torque:
• The torque values for the premolar is same to
that of the Andrews.
• The upper molars frequently show excessive
buccal crown torque with palatal cusps
"Hanging down" and creating centric, balancing
side and working side interferences.
• For this reason, MBT prefer -14 degree torque
of buccal root torque in these teeth, as
opposed to -9 degree of buccal root torque.

• For this reason, MBT
prefer -14 degree
torque of buccal root
torque in these teeth,
as opposed to -9 degree
of buccal root torque.

Lower posterior torque:
The lingual tip in the lower premolar and
the molar teeth is reduced. This is
because:
- Many orthodontic cases
demonstrate narrowing in the maxillary
arch with lower posterior segments that
are compensated towards lingual.
-These cases benefit from buccal
uprighting of the lower posterior
segments.

• It has been consistently observed that
lower second molars with -35 degree of
torque that consistently "roll in" lingually.
• Therefore MBT have chosen to reduce
lingual crown torque in the lower cuspids,
bicuspids, first molar and second molar.

In-out modifications
• Upper second bicuspids are
frequently smaller in size
than upper first bicuspids.
• For this reason an upper
Second bicuspid bracket has
been provided with
additional 0.5 mm of in-out
compensation

MBT system comes witht three different types
ofbrackeytypes:
• Victory series bracket:- This is the mid sized bracket
which is beneficial in cases with smaller teeth and
minimal to moderate degrees of difficulty.

• Unitek Full sized Twin brackets:- This bracket
is larger in size and beneficial in cases with
larger teeth, patients with difficult
malocclusions where control is essential and
with patients who are prone to breakage.
• Clarity brackets:- This is ceramic bracket,
beneficial in terms of esthetics.

ARCH FORM:
• MBT also gave three different types
ofarchforms which can be effectively
used to fabricate archwires. Theyare:

l. Tapered arch form:-
• This arch form provides the most narrow
intercuspid width and is indicated in patients
with narrow, tapered arch forms

2. Square arch form:-
• This arch form is indicated in cases with broad
arches.
• It is also indicated, in treatment, in cases
requiring buccal uprighting of the lower
posterior segment and expansion of the arch

3. 0void arch form:-
• This arch form is preferred when using multi
strand wires, 0.014 and 0.016 stainless steel
round wires and all Niti and heat activated Niti
wires.

Buccal tubes:
• The buccal tubes which is used in the molars can be
of different types.
• In the maxillary buccal tubes, 3 compartments are
seen - Headgear tube, Rickett's tube and Archwire
tube.

• Headgear tube is used to insert
inner bow of headgear
• Rickett's tube is used to insert
additional appliance like utility
arch
• Archwire tube is used to insert
regular archwire.

• In the mandibular buccal
tubes, only 2 compartments
are seen
• Rickett's tube and
• Conventional tube.

MBT BRACKET
PLACEMENT
TECHNIQUE
ACADEMY

• Andrew recommended that pre-adjusted appliance
brackets be placed with the twin bracket wings
straddling, in a parallel fashion, to the vertical long
the axis of the clinical crown,
• And that the center of the bracket slot be placed on
the center of the clinical crown.

• Potential errors or potential deviations from
this desired position can occur as follows:

Horizontal errors:
• Brackets can be placed
to the mesial or distal
of the vertical long axis
of the clinical crown,
leading to improper
tooth rotation.

• Elimination of such errors can be best
achieved 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.
• It is even better to draw a line through the
vertical long axis of the clinical crown for
more accurate visualization.

Axial or paralleling errors:
• Brackets can be rotated off
the vertical long axis of the
clinical crown if the bracket
wings do not straddle the long
axis of the crown in a parallel
manner.

Thickness errors:
• Such errors can occur if
excessive adhesive is left
underneath one portion of the
bracket base, or if the contour
of the tooth does not
correspond accurately to the
contour of the base of the
bracket.

• Such errors can cause improper tooth torque
or rotation, and can be eliminated by
pressing the bracket against the tooth at
placement, so that excessive adhesive flows
from beneath the bracket,
• or by contouring the bracket base to more
accurately fit the tooth surface.

Vertical errors:
• Vertical bracket placement
errors occur when the
bracket is placed gingival
or incisal/occlusal to the
center of the clinical
crown.

• Such errors lead to extrusion or intrusion of
teeth, as well as potential torque and
in/out errors.
• The human eye is quite accurate at
bisecting and locating the center of a given
object such as a crown. Therefore,
brackets can be placed accurately using
direct visualization on fully erupted and
anatomically normal teeth.

• However, in the following clinical situations
(which occur quite frequently), direct
visualization is more difficult.

Gingival Concerns
ACADEMY

1. Partially erupted teeth:
• It is difficult to locate the center of the
clinical crown on partially erupted teeth
when treating young patients.
• The tendency is to place the bracket too
incisally or occlusally, especially with
bicuspids and lower second molars.

2. Gingival inflammation:
• Gingival inflammation
causes foreshortening, with
the tendency to place the
bracket too occlusally or
incisally.

3. Teeth with palatally or
lingually displaced roots:
• With such teeth, gingival tissue 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.

Incisal or Occlusal
Concerns:
ACADEMY

1. Incisal or Occlusal crown
fractures or tooth wear:
• It is difficult to visualize the center of the
clinical crown since the apparent clinical
crown is foreshortened.

• Correction of this problem can be made by
either restoring the crown to its appropriate
length, or by estimating how long the crown
was before fracture or wear.

2. Crowns with long tapered
buccal cusps:
• Occasionally a crown on a tooth such as a
cuspid or bicuspid will show an unusually
long and tapered buccal cusp.
• If the bracket is placed in the center of the
clinical crown, adjacent marginal ridges will
not be properly aligned.
• This situation can be corrected by selectively
reducing the height of the cusp prior to
bracket placement.

BRACKET PLACEMENT
CHART
ACADEMY

• In an attempt to reduce the errors inherent in
using only a direct visualization method of
bracket placement, a study was carried out to
provide a method that could serve as a
supplement to the direct visualization
technique. .

• The result of this study was the
development of a bracket placement
chart:

• Use of the Bracket Placement Chart
eliminates potential gingival errors
because measurements are made from the
occlusal or incisal edge of the teeth.
• This alone is a major advantage, since the
majority of vertical bracket placement
errors that do occur are the results of
inability to accurately visualize the gingival
half of the clinical crown.

• The only potential errors that cannot be
avoided are on crowns with incisal or
occlusal fractures or wear, or on crowns
with unusually long tapered facial
cusps.
• When these situations occur,
appropriate millimeter adjustment
needs to be made to allow the crown to
be properly positioned.

The technique that has been developed
for bracket placement with this method
is as follows:
Step one
• Divider and a millimeter ruler are used to
measure the clinical crown heights on as
many fully erupted teeth as possible on the
patient's study models.

Step two
• These figures are recorded, divided in half
and rounded to the nearest .5mm
Step three
• The row on the bracket placement chart that
contains the greatest number of recorded
figures is selected for bracket placement.

Step four
• At the time of banding and bonding,
brackets are placed by visualizing the
vertical long axis of clinical crowns
(buccal groove on the molars) as a
vertical reference and the estimated
center of the clinical crown as a
horizontal reference.

Step five:
• A bracket placement gauge is then used to confirm
that the brackets are at a height that represents
the appropriate figures in the selected column of
the bracket placement chart.

ANCHORAGE IN
PEA
ACADEMY

• Anchorage control in PEA means
" The maneuvers used to restrict
undesirable changes during the opening
phase of treatment, so that the leveling
and aligning is achieved without key
features of malocclusion becoming
worse" - Bennet & Mc.Laughlin.

• Bennet and Mc.Laughlin emphasize the need to
consider anchorage in all three planes of
space.

I.Horizontal anchorage control:
• Limiting the mesial
movement of the posterior
segment and encouraging
the distal movement of
anterior teeth.

2.Vertical anchorage control:
• Involves the need to try to
influence vertical skeletal &
dental development in the
posterior segment [as with high
angled cases] and at times
attempt to limit vertical
eruption of anterior segments
or even intrude these segments.

3.Lateral or transverse anchorage
control:
• Involves the maintenance of expansion
procedures, primarily in upper arch, and the
avoidance of tipping or extrusion of the
posterior teeth during expansion.

Anchorage control is done with
• Extra oral - Headgears and face masks
• Intra oral - Banding II molars,
lacebacks, TPA, Holding arch, Lip
bumpers, etc.

l.ANCHORAGE CONTROL IN HORIZONTAL
SEGMENT:
1) Control of the anterior segment:
-There is a tendency for the anteriors
to incline forward during the initial
phase of leveling and aligning.
-Early attempts were made to
eliminate or minimize the efforts by
connecting anterior segments to
posterior segments, usually with elastic
forces.

But as the elastic forces were greater
than the leveling force of the archwire,
there was a tendency for the anterior
teeth to tip & rotate distally, increasing
the curve of spee & deepening the bite,
This effect is known as "Roller coaster"
effect.

• MBT introduced ''lacebacks" to reduce these
effects.
• These are constructed using 0.009 or 0.010
ligature wire tied in a figure of eight fashion.
• They extend from most distally banded molars
to the canines in all quadrant.

• Even though the initial purpose of the
lace backs was to prevent canines from
tipping forward, it was noted that the
lace backs can also be effectively used
to distalize the canines without the
unwanted tipping which is known as
'walking canines'.

• There is initial tipping of
the canines distally.
• This is followed by a
period of rebound, where
the leveling effect of the
arch wire will allow the
roots of the canines to
move distally.

Bend backs
• MBT also introduced another method
known as "Bend backs" where the arch
wire is bent immediately behind the
most distally banded posterior teeth,
which will minimize the forward tipping
of the incisors.

b. Control of posterior
segments:
1. Upper posterior arch:
The posterior anchorage control requirements
are normally greater in the upper arch than in
the lower arch due to 4 main factors:
• Upper anterior teeth has larger teeth than
the lower anterior teeth.

• Upper anterior brackets have a greater
amount of tip built into them than the
lower anterior brackets
• Upper incisor require more torque
control and bodily movement than
lower incisors
• Upper molars usually move mesially
more readily than the lower incisors.

Extra oral force:
• Extra oral force is normally the most
effective way to provide posterior
anchorage control in the upper arch.

• Even though 3 types of headgears are there -
Occipital, Cervical & Combi pull, the most
preferred one by MBT is -Combi pull.
• This type of headgear allows a distal force to
pass straight through the center of resistance
of' the maxillary dentition. This is done by
making the outer bow of the facebow angled
upward by 15 degrees.

• MBT suggested a force level of 150-250 gm
for occipital pull and 100-150 gm for cervical
pull.
• This slightly stronger pull on the occipital
compartment will help the force directly
slightly above the occlusal plane &
simultaneously allowing effective
distalization of the molars.
• In the high angled cases only occipital pull
should be applied and in the low angled
cases, only cervical pull is advocated.

Trans Palatal Arch:
• A Trans palatal arch can be
used in moderate
anchorage cases
• This restricts the mesial
movement of the maxillary
molars

Nance holding arch:
• The Nance holding arch
reinforces anchorage during
leveling and aligning, and
canine retraction.
• It can also be used
immediately after
distalization procedures to
hold molars in place

Banding the second molars:
• Banding the second molars is helpful in
the moderate anchorage; cases, but it is
not recommended in the high angled
cases.
• This is because banding the second
molars will cause the extrusion of the
second molars, which will further
increase the MPA angle

Lower posterior arch:
Lingual holding arch:
• A lingual holding arch, fabricated from
0.045 or 0.051 round stainless steel wire
is helpful during the initial phase of
unraveling the crowded incisors with
lacebacks.

LEVELING &
ALIGNING WITH PEA
ACADEMY

Wire selection:
• Initial archwires should provide light
continuous force.
• Archwire should move freely within the
bracket slot. There should be at least 0.002
clearance, and ideal is 0.004.
• During initial alignment, rectangular wires
can be avoided since it creates unnecessary
root movement, which will increase the
possibility of resorption.

• The archwire used for initial alignment
requires a combination of excellent strength,
good springiness, long range of action & low
load deflection rate.
• Austenitic Niti like copper Niti or Chinese Niti
is much preferable.
• Size of the archwire should be 0.016 or
0.018 depending upon the slot size.

• Sometimes a 0.015 or 0.017 multi strand
stainless steel can be used initially.
• The advantage is that there is less
"Initial discomfort" for patients & some
wire bending in additional to normal
archform can be accomplished.

DEEP BITE
CORRECTION WITH
PEA
ACADEMY

Although moderate deep bite cases gets
corrected as a result of routine leveling &
aligning procedures, a severe deep bite cases
require different corrective procedures
• Certain points should be considered in
deep bite correction:

• In low angled deep bite cases with
extraction, control of the overbite is very
difficult.
• This is because the strong muscle force in this situation
makes it more difficult for the posterior teeth to move
anteriorly into extraction site.
• The anterior teeth tend to upright as they move posteriorly
with subsequent further bite deepening.

• In high angled cases, care should be
taken to avoid the extrusion of the
posterior teeth since it further increases
the Mandibular Plane angle and
downward & backward rotation of the
mandible.

Incisor position
• When the incisors are retrusive and can be
advanced, this helps in bite opening process.
• When they are protrusive and need to be
retracted, the bite tends to deepen &
mechanics become more difficult.

l. BITE PLATE:
• The use of anterior bite
plate is most effective in
the initial treatment
stages of deep bite cases,
especially in non
extraction cases.

• It helps in the extrusion of lower
posterior teeth & allows early
placement of brackets in lower incisors.
• It is contra indicated in high angled
cases since extrusion of posterior teeth
further increases the MP angle.

2.BITE OPENING CURVE:
• At the end of initial leveling &
aligning, a rectangular stainless
steel archwire with bite opening
curve can be placed.
• A reverse curve in the lower
archwire & accented curve in
the upper archwire.
• It may not be beneficial in all
cases.

3.INTRUSION UTILITY ARCH:
• Intrusion utility arch was devised by
Ricketts with the help of basic
biomechanical principles developed by
Burstone.
• This appliance consist of a continuous
wire that extends across both buccal
segments but engages only the first
permanent molars and four incisors.

Components:
• Molar segment, which is adapted into the
auxiliary tube.
• Posterior vertical segment
• Vestibular segment, which runs in the buccal
vestibule.
• Anterior vertical segment
• Incisal segment, which is adapted to the four
incisors.

Wire selection:.
• For 0.018 slot - Mandible - 0.016*0.022 or
0.016*0.016
Maxillary - 0.016*0.022
• For 0.022 slot - 0.019*0.025 for both the
arches.
• Rectangular wire is preferred to round wire
to control torque and to prevent unwanted
tipping of the incisors.

Fabrication:
• The intrusion arch is stepped gingivally
at the molars, passes the buccal
vestibule and then it is stepped at the
incisors to avoid distortion from the
occlusal forces.
• There should be 5 mm distance between
the anterior border of the auxillary tube
and posterior vertical segment.

Activation
• Two types of activation can be done:
• Retraction
• Intrusion

Retraction:
• Incisor retraction is achieved by bending down
the end of the molar segment gingivally. This
helps in prevention of protrusion of lower
incisors during intrusion.

Intrusion
• Intrusion is achieved by placing an occlusally
directed gable bend in the posterior portion
of the vestibular segment.

4.THREE PIECE INTRUSION ARCH:
• This appliance was introduced by Shraff,
Lindhauer & Burstone.
• Along with the intrusion of anterior teeth, it
helps in the retraction of the anterior teeth
& thereby enhancing the space closure.

This appliance consists of :
• Posterior segment,
• Which is adapted into the molars and premolar.
• Anterior segment with posterior extension,
• which runs through the four incisors and canine
• Intrusive cantilever spring,
• which is placed between the anterior segment
and posterior segment

• The posterior segment is made of
0.017*0.025 stainless steel
• A T.P.A can also be given for more
consolidation in the posterior teeth.
• The anterior segment is placed, which is bent
gingivally distal to the laterals, then
horizontally creating a step of 3mm.
• The distal part of the segment extends
posterior to the distal end of the canine
bracket, where it forms a hook.

The intrusion springs are fabricated
-The wire is bent gingivally, mesial to the
molar tube & a helix is formed.
- On the mesial end of the spring, a hook
is made through which it is attached to the
anterior segment.
-The spring is activated by making a bend
mesial to the helix and then clinched back and
attached to the anterior segment.

• This will cause anterior intrusion and the
extrusion of the molars.
• Along with this, a chain elastic can be
attached from the hook of the anterior
segment to the molar tube to get retraction
along with the intrusion of the anteriors.

5.TIP BACK SPRINGS:

These springs are indicated in cases requiring
true intrusion of the incisor and can be used
in the following conditions:
1. Growing patients with forward growth
rotations
2. For a very deep curve of spee in lower arch
3. Cases with a deep overbite due to extrusion
of incisors
4. For a steep natural plane of occlusion

• These springs originally proposed by
Burstone, are made of 0.017*0.025 TMA
or 0.017*0.025 stainless steel wire.
• The anchor molars are reinforced with a
TPA in upper and a lingual holding arch
in the lower.
• The wire is bent gingivally mesial to the
molar tube and then a helix is formed

• The mesial end of the spring is bent into
a hook & is engaged into the main
archwire distal to the lateral incisors
which, according to Burstone, is the
approximate center of resistance of the
four incisors.

• Mesial end of the spring lies passively at
the height of the mucobuccal fold and
the spring is activated by pulling the
hook down and engaging it into the arch
wire, thereby causing intrusion of the
upper incisors.

SPACE CLOSURE WITH
PEA
ACADEMY

One has to consider three main
factors:
• Whether canines & incisors are to be
retracted separately or En masse
• Whether sliding mechanics or
frictionless mechanics should be used
• Whether pure retraction or retraction
with intrusion is to be used

Depending upon these factors, the appliance
choice is made.
• When the canines & incisors are retracted
separately, it will help in conserving the
anchorage especially when sliding mechanics
are used.
• The principle is that by retracting fewer teeth
at a time, less stress is placed on the posterior
anchorage.

• In En masse retraction, the method of
anchorage is based on the types of
tooth movement in the posterior &
anterior segments and does not entirely
depend upon the number of teeth in
each segment.

Sliding mechanics:
• In friction or sliding mechanics an elastic chain
or thread is attached to the tooth & a
continuous arch wire is placed.

• The elastic chain is the force component of
the retraction assembly & the wire bracket
interaction produces the moment.
• Since the e chain is placed at the bracket
level & not at the center of resistance, tooth
experiences a moment in two-planes of
space.

• One moment rotates the tooth mesial-out & the
other causes distal tipping of the crown.

Advantages of sliding
mechanics:
• Complicated wire bending is not required.
• Initial wire placement is less time consuming.
• Enhances patient comfort
• Since the space closure is slow, there is less
chance of resorption & relapse

Disadvantages:
• Confusion concerning the ideal force levels.
• There are no essential guidelines concerning
the amount of force to be used during space
closure.
• Tendency to over activate the elastic &
spring forces, which cause initial tipping but
gives inadequate rebound time for
uprighting.

Wire selection:
• A 0.016*0.022 stainless steel wire in a 0.018
slot
• and a 0.017*0.025 stainless steel wire in a
0.022 slot is ideal for sliding mechanics.
• The composition of bracket also affects
sliding mechanics.
• For example ceramic brackets create more
friction than stainless steel brackets.

Canine retraction with sliding mechanics:
• In maximum anchorage situations it would be
ideal to retract the canines separately,
consolidate the anchorage & then retract the
incisors.
• Minor cuspid retraction can be carried out
with the use of lacebacks.
• For the major cuspid retraction, an elastic
chain may be attached to the power arm on
the cuspid bracket.

• Since the force is passed close to the center of
resistance of the canine, it helps to achieve the
translatory movement.

• Due to the force of the elastic chain,
the canine tooth initially tips distally,
followed by a period of "rebound" due
to the leveling effect of the archwire-
bracket interaction, which causes distal
uprighting of the root, thereby helping
in the retraction.

Nickel Titanium springs:
• Bennet & Mc. Laughlin say
that the rate of space
closure is significantly
greater and more
consistent with Nickel
titanium springs than the
elastic chains.

FRICTIONLESS MECHANICS:
• In the frictionless mechanics, teeth are
moved without the brackets sliding along the
archwire & activating the loop produces the
force, which helps in retraction

Advantages of Frictionless
mechanics:
• Offers more control than the sliding
mechanics
• Precise control over posterior & anterior
anchorage.
• Tooth will move only to the limit to
which it is activated.
• Differential tooth movement is possible

Disadvantages:
• Precise understanding in mechanics is
required, since minor error in
mechanics can result in a major error in
tooth movement.
• More wire bending skills & chair time is
required than sliding mechanics.
• Loops may be uncomfortable to some
patients.

T LOOP RETRACTION SPRING:
• Burstone developed T Loop for the space
closure in an extraction case.
• He used 0.017*0.025 beta titanium wire in an
0.018 slot.
• Advantage of T loop over the normal vertical
loop is that the T loop produces a higher M/F
ratio, a lower load deflection rate and delivers
a more constant force & M/F ratio

PG RETRACTION SPRING:
• This spring is constructed from 0.016*0.022
stainless steel wire.
• The principal element of this spring is a
double ovoid loop of 10mm in height.
• It is included in order to reduce the load
deflection of the spring & is placed gingivally
so that the activation will cause a tipping of
the short horizontal arm in a direction that
will increase the couple acting on the tooth.

• The gentle round form avoids the effect of
sharp bends on load deflection
• A desirable force level of approximately l60 gm
is obtained when the two sections of the double
helix is separated at 1mm.

CONCLUSION
• Straightwire appliance is not a computer
software which can be downloaded from the
bracket case & executed in the teeth to get
desired results.
• Preadjusted edgewise appliance will not
diagnose cases, it will not set up treatment
plan, and will not figure out the mechanics
needed to correct the malocclusion.
• But a properly placed Staightwire appliance will
detail the tooth positions better, more
consistently, and faster than one can by bending
offsets into the archwire

• The key is to get the brackets properly placed.
• This requires lot of self discipline &
persistence, but the benefits are well worth
the efforts.
• It allows one to detail & finish cases more
accurately.
• Above all we should accept the fact that wire
bending is always necessary in the Pre
adjusted edgewise appliance!

t by –
dr. Kapil Saroha
BDS, MDS
ACADEMY
DENDEN ISTIST

MBT

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to MBT

Similar to MBT (20)

More from kapil saroha

More from kapil saroha (9)

Recently uploaded

Recently uploaded (20)

MBT