MBT system in orthodontics /certified fixed orthodontic courses by Indian dental academy

MBT SYSTEM

STRAIGHT WIRE TECHNIQUE

INDIAN DENTAL ACADEMY
Leader in Continuing Dental Education
www.indiandentalacademy.com


 Orthodontic treatment mechanics are
determined by four elements-
-bracket positioning
-bracket selection
-archwire selection
-force levels


WORK OF ANDREWS
First Generation

The original SWA was introduced by Andrews in 1972
and it had the features of Siamese edgewise bracket.

He recommended a wide range of brackets
- For extraction cases,canine brackets with anti-tip,anti-
rotation, and power arms
-Three sets of incisor brackets with varying degrees of
torque for different clinical situation.


WORK OF ROTH
Second Generation
 To avoid inventory difficulties of a multiple
bracket system, ROTH recommended a
single appliance system to manage both
extraction and non-extraction cases.
 The appliance prescriptions developed by
Andrews and Roth were based on the
treatment mechanics used in their practice.


WORK OF McLAUGHLIN,BENNETT
AND TREVISI
Third Generation

 The MBT has been developed from the
combined clinical experience of the authors for
more than 70 years.
 It also introduced additional research input from
Japanese sources to update the scientific input.
 It is designed ideally to work with sliding
mechanics,with light continuous forces,
lacebacks and bendbacks.

Following elements make up the MBT treatment
philosophy

Bracket selection, versatility of bracket
system, accuracy of bracket positioning, light
continuous forces, 0.022 versus 0.018 slot,
anchorage control, group movement, use of
three arch forms, one size of rectangular
steel wire, archwire hooks, methods of
archwire ligation, awareness of tooth size
discrepancies, persistence in finishing.


The MBT Bracket System

 The MBT bracket system is based on a
more balanced mix of science,tradition
and experience.
 It is a bracket system for use with light
continuous forces, lacebacks and
bendbacks
 It is designed ideally to work with sliding
mechanics.


EXCLUSIVE MBT
APPLIANCE FEATURES.
 Reduced anterior tip.
 Upper bicuspid brackets with 0 0 tip.
 Lower bicuspid brackets with 2 0 tip.
 Additional palatal root torque for upper
incisors and additional labial root torque
for lower incisors.
 Upper cuspid brackets with the normal
–70 torque or 00 torque.

 Upper molar brackets with additional 50
buccal root torque.
 Progressive buccal crown torque in lower
cuspids and lower buccal segments.
 Optional upper second bicuspid brackets with
an additional 0.5mm of in-out compensation.
 Three bracket types,Clarity Aesthetic
Brackets, Victory Series brackets, and Unitek
Full Size Twin Brackets,all available with APC
Adhesive Coating.

Design features of a modern bracket
system

 Range of brackets
- Standard size metal brackets.
- Mid-size metal brackets.
-Esthetic brackets.
 Improved i.d system
Laser numbering of standard size metal
brackets.
 Rhomboidal shape
Reduces bulk and assists accuracy of bracket
placement.

 Drawing of original
SWA bracket.
 Dots (upper) and
dashes (lower) were
used for i.d
purposes.


 Drawing of MBT
brackets.
 Standard size
brackets have a
rhomboidal form
and numerical
i.d.system.


VERSATILITY
 Seven areas
Options for palatally placed upper lateral incisors(-10*)
Three torque options for upper canine(-7,0,+7)
Three torque options for lower canine(-6,0,+6)
Interchangeable lower incisor brackets
Interchangeable upper premolar brackets
Use of upper second molar tubes in first molars in non-HG
cases
Use of lower second molar tubes for upper first and second
molar of opposite sides when finishing cases to class II
molar relationship.


Horizontal bracket placement
errors
 If brackets are
placed to the mesial
or distal of the
vertical long axis of
the clinical
crown,improper
tooth rotation can
occur.


Axial or paralleling errors

 These will occur if
the bracket wings do
not straddle the
vertical long axis of
the crown in a
parallel manner.
 Such errors lead to
improper crown tip.


Thickness errors.
 Excess bonding
agent beneath the
bracket base can
cause thickness and
rotational errors.
 Can be eliminated
by pressing the
bracket against the
tooth.

Vertical errors
 Vertical errors in
bracket placement
are caused by
placing brackets
gingival or
incisalocclusal to
the center of the
clinical crown.


Gingival Concern.

 Partially erupted tooth.
 It is difficult to visualize
the center of the
clinical crown on
partially erupted
teeth,when treating
young patients.


Gingival Inflammation
Gingival inflammation causes foreshortening,effectively
reducing the length of the clinical crowns.

 Top:Healthy gingivae.
 Bottom :The same
case with inflamed
gingivae in the upper
right quadrant.


Teeth with palatally or lingually
displaced roots.

 Individual teeth with
lingually displaced
roots can produce
short clinical
crowns.


Teeth with facially displaced
roots.

 Individual teeth with
facially displaced
roots can produce
long clinical crowns.


Incisal or Occlusal concerns.
 Incisal crown
fractures or
tooth wear
make it difficult
to visualize the
center of the
clinical crown.


Crowns with long tapered
buccal cusps

 Cuspids with
tapered clinical
crowns often do
not have adequate
contact with the
opposing teeth.


Axial/paralleling variation

The tip position of the lateral
incisor brackets was varied to
help root paralleling.

In this case a lower incisor has been
extracted and root paralleling has
been helped by changing axial
positions of adjacent brackets.


Tip specification
ANTERIOR TIP
Reduced anterior tip was
incorporated into the appliance
to conform to Andrews original
research,and to dramatically
reduce the anchorage needs of
each case. www.indiandentalacademy.com

Incisor Tip Cuspid Tip

Upper Upper Lower Lower Upper Lower
Central Lateral Central Lateral

MBT 4.0° 8.0° 0° 0° 8.0° 3.0°
Versatile+
Original 5.0° 9.0° 2.0° 2.0° 11.0° 5.0°
SWA3


Upper tip considerations
The authors prefer a 00 tip bracket,with
the band seated parallel to the buccal
cusps.This gives 50 tip.

If a 50 bracket is used,the band must be
seated more gingivally at the mesial.

If a 50 bracket is used,and the band is
seated parallel to the buccal cusps,this
will result in an effective 100 tip on the
molar.

Lower Bicuspid Tip Lower Molar Tip

Lower First Lower Lower First Lower
Second Second

MBT Versatile+ 2.0° 2.0° 0° 0°

Original SWA 2.0° 2.0° 2.0° 2.0°


UPPER POSTERIOR TIP
Upper bicuspid brackets are
provided with 00 tip to keep these
teeth in a more upright position .
Upper molar brackets are provided
with 00 tip, which when placed
parallel to the occlusal
plane,introduces 50 tip into the upper
molars.

LOWER POSTERIOR TIP
Lower posterior tip in the first and
second bicuspid brackets is maintained
at 20, to slightly incline these teeth
forward.
For the lower first and second molars,
00 tipped brackets are provided, which
when placed parallel to the occlusal
plane,introduces 20 of tip to these
teeth.

Bicuspid Tip Molar Tip

Upper First Upper Upper First Upper
Second Second

MBT Versatile+ 0° 0° 0° 0°

Original SWA 2.0° 2.0° 5.0° 5.0°


 Torque in base-the CAD factor
Using CAD it is possible to program the
computer to create the correct relationship
between the mid-point on the tooth and the
slot base,as with traditional torque-in-base.

 Refinement of bracket base design
It is incorporated to increase strength and
help plaque control in difficult areas.


In-out specification

 It is 100% fully expressed.
 In upper premolars an alternative
bracket which is 0.5mm thicker than
normal,is used.
 This is helpful in obtaining good
alignment of marginal ridges in cases
with small upper second premolars.


In-out modifications.

 An upper second bicuspid
bracket with an additional
0.5mm of in-out
compensation is provided
for the common situation
in which upper second
bicuspids are smaller than
upper first bicuspids.


Torque specification

INCISOR TORQUE
Upper incisor brackets are provided with
additional palatal root torque;while lower
incisor brackets are provided with
additional labial root torque.
This adjustment aids in the correction of
the most common torque problems
occurring in the incisor areas.


Upper central incisor torque

 Increased
palatal root
torque for upper
centrals.


Upper lateral incisor torque

 Increased
palatal root
torque for
upper lateral
incisors.


Lower incisor torque

 Increased
labial root
torque for
lower
incisors.


 Upper canine torque.
 Available in –70 ,00 ,
+70 , torque.
 The 00 and +70 options
are for cases with
narrow maxillary bone
form andor prominent
canine roots,and are
often used with
archwires in the
tapered form.


Upper Cuspid ,bicuspid and molar

torque .
• Upper cuspid and bicuspid
brackets are provided with the
normal -70 of torque.
Upper molar brackets are provided with
an additional 50 of buccal root torque (-90
to -140 ) to reduce palatal cusp
interferences with these teeth.

Incisor Torque Incisor Torque

Upper Central Upper Lower Lower
Lateral Central Lateral
MBT Versatile+ 17.0° 10.0° -6.0° -6.0°

Original SWA 7.0° 3.0° -1.0° -1.0°


Palatally positioned lateral
incisors.
It is important to create adequate
space before attempting to move
palatally placed incisors.

It is beneficial to invert the
bracket on instanding lateral
incisors,giving –100 torque.

Arch form considerations for
stability and esthetics.
 Bonwill and Hawley in 1905,suggested the
geometric method of constructing the ideal
arch form.
- The lower six anterior teeth lie along a
circle whose radius equaled their combined
widths.
-From this circle an equilateral triangle is
created,the base of which represented the
condylar width.
-Premolars and molars should lie along
these extended lines.

Traditional
edgewise wire
bending and
Boone arch form.


Brader Archform


 The Catenary curve is
formed by extending a
chain from two fixed
points.
 Many of the tapered
arch forms provided by
orthodontic
manufactures today are
based on Catenary
curve.


 In 1907 Angle-
- The form of line from the premolars and
molars should resemble a parabolic curve.
-He proposed the need for natural
curvature in molar region.
 In 1934 Chuck-
-Noted variation in arch form –square,
oval, tapering.
-The premolar region should be wider than
canines to prevent excessive expansion of
the canines.


 In 1963 Boone –
-Superimposed Bonwill-Hawley arch
form on a millimeter grid and used Angles
method for construction.
-Thus Bonwill-Hawley arch form is used
as a template in edgewise.
 Braun et al,1998
-Reported that the human arch form could
be represented by a complex mathematical
formula,known as the Beta function.
-This was calculated by entering
measurements of dental landmarks on
orthodontic models into a computer curve-
fitting program.

Selection of Archform

i. Arch form template are placed on lower
study models.
-The inter-canine width is evaluated.

ii.If buccal uprighting is needed in the lower
arch, a wider arch form is selected.


In 70% of cases buccal uprighting will result in
lower anterior relapse.
Cases in which buccal uprighting will be stable
include-
(a) Cases in which maxillary expansion is
indicated.
(b)Deep bite cases such as Class II /2 cases.

iii.Contour and width in the lower posterior
segment is estimated but this can be easily
customized.


MBT ARCH FORM
 The three basic arch forms are tapered,
square and ovoid.
 When superimposed they vary mainly in inter-
canine width,giving a range of approximately
6mm.
 Inter-molar widths are similar ,but the molar
areas can be widened or narrowed as
needed,by easy wire bending.


ARCH FORMS - MBT


THE TAPERED ARCH FORM
 Indicated for patients with narrow
,tapered arch form and gingival
recession in canine and premolar
regions.
 Cases undergoing single arch
treatment,in this way no expansion of
treated arch occurs.


THE SQUARE ARCH FORM
 Indicated in cases with broad arch form.
 Cases that require buccal uprighting of
the lower posterior segments and
expansion of the upper arch.
 After over-expansion has been
achieved ,it may be beneficial to
change to the ovoid arch form in the
later stages of treatment.


THE OVOID ARCH FORM
 It is the most preferred arch form. The ovoid
arch form has proved to be good, reliable
arch form for high percentage of cases
treated with PAE

 Treated cases have shown good stability,
with minimal amounts of post-treatment
relapse.


The four components of archform

i. ANTERIOR CURVATURE

Based on inter-canine width. Its shape
becomes more tapered when inter-canine
width is narrow and more square when
inter-canine width is wide.

ii. INTER-CANINE WIDTH
This appears to be the most critical
aspect of arch form,because significant
relapse occurs if this dimension is changed.


 POSTERIOR CURVATURE
In the posterior area a gradual curvature
between canine and second molars are
preferred.

 INTER-MOLAR WIDTH
Treatment changes in this dimension is
more stable.
Arch form in the inter-molar region can
be widened or narrowed,depending on the
needs of the case.


Relapse tendency after changing
arch form.
 Riedel in 1969,postulated that arch form, in
the mandibular arch,cannot be permanently
altered during appliance therapy.
 Similar research was done by Shapiro,
Gardner, Felton,De La Cruz and Burke
suggesting that changes in inter-molar width
seem to be more stable than those of inter-
canine width.


TREATMENT MECHANICS

 Anchorage control
 Leveling and aligning
 Overbite control
 Overjet reduction
 Space closure
 Finishing


Anchorage control during leveling and
aligning

 The tooth movements needed to achieve
passive engagement of a plain, rectangular
archwire of 0.019/0.025 dimension, having
standard archform, into a correctly placed
preadjusted 0.022 bracket system.
 The manoeuvres used to restrict undesirable
changes during the opening phase of
treatment, so that leveling and aligning is
achieved without key features of the
malocclusion becoming worse.

 Recognizing the anchorage needs of a
case
 Mistakes in tooth leveling and aligning in
the early years
 Reduced anchorage needs
 Control in three planes:-

-horizontal
-vertical
-laterally


OVERBITE CONTROL
 Development of overbite


Tooth movements for bite opening

 Extrusion of posterior teeth
 Distal tipping of posterior teeth
 Proclination of incisors
 Intrusion of anterior teeth
 Combination of two or more of the
above tooth movements.


NON-EXTRACTION TREATMENT

 Initial archwire
placement
 Bite-plate effect
 Importance of
second molars
 Torque issues
 Bite opening curves
 Elastics


OVERJET REDUCTION

 Mesial movement of lower incisors
 Distal movement of upper incisors
 Distalizing or limiting the forward growth of
the maxilla
 Mesial movement of the mandible due to

a) forward mandibular growth rotation or
b) limiting posterior dental and skeletal
vertical dvelopment.

SPACE CLOSURE

 Closing loop archwires
 Sliding mechanics with heavy forces
 Elastic chain
 Sliding mechanics with light continous forces
(recommended):-
archwires
soldered hooks
passive tiebacks
active tiebacks using elastomeric modules
force levels

 Trampoline effect
 Type one active
tieback(distal
module)


 Type two active
tieback(mesial
module)


 Active tiebacks
using a NiTi coil
spring


Obstacles to space closure

 Inadequate leveling
 Damaged brackets
 Incorrect force levels
 Interference from opposing tooth
 Soft tissue resistance


FINISHING

 During the closing stages of treatment
attention needs to be given to the
following considerations:-
Horizontal
Vertical
Transverse
Dynamic
Cephalometric and esthetic.

In 1976,Dougherty described 17 factors that should be
considered during finishing:-
 Correction and overcorrection of the A-P jaw relationship
 Establishing the correct tip
 Establishing correct torque
 Co-ordinating arch width and form
 Establishing correct posterior crown torque
 Establishing marginal ridge relationship and contact
points
 Correction of midline discrepancies
 Establishing interdigitation of teeth
 Checking cephalometric objectives
 Checking the parallelism of roots
 Maintaining the closure of all spaces
 Evaluating facial and profile esthetics
 Checking for TMJ dysfunctions
 Checking functional movements
 Correction of habits

Horizontal
 Coordination of tooth fit-anterior and
posterior areas.
 Establishing correct tip of anterior and
posterior teeth
 Management of tooth size discrepancies
 Controlling rotations
 Maintaining the closure of al spaces
 Horizontal overcorrection


Vertical

 Correct crown length,marginal ridge
relationships,and contact points
 Final management of the curve of Spee
 -low angle cases
-high angle cases
 Vertical overcorrection-deep bite

-open bite

Transverse

 Arch form
 Archwire coordination
 Establishing posterior torque
 Transverse overcorrection


Dynamic

 Establishing
centric relation and
checking functional movements

 Checking for temporomandibular joint
dysfunction


Cephalometric and esthetic
 Progress headfilms should be taken halfway through
orthodontic treatment to determine how the skeletal,
dental and soft tissue components are being managed.
 Final ceph radiograph 3-4 months before debanding
 Factors considered-
Soft tissue profile, antero-posterior positionof the
incisors, torque of incisors, changes in the mandibular
plane, degree to which vertical development of patient
occurred or restricted and success in correcting the
horizontal,skeletal,and dental components
 Evaluation involves superimposition of progress


Settling

 0.014 or 0.016
round HANT wires
used
 Vertical triangular
elastics


 Variations:-
Cuspid labially placed, diastemas,
extraction cases, expansion cases, severe
class II malocclusion.
Settling may take longer than 6 weeks,it is
beneficial to leave lower rectangular steel
wire to maintain the arch form.
When only three weeks treatment
remaining, a normal lower 0.014 steel or
0.016 heat activated can be placed.


FINISHING TO ABO REQUIREMENTS
 In July 2000, the ABO came out with revised
requirements and a grading system for dental casts and
panoramic radiographs.The ABO places emphasis on
self assessment of seven features of dental casts.These
include:-
tooth alignment
Marginal ridges
buccolingual inclination
occlusal relationships
occlusal contacts
overjet
interproximal contacts

Appliance removal and retention

 Bracket and band removal
 Removal of remaining cement and
bonding agents
 Placement of positioners
 Retainers-bonded and removable


THANK YOU

INDIAN DENTAL ACADEMY


MBT system in orthodontics /certified fixed orthodontic courses by Indian dental academy

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MBT system in orthodontics /certified fixed orthodontic courses by Indian dental academy