This document discusses principles of anchorage control during tooth leveling and aligning using the MBT preadjusted appliance system. It covers anchorage in the anteroposterior, vertical, and transverse planes of space. Techniques described include lacebacks, bendbacks, headgear, palatal bars, and intrusion mechanics. Overbite control methods like bite plates and second molar inclusion are also outlined. The document emphasizes controlling tipping moments and using light continuous archwire forces for optimal anchorage during the leveling phase.

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Anchorage control during tooth leveling
and aligning and over bite control- MBT
TO EVERY ACTION, THERE IS EQUAL AND OPPOSITE REACTION
PRESENTED BY: Dr. Zynul Ali Sirsmith John

2. CONTENTS
INTRODUCTION
ANCHORAGE IN 3 PLANES OF SPACE
MISTAKES DURING LEVELING AND ALIGNMENT
HOW MISTAKES WERE OVERCOMED
ANTERO-POSTERIOR ANCHORAGE
ANCHORAGE IN TRANSVERSE PLANE
ANCHORAGE IN VERTICAL PLANE
ARCH LEVELING AND OVERBITE CONTROL

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Definition:
The maneuvers used to restrict undesirable changes during
the opening phase of treatment, so that leveling and aligning
are achieved without key features of malocclusion becoming
worse.
Principles of anchorage control:
• Unnecessary
anchorage
taxation
REDUCTION
OF
ANCHORAGE
NEEDS
• Palatal bow,
lingual arch
ANCHORAGE
SUPPORT
DURING L/A

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ANCHORAGE
CONROL
LATERAL
HORIZONTAL
VERTICAL

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The tip built into the anterior brackets caused the
crowns of the anterior teeth to incline forward
during initial phase of leveling and aligning.
Mistakes in tooth leveling & aligning

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• Also if the elastic forces were greater than the leveling forces
of the archwire, their was the tendency for anterior teeth to
tip & rotate distally.
Anchorage control during tooth leveling and aligning.
Mistakes in tooth leveling & aligning

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• The “roller coaster effect” is seldom seen in today’s cases:
Reduced tip in MBT bracket system and increased torque
Lighter archwire forces
Use of lacebacks for canines.

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Anchorage support: Antero-posterior direction.
Lacebacks : A/P canine control
Adverse tipping occurred in the early leveling stages if elastic
forces (even very light forces) were applied to the cuspids. MBT
instead placed “lacebacks”.

11. • Robins on investigated 57 premolar extraction cases:
• The initial purpose of lacebacks was to prevent canines from tipping forward,
but it was found that, where necessary, these wires were an effective means
of distalizing the canines without the unwanted tipping.
• They are mainly used in extraction cases, but they may also be required in
non extraction case where there is local threat to anchorage.
11

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Slight tipping of the canines against the
alveolar crest at the gingival aspect of the
canines.
Period of rebound (due to the leveling
effect of the archwire), during which the
roots of the canines are allowed to move
distally. If elastic forces are used, the
rebound does not occur because of the
presence of a continuous tipping force.
This theoretical explanation is supported by the clinical finding that
when a patient returns for routine adjustments, the lacebacks are
consistently loose and need minimal tightening.

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Bendbacks : A/P incisor control
•Bendbacks are used in combination with lacebacks.
•Archwire bent back immediately behind the tube on the most
distally banded molar serves to minimize forward tipping of the
incisors.

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A/P molar control
Posterior anchorage control requirements are normally
greater in the upper arch:
A/P: anteroposterior
Upper molars tip
mesially
Upper anteriors
have large TTM
More built in tip in
upper anteriors
Torque requirement
with upper anteriors
MOLAR
CONTROL

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A/P Upper Molar control: Headgear
Occipital
Combination
Cervical
Occlusal plane
MBT philosophy prefers to use combination HG for most cases.
The force levels used for the combination HG are 150 -250 gms
for occipital pull & 100 – 150 gms for cervical pull .
A/P: anteroposterior

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A/P Upper Molar control: Palatal bar
The palatal bar can be constructed of heavy 0.045/0.051” round
wire extending from molar to molar with a loop placed in the
middle of the palate & the wire about 2mm from the roof of the
palate.

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A/P lower molar control:
Headgear Class III elastics & Headgear
It is preferred to delay Class III
elastics until the 0.016 round wire
stage to prevent extrusion of the
incisors.
Lingual arch

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Anchorage support: vertical direction.
Vertical incisor control
This effect can be avoided by not bracketing the incisors at the start of
the treatment until the canine roots have been uprighted using
lacebacks.

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Vertical canine control

22.  If the upper 1st molars require
expansion, an attempt is made to
achieve bodily movement rather
than tipping to avoid extrusion of
the palatal cusps.
 Use of cervical pull HG is
avoided.
 TPA is designed with U loop
facing forward & such that it lies
2 mm away from the palate so
that the tongue can exert a
vertical intrusive effect.
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Vertical molar control: high angle cases.
Anchorage control during tooth leveling and aligning.
Principles of anchorage control
Anchorage support

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Anchorage support: transverse direction.
Inter canine width

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Anchorage support: transverse direction.
Molar crossbites
Care is needed to avoid arbitrary correction of molar
crossbites by tipping movements.
Anchorage control during tooth leveling and aligning.
Principles of anchorage control

25. Recommended sequencing
25

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Overbite control

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Tooth leveling & aligning is normally the first orthodontic objective during
the initial stages of treatment.
Definition:
The tooth movements needed to achieve passive engagement of a steel
rectangular wire of 0.019 X 0.025 dimension & of suitable archform, into
a correctly placed preadjusted 0.022 bracket system.
Arch leveling & Overbite control

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Development of deep overbite
Lower anterior teeth normally erupt
until contact is made with upper
anterior teeth.
The tongue can restrict over-eruption
of lower incisors in some class II
cases.
Arch leveling & Overbite control

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If the molar relationship is class II, the
lower incisors can erupt until they
contact the palate. This can cause a steep
anterior curve of Spee.
Unrestricted eruption of lower 2nd
molars in class II case contributes to
development of posterior part of
curve of Spee.
Development of deep overbite
Arch leveling & Overbite control

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Tooth movements of bite opening:
Eruption & extrusion of posterior teeth
Distal tipping of posterior teeth
Proclination of incisors
Intrusion of incisors
Combination of above
Skeletal convexity
Vertical dimension & growth
Freeway space
Anterior esthetics
Arch leveling & Overbite control

31. Factors for considering intrusive mechanics
Type of intrusion

32. According to Burstone the average force values for
intrusions are :
•Moment values are based on 30 mm distance from incisors to the
center of resistance of posterior segment.
Teeth Force /Side Total force in
midline
Moment/side
(gm- mm)
Upper
Central incisors.
Central & lateral incisors.
Central & lateral incisors &
canine.
25
50
100
50
100
200
750
1,500
3,000
Lower
Central & lateral incisors.
Central & lateral incisors &
canines.
20
80
40
160
600
2,400

33. Point of force
application

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Non - Extraction Treatment
Initial archwire placement:
When flat archwires are placed into dental arches with curves of
Spee, the archwires tend to return to their original shape & this starts
the bite opening process. Also, expression of the tip in the brackets
begins the bite opening process.
Bite plate effect:
Introducing bite plate effect in deep bite cases is helpful in following ways:
It allows early placement of brackets on
lower incisors.
Anterior bite plates can produce an
intrusive force on lower incisors.
Anterior bite plates allow for the
eruption, extrusion & /or uprighting of
posterior teeth.
Arch leveling & Overbite control

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Creating bite plate effect:
Non - Extraction Treatment
Arch leveling & Overbite control

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Arch leveling & Overbite control
Turbo Jet from Ormco
TM

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The importance of second molars:
In average to low angle deep bite cases, the earliest possible banding or
bonding of the second molars is most beneficial in bite opening.
Inclusion of the second molars provides an excellent lever arm for eruption &
extrusion of premolars & first molars, and assists in incisor intrusion.
Bite opening curves :
It is preferred not to place bite opening curves in round wires or to have
such curves built in rectangular heat activated wires. These wires do not
complete the leveling of the arches & the bite opening process.
In the great majority of cases after rectangular SS wires have been in place for
6 weeks, the arches are normally level & adequate bite opening has been
achieved. If this is not so, bite opening curves can be placed into the
rectangular steel wires.

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Bite opening curves :
Upper
Lower

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Anteroposterior issues and elastics :
Intermaxillary elastics can contribute to bite opening effect by assisting
in extrusion of molars as the A/P problem is corrected.
They are beneficial in treatment of most growing patients. If possible they
should be avoided in most non growing patients and adult high angle cases.

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Overbite control during leveling & aligning
There is tendency for incisors and canines to tip mesially after placement
of the opening archwires. Canine lacebacks should be used to resist this
mesial tipping of the canines and to retract these teeth effectively without
distal tipping. Elastic forces should be avoided.
When canines are unfavourably angled, it may be beneficial to avoid
bracketing the incisors until the canine roots have been retracted.
An alternative technique involves placing a bend in the archwire mesial
to the canine.
According to MBT, incisors that are in reasonably good alignment should be
bracketed & included in the initial archwires. This provides greater stability to
the archform & minimizes distal tipping of the canines.
Arch leveling & Overbite control

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Overbite control during space closure:
It is important to use light forces during space closure.
Heavy forces causes bite to deepen in two ways:
The canines can tip into the extraction sites causing archwire deflection
and binding. The sliding mechanics then becomes ineffective, and the
overbite deepens.
Excessive forces overpowers the incisor torque control of the rectangular
wire, causing distal tipping and bite deepening.
Arch leveling & Overbite control

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Management of openbite during full
orthodontic treatment
Arch leveling & Overbite control
If upper and lower arches are crowded and/or show protrusion, upper and lower
bicuspid extractions can be considered.
If the lower arch does not require extraction of lower incisor retroclination,
and the molars are more than 3-4 mm class II, extractions of upper bicuspids
only can be considered.
Appropriate bracket placement.

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Management of openbite during full
orthodontic treatment
Arch leveling & Overbite control
Second molars should not be banded in early and middle stages. because this can
lead to the extrusion of the premolars and first molars, and further bile opening.
If second molars need to be banded for improved positioning or for torque control
later in treatment, it is beneficial to leave curve of Spec in the posterior aspect of the
lower arch and to step the archwire up to the second molars in the upper arch.
This will minimize extrusion of first molars and bicuspids.

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“It is the appliance for the patient and not the
patient for the appliance.”
Conclusion
The key to the success :
 Accurate diagnosis
 Proper treatment planning and execution
 Adequate motivational skills

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References
McLaughlin RP, Bennett JC. The dental VTO: an analysis of orthodontic tooth
movement. J Clin Orthod. 1999 Jul;33(7):394-403.
McLaughlin RP, Bennett JC. Bracket placement with the preadjusted appliance.
J Clin Orthod. 1995 May;29(5):302-11.
Bennett JC, McLaughlin RP. Overjet reduction with a preadjusted appliance
system. J Clin Orthod. 1992 May;26(5):293-309.
McLaughlin RP, Bennett JC. Anchorage control during leveling and aligning with
a preadjusted appliance system. J Clin Orthod. 1991 Nov;25(11):687-96.
McLaughlin RP, Bennett JC. Finishing and detailing with a
preadjusted appliance system. J Clin Orthod. 1991 Apr;25(4):251-64.

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References
Bennett JC, McLaughlin RP. Controlled space closure with a preadjusted
appliance system. J Clin Orthod. 1990 Apr;24(4):251-60
McLaughlin RP, Bennett JC. The transition from standard edgewise to
preadjusted appliance systems.J Clin Orthod. 1989 Mar;23(3):142-53.
Bennett JC, McLaughlin RP. Management of deep overbite with a
preadjusted appliance system. J Clin Orthod. 1990;24(11):684-96.

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