Anchorage in orthodontics /certified fixed orthodontic courses by Indian dental academy

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Introduction


Orthodontic tooth movement

Force
Active components???


Introduction


Active components
Generate forces
In one direction
Equal and opposite force
Newton’s third law of motion


Introduction


Desired tooth movement is inevitably asso with an
opposing force.
Anchorage units
Anchorage loss
Anchorage management


Definitions
Moyers :
 “ Resistance to displacement.”
 Active elements and resistance elements.
T.M. Graber :
 “The nature and degree of resistance to displacement
offered by an anatomic unit when used for the
purpose of effecting tooth movement.”


Definitions
Proffit :


“Resistance to unwanted tooth movement.”



“Resistance to reaction forces that is provided
(usually) by other teeth, or (sometimes) by the palate,
head or neck (via extraoral force), or implants in
bone.”

Definitions
Nanda :


“The amount of movement of posterior teeth (molars,
premolars) to close the extraction space in order to
achieve selected treatment goals.”

Reversal of anchorage

Classification – Moyers
Anchorage
Intraoral

Muscular

Intramaxillary

Cervical
Occipital
Cranial
Facial

Intermaxillary
Simple
Stationary
Reciprocal

Extraoral

Single
Compound
Reinforced

Classification
Nanda :
1. A anchorage : critical / severe
75 % or more of the extraction space is needed for
anterior retraction
.
2. B anchorage : moderate
Relatively symmetric space closure (50%)
3. C anchorage : mild / non critical
75% or more of space closure by mesial movement
of posterior teeth

Classification


Classification


Burstone



Group A: Postr teeth contribute less than one quarter
to total space closure



Group B: Postr teeth contribute from one quarter to
one half to total space closure



Group C: Postr teeth contribute more than one half
to total space closure

Biologic Aspect Of Anchorage


Anchorage value
Teeth to be moved
Active components
Anchorage
Extraoral vs intraoral anchorage




Factors affecting anchorage value
Force magnitude

Physiologic force
concept
F/A




Surface area

Major determinant

Lower incisor vs molar anchorage
First principle of orthodontic anchorage



For a tooth or group of teeth acting as anchorage
unit, pressure within the pdl should be kept as low
as possible

Heavy forces




Pressure Response Curve for Anchor Teeth (A) and
Teeth to be Moved (M)



Pressure in the PDL of A is less than the pressure in
the PDL of M




2nd factor – pressure distribution
Single force vs force couple

Second

principle of orthodontic anchorage



Proffit
Tipping – 50-75 g
Bodily - 100-150 g
Intrusion - 50-75 g
Extrusion - 50-75 g
Rotation - 50-75 g
Uprighting- 75- 125g





Tooth which is free to tip has a less anchorage value
than a tooth which is restricted in tipping by the
application of a force couple




3rd factor – no. of roots and root morphology
Multirooted > single rooted
Longer rooted > shorter rooted
Triangular shaped root > conical or ovoid root
Larger surface area > smaller surface area







4th factor – neighbouring structures
Quality of the alveolar bone
Traumatic extraction
2nd molars inclusion






Soft tissues
Fixed app incorporating lip bumper
Palatal button


Types of anchorage


Simple Anchorage:
‘Dental anchorage in which the
manner and application of force
tends to displace or change the
axial inclination of the teeth
that form the anchorage unit in
the plane of space in which the
force is being applied.’


Types of anchorage





Stationary Anchorage:
‘Dental anchorage in which the manner and
application of force tends to displace the anchorage
unit bodily in the plane of space in which the force is
being applied.’
Refers to the advantage that can be obtained by
pitting bodily movement of one group of teeth against
tipping of another


Types of anchorage


Eg: Retraction of
mandibular incisors
using first molars as
anchorage



Considerably more than
Simple Anchorage


Types of anchorage



Reciprocal Anchorage:
Anchorage in which the
resistance of one or more dental
units is utilized to move one or
more opposing dental units



Dissipation of equal and
opposite forces



Diastema closure

Types of anchorage


Correction of posterior cross bite through cross
elastics


Types of anchorage

Close to reciprocal anchorage

Types of anchorage





Multiple or Reinforced
Anchorage:
Multiple dental anchorage:
Reduces pressure on the anchor
units moving them down the
slope of the pressure-response
curve
Tissue - borne anchorage:

Types of anchorage


Cortical Anchorage:



Torquing the roots of posterior teeth outward against
the cortical plate to inhibit their mesial movement


Types of anchorage


Intramaxillry anchorage/ traction


Resistance units are situated within the same jaw


Types of anchorage


Intermaxillary anchorage/ traction
Resistance units situated in one jaw are used to
effect tooth movement in the other jaw


Class III traction

Class II traction


Palatal and lingual arches

Maintain intermolar width
Restrict mesial tipping
Correction of rotations

Two couple orthodontic appliance system :
Transpalatal arches


Two bracket system



Cinched



Passive and rigid


Transpalatal arches


Bilateral expansion


Transpalatal arches


Bilateral constriction


Transpalatal arches


Symmetrical V- Bend

Bilateral First order activations
(Mesiofacial Rotations)


Transpalatal arches
Clinical uses


Required in non-extraction T/t



To counter the M-Li rotations
produced by space closing forces



Before initiating head gear
therapy

Transpalatal arches
To decrease the arch perimeter
To close any remaining
posterior spaces
To seat the molar properly for
a classII molar finish
Mesiolingual Rotations

Transpalatal arches


Symmetrical V- Bend
Bilateral Second order
activations
(M-D tipping)


Transpalatal arches

•Correction of unilateral classII dental malocclusion

Transpalatal arches


Symmetrical V- Bend
Bilateral Third order activations
(Facial Root Torque)

•To upright the molar roots

Transpalatal arches


Asymmetrical V- Bend
Unilateral First order activations
(Mesiofacial Rotations)

•Correction of unilateral
classII
dental malocclusion

Transpalatal arches


Unilateral First order
activations
(Mesiolingual Rotations)

Unilateral Loss of molar anchorage is required

Transpalatal arches


Unilateral Third order
activations
(Facial Root Torque)

•To correct the unilateral cross bites

Transpalatal arches

Step bends

Anchorage and choice of extraction


Thank you
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Anchorage in orthodontics /certified fixed orthodontic courses by Indian dental academy

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