Anch

Introduction
 Orthodontic tooth movement
Force
Active components???
www.indiandentalacademy.com

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 Extraoral
Cervical
Occipital
Cranial
Facial
Intramaxillary
Intermaxillary
Simple
Stationary
Reciprocal
Single
Compound
Reinforced
Muscular

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
 Factors affecting anchorage value
Force magnitude

 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 rootedMultirooted > single rooted
Longer rooted > shorter rootedLonger rooted > shorter rooted
Triangular shaped root > conical or ovoid rootTriangular shaped root > conical or ovoid root
Larger surface area > smaller surface areaLarger 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
 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 jawResistance units are situated within the same jaw

Types of anchorage
 Intermaxillary anchorage/ traction
Resistance units situated in one jaw are used toResistance units situated in one jaw are used to
effect tooth movement in the other jaweffect tooth movement in the other jaw
Class II tractionClass III traction www.indiandentalacademy.com

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
 Required in non-extraction T/t
 To counter the M-Li rotations
produced by space closing forces
 Before initiating head gear
therapy
Clinical uses

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

Transpalatal arches
Bilateral Second order
activations
(M-D tipping)

Transpalatal arches
•Correction of unilateral classII dental malocclusion

Transpalatal arches
Bilateral Third order activations
(Facial Root Torque)
•To upright the molar rootswww.indiandentalacademy.com

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

Anch

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