Anchorage (2)

ANCHORAGEANCHORAGE
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Graber has defined anchorage inGraber has defined anchorage in
orthodontics as the nature and theorthodontics as the nature and the
degree of resistance to displacementdegree of resistance to displacement
offered by anatomic unit for theoffered by anatomic unit for the
purpose of effecting the toothpurpose of effecting the tooth
movement.movement.
Proffit defines anchorage asProffit defines anchorage as
resistance to unwanted toothresistance to unwanted tooth
movement.movement.
According to Moyers anchorageAccording to Moyers anchorage
means resistance to displacement.means resistance to displacement.

According to white and GardienerAccording to white and Gardiener
anchorage is a site of delivery fromanchorage is a site of delivery from
which force is delivered.which force is delivered.

SOURCES OF ANCHORAGESOURCES OF ANCHORAGE
Anchorage during orthodonticAnchorage during orthodontic
therapy is mainly obtained through 2therapy is mainly obtained through 2
sources:sources:
1) Intra oral sources1) Intra oral sources
2) Extra oral sources2) Extra oral sources

The intra oral sources of anchorageThe intra oral sources of anchorage
include the teeth,alveolar bone, theinclude the teeth,alveolar bone, the
basal jaw bone and the musculature.basal jaw bone and the musculature.
1) The Teeth1) The Teeth
Whenever some teeth are movedWhenever some teeth are moved
orthodontically , theorthodontically , the
remaining teeth of the oral cavityremaining teeth of the oral cavity
can act as anchorage or resistancecan act as anchorage or resistance
units.units.
The ancorage potential of teethThe ancorage potential of teeth
depends on a number of factors suchdepends on a number of factors such
INTRAORAL SOURCESINTRAORAL SOURCES

Root formRoot form
Root sizeRoot size
Number of rootsNumber of roots
Root lengthRoot length
Inclination of rootsInclination of roots
Ankylosed teethAnkylosed teeth
2) Alveolar bone2) Alveolar bone
The alveolar bone that surrounds a toothThe alveolar bone that surrounds a tooth
offers resistance to tooth movement uptooffers resistance to tooth movement upto
a certain amount of force.a certain amount of force.
When the force applied exceeds a certainWhen the force applied exceeds a certain
limit, the alveolar bone permits toothlimit, the alveolar bone permits tooth
movement by bone remodelling.movement by bone remodelling.

3) Basal bone3) Basal bone
These areas include the hard palate andThese areas include the hard palate and
the lingual surface of mandible in thethe lingual surface of mandible in the
region of the roots .These intra oral hardregion of the roots .These intra oral hard
areas of basal bone can be used toareas of basal bone can be used to
augment intermaxillary or intramaxillaryaugment intermaxillary or intramaxillary
anchorage.anchorage.
4) Musculature4) Musculature
Dental anchorage may be increased byDental anchorage may be increased by
making use of hypertonc labialmaking use of hypertonc labial
musculature as in the case of lip bumper.musculature as in the case of lip bumper.

EXTRAORAL SOURCESEXTRAORAL SOURCES
They are mainly used when adequateThey are mainly used when adequate
resistance cannot be obtained fromresistance cannot be obtained from
intra oral sources for the purpose ofintra oral sources for the purpose of
1) Cranium (occipital or parietal1) Cranium (occipital or parietal
anchorage)anchorage)
Extra oral anchorage is obtained byExtra oral anchorage is obtained by
using head gears that deriveusing head gears that derive
anchorage from the occipital oranchorage from the occipital or
parietal region of the cranium.parietal region of the cranium.
These devices areThese devices are
used along with a face bow to restrictused along with a face bow to restrict

2) Back of the neck (Cervical anchorage)2) Back of the neck (Cervical anchorage)
This anchorage is obtained from neckThis anchorage is obtained from neck
or cervical region. Such a type of heador cervical region. Such a type of head
gear is called as Cervical head gear.gear is called as Cervical head gear.
3) Facial bones3) Facial bones
The frontal bone and the mandibularThe frontal bone and the mandibular
symphysis offer anchorage during facesymphysis offer anchorage during face
mask therapy in order to protect themask therapy in order to protect the
maxilla. Headmaxilla. Head
gears that makes use of anchorage fromgears that makes use of anchorage from
the head gear and chin are called asthe head gear and chin are called as
Reverse head gears.Reverse head gears.

CLASSIFICATION OFCLASSIFICATION OF
ANCHORAGEANCHORAGE
Given by MoyersGiven by Moyers

According to the manner of forceAccording to the manner of force
application :application :
1) Simple Anchorage1) Simple Anchorage
2) Stationary Anchorage2) Stationary Anchorage
3) Reciprocal Anchorage3) Reciprocal Anchorage
According to jaws involved:According to jaws involved:
1)Intramaxillary Anchorage1)Intramaxillary Anchorage
2)Intermaxillary Anchorage2)Intermaxillary Anchorage
According to the site of Anchorage:According to the site of Anchorage:
1)Intra oral Anchorage1)Intra oral Anchorage
2)Extra oral Anchorage2)Extra oral Anchoragewww.indiandentalacademy.comwww.indiandentalacademy.com

a) Cervicala) Cervical
b) Occipitalb) Occipital
c) Cranialc) Cranial
d) Faciald) Facial
3) Muscular Anchorage3) Muscular Anchorage
According to the number ofAccording to the number of
Anchorage Units:Anchorage Units:
1) Simple or Primary Anchorage1) Simple or Primary Anchorage
2) Compound Anchorage2) Compound Anchorage
3) Multiple or Reinforced Anchorage3) Multiple or Reinforced Anchorage

TYPES OF ANCHORAGETYPES OF ANCHORAGE

1) SIMPLE ANCHORAGE1) SIMPLE ANCHORAGE
It is defined as the dental anchorage in whichIt is defined as the dental anchorage in which
the manner and application of force is such that itthe manner and application of force is such that it
tends to change the axial inclination of the toothtends to change the axial inclination of the tooth
or teeth that form the anchorage unit in the planeor teeth that form the anchorage unit in the plane
of space in which the force is being applied. Thusof space in which the force is being applied. Thus
the resistance of the anchorage unit to tipping isthe resistance of the anchorage unit to tipping is
utilized to move another tooth or teeth.utilized to move another tooth or teeth.
Simple anchorage is obtained by engaging withSimple anchorage is obtained by engaging with
the appliance a greater number of teeth than arethe appliance a greater number of teeth than are
to be moved with ih the same dental arch.to be moved with ih the same dental arch.
The combined root surface area of the teethThe combined root surface area of the teeth
forming the anchorage unit must be double thatforming the anchorage unit must be double that
of the teeth to be moved.of the teeth to be moved.
Eg: when a palatally placed Premolar is pushedEg: when a palatally placed Premolar is pushed
bucally with the rest of the teeth in the dentalbucally with the rest of the teeth in the dental
arch as the anchor units.arch as the anchor units.

2) STATIONARY ANCHORAGE2) STATIONARY ANCHORAGE
It is defined as dental anchorageIt is defined as dental anchorage
in which the manner and applicationin which the manner and application
of force tends to displace theof force tends to displace the
anchorage unit bodily in the plane ofanchorage unit bodily in the plane of
space in which the force is beingspace in which the force is being
applied .applied .

3)RECIPROCAL ANCHORAGE3)RECIPROCAL ANCHORAGE
The term generally refers to theThe term generally refers to the
resistance offered by two malposedresistance offered by two malposed
units when the dissipation of equalunits when the dissipation of equal
and opposite forces tends to moveand opposite forces tends to move
each unit towards a more normaleach unit towards a more normal
occlusion.occlusion.
Here two teeth or more groups ofHere two teeth or more groups of
teeth of equal anchorage value areteeth of equal anchorage value are
made to move in opposite directions.made to move in opposite directions.

Eg:Eg:
- closure of midline diastema by- closure of midline diastema by
moving the two central incisorsmoving the two central incisors
towards each other.towards each other.
-use of crossbite elastics-use of crossbite elastics
-Dental arch expansion-Dental arch expansion

4)INTRA ORAL ANCHORAGE4)INTRA ORAL ANCHORAGE
Anchorage in which all the resistance units areAnchorage in which all the resistance units are
situated within the oral cavity is termed as intrasituated within the oral cavity is termed as intra
oral anchorage.oral anchorage.
The teeth to be moved and the anatomic areasThe teeth to be moved and the anatomic areas
that offer anchorage are all with in the oralthat offer anchorage are all with in the oral
cavity.cavity.
Various intra oral anatomic units employed areVarious intra oral anatomic units employed are
teeth,palate and lingual alveolar bone ofteeth,palate and lingual alveolar bone of
mandiblemandible

5)5)

Example of extra oral anchorageExample of extra oral anchorage
include the use of head gears that deriveinclude the use of head gears that derive
anchorage from the cervical or cranialanchorage from the cervical or cranial
regions and face masks that derivesregions and face masks that derives
anchorage from the facial bones.anchorage from the facial bones.

6) MUSCULAR ANCHORAGE6) MUSCULAR ANCHORAGE
Muscular anchorage makes use ofMuscular anchorage makes use of
forces generated by muscles to aid inforces generated by muscles to aid in
the movement of teeth.the movement of teeth.
Example of muscular anchorage isExample of muscular anchorage is
use of lip bumper to distalize molars.use of lip bumper to distalize molars.

7) INTRA MAXILLARY ANCHORAGE7) INTRA MAXILLARY ANCHORAGE
When all the units offeringWhen all the units offering
resistance are situted with in theresistance are situted with in the
same jaw the anchorage is describedsame jaw the anchorage is described
as intra maxillary anchorage.as intra maxillary anchorage.
In this type of anchorage theIn this type of anchorage the
teeth to be moved and theteeth to be moved and the
anchorage units are all situatedanchorage units are all situated
either entirely in the maxillary or ineither entirely in the maxillary or in
the mandibular arches.the mandibular arches.

8)INTER MAXILLARY ANCHORAGE8)INTER MAXILLARY ANCHORAGE
Anchorage in which the resistance unitsAnchorage in which the resistance units
situated in one jaw are used to effectsituated in one jaw are used to effect
tooth movement in the opposing jaw istooth movement in the opposing jaw is
called Inter maxillary anchorage.called Inter maxillary anchorage.
It is also termed as Bakers anchorage.It is also termed as Bakers anchorage.
Eg:- Class 2 elastic traction appliedEg:- Class 2 elastic traction applied
between the lower molar and upperbetween the lower molar and upper
anteriors as wll as Class 3 elastic tractionanteriors as wll as Class 3 elastic traction
applied between the upper molar andapplied between the upper molar and
lower anteriors are types of intermaxillarylower anteriors are types of intermaxillary

9) SINGLE OR PRIMARY ANCHORAGE9) SINGLE OR PRIMARY ANCHORAGE
The resistance provided by aThe resistance provided by a
single tooth with greater alveolarsingle tooth with greater alveolar
support is used to move anothersupport is used to move another
tooth with lesser support is referredtooth with lesser support is referred
to as Single or Primary anchorage.to as Single or Primary anchorage.
..

10)10)
Anchorage where the resistanceAnchorage where the resistance
provided by more than one toothprovided by more than one tooth
with greater support is used to movewith greater support is used to move
teeth with lesser support is called asteeth with lesser support is called as
Compound AnchorageCompound Anchorage

11) REINFORCED OR MULTIPLE11) REINFORCED OR MULTIPLE
ANCHORAGEANCHORAGE
Anchorage in which more than one type ofAnchorage in which more than one type of
resistance unitis utilized is termed asresistance unitis utilized is termed as
Reinforced Anchorage.Reinforced Anchorage.
Reinforced Anchorage refers to theReinforced Anchorage refers to the
augmentation of anchorage by variousaugmentation of anchorage by various
means such as :means such as :
A)Extra oral forces to augmentA)Extra oral forces to augment
anchorage : Forces generated from extraanchorage : Forces generated from extra
oral areas such as cranium, back of theoral areas such as cranium, back of the
neck and face can be used to reinforceneck and face can be used to reinforce

B) Upper anterior inclined Plane:B) Upper anterior inclined Plane:
A removable appliance incorporating anA removable appliance incorporating an
upper anterior inclined plane results inupper anterior inclined plane results in
forward glide of the mandible duringforward glide of the mandible during
closure of the jaw.closure of the jaw.
This results in stretching of the retractorThis results in stretching of the retractor
muscles of the mandible whichmuscles of the mandible which
subsequently contracts and forces thesubsequently contracts and forces the
mandible against the upper inclined plane.mandible against the upper inclined plane.
Thus a distal force is applied on theThus a distal force is applied on the
maxillary teeth there by reinforcingmaxillary teeth there by reinforcing
maxillary anchorage.maxillary anchorage.
A modification of the anterior inclinedA modification of the anterior inclined
plane is the Sved appliance that has anplane is the Sved appliance that has an
additional upper incisal capping.additional upper incisal capping.

c) Transpalatal Archc) Transpalatal Arch
This is a wire thatThis is a wire that
spans the palate in aspans the palate in a
transverse direction losstransverse direction loss
connecting the firstconnecting the first
permanent molars ofpermanent molars of
either side.either side.
They are used inThey are used in
fixed mechanotherapy tofixed mechanotherapy to
augment anchorage.augment anchorage.

ANCHORAGE PLANNINGANCHORAGE PLANNING
It is essential to carefully assess theIt is essential to carefully assess the
anchorage demands of an individual caseanchorage demands of an individual case
so that appropriate treatment modalitiesso that appropriate treatment modalities
can be executed.can be executed.
The anchorage requirement depends on aThe anchorage requirement depends on a
number of factors listed below:number of factors listed below:
1) Number of teeth being moved- Greater1) Number of teeth being moved- Greater
the number of teeth being moved ,greaterthe number of teeth being moved ,greater
is the demand of anchorage.is the demand of anchorage.
2) Type of teeth being moved- The2) Type of teeth being moved- The
movement of slender anterior teeth offersmovement of slender anterior teeth offers
less strain on the anchorage than robustless strain on the anchorage than robust
multirooted tooth.multirooted tooth.

3) Type of tooth movement-3) Type of tooth movement-
Whenever bodily tooth movement isWhenever bodily tooth movement is
required there is a greater strain onrequired there is a greater strain on
the anchorage.the anchorage.
In contrast, tipping movements offerIn contrast, tipping movements offer
a relatively lesser strain ona relatively lesser strain on
anchorage units.anchorage units.
4) Duration of tooth movement-4) Duration of tooth movement-
Treatment for a prolonged durationTreatment for a prolonged duration
places an undue strain on anchorage.places an undue strain on anchorage.

ANCHORAGE LOSSANCHORAGE LOSS
Inspite of the precaution taken in planningInspite of the precaution taken in planning
anchorage , a certain amount of unwantedanchorage , a certain amount of unwanted
movement of the anchor teeth invariablymovement of the anchor teeth invariably
occurs during orthodontic treatment. Suchoccurs during orthodontic treatment. Such
unwanted movements of anchor teeth isunwanted movements of anchor teeth is
called as Anchorage loss.called as Anchorage loss.
Based on the anchorage lossthat isBased on the anchorage lossthat is
permissible , the anchorage demand of anpermissible , the anchorage demand of an
extraction case can be of 3 types:-extraction case can be of 3 types:-
1) Maximum Anchorage Cases :1) Maximum Anchorage Cases :
Where the anchorage demand is very highWhere the anchorage demand is very high
, not more than 1/4, not more than 1/4thth
of the extraction spaceof the extraction space
should be lost by forward movement of theshould be lost by forward movement of the
anterior teeth.anterior teeth. www.indiandentalacademy.comwww.indiandentalacademy.com

2) Moderate Anchorage Cases2) Moderate Anchorage Cases
In these cases, the anchor teethIn these cases, the anchor teeth
can be permitted to move forwardcan be permitted to move forward
into 1/4into 1/4thth
to ½ of the extractionto ½ of the extraction
space.space.
3) Minimum Anchorage Cases3) Minimum Anchorage Cases
In these cases, the anchorageIn these cases, the anchorage
demand is very low. More than halfdemand is very low. More than half
of the extraction space can be lost byof the extraction space can be lost by
the anchor teeth moving mesially.the anchor teeth moving mesially.

Anchorage (2)

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