Anchorage ortho

ANCHORAG
E
www.indiandentalacademy.com

INDEX
 DEFINITION
 CLASSIFICATION
 FACTORS AFFECTIONG ANCHORAGE
 SOURCES OF ANCHORAGE
 ANCHORAGE PLANNING
 DIFFERENT ANCHORAGES
 ANCHORAGE LAOSS & DEMAND
 ADVANCEMENT IN ANCHORAGE
 CONCLUSION
 REFERENCES

INTRODUCTION

 ANCHORAGE = RESISTANCE TO UNWANTED
TOOTH MOVEMENT.
 ANCHORAGE UNITS : The areas or units which
provide this undesirable movement.

DEFINITITION

 THE SITE OF DELIVERY FROM WHICH
FORCE IS EXERTED
- white n gardner
The nature and degree of resistance to
displacement offered by an anatomic unit
when used for the purpose of affecting
tooth movement
- GRABER

CLASSIFICATION

 Acc. to manner of the force application as:
1. Simple
2. Stationary
3. Reciprocal
 Acc. to the jaws involved as :
1. Intra maxillary
2. Inter maxillary

 Acc. to the site of anchorage
1. Intra oral
2. Extra oral
3. Muscular
 Acc.to the no. of anchorage units as :
1. Simple
2. Compound
3. Reinforced

 Acc. To white n gardner
1. Simple
2. Stationary
3. Reciprocal
4. Reinforced
5. Inter maxillary
6. Extra oral

Factors affecting
anchorage

1. Teeth
2. Root forms
 Round – resistance is same in any direction
 Flat – resist tooth movement in M-D direction eg. mand.
Incisors & molars , buccal roots of max. molars ( tripod
arrangement of roots )
 Triangular – offers greater resistance to movement. Eg.
Maxillary canine & lateral incisor

1. Size n no. of roots – large surface area & multirooted
teeth > resistance
2. Root length – deeper the root embeded > resistance
3. Position of tooth in the dental arch – eg. Mandi. 2nd
molar
is located bt. Two ridges of basal bone , so offer more
resistance to bodily movement
4. Inclination of tooth – axial inclination is in opposite
direction to force , greater resistance
5. Mutual support

1. Basal bone – eg.hard
palate & lingual surface
of the mandible in
anterior region.
2. The musculature –
Hypotonic m. - Flaring &
spacing
Hypertonic m. - Collapse
of the teeth lingually
eg.Nance palatal button
( use of hard palate to
provide resistance to
mesial movement of
max. molar

SOURCES OF ANCHORAGE

 INTRA –ORAL :
1. Individual teeth
2. Multiple tooth units
3. Encasement (eg.Inclined planes)
4. Occluding teeth
 OTHERS :
1. Holding Arches
2. Basal bone
3. Neck cranium
4. Occipital region
 MUSCULATURE : lip bumper

ANCHORAGE
PLANNING

Depends on : -
1. The number of teeth to be moved
2. The type of teeth to be moved
3. Type of tooth movement
4. Periodontal condition
5. Duration of tooth movement

INTRA
MAXILLARY
ANCHORAGE

 Within the same jaw ( either maxilla or
mandible )
 Eg.Elastic chains are
used to retract the
anterior segment
using the posterior
teeth as anchorage
unit.

Sub- divisions
1. Simple
2. Stationary
3. Reciprocal

INTER MAXILLARY
ANCHORAGE

 When the anchorage units situated in the one
jaw are used to provide the force required to
move teeth in the opposing jaw.
 SUB DIVISION :
1. Simple
2. Staionary
3. Reciprocal
Also called “BAKER’S ANCHORAGE”

 Eg. When class II elastics are used to
retract the maxillary anteriors , the
anchorage units are situated in the
mandibular arch.

 CLASS III INTER MAXILLARY ELASTICS

SIMPLE
ANCHORAGE

 When the manner & application of force is
such that it tends to change the axial
inclination of the tooth or teeth that form the
anchorage unit in the plane of the space in
which the force is applied.
 Simple anchorage is obtained by engaging
a greater number of teeth than are to be
moved

NT: The root surface area of the anchorage unit
should be at least double that of the units to be
moved.
eg. Anterior retraction with the
help of a HAWLEY’S
appliance
The movement of a single
tooth using a screw
appliance

STATIONARY
ANCHORAGE

 When the application of force tends to displace
the anchorage unit bodily in the plane of space in
which force is being applied
 The anchorage potential of teeth being moved
bodily is considerably greater as compare to
teeth being moved using a tipping force.

 Mandibular molars are bodily pitted against
the tipping forces of the maxillary anteriors.

RECIPROCAL
ANCHORAGE

 When two teeth or two sets of teeth move to an
equal extend in an opposite direction .
 Here the root surface area of the anchorage unit
is equal to that of the teeth to be moved.
 The effect of the forces exerted is equal.

• Cross Elastic To Correct
Molar Cross-bite
 Ni-Ti Molar
Rotator
 Arch expansion using a mid-
line screw

SINGLE OR PRIMARY ANCHORAGE
 The resistance provided by single tooth
with greater alveolar support is used to
move another tooth with lesser alveolar
support.
 Eg. Molar being used to retract a pre
molar

COMPOUND ANCHORAGE
 The resistance is provided by more than one
tooth with greater support is used to move
teeth with less support.
 Eg. Retracting incisors using loop mechanics

REINFORCED
ANCHORAGE

 The anchorage units are reinforced by the
use of more than one type of resistance
units.

 Anterior inclined plane
Exerts a backward
pull on the maxillary
appliance through the
mandible

 SVED BITE PLANE :
Prevent from being
inclined labially.

 A rigid labial bow :
To engage labial surface
of the incisor at the
junction of cervical &
incisal third of each
crown.

 Banding of 2nd
molar
for the retraction of
permanent canine

EXTRA ORAL
ANCHORAGE

 The extra oral structure most commonly
used are :
1. Cervical region
2. The occiput
3. The forehead
4. The chin

Extra oral forces to augment
anchorage

Advantage
 The anchorage unit is far away from the
actual site where the movement is taking
place, so less chances of any change in
the anchorage units

Disadvantage
 Lack of patient’s co- operation
 Anchorage assembly is bulky & externally
visible
 Decrease in the number of hours for which the
anchorage assembly is worn, so affects quality
of result achieved

MUSCULAR
ANCHORAGE

 Peri oral musculature is not so strong but also
resilient.
 The forces generated by the musculature
sometimes used to bring about tooth
movement.
 eg.Lip bumper appliance
(to distalize mandibular
1st
molars)

ANCHORAGE LOSS
 It is the movement of the reaction unit or
the anchor unit instead of the teeth to be
moved.

ANCHORAGE DEMAND
 Depending on anchorage loss : -
1. Maximum anchorage case
2. Moderate anchorage case
3. Minimum anchorage case

Maximum anchorage cases
 Anchorage demand is
very high
 Not more than ¼ th of
the extraction space
should be lost by
forward movement of
the anchor teeth

Moderate anchorage cases
 Anchor teeth can be
permitted to move
forward into ¼ th to ½
of the extraction
space.

Minimum anchorage cases
 Anchorage demand is
very low

ADVANCEMENT
IN
ANCHORAGE

REFERENCES
 Contemporary Orthodontics –
(2nd
edition) BY WILLIUM R. PROFIT
 Text book of orthodontics –
(1st
edition) BY GURKEERAT SINGH
 Orthodontics principles and practice -
(3rd
edition) BY GRABER
 Textbook of orthodontics –
( 3rd
edition) BY M.S RANI
 Internet – (www.google.com)
(http:www.miniimplantanchorage.com)

Anchorage ortho

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