This document defines anchorage in orthodontics and discusses different types and sources of anchorage. Anchorage refers to the resistance to unwanted tooth movement provided by teeth or other structures when moving other teeth. Anchorage can come from intraoral sources like teeth and bone, or extraoral sources like headgear. Different classifications of anchorage include simple, stationary, reciprocal and types based on location or number of units. Temporary anchorage devices are also discussed as useful aids when maximal anchorage is needed. Careful anchorage planning is important based on factors like teeth being moved and skeletal pattern.

2. Contents:
 Introduction
 Definition and Sources of anchorage
 Classification of anchorage
 Temporary anchorage device
 Anchorage planning

3.  Tooth movement during orthodontic therapy is
brought about by forces generated by the active
components of an orthodontic appliance.
 The force used to move teeth is derived from
certain anatomic areas, which acts as anchors.
 The forces used to move teeth may induce an
equal and opposite force on the anchorage units
tending to cause their movement which is not
desirable.
 The resistance that the anchorage areas offer to
these unwanted tooth movements is called
anchorage.

4.  Graber has defined anchorage in orthodontics
as the nature and degree of resistance to
displacement offered by an anatomic unit for
the purpose of effecting tooth movement .
 White and Gardiner, ‘Anchorage is the site of
delivery from which a force is exerted.’
 Anchorage is mainly obtained from two
sources:
a)Intraoral sources
b)Extraoral sources

5. Intraoral sources include:
 The teeth-Whenever some teeth are moved
orthodontically, the remaining tooth of the oral
cavity can act as anchorage or resistance units.
 Alveolar bone-The alveolar bone that surrounds
a tooth offers resistance to tooth movement up
to a certain amount of force.
 Basal bone- hard palate and the lingual surface
of the mandible in the region of the roots.
 Musculature-dental anchorage may be increased
by making use of hypertonic labial musculature
Extraoral sources:
 They are mainly use when adequate resistance
cannot be obtained from intraoral sources for the
purpose of anchorage.

6.  Extraoral sources of anchorage include:
 Cranium:Anchorge can be obtained by using
headgears that derived anchorage from the
occipital or parietal region of the cranium.
 Back of the neck:Anchorage obtained from
the neck or cervical region.
 Facial bones-The frontal bone and the
mandibular symphysis offer anchorage
during face mask therapy in order to protract
the maxilla.

7. According to the manner of force application:
1.Simple anchorage
2.Stationary anchorage
3.Reciprocal anchorage
According to jaws involved
1.Intra-maxillary
2.Inter-maxillary
According to the site of anchorage
1.Intraoral
2.Extraoral:a)Cervical b)Occipital c)Cranial d)Facial
3.Muscular
According to the number of anchorage units:
1. Single or primary anchorage
2. Compound anchorage
3. Multiple or reinforced anchorage

8.  1. simple anchorage
 It is defined as dental anchorage in which the
manner and application of force is such that it
tends to change the axial inclination of the teeth
or tooth that form the anchorage unit in the
plane of space in which the force is being
applied.Thus the resistance of anchorage unit to
tipping is utilized to move another toothor teeth.
 2.Stationary anchorage-Manner and application
of the force tends to displace the anchorage unit
bodily in the plane of space in which the force is
being applied.

9.  Reciprocal anchorage-Resistance offered by two malposed
units when thedissipation of equal and opposite forces
tends to move each unit towards a more normal occlusion.
Eg-closure of midline diastema by miving the two central
incisors towards each other.
 Intraoral anchorage-anchorage in which all the resistance
units are situated within the oral cavity.
 Extraoral anchorage-resistance units are situated outside
the oral cavity.
 Muscular anchorage-perioral musculature is employed as
resistance units.
 Inter-maxillary anchorage-when all the units offering
resistance are situated within the same jaw.
 Inter-maxillary-=resistance units situated in one jaw are
used to effect tooth movement in the opposing jaw.
 Single or primary- resistance provided by single tooth with
greater alveolar support is used to move another tooth
with lesser support.
 Compound anchorage-resistance provided by more than
one tooth with greater support is used to move the tooth.
 Reinforced or multiple anchorage-more than one type of
resistance units is utilized.

10. Use of implants or temporary anchorage
device(TAD)
 They are especially useful in patients who have
lost lot of teeth or hypodontia.
 When maximal anchorage is required during
orthodontic treatment,additional aids are often
needed to support the anchoring teeth.
 TAD are mini-implant,ortho-implant,micro-
implant,mini-srews,micro-screws.
 Indications of TAD:-3 groups of tooth
movements for which mini-screws could be
used-
 a)mesial or distal movement of buccal teeth
 b)lingual or labial movement of anterior teeth
 c)vertical intrusive movement of buccal or
anterior teeth.

11.  ANCHORAGE PLANNING:Prior to initiation of
orthodontic therapy , it is essential to carefully
assess the anchorage demands of an indivisual
case.
 Anchorage requirements depends on:
 Number of teeth being moved
 Type of teeth being moved-Slender anterior teeth
offers lesser strain than robust multirooted teeth.
 Type of tooth movement-Bodily tooth movement
offer a greater strain on the anchorage than a
tipping tooth movements
 Duration of tooth movement
 Skeletal pattern
 Occlusal interlock-a good buccal occlusion resist
tooth movement.

12.  LOSS OF ANCHORAGE-Unplanned and
unexpected movement of the anchor teeth
during orthodontic treatment.
 Causes –a) poor appliance design-when
removable appliance are used, they should have
adequate retention by way of good clasps on the
posterior teeth.
 b)poor appliance adjustment- use of excessive
force or trying to move too many teeth at the
same time may result in unwanted movement.
 c)poor patient wear-poor patient co-operation by
way of inadequate wear of the appliance can
prolong the duration of the treatment.