This document discusses anchorage, which refers to resistance to unwanted tooth movement. It is classified based on the manner of force application, jaws involved, site of anchorage, and number of anchorage units. Factors like tooth morphology, position, and mutual support affect anchorage. Sources include individual/multiple teeth, basal bone, and musculature. Anchorage planning depends on the number/type of teeth to be moved and treatment factors. Different anchorage techniques are described like intra/inter-maxillary, simple, stationary, and reciprocal anchorage. Anchorage loss and demand vary based on the case. Recent advancements have improved anchorage control.
6. 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
8. 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
9. 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
10. Acc. To white n gardner
1. Simple
2. Stationary
3. Reciprocal
4. Reinforced
5. Inter maxillary
6. Extra oral
12. 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
13. 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
14. 1. Basal bone – eg.hard
palate & lingual surface
of the mandible in
anterior region.
2. The musculature –
Hypotonic m. - Flaring &
spacing
eg.Nance palatal button
Hypertonic m. - Collapse of
the teeth lingually ( use of hard palate to
provide resistance to
mesial movement of
max. molar
18. 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
20. 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.
23. Also called “BAKER’S 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
24. Eg. When class II elastics are used to
retract the maxillary anteriors , the
anchorage units are situated in the
mandibular arch.
27. 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
28. 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
30. 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.
31. Mandibular molars are bodily pitted against
the tipping forces of the maxillary anteriors.
33. 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.
34. • Cross Elastic To Correct
Molar Cross-bite
Ni-Ti Molar
Rotator
Arch expansion using a mid-
line screw
35. 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
36. 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
49. 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
50. 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
52. 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)
53. ANCHORAGE LOSS
It is the movement of the reaction unit or
the anchor unit instead of the teeth to be
moved.
54. ANCHORAGE DEMAND
Depending on anchorage loss : -
1. Maximum anchorage case
2. Moderate anchorage case
3. Minimum anchorage case
55. 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
56. Moderate anchorage cases
Anchor teeth can be
permitted to move
forward into ¼ th to ½
of the extraction
space.