Anchorage in orthodontics 2 /certified fixed orthodontic courses by Indian dental academy

INDIAN DENTAL ACADEMY
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Extra oral anchorage

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Principle use
Forces derived from EOA
Stabilize the position of the teeth
Produce tooth movement
Orthopedic changes


Extra oral traction

Mild cases
Cases with severe crowding and overjet
Severe cases – additional space is required even after
extraction


Application of EOF
Face bow


Stops – inner bow


J hook head gear


Directional control
Effects of EOF depends on

Duration
Direction
Magnitude
1 ounce – 28.35 gms

Types of head gears



Basic concept for types of head gears

Relationship to the occlusal plane

Low pull
High pull
Medium pull


Low pull head gear

Extrusion of the molars


undesirable

High pull head gear



Intrusion of the molars
undesirable

Medium pull head gear





Protraction head gear


Orthopedic effects

Restrict forward and downward movement
350-450 gms/each side – 14hrs/day

Practical aspects

Good fitting bands

Inner bow – passive
Should not contact any teeth
Ant. Segment – between the lips
Expansion – distalization

Mandibular arch

Use of class III intermaxillary traction
with head gear


Mechanical aspect of anchorage
Sliding mechanics
Force is required for 2 purposes
Bone remodeling
Frictional resistance
Controlling and minimizing friction is an imp. Aspect
of anchorage control

Friction ???
Frictional force

Nature of surface at the interface (rough or smooth,
chemically reactive or passive, modified by
lubricants)
Independent of the apparent area of contact

Real contact occurs only at a limited number of small
spots: Asperities


Metal wire in a ceramic bracket

Stick slip phenomenon

2 other factors can affect the resistance to sliding
Interlocking of surface irregularities
Extent of plowing
In clinical practice friction is largely determined by
the shearing component


Surface quality of the wires
NiTi > βTi > SS

Roughness

There is no correlation between surface roughness
and coefficient of friction

β Ti has greatest frictional resistance

Surface quality of the wires
Changes in surface chemistry due to increased
Ti content
Cold weld effect


Possible solution to this problem

Alteration of the surface of Ti wires

Among all, SS/SS couple is most effective for sliding
followed by CoCr/SS, NiTi/SS, βTi/SS

Surface quality of the brackets
SS brackets
Ti brackets
Ceramic brackets
Ceramic brackets with metal slots
Composite brackets
Polycarbonate plastic brackets

Flexibility of arch wire and width of the bracket

Force that pulls the wire into the bracket
Self ligating brackets- reduced friction that allows
more effective sliding- better anchorage control

Magnitude of friction

Retraction springs
Closing loops

Conventional Begg
Differential force concept
1st premolar extraction
8 teeth extraction

Begg was applying the principles of differential forces

Conventional Begg
Storey and Smith (1952)
Statistical evidence confirmed the
results of Begg’s clinical
experience
Edgewise app and springs


Conventional Begg
Tooth with a greater root surface area needs
greater force to be moved

canine: molar = 3:8

Conventional Begg


Conventional Begg
Reason for different rates of movement of canines
Storey and Smith presented the concept of
undermining resorption
Sandstedt (1904)
Schwarz (1932)


Conventional Begg
Teeth subjected to very high forces

Resorption of tooth investing tissues

Teeth are loosened within the sockets

Conventional Begg
Use of differential forces
Reduction of anterior overbite
Use of anchor bends

Light wires
Heavy wires

Conventional Begg
 Strang (1954) – Treatment problems, their origin

and elimination
 Edgewise app
 Closing extraction space requires more force
 Use of head gears - recommended


Conventional Begg
Space closure

Premolars bypassed
Extra oral anchorage is not required

Conventional Begg
Means of preventing anchorage failure

Use of thin round steel wires
Anchor bends
Stationary anchorage
Premolars not bracketed
Light torquing forces in 3rd stage
Use of reverse torquing auxillaries

Refined Begg ( Dr. V P Jayade )
Differential force concept was misunderstood
Excessive retraction
Prevented in refined begg by applying efficient
brakes along with heavy differential forces


Perfect example of stationary anchorage
Saggital
Vertical
transverse


Stage I


Active components in stage I
Light or ultra light class II elastics

Lower class I elastics

Upper palatal elastics / elastics from power arm


Upper Class I are seldom used

Uneven class I ,class II for midline correction

Anchorage considerations in stage I
Palatal elastics or elastics from power arm
Upper molars to be supported with TPA


Conserving lower molar anchorage
Stiffer wires
Light or ultra light elastics
Molar stops


High angle cases
Light anchor bends
Light elastics
TPA – away from the palate
High pull head gear


Transverse plane
Stiffer arch wires
Expansion in arch wires
TPA
Sufficiently expanded face bow or lip bumper


Stage II – easiest
Objectives

Maintain all the corrections of stage I
Closure of extraction spaces
Controlled tipping of anteriors
Protraction of posteriors
Correction of molar relation
Correction of premolar crossbites and rotation

Stage II
Archwires used
Reduction in the anchor bend


Braking mechanics
Reversal of anchorage
Def – the brakes reverses the anchorage site from
posterior to anterior segment by permitting only
bodily movement of the anterior teeth, instead of
allowing them freedom to tip
Braking springs/ T pins
Torquing components

Braking springs


Angulated T pins


Combination wires

Material
Ant. Seg – rectangular (022 x 018)
Post. Seg – round 018


Torquing auxiliaries
2 spur or 4 spur
MAA – 010 / 011
Strong base wires


Active components in stage II


Stage III – most complicated and anchorage
consuming
Objectives of stage III
Maintain all the corrections

Distal root uprighting auxilliary

Palatal root torquing auxilliary


Stage III - objectives
To achieve desired root movements
Monitor anchorage in all 3 panes
To correct the position of 2nd molars
To monitor undesirable effects


Stage III
Reciprocal mesial crown moving forces
Upper arch
Lower arch


How to overcome stage III problems???
Proper diagnosis and treatment planning
Using efficient brakes
Controlled tipping of incisors
Use of heavy base arch wires
Lighter auxiliaries and uprighting springs
Light cl II elastics
Reinforcement of anchorage
Contraction and toe in built into
the wires

Tweed’s anchorage preparation
Tweed Merrifield appliance
Level Anchorage System
Vari Simplex Discipline
Rickett’s Bioprogressive Therapy
MBT appliance


Tipping the posterior segment distally
Lower posterior segment


When teeth are tipped distally as they are in
anchorage preparation, osteoid tissue appears to be
laid down adjacent to the mesial surface of the tooth
being moved distally.”

- Kaare Reitan

Such conclusions do not make the necessity of
anchorage preparation obselete


Clinical orthodontist who routinely create excellent
facial changes are those who recognize the
importance of and prepare anchorage in their
practice


Concept
Upright the mesially inclined lower posterior segment
Terminal molar to be tipped distally
Angle formed between the class II elastic and long
axis of terminal molar

Mandible will be much more stable and will resist
forward displacement

After anchorage preparation, if movement does occur

Slow mesial bodily movement
Anchorage not prepared
Uprooting and elevation of the molars

Tweed classified anchorage preparation
First degree
Second degree
Third degree


First degree / minimal anchorage preparation
ANB 0º- 4º, facial esthetics are good
Discrepancy < 10 mm
Mandibular terminal molars must be uprighted
Direction of intermaxillary elastic pull
should not exceed 90º

Second degree
ANB exceeds 4.5

Class II

Mandibular second molars should always be banded
Must be tipped distally so that their distal marginal
ridges are at gum level
Direction of pull of intermaxillary elastics should
always be > 90º

Third Degree or Total Anchorage Preparation
ANB does not exceed 5º
Discrepancy – 14 -20 mm
All posterior teeth (second premolar to terminal molars)
are tipped distally
Distal marginal ridges of terminal molars are below
gum level

Severe cases – anchorage prepared in both the arches
How to tip lower posterior segment ???

Sliding jig



Lower anchorage preparation completed
Lower canines and incisors retracted
Upper extractions
Class II elastics – distal tipping of upper
posterior segment

Attachments

022 edgewise slot
Permits variety of archwire use


Highlighting points – Anchorage preparation

Sequential banding and bonding
Sequential tooth movement
Sequential anchorage preparation
Directional force system


Sequential banding and bonding

Less traumatic
Longer interbracket span
Heavy wires


Sequential tooth movement

Enmasse retraction
Placing all bends at a time
Not followed



High pull head gear
Vertical spurs soldered
Distal to Mb. Lateral incisor
10 – 2 anchorage system


Distal tip achieved
Read out
15º


Before tipping premolars
Read out to be performed

Distal tip achieved

During the course of treatment, various hooks are
soldered


Directional force system
Defined as controlled forces which place the teeth
in most harmonious relation with their
environment



Favorable

Unfavorable

Level anchorage system
Terrell L. Root
Aim – quantify the anchorage requirement
018 edgewise slot
Mandibular molars – 2 choices of distal crown tip


Anchorage – Resistance to movement
Distance to move
Anchorage savers
Those orthodontic adjunctive procedures that reduce
the amount of tooth anchorage necessary to correct
the malocclusion


High pull headgear to maxillary 1st molars or J hook
headgear to anteriors: reduction in ANB by 1 degree
every 6 months
Palatal bar: decreases vertical descent due to tongue
pressure.
Delaying upper first premolar extraction by one year:
reduces mandibular anchorage space by 1mm
Class III elastics worn 24 hrs: flatten the curve of
Spee and upright buccal segments at the rate of
1mm / month

Vari-simplex discipline-Alexander
Vari – variety of bracket used
Simplex – KISS principle
fewer archwire changes

1.
2.
3.

Treatment philosophy – Tweeds fundamentals
Anchorage preparation
Positioning Mb incisors over basal bone
Orthopedic alteration using head gear

Key objective
Non extraction therapy as far as possible
Interproximal enamel reduction
Control of Mb incisor position with –ve torque


Bracket selection
Twin brackets
Lang brackets
Lewis brackets


Anchorage considerations

Tip values

Gain in the arch length
Promotes leveling
0° angulation in Mb 2nd molar–
Need not to be uprighted excessively

-5°of labial root torque
Holds the Mb incisors to their original position

Major change


Head gears / Retractors
Retractors’ ( Dr. Fred Schudy)
Cervical, combination or high pull depending on
growth pattern and control needed


Other intra oral appliances to control anchorage:


Other intra oral appliances to control anchorage:
Mandibular lingual arch: sagittal and transverse
control
Lip bumper:
- uprighting of mandibular first molars
- distal force on lower molars
- muscular anchorage

Rickett’s Bioprogressive Therapy
Muscular anchorage
Cortical anchorage

Nance button
Quad helix
Headgears: cervical, combination and
high pull www.indiandentalacademy.com

Anchorage control in MBT
2nd principle of orthodontic anchorage
Anchorage loss – maximum in the first stage
Def – Tooth movement needed to achieve passive
engagement of steel 19 x 25 wire of suitable arch
form into a correctly placed 022 preadjusted bracket
system


Major reason for anchorage loss ???
Mesial tip built into the bracket system
Anchorage control
The maneuvers used to restrict undesirable changes
during the opening phase of treatment, so that
leveling and aligning is achieved without key
features of the malocclusion becoming worse.’

1st step in anchorage control

Recognize the anchorage needs of the case

Diagnosis and treatment planning stage


Eg – class II div 1
Goal is set for incisor position - PIP

Class III

Mistakes in tooth leveling and aligning during
early years

Roller coaster effect


Roller coaster effect has been eliminated from the
present day practice
Reduced tip in bracket system
Light arch wire forces
Use of lacebacks instead of elastic forces


Lacebacks for A/P canine control

Restrict canine crown from tipping forward

Lacebacks for A/P canine control
Robinson – 57 PM extn cases


Restrict canine crown from tipping forward
Distalizing canines without causing unwanted
tipping


Continued till rectangular SS wire stage
Discontinued if space appears betn lateral &
canine


Bendbacks for A/P incisor control


Bendbacks for A/P incisor control

Bend is placed 1-2 mm
distal to molar tube

A/P anchorage control of
lower molars – the lingual arch

Class III elastics & headgear

A/P anchorage support & control for upper molars –
 The upper molars move mesially more easily
than lower molars
 Upp ant segment has larger teeth than low ant
 Upp ant brackets have more tip built
 Upp incisors require more torque control &
bodily movement
 More Class II type malocclusions than Class III

A/P anchorage support & control for upper molars –

Head gears

TPA

Vertical anchorage control of incisors


Vertical control of canines


Vertical control of molars in high angle cases
Palatal bar

Upp 2nd molars not initially banded

Headgear – high pull

Anchorage control in Transverse plane

Intercanine width
Molar crossbites


Thank you
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Anchorage in orthodontics 2 /certified fixed orthodontic courses by Indian dental academy

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