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2. INTRODUCTION
An important aspect of treatment is
maximizing the tooth movement that is desired,
while minimizing undesirable side effects
In planning orthodontic therapy, it is
simply not possible to consider only the teeth
whose movement is desired, reciprocal effects
throughout the dental arches must be carefully
analyzed, evaluated & controlled.
3. ANCHORAGE
Nature & degree of resistance to displacement
offered by an anatomic unit when used for the
purpose of effecting tooth movement. [Graber]
Resistance to unwanted tooth movement.
[Profitt]
4. ANATOMIC UNITS USED FOR
ANCHORAGE
Teeth – most commonly used
Palate
Lingual alveolar supporting bone in
mandible
Cortical bone
Muscular anchorage
Occiput
Back of the neck
6. MAXIMUN, MODERATE, MINIMUM
ANCHORAGE
GROUP A or MAXIMUM ANCHORAGE
Posterior teeth contribute less than ¼ to space closure
GROUP B or MODERATE ANCHORAGE
Post. teeth contribute from ¼ to ½ to space closure
GROUP C or MINIMUM ANCHORAGE
Post. teeth contribute more than ½ to total space closure
7. ANCHORAGE
1) Tooth anchorage
2) Anchorage savers
reduce the amount of tooth anchorage
necessary to correct the malocclusion
Head gear
Palatal bar
Lip bumper
8. STRATEGY FOR ANCHORAGE
CONTROL
To concentrate the force needed to produce
tooth movement where it is desired
To dissipate the reaction force over as many
other teeth as possible, keeping the pressure in
the PDL of anchor teeth as low as possible.
9. SIMPLE ANCHORAGE
Dental anchorage in which the manner &
application of force tends to displace or change
the axial inclination of the tooth or
teeth that forms the anchorage unit in the plane
of space in which the force is being applied.
10. STATIONARY ANCHORAGE
Dental anchorage in which the manner &
application of force tend to displace
the anchorage unit bodily in
the plane of space in which the force is
being applied.
11. RECIPROCAL ANCHORAGE
Anchorage in which the resistance of one
or more dental units is utilized to move one or
more opposing dental units
13. EXTRAORAL ANCHORAGE
One of the anchorage unit is situated outside
the oral cavity
Cervical
Occipital
Cranial
14. INTRAMAXILLARY ANCHORAGE
•Resistance units are all situated within the
same jaw
INTERMAXILLARY ANCHORAGE
[BAKERS ANCHORAGE]
•Anchorage units situated in one jaw are used to
effect tooth movement in other jaw
15. CORTICAL ANCHORAGE
The different response of cortical compared to
medullary bone can be utilized for anchorage
Cortical bone is more resistant to resorption &
tooth movement is slowed when a root contacts
the cortical bone
17. ROOT AREA OF ANCHOR
TEETH
Large surface area Vs small surface area
Multirooted tooth Vs single rooted tooth
Longer rooted tooth Vs shorter rooted tooth
Triangular rooted tooth Vs conical root
18. FORCES USED
Concentrate the force needed to produce tooth
movement where desired & to dissipate the
reaction force over as many other teeth as possible
Light force - below the threshold value
Heavy force – exceed the threshold value for
anchor teeth.
27. TRANS PALATAL ARCH
Extends from one maxillary first molar along
the contour of the palate to the molar on the
opposite side
Removable
Fixed
28. FUNCTIONS OF TPA
To prevent the mesial migration of the upper I
molar during the transition from II deciduous
molars to the second premolars
Can produce molar rotations & change in root
torque
Molar stabilization & Anchorage
Intrusion of molars
30. NANCE PALATAL BUTTON
INDICATIONS
Class I, crowding cases
To hold the maxillary expansion achieved by
expansion appliances
CONTRAINDICATION
Class II maxillary protrusion cases
36. No extra oral anchorage
Initial stages
Bodily control given to the anchor units
The units that are to be moved are free
to tilt
Light forces
Final stages
Reciprocal forces from the root torquing
auxiliaries are born by the dental arch as
a unit, not by a section of the dental arch
37. THEORY OF DIFFERENTIAL
PRESSURES
Dr.Begg- AJO-1956
There was a range of light pressures which would
cause teeth to move at an optimal rate & with minimal
disturbance of the supportive tissues.
Force below this range – Slow rate of response
Force above this range – undermining resorption
38. BEGG TECHNIQUE
STAGE I
Light class II elastics
Retraction of upper anteriors
Minimal mesial movement of anchor molar
STAGE II
Heavy force
Excess pressure in the anteriors
Mesial movement of molars
39. ANCHORAGE BEND – Horizontal &
vertical movement of teeth
Anchorage for vertical movement:
40. ORTHODONTIC JUDO
Using the opponent’s strength & weight
to his disadvantage
Attainment of beneficial crown tipping
movements from root tipping forces or the
prevention of detrimental crown movements
by using these forces is called orthodontic
Judo.
41. ELEMENTS
1) Lever arm - archwire
2) Area of high resistance- supporting bone
around the roots
44. Anchor curve instead of anchor bend
Suggested by Mollenhauer
Causes extrusion of premolars – indicated in
low angle growing patients
Anchorage reinforcement mechanisms
TPA
Head gear
Lip Bumpers
46. COMBINED ANCHORAGE TECHNIQUE
[FOUR STAGE LIGHT WIRE APPLIANCE
Developed by J.Thompson in 1981, AJO
Combination of light & straight wire appliance
Brackets have both Ribbon arch & Edgewise
slots
Buccal tubes have both round & rectangular tubes
47.
48. ANCHORAGE CONTROL
DYNAMIC ANCHORAGE
Physical forces + Biologic forces
STATIC ANCHORAGE
Pure stationary anchorage
Stage I - Dynamic anchorage
Stage II - Dynamic anchorage
Stage III – Dynamic / Static
Stage IV – Static anchorage
50. HIGH ANGLE CASES
Molar extrusion is not desirable
Controlled by
Decreasing the anchor bend
Modifying class II elastics
Decreasing the - force level
- time of wear
51. OVERBITE CORRECTION IN ADULTS
Primarily by incisor intrusion, secondarily by
molar extrusion
45°anchorage bend & mild reverse curve in the
anterior segment to get maximum incisor intrusion
Class II elastics & check elastics to extrude the
molars
52. SAGITTAL CONTROL
AP correction is achieved through
anchor bend & intermaxillary elastics
Autonomous retraction of canines
Lingual tipping movement of lower incisors &
canines without retractive force
53. REDUCTION IN ANB ANGLE
Lingual movement of A point occurring as
maxillary incisors are torqued lingually
Inhibition of maxillary anterior growth
&enhancing forward growth of mandible by class
II elastic traction
54. BRAKING MECHANICS
Braking springs on the canines & lateral
incisors or torquing auxiliary on incisors
Rectangular archwire in the edgewise
slot & it is inserted into the Begg tube
56. Developed by Kesling
Tip Edge brackets are modifications of Edgewise
brackets
DSAT & TIP-EDGE BRACKETS
57. ANCHORAGE CONSIDERATIONS
Differential force technique
Extra oral anchorage is absolutely not needed in
this technique
Reduced friction - Very light forces can be used -
Less strain on the anchor teeth
Anteroposterior & vertical control – Anchor bend
58. VERTICAL CONTROL
OVERBITE CORRECTION
Intrusion with lighter forces - 5gm/ tooth
Conventional Edgewise slots - Prevent free root
movement & cause lateral movement
Tip edge slots - uni- point contact – no lateral
pressure
62. STAGE II
0.022’’ ss archwire with appropriate bite
opening bends
Maximum anchorage situations
Archwire is inserted into the large diameter
gingival round tubes
Mild to moderate anchorage situations
Archwire is engaged through the occlusal
rectangular molar tubes
63. BRAKING MECHANICS
Side winder springs on PM, canines &
incisors
0.022’’ss or 0.0215x0.028’’ archwire
Heavy forces [6-8 oz] are used for molar
protraction
64. STAGE III
Anchorage strain during uprighting & torquing
Can be prevented by
Keeping the occlusion in class I,
No spacing,
Ideal overbite & overjet
0.022 ss / .0215x.028 ss can be used
Ends of the archwire are bent
Intermaxillary elastics to maintain incisor relation
70. CAUSES OF MOLAR DISPLACEMENT
Vertical forces through molar tubes
Prevented by Horizontal bends
71. SEQUENCE OF MOLAR CONTROL
BENDS
Rotations first & displacements
second
Rotation correction - Toe-in / out
Displacement correction- in/out bends
72. IN / OUT BENDS
Placed in the embrasures b/w cuspids & bicuspids
73. TOE IN / OUT BENDS
Off centered bends
- located just mesial to molar tubes
Toe in bend produce horizontal force in
a buccal direction & distal in moment
74. STEP BENDS
Whenever 2 bends are involved & each bend
produces forces in the same direction we are
dealing with a step bend
75. CENTER BEND
Whenever 2 bends are involved &produce
forces in the opposite direction we are
dealing with a center bend
78. FIRST DEGREE ANCHORAGE
PREPARATION
ANB – 0° - 4°, Good facial esthetics, Total
discrepancy within 10mm
Mandibular terminal molar – upright
Direction of pull of intermaxillary elastics will
not exceed 90° when related to the long axis of
these teeth
79. SECOND DEGREE PREPARATION
ANB - > 4.5°
Facial esthetics make it desirable to move
point B anteriorly & point A posteriorly
Prolonged cl II elastics
Mandibular terminal molars must be tipped
distally so that their distal marginal ridges are
at gum level.
80. THIRD DEGREE [TOTAL] ANCHORGE
PREPARATION
Total discrepancy 14 to 20 mm, ANB
doesn’t exceed 5°
All the posterior teeth from II Pm to the
terminal molar be tipped distally to anchorage
preparation positions
Distal marginal ridges of the terminal molars
are below gum level
81. SEQUENTIAL MANDIBULAR
ANCHORAGE PEREPARATION
First described by Tweed
Cl III elastics & compensation bends
All the bends at the same time
Modified by Merrifield
Tipping only 2 teeth at a time
High pull head gear [ not cl III elastics]
Merrifield ‘10 – 2’ system
82. II MOLAR PREPARATION
Maxillary archwire – 17x 22
Mandibular archwire – 18x 25
Stop loops – Flush with II molar tube
Maxillary II molar - 5°distal tip
Mandibular II molar - 15°distal tip
83. I MOLAR PREPARATION
Mandibular archwire – 19x25
Stop loops – flush with II molar tube
10° distal tip
Compensating bend to maintain II
molar
87. ANCHOR LOSS
Attempting to upright extremely distally tipped
canines
Retraction of extremely procumbent anterior
teeth
Leveling the curve of spee with a continuous
archwire
Lingual root torquing of maxillary anteriors
Expanding the mandibular arch with a labial
arch wire
88. SAGITTAL CONTROL
II molar banding
Upright anteriors - little resistance to lingual
tipping
Anterior facebow is used to retract the proclined
incisors
Maximum anchorage – Asher facebow
Moderate anchorage - Double key- hole loops
89. LEVELLING & ALIGNING
Begin leveling with very small flexible
wires - .015’’ Wildcat / Respond
These wires can not overcome the
occlusal & other forces & can only bring
about bracket alignment
90. VERTICAL CONTROL
CURVE OF SPEE CORRECTION
Utility arches to intrude incisors
SHORT INTERMAXILLARY ELASTICS
1/8’’, 4-8 oz pull – no extrusion of molars
TRANSPALATAL ARCH
6-8mm away from the palate – intrusion of
molars
92. VARI- SIMPLEX DISCIPLINE
Developed by Wick Alexander
Single width brackets except u/incisors
Increased interbracket distance - Lighter force
Driftodontics in lower arch
Lewis Lang
93. DRIFTODONTICS
The mandibular anterior teeth have a tendency to drift
distally & the mandibular posterior teeth to drift
mesially.
Appliances are placed only on the maxillary arch until
a class I cuspid relation is achieved. The late placement
of mandibular appliance is referred to as driftodontics.
94. INDIVIDUAL CANINE RETRACTION
More control over molar anchorage
Cuspid is the longest rooted tooth in the mouth, it is
important to put it into position as quickly as possible.
By retracting cuspids first, incisor retraction can be
achieved with out significant loss of torque.
97. RETRACTOR / HEADGEAR
The most important element of varisimplex
discipline
It is the only appliance with which the
orthodontist can control all 3 dimensions –
vertical , sagittal & transverse both skeletally
& dentally
98. DIRECTION OF PULL & INDICATION
Low angle/normally growing patients – Cervical
[SN –MP < 37°] pull
SN – MP - 37 to 41° - Combination pull
SN – MP > 42° - High pull
99. FORCE & TIME OF WEAR
Initially - 8 oz , from next appointment – 16oz
If ANB is 3° or less – Only during sleeping
ANB 3 to 5° - 10 hrs / day
ANB > 5° - 14 hrs / day or more
100. ELASTICS
To align maxillary dentition with mandibular
dentition
Cross bite or midline discrepancy correction
To finalize the occlusion at the end of Rx
101. ANCHORAGE CONSIDERATIONS
DURING ELASTIC WEAR
Elastics are not used until the pt is in finishing
archwires - 17x25 ss in both arches
Attached from the mandibular II molar to the
hook on maxillary lateral incisor
Elastics are used only for a few months near
the end of treatment
102. OTHER INTRA ORAL APPLIANCES
Trans palatal arch
Lower lingual arch
Nance holding arch
Contraindication – Class II maxillary protrusion
105. HORIZONRTAL ANCHORAGE CONTROL
To achieve a correct antero-posterior position of
teeth in the profile
CONTROL OF ANTERIOR
SEGMENTS
ROLLER COASTER EFFECT
Tipping & rotation of teeth into extraction site
Deepening of the bite
Bite opening in the PM region
106. To minimize Roller coaster effect
No elastic force
Lacebacks
Bendbacks
107. CONTROL OF POSTERIOR SEGMENTS
UPPER ARCH
Anchorage control requirements are greater in
u/ arch
Upper ant segment has larger teeth
Greater amount of tip in upper brackets
Upper incisors require more torque control
U/molars move mesially more readily
Typical caseload has more cl II malocclusion
109. CONTROL OF POSTERIOR
SEGMENTS IN LOWER ARCH
Lingual arch
Lacebacks
Push coil springs – in crowded blocked out
incisors
Class III elastics to the lower cuspids
110. ANCHORAGE ASSESMENT IN
VERTICL PLANE
INCISOR VERTICAL CONTROL
To restrict temporary increase in the overbite
in deep bite cases
MOLAR VERTICAL CONTROL
In high angle cases to prevent extrusion of
posterior teeth & further opening of mandibular
plane angle
113. MOLAR VERTICAL CONTROL
HIGH ANGLE CASES
Upper II molars are not included
Bodily expansion of I molars – Fixed expander
+ High pull HG
TPA - 2mm away from the palate
High / combi pull HG
Posterior bite plates to minimize molar extrusion
114. TRANSEVERSE CONTROL
INTER CANINE WIDTH
kept as close as possible to starting dimension
MOLAR CROSSBITES
tipping of molars should be avoided
115. SPACE CLOSURE
MAXIMUM ANCHORAGE
II molars are included
Palatal bars, lingual arches to restrict mesial
movement of molars
Headgears + class III elastics
116. MINIMUM ANCHORAGE
II molars are not included
Mesial movement of molars should be started
as soon after extraction of II pm, to avoid the
possibility of alveolar bone becoming narrow.
Light class II along with sliding mechanics
118. SEGMENTED ARCH TECHNIQUE
Segmentation allows the Rx to proceed by
consolidation of teeth into segments
Right & left buccal segments are consolidated
by TPA & lingual arches
Once teeth within each segments are aligned,
each is treated as one large multi-rooted teeth.
119. ANCHORAGE CONTROL
Stress levels on the anchor unit should be kept
low
Heavy rigid archwire segments in anchor unit
Applying a moment for bodily control of anchor
unit
Differential force system to control the moment
to force system
120. ANCHORAGE UNITS
Posterior units consists of buccal segments –
Pm,I molar, II molar
Connected by TPA in the maxilla & Lingual
arch in the mandible
Buccal stabilizing segments – 19x25
- 21x25 ss / TMA
122. PRINCIPLES OF ANTERIOR INTRUSION
Use of optimal magnitudes of force & constant
force delivery
Use of point contacts in the anterior region
Careful selection of point of force application
Selective intrusion based on anterior tooth
geometry
Control over the reactive units
Inhibition of eruption of posterior teeth
123. POINT OF FORCE APPLICATION
Intrusive force should pass through the CRes
for true intrusion
Proclined Incisors
Should be upright
Apply vertical force lingual to the Cres
[continuous intrusion arch / 3 piece int. arch,
17x25
124. CONTROL OF REACTIVE UNITS
Minimize the forces used for intrusion
Incorporate as many teeth as possible in the
anchor unit
Do as much retraction as possible to decrease
the length of moment arm
Lingual displacement due to extrusive force can
be prevented by lingual arch
125. POSTERIOR EXTRUSION
Extrusion arches with higher forces promote
posterior eruption
Extrusion arch is similar to intrusion arch
except larger forces are produced & hence ss is
used instead of TMA
126. SAGITTAL CONTROL
TIE BACK
Buccal segment wire is bent gingivally in
to a small hook
0.018’’TMA can be welded mesial to the
molar
Omega loop – mesial to the I molar
Washer can be crimped on the wire
128. GROUP A ANCHORAGE
Requires a relative increase in the posterior
M/F ratio & decrease in the anterior M/F ratio
Spring is positioned closer to the posterior
segment
Extra oral appliances
Inter maxillary elastics
Applying differential M/F ratio
129. GROUP B ANCHORAGE
Requires equal translation of the anterior &
posterior segments into the extraction space
Equal & opposite forces & moments are
indicated
T- loop is placed in the center b/w anterior &
posterior attachments
130. GROUP C ANCHORAGE
Alpha moment is increased relative to the
Beta moment
Spring is positioned closure to the
anterior segment
Anchorage reinforcement
Intermaxillary elastics
Protraction headgear
135. ANALYSIS & TREATMENT PLAN CHART
Treatment time for each step
Length of time class II & class III elastics were
worn
Type of head gear & length of time worn
Length of time palatal bars were worn
High / Low mandibular plane angle.
136.
137.
138.
139. PURPOSE OF FILLING ANALYSIS
CHART
To visualize how to treat the
malocclusion
Establishes a definite goal & reveals
which teeth to extract.
141. Anchorage preparation in maxilla
Rx begins in the maxilla,
Starts from distal segment & moves sectionally
towards mesial --- Distomesial sequence
142. EQUATION FOR INVERSE ANCHORAGE
C = Dc / 2 + R1
Dc – Lower arch length discrepancy
R1 - Cephalometric anterior limit of mand. Incisors
C - Distance from the cusp tip of u/canine to the
distal surface of L/canine
143. STAGES OF TREATMENT
Maxillary stage – Sequence of movement in U/ jaw
Mandibular stage - Sequence of movement in l/ jaw
Steps
Posterior leveling
Posterior retraction
Anterior leveling
Anterior retraction
144. PLAN OF CL II, DIV 1 EXTRCTION Rx
C = Dc / 2 + R
8/2 +2
152. SKELETAL ANCHORAGE
The conventional methods of reinforcing
anchorage are less than ideal, because they
either rely on structures that are themselves
potentially mobile [teeth] or they rely too
heavily on patient compliance [ HG & Elastics].
Skeletal anchorage overcomes many of these
shortcomings.
153. REQUIREMENTS OF AN ORTHODONTIC
ANCHOR IMPLANT
Small
Affordable
Easy to place
Resistant to orthodontic forces
Able to be immediately loaded
Usable with familiar orthodontic mechanics
Easy to remove
154. CONVENTIONAL DENTAL IMPLANTS
Can only be placed in retromolar or edentulous
areas
Too large for horizontal orthodontic traction
Troublesome for patients because of
Severity of the surgery
Discomfort of initial healing
Difficulty of oral hygiene maintenance
Time required for osseous integration
155. TYPES OF SKELETAL ANCHORAGE
Direct anchorage
Utilizes force from the actual implant that takes the
place of a missing tooth & eventually supports a dental
restoration
Indirect anchorage
Placed solely for orthodontic purposes & is
generally removed once its anchorage duties have been
fulfilled
156. CLASSIFICATION
Based on implant morphology
1) Implant disks
Onplant
2) Screw designs
Mini-implant
Orthosystem implant system
Aarhus implant
Micro implant
Newer systems – Spider screw,OMAS system,
157. 3) Plate designs
Skeletal anchorage system [SAS]
Graz implant supported system
Zygoma anchorage system
BASED ON AREA OF PLACEMENT
Subperiosteal implants
Osseous implants
Inter dental implants
159. OSSEOUS IMPLANTS
Placed in Zygoma, body & ramus area,
midpalatal areas.
Skeletal anchorage systems
Graz implant supported system
Zygoma anchorage system
163. ZYGOMA ANCHORAGE SYSTEM
Hugo De Clerck & Geerinckx, JCO-2002
Curved Ti miniplate
3 screws of 2.3 mm
Lower end – projects outward
vertical slot
Zygomaticomaxillary buttress
164. INTER DENTAL IMPLANTS
Endosseous implants
Smaller diameter
Mechanical retention
Advantages
Placement is easy, can be done under LA
Brings about all types of tooth movement
Removal is easy.
168. SPIDER SCREWS
JCO 2003, Giuliano Maino
Self tapping mini screws available in 3 lengths– 7,9,11 mm
3 Types
Regular
Low profile
Low profile flat
169. ANATOMOCAL SITES
Alveolar bone in an extraction site
Palate in the median / paramedian area
Retroincisive
Retromolar site
Anterior nasal spine
Chin symphysis
170. CONCLUSION
Conservation of anchorage in the
correct areas and at the proper time is one
of the most important & difficult tasks in
orthodontics.
The biomechanical setup that delivers
the correct type & magnitude of force
must be established to achieve the goals of
the treatment.