Anchorage in orthodontics

ANCHORAGE
IN
ORTHODONTICS
www.indiandentalacademy.com

A TOOTH DOES NOT MOVE ITSELF ANY MORE
THAN A MAN CAN PULL HIMSELF UP BY HIS
OWN BOOTSTRAPS
“ACTION AND REACTION ARE EQUAL AND
OPPOSITE.”
“FOR EVERY FORCE APPLIED ,THERE IS EQUAL
AND OPPOSITE FORCE.”
-SIR ISAAC NEWTON

ANCHOR - A HEAVY DEVICE DROPPED BY A
CHAIN OR CABLE OR ROPE TO BOTTOM OF
BODY OF WATER FOR RESTRAINING MOTION
OF A VESSEL OR OTHER FLOATING OBJECT
[WEBSTER DICTIONARY ]
DENTAL ANCHORS – FORCE USED TO MOVE
TEETH IS DERIVED FROM CERTAIN
ANATOMIC AREAS THAT ACT AS ANCHORS

DEF`n
OF ANCHORAGE-
IT IS THE RESISTANCE TO UNWANTED TOOTH
MOVEMENT -Proffit
ANCHORAGE IS THE NATURE AND DEGREE OF
RESISTANCE TO DISPLACEMAENT OFFERED BY AN
ANATOMIC UNIT FOR PURPOSE OF EFFECTIVE
TOOTH MOVEMENT -
Graber
ANCHORAGE IS THE SITE OF DELIVERY FROM
WHICH A FORCE IS EXERTED -White
& Gardiner

DIFFERENT SOURCES OF ANCHORAGE
A. INTRA ORAL SOURCES
-THE TEETH
-THE ALVEOLAR BONE
-THE BASAL BONE
-ORAL MUCOSA
-MUSCULATURE
B. EXTRA ORAL SOURCES
-CRANIUM [ OCCIPITAL & PARITEL BONES ]
-BACK OF NECK [ CERVICAL MUSCLES ]
-FACIAL BONES [ FRONTAL BONE & CHIN ]

FACTORS DETERMINING ANCHORAGE POTENTIAL OF
TOOTH:-
1.ROOT FORM
2.SIZE & NUMBER OF ROOTS
3.ROOT LENGTH
4.INCLINATION OF TEETH
5.ANKYLOSED TEETH
6.OCCLUSION

ROOT FORM OR SHAPE –
a. ROUND ROOTS-
e.g. BICUSPIDS , PALATAL ROOT OF MAXILLARY
MOLARS
-RESIST HORYZONTAL FORCES
b. FLAT ROOT-
e.g.MAND. INCISORS & MOLARS, BUCCAL ROOTS OF
MAXI. MOLARS
-RESIST MESIO-DISTAL MOVEMENT
c. TRANGULAR ROOT-
e.g.MAXI. ANTERIORS
-MAXIMUM RESISTANCE TO DISPLACEMENT

CLASSIFICATION OF
ANCHORAGE
ACCORDING TO MANNER OF FORCE APPLICATION
1-SIMPLE ANCHORAGE
2-STATIONARY ANCHORAGE
3-RECIPROCAL ANCHORAGE
ACCORDING TO JAWS INVOLVED
1-INTRAMAXILLARY
2-INTERMAXILLARY

ACCORDING TO SITE OF ANCHORAGE:
1-INTRAORAL
2-EXTRAORAL -CERVICAL
-OCCIPITAL
-CRANIAL
-FACIAL
3-MUSCULAR
ACCORDING TO NO. OF ANCHORAGE UNITS:
1-SIMPLE OR PRIMARY ANCHORAGE
2-COMPOUND ANCHORAGE
3-MULTIPLE OR REINFORCED ANCHORAGEwww.indiandentalacademy.com

SIMPLE ANCHORAGE-
A TOOTH OR TEETH THAT
OFFERS GREATER RESISTANCE TO DISPLACEMENT
THAN THE TOOTH THAT NEEDS TO BE MOVED.
OR-
IT IS DEFINED AS DENTAL
ANCHORAGE IN WHICH THE MANNER & APPLICATION OF
FORCE IS SUCH THAT IT TENDS TO CHANGE THE AXIAL
INCLINATION OF TEETH THAT FORM THE ANCHORAGE
UNIT IN PLANE OF SPACE IN WHICH FORCE IS BEING
APPLIED.
-WITHIN SAME ARCH
-ENGAGING MORE NO OF TEETH
-TOTAL ROOT SURFACE AREA OF ANCHORS IS
GREATER THAN TEETH TO BE MOVED

STATIONARY ANCHORAGE-
DENTAL ANCHORAGE IN WHICH
MANNER AND APPLICATION OF FORCE TENDS TO
DISPLACE THE ANCHORAGE UNIT BODILY IN PLANE OF
SPACE IN WHICH FORCE IS BEING APPLIED
ADV :- -BODILY MOVING ANCHOR TEETH &
-TIPPING OF MOVEMENT TEETH

RECIPROCAL ANCHORAGE-
RESISTANCE OFFERED BY TWO
MALPOSED UNITS WHEN DESSIPATION OF EQUAL AND
OPPOSITE FORCES TENDS TO MOVE EACH UNIT
TOWARDS MORE NORMAL OCCLUSION.
AS FORCES ARE EQUAL ,FORCE
DISTRIBUTION IN PDL-AREA IS EQUAL.
e.g.cross bite elastics
dental arch expansion
midline diastema closure
NECESSITY- RECIPROCAL MOVEMENT NEEDS SAME
TOTAL PDL AREA FOR TWO UNITS

ANCHORAGE VALUE-
IT IS THE RESISTANCE TO MOVEMENT, THAT
IS A FUNCTION OF ITS ROOT SURFACE AREA AND IT IS
SAME AS ITS PDL AREA.

EXTRA ORAL ANCHORAGE-
HERE THE RESISTANCE UNITS ARE SITUATED
OUTSIDE THE ORAL CAVITY.
-THE OCCIPUT
-BACK OF NECK
-CRANIAL BONES
-FACE
USED IN COMBINATION WITH INTRA ORAL APPLIANCES
USES-ADDITIONAL SUPPORT FOR INTRAORAL
ANCHORAGE
-PREVENT BUCCAL TEETH FROM SLIDING
FORWARD
-TO PREVENT ENTIRE ARCH PROCUMBENCY OF
MAND. INCISORS
-TO MOVE ENTIRE ARCH DISTALLYwww.indiandentalacademy.com

MUSCULAR ANCHORAGE-
THE FORCES GENERATED BY PERIORAL
MUSCLES ARE USED TO AID IN THE MOVEMENT OF
TEETH.
e,.g. LIP BUMPER TO DISTALISE MOLARS TAKES
ANCHORAGE FROM LABIAL MUSCLES.

INTRA MAXILLARY ANCHORAGE-
WHEN ALL THE UNITS OFFERING RESISTANCE
ARE SITUATED IN SAME JAW ,THE ANCHORAGE IS
CALLED INTRAMAXILLARY.
INTERMAXILLARY ANCHORAGE -
THE RESISTANCE UNITS SITUATED IN ONE JAW
ARE USED TO EFFECT TOOTH MOVEMENT IN THE
OPPOSING JAW , IT IS CALLED INTERMAXILLARY
ANCHORAGE.
-ALSO CALLED AS BAKERS ANCHORAGE
-MOSTLY IN THE FORM OF ELASTIC TRACTION

BAKERS ANCHORAGE-
CLASS –II ELASTIC TRACTION: -
PITTING UPPER ARCH AGAINST LOWER ARCH – TO
MOVE LOWER TEETH & JAWS FORWARD AND
RETRACTION OF UPPER ANTERIORS.
CLASS-III ELASTIC TRACTION:-
PITTING LOWER INCISORS AGAINST UPPER
POSTERIORS –TO MOVE LOWER ANTERIORS
BACKWARDS & UPPER TEETH FORWARD

SINGLE OR PRIMARY ANCHORAGE-
RESISTANCE PROVIDED BY SINGLE TOOTH WITH
GREATER ALVEOLAR SUPPORT IS USED TO MOVE
ANOTHER TOOTH WITH LESSER SUPPORT, IS CALLED
SINGLE ANHORAGE.
COMPOUND ANCHORAGE-
RESISTANCE PROVIDED BY MORE THAN ONE TEETH
WITH GREATER SUPPORT IS USED TO MOVE TEETH
WITH LESSER SUPPORT , IS CALLED COMPOUND
ANCHORAGE.

REINFORCED OR MULTIPLE ANCHORAGE-
ANCHORAGE WHERE MORE THAN ONE TYPE OF
RESISTANCE UNIT IS UTILISED IS CALLED AS
REINFORCED ANCHORAGE.
IT IS AUGMENTATION OF ANCHORAGE BY
VARIOUS MEANS i.e. ADDING MORE RESISTANCE
UNITS- TO DISTRIBUTE REACTION FORCE OVER LARGE
PDL SPACE.

REINFORCED ANCHORAGE IS FREQUENTLY
REQUIRED FOR-
1. LOWER LIP IS BEHIND THE UPPER ANTERIORS
HABITUALLY AT REST
2. TONGUE IS POSITIONED OVRER INCISAL &
OCCLUSAL SURFACES
3. BITE PLANE USE FOR OPENING OF BITE IN CLASS II
MALOCCLUSION
4. TO PREVENT LOSS OF MANDIBULAR STABILITY
WITH INTERMAXILLARY ELASTICS
5. TO MOVE TEETH DISTALLY

ANCHORAGE PLANNING:-
PRIOR TO ORTHO. TREATMENT, ESSENTIAL TO
ASSESS ANCHORAGE DEMAND OF INDIVIDUAL CASE .
REQUIREMENTS DEPEND UPON-
1. NO. OF TEETH BEING MOVED
2. TYPE OF TEETH BEING MOVED
3. TYPE OF TOOTH MOVEMENT
4. DURATION OF TOOTH MOVEMENT

RELATIONSHIP OF TOOTH MOVEMENT TO FORCE:-

METHODS TO CONTROL THE ANCHORAGE:-
A. REINFORCEMENT
B. SUBDIVISION OF DESIRED MOVEMENT
C. TIPPING & UPRIGHTING
D. FRICTION & ANCHORAGE CONTROLL
E. CORTICAL ANCHORAGE CONTROLL

REINFORCEMENT :-
- INCLUDE AS MANY TEETH AS POSSIBLE, SO THAT
RATIO OF = ANCHOR UNIT : MOVEMENT UNIT
2 : 1 [without friction]
4 : 1 [with friction]
-ADDITION OF OPPOSITE DENTAL ARCH
-AUGMENTATION WITH EXTRAORAL FORCES
-PRINCIPLE OF STATIONARY ANCHORAGE

SUBDIVISION OF DESIRED MOVEMENT:-
- TO PIT THE RESISTANCE OF GROUP OF TEETH
AGAINST MOVEMENT OF SINGLE TOOTH.
- DONE BY TWO STEP PROCEDURE.
- DISAD:- TAKES EXTRA TIME

FRICTION AND ANCHORAGE CONTROLL:-
PRINCIPLE – WHEN ONE MOVING
OBJECT CONTACTS ANOTHER, FRICTION AT THEIR
INTERFACE PRODUCES RESISTANCE TO MOVEMENT
PROPORTIONAL TO- FORCE OF CONTACTING
SURFACES TO PRESS EACH OTHER
DEPENDS ON – NATURE OF SURFACE i.e. SMOOTH,
ROUGH, CHEMICALLY REACTIVE, PASSIVE,
LUBRICATED etc…

COEFFICIENT OF FRICTIONAL RESISTANCE-
PROPORTIONAL TO- SHEAR STRENGTH OF
JUNCTIONS & INVERSELY PROP.TO YIELD STRENGTH
OF MATERIAL
TOTAL FRICTIONAL RESISTANCE IS SUM OF=
1.FORCE NEEDED TO SHEAR ALL JUNCTIONS
2.RESISTANCE GIVEN BY INTERLOCKING OF
ROUGHNESS
3.PLOWING COMPONENT OF TOTAL FRICTIONAL
FORCE
ANCH. CONTROLL- MODIFY ANY OR ALL FACTORS
FRICTIONLESS APPLIANCE- EFFICIENT & FASTER TRET.
APPLIANCE PHILOSOPHY- ANCH. CONTROL THAT IS
INBUILT INTO APPLIANCE DESIGN

CORTICAL ANCHORAGE CONTROL
CORTICAL BONE MORE RESISTANT TO RESORPTION
THAN MEDULLARY BONE, SO TOOTH MOVEMENT
SLOWS WHEN ROOT CONTACTS IT.
APPLICATION-TORQUING ROOTS OF POSTERIOR
TEETH OUTWARD AGAINST CORTICAL PLATE AS A
WAY TO INHIBIT THEIR MESIAL MOVT. WHEN
EXTRACTION SPACES ARE TO BE CLOSED
CONTRAVERSY- AS MESIAL MOVEMENT IS ALONG
THE CORTICAL PLATE, RATHER THAN AGAINST IT.
DIS.-LIMITED MOVT. BY LABIAL & LINGUAL
CORTICAL PLATES. IF EXCESS FORCE APPLIED, ROOT
RESORPTION IS LIKELY.

ANCHORAGE PREPARATION
NEED FOR PREPARATION- INTERMAXILLARY CLASS II
ELASTIC CASE-
-MANDIBULAR ANCHOR MOLARS WILL BE
PULLED UPWARD & FORWARD.
- ELEVATION & UPROOTING OF TERMINAL
ANCHOR MOLARS -
DEPRESSION OF MAND. INCISORS &
ALTERATION OF OCCLUSAL PLANE -
FMPA WILL OPEN UP -
Pt. B WILL DROP DOWNWARD & BACKWARD -
MAND. DENTURE WILL BE TIPPED FORWARD
INTO PROTRUSION
THREE CATEGORIES -FIRST DEGREE PREPARATION
-SECOND DEGREE ,,
-THIRD DEGREE ,,

FIRST DEGREE[MINIMAL]
INDICATIUONS-
ANB 0 to 4 degrees
-GOOD FACIAL ESTHETICS
-DISCREPANCY UP TO 10 mm.
e.g. HIGH CUSPID, CROSS BITE, PSEUDO & TRUE
CLASS III
PREPARATION-
INCLINATION OF TERMINAL MAND. MOLARS SHD.
BE UPRIGHT AND
DIRECTION OF PULL OF INTERMAXILLARY
ELASTICS WITH LONG AXIS OF TERMINAL MOLARS
SHD. NOT EXCEED 90 degrees

SECOND DEGREE
INDICATIONS-
-ANB EXCEEDS 4.5 degrees
-FACIAL ESTHETICS NEEDS Pt. B TO MOVE
ANTERIORLY & Pt. A TO MOVE POSTERIORLY
-USUALLY CLASS II MALOCCLUSION
PREPARATION-
-MAND. TERMINAL MOLARS SHD. BE TIPPED
DISTALLY WITH DISTAL MARGINAL RIDGE AT
GUM LEVEL.
-CLASS II ELASTIC PUL SHD. BE GREATER THAN
90 degrees ,

THIRD DEGREE
INDICATIONS-
-DISCREPANCY VARY FROM 14 TO 20 mm.
-ANB UP TO 5 degrees
-USUALLY CLASS I MALOCCLUSION WITH
IRREGULAR TEETH e.g. BIMAXILLARY PROTRUSION
WITH MESIALLY INCLINED TEETH
PREPARATION-
-JIGS ARE USED
-ALL THREE POSTERIORS [ SECOND PREMOLAR &
TERMINAL MOLARS ] SHD. BE TIPPED DISTALLY
-DISTAL MARGINAL RIDGE OF TERMINAL MOLAR
SHD. BE BELOW GUM LEVEL

ANCHORAGE LOSS
IN SPITE OF PRECAUTIONS TAKEN IN PLANNING OF
ANCHORAGE, A CERTAIN AMOUNT OF UNWANTED
MOVEMENT OF ANCHOR TEETH INVARIABLY
OCCURES DURING ORTHO. TRET. SUCH UNWANTED
MOVT. OF ANCHOR TEETH IS CALLED ANCHORAGE
LOSS.
THREE TYPES OF ANCHORAGE DEMAND OF
AN EXTRACTION CASE :-
1 MAXIMUM ANCHORAGE CASE
2 MODERATE ANCHORAGE CASE
3 MINIMUM ANCHORAGE CASE

LIMITATIONS OF CONVENTIONAL MEANS
OF ANCHORAGE
1 RELY ON STRUCTURES THAT ARE THEMSELVES
MOBILE
2 RELY ON PATIENT COMPLIANCE
3 MANY APPROACHES [ e.g. LIP BUMPER, NANCE`S
APPLIANCE ] ARE- CUMBERSTONE,
UNCOMFORTABLE , INCONVINIENT & UNHYGIENIC
4 EXTRA ORAL FORCES CAN NOT EMPLOY
CONTINIOUS FORCE & CHANCES OF INJURIES
5 ASSOCIATED ANCHORAGE LOSS
6 LIMIT TRET. OPTIONS & COMPRIMISED RESULTS

IMPLANTS
AS DEFINED BY BOUCHER-
IMPLANTS ARE ALLOPLASTIC DEVICES WHICH
ARE SURGICALLY INSERTED INTO OR ONTO JAW
BONES.
OSSEOINTEGRATION- AN INTIMATE STRUCTURAL
CONTACT AT IMPLANT SURFACE AND ADJUSCENT
VITAL BONE, DEVOID OF ANY INTERVENING FIBROUS
TISSUE
TYPES OF IMPLANT DESIGN-
-SUBPERIOSTEAL
-TRANS OSSEOUS
-ENDO OSSEOUS
PARTS OF IMPANT DESIGN 1. IMPLANT BODY
2. IMPLANT HEADwww.indiandentalacademy.com

ANCHORAGE DERIVED FROM IMPLANTS IS
CATEGORISED AS –1 . DIRECT ANCHORAGE
2. INDIRECT ANCHORAGE
DIRECT ANCHORAGE—WHEN ANCHORAGE UTILISES
FORCES FROM THE ACTUAL IMPLANT, AS WHEN A
DENTAL IMPLANT TAKES PLACE OF MISSIMNG TOOTH
& EVENTUALLY SUPPORETS A DENTAL RESTORATION.
-RESTORATION OR TOOTH OVER THE IMPLANT IS
USED TO SECURE THE ORTHO. BANDED ATTACHMENT
INDIRECT ANCHORAGE—THERE IS USE OF IMPLANT TO
STABILISE SPECIFIC DENTAL UNITS TO WHICH CLINICAL
FORCES ARE APPLIED.
-UNDERGOING RAPID RESEARCH & PROMISING
TO ALTER DESIGN & FUNCTION OF ORTHO.
APPLIANCES

APPLICATIONS IN ORTHODONTICS—
I. AS SOURCE OF ANCHORAGE ALONE -
a.ORTHOPAEDIC ANCH.
-MAXILLARY EXPANTION
-HEADGEAR LIKE EFFECTS
b. DENTAL ANCH.
-SPACE CLOSURE
-INTRUSION
-DISTALISATION
II. WITH PROSTHETIC REHABILITATION
[ DIRECT ANCHORAGE ]

RECENT PROPOSITIONS
-ONPLANT
-MINI IMPLANT
-MICRO IMPLANT
-SKELETAL ANCHORAGE SYSTEM
-IMPACTED TITANIUM POSTS

Anchorage in orthodontics

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