Activator part 1

ACTIVATOR PART I
www.indiandentalacademy.com

CONTENTS
 Introduction
 HISTORY AND EVOLUTION
 CONSTRUCTION BITE
 FABRICATION OF ACTIVATOR
 TRIMMING OF ACTIVATOR
 CONCLUSION
 BIBLIOGRAPHY

INTRODUCTION

Moffet
Fox
Kingsley
Hotz

DUAL BITE
Jumping the bite

DUAL BITE
HABITUAL
OCCLUSI
ON
CENTRIC
RELATION
APPEARS
CORRECT IN
BUCCAL
OCCLUSION
PROTRACTIN
G
MUSCULATUR
E TO ACHIEVE
FULL
OCCLUSION
APPLIANC
E
REMOVED

HABITUAL
OCCLUSI
ON
MASTICATI
ON
JIGGLING
OF TEETH
DAMAGE
TMJ

DUAL BITE

DUAL BITEwww.indiandentalacademy.com

ANDRESEN
IMPRESSED BY KINGSLEY’S
CONCEPTS & APPLIANCES.
PROGENITOR OF APPLIANCE 
BIOMECHANICAL WORKING RETAINER
DEVELOPED A LOOSE FITTING
APPLIANCE MODIFICATION.

ROBIN
DEVELOPED MONOBLOC
FUNCTION

ANDRESEN MOVED
FROM DENMARK TO
NORWAY
 ASSOCIATED WITH HAUPL
 HAUPL
IMPRESSED WITH RESULTS OF BIOMECHANICAL WORKING
RETAINER.
INTERSTED IN ITS EFFECTS ON UNDERLYING TISSUES.
CONVINCED THAT THE APPLIANCE:-
INDUCED GROWTH CHANGES IN THE PHYSIOLOGIC MANNER.
STIMULATED OR TRANSFORMED THE NATURAL FORCES.
 ACTIVATOR

HAUPL
 Influence and Limitations of activator on growth
process.
Individu
al
Optimu
m
Whether activator can promote mandibular growth?
Activator can not create large mandible from a small one.
But it can help to achieve the OPTIMAL SIZE consistent with
individual’s morphogenetic pattern.
Philosophy of treatment changes.
Purpose of the appliance.

ORIGINAL APPLIANCE – ANDRESEN & HAUPL

FOR EXPANSION

ANDRESEN – HAUPL - PETRIK
 Produced 5th edition of their book – on
functional jaw orthopedics in 1957.
 Many additional wire elements were
described.

ESCHLER(1952)
COMBINED LABIAL BOW

ACTIVE
PASSIVE

ORIGINAL
APPLIANCE
MODIFICATIO
NS
ONE RIGID
MASS FOR
MAXILLARY &
MANDIBULAR
ARCHES, BUT
WITH
REDUCED
BULK
UPPER AND
LOWER PARTS
JOINED BY
WIRE
ELEMENTS
OPEN
ACTIVATORS
REDUCED IN
ANTERIOR
PALATAL
REGION
REDUCED
ALVEOLAR
REGION &
CROSS PALATAL
WIRES INSTEAD
OF FULL ACRYLIC
PLATES.

TWO PARTS
UPPER AND
LOWER JOINED
BY WIRE BOWS
MUSCLE
IMPULSES
REINFORCED
BY WIRE
ELEMENTS
FLEXIBILITY:
MANDIBULAR
MOVEMENTS IN
ALL
DIRECTIONS

MODE OF ACTION

LATER MODIFICATIONS
MORPHOGENETI
C PATTERN
GROWTH
DIRECTION
HORIZONTAL & VERTICAL COMPONENTS OF
THE CONTRUCTION BITE DIFFER 
DEPENDING ON GOAL OF TREATMENT

EFFICACY OF ACTIVATOR(ANDRESEN & HAUPL 1955)
 MUSCULOSKELETAL ADAPTATION.
 NEUROMUSCULAR ADAPTATION.
 CONDYLAR ADAPTATION.
 CONSTRUCTION BITE.
 MYOTATIC REFLEX ACTIVITY.

Controvers
y

GRUDE(1952)
 Andresen - Haupl devised mode of action of
activator valid only when Mandible not
displaced beyond postural rest position.
 If mandible opened beyond 4mm(iod) limit 
activator works by stretching the soft tissues
or relying on viscoelastic properties of the
muscles.
WOODSID
E

GRUDE
 OPENING OF 4MM FROM OCCLUSAL
POSITION DOES NOT INDUCE SAME
MUSCLE ACTIVATION IN EVERY PATIENT.
WIDE RANGE OF VARIATION IN
INTEROCCLUSAL CLEARANCE:
DIFFERENT INDIVIDUALS
TIME TO TIME
HEAD & BODY POSTURE/WAKEFULNESS
OR SLEEP.

CLASSIFICATION OF VIEWS

GROUP
1
PETROVIC
MCNAMA
RA
GRUD
E
GROUP
2
LPM
ACTIVITY
HERREN
HARVOL
D
WOODSID
E
GROUP
3

 ESCHLER(1952):
BOTH ISOMETRIC & ISOTONIC MUSCLE
CONTRACTIONS.(WHEN MANDIBLE OPENED
BEYOND 4MM LIMIT)
 AHLGREN’S ELECTROMYOGRAPHIC RESEARCH:
ACTIVATOR FUNCTIONS AS AN INTERFERENCE,
PRODUCING NEW CONTRACTION PATTERNS IN
JAW MUSCLES.
 SCHMUTH(1994);WITT(1981);WITT &
KOMPOSCH(1979)
CONSTRUCTION BITE THAT DISPLACE MANDIBLE
BEYOND 4TO 6MM FROM HABITUAL OCCLUSION
 LONG PERIODS OF CONTINOUS PRESSURE

MODE OF
ACTION
CONSTRUCTIO
N BITE
ANDRESE
N HAUPL
HERREN
HARVOLD
WOODSID
E
TRANSITION
AL

LIMITATIONS/
DEGREE OF
SUCCESS
BEST TIME
MODE OF
ACTION
INDICATIONS
USES

SKELETAL & DENTOALVEOLAR EFFECTS
SKELETA
L
DENTO
ALVEOLA
R

SKELETAL EFFECTS
GROWTH POTENTIAL
GROWTH VECTORS
LOWER GROWTH VECTOR
PETROVIC – LPM
GROWTH DIRECTION &
GROWTH INCREMENT

UPPER GROWTH VECTOR
 ACTIVATOR CAN CONTROL UPPER
GROWTH VECTOR.
 MAXILLARY GROWTH CAN BE INHIBITED
OR REDIRECTED , IF MANDIBLE CAN
NOT BE POSITIONED ANTERIORLY.
 WOODSIDE :
SMALL VERTICAL OPENING :
WIDE VERTICAL OPENING:

VERTICAL SKELETAL RELATION
 CHANGING MAXILLAR Y BASE
INCLINATION, CAN, COMPENSATE FOR
ROTATIONS OF MANDIBULAR GROWTH
VECTOR.
 DOWNWARD DISPLACEMENT OF
MAXILLARY BASE ALLOWS MAXILLA TO
ADAPT TO A VERTICAL ROTATION OF
MANDIBLE

TYPES OF FORCES EMPLOYED IN ACTIVATOR
THERAPY

CONSTRUCTI
ON BITE

 Proper activator fabrication require 
determination & reproduction of a correct
construction bite/working bite.
 Purpose: to relocate the jaws in the direction
of treatment objectives.

PLANNING FOR CONSTRUCTION BITE
 For average class II problem:

 Contraindication to edge to edge
construction bite:
Overjet too large.

 Labial tipping of maxillary incisors.
 An incisor erupted markedly to the lingual.

OPENING THE BITE
 Principles:
1 2 3
Force: Direction
Magnitude
Movement/influence:
Construction bite opening:
2) Forward positioning 7-8mm
Vertical opening 2-4mm (slight to moderate
3) Forward positioning no more than 3-5m
Vertical opening 4-6mm

CONSTRUCTION BITE – EXECUTION TECHNIQUE
HORSE SHOE SHAPED WAX BITE RIM
ARCH FORM & SIZE
THICKNESS
MADE ON EITHER UPPER OR LOWER OCCLUSAL SURFACES
PATIENT SITS UPRIGHT
GUIDE MANDIBLE INTO PREDETERMINED POSITION
PATIENT REPEATS THE EXERCISE HIMSELF & HOLDS THE POSITION
FOR A SHORT TIME.
SOFTENED WAX BITE PLACED IN MOUTH
OPERATOR CONTROLS EDGE TO EDGE INCISAL RELATION & MIDLINE
REGISTRATION(DURING CLOSING MOVEMENT)
WAX CUT AWAY FROM LABIAL OF CENTRAL INCISORS
WAX CAREFULLY REMOVED
CHECKED ON UPPER & LOWER MODELS – FITTED ON CASTS
MARGINS TRIMMED WITH SCISSORS
CHILLED & CHECKED ONCE AGAIN

H - ACTIVATOR
 Low vertical opening
More horizontal registration
Low construction bite with markedly forward
mandibular positioning.
General rule for construction bite:
Sagittal
Vertical

INDICATION
Class II div 1 malocclusion with sufficient
overjet.
Class II caused by mandibular overclosure that
results in functional retrusion.
Class II div 1 with posterior positioning of the
mandible , caused by growth deficiency but
future horizontal growth expected.

Postural
rest
position
Habitual
occlusio
n

Postural
rest
position
Habitual
occlusion

EFFECTS
 Mandible
 Maxillary incisors
 Anterior growth vector of maxilla
 Maxillary base

LABIALLY TIPPED
LOWER INCISOR

V ACTIVATOR
 ANTERIOR POSITION: LESS (3 TO 5MM
AHEAD OF HABITUAL OCCLUSION)
 VERTICAL : MAXIMUM OF 4MM FROM
POSTURAL REST VERTICAL DIMENSION.

INDICATION
 CLASS II DIV 1 CASES WITH VERTICAL
GROWTH PATTERN.
This case can not be improved significantly
sagittally by anterior positioning of mandible.
Goal:
Minimal forward positioning of mandible.
Actual adaptation of maxilla to lower arch.
Dentoalveolar compensation.

CONSTRUCTION BITE WITHOUT FORWARD
MANDIBULAR POSITIONING

 Forward positioning of mandible not
indicated in activator construction if sagittal
correction is unnecessary.
 Indicated primarily in vertical bite problems:
Deep bite
Open bite

DEEP BITE
 Dentoalveolar:
Infraocclusion of buccal segments:
True over bite cases with large clearance
Construction bite: moderate or high ,
depending on size of freeway space.
Activator trimmed to permit extrusion of molars.

DEEP BITE
 Supra-occlusion of incisors:
Interocclusal space usually small.
Construction bite shouldnt be high.
Intrusion of incisors:
Loading incisal edges with acrylic cover.
Relative rather than absolute

DEEP BITE
 Skeletal:
Usually horizontal growth pattern
Construction bite : 5-6mm beyond freeway
space.
Dentoalveolar compensation:
Extrusion of lower molars
Distal driving of upper molars

OPEN BITE
 If skeletal relation orthognathic: anterior
positioning of mandible is not necessary.
 Construction bite : 4 to 5mm
To develop sufficient elastic depressing force
& load the molars that are in premature
contact.
(depressing posterior maxillary segments)

CONSTRUCTION BITE WITH OPENING &
POSTERIOR POSITIONING OF MANDIBLE

 Construction bite :
Taken by retruding the lower jaw. (Sagittal)
Vertical opening depends on the retrusion
possible.

TOOTH GUIDANCE OR FUNCTIONAL PROTRUSION
CLASS III MALOCCLUSIONS
 Construction bite: high enough to clear the
incisal guidance.
 This eliminates protrusive relationship.
 Prognosis for pseudo class III is good.
 Early mixed dentition period:
Skeletal manifestations not severe usually.

SKELETAL CLASS III MALOCCLUSION WITH A
NORMAL PATH OF CLOURE FROM POSTURAL
REST TO HABITUAL OCCLUSION.
 Construction bite: opening depends on the
possibility of achieving an end to end incisal
relation.
if overjet is large  construction bite
requires larger opening.
 Indications for treatment of true class III with
activator are limited.
 Early mixed dentition

FABRICATION OF ACTIVATOR
 FIXATOR
 SHIPPED SEPARATELY
 CARE OF THE CONSTRUCTION BITE
 ACRYLIC EXTENSION,WIRE ELEMENTS.
 PROPER COMMUNICATION WITH THE
LABORATORY.

LABORATORY PROCEDURES
 ACCURATE TRANSFER OF
CONSTRUCTION BITE INTO THE
ACTIVATOR.
 ACRYLIC COMPONENTS AND WIRE
ELEMENTS.

WIRE ELEMENTS
 UPPER LABIAL BOW

WIRE ELEMENTS
LOWER LABIAL BOW

ADDITIONAL ELEMENTS

FIXATION OF JACKSCREWS & WIRE ELEMENTS

FABRICATION OF ACRYLIC PORTION

THE UPPER & LOWER PORTIONS ARE MOLDED FROM SELF
CURE ACRYLIC.
THEY ARE JOINED AT THE INTERDENTAL AREA.
APPLICATION FROM BOTH BUCCAL & LINGUAL SIDES.

TRIMMING OF ACTIVATOR

 Principles of force application in the trimming
process are determined by:
Direction of force
Magnitude of force
 Trimming plan

TRIMMING ACTIVATOR FOR VERTICAL CONTROL

INTRUSION

EXTRUSION

EXTRUSION - MOLARS

 TRIMMING OF ALL MOLARS IN ONE
ARCH:
 SIMULTANEOUS EXTRUSION OF BUCCAL
SEGMENT TEETH IN BOTH UPPER AND
LOWER ARCHES:
 CONTROLLED DIFFERENTIAL ERUPTION
GUIDANCE – SELECTIVE TRIMMING OF
ACTIVATOR.

PATH OF ERUPTION OF MOLARS

SAGITTAL CONTROL
GRINDING OF
ACRYLIC &
GUIDE
PLANES
ADJUSTMENT
OF LABIAL
BOW

PROTRUSION OF INCISORS

AUXILLARY ELEMENTS – INCISOR PROTRUSION
 PROTRUSION SPRINGS:

 WOODEN PEGS:

 GUTTA PERCHA:
 COLD CURE ACRYLIC:

RETRUSION - INCISORS

CONTROLLING AXIAL INCLINATION

MOVEMENT OF POSTERIOR TEETH IN SAGITTAL
PLANE

DISTALIZING
MESIO
LINGUAL
SURFACE
LOADED

ADDITIONAL ELEMENTS
STABILIZING WIRES
ACTIVE OPEN SPRING

MESIAL MOVEMENT OF BUCCAL SEGMENT
TEETH
DISTO-
LINGUAL
SURFACES
LOADED

MOVEMENT IN TRANSVERSE PLANE

FOR CROSSBITE
CLOSED
LOOP
PROTRUSIV
E SPRING

CONCLUSION

BIBLIOGRAPHY
 T.M GRABER, DENTOFACIAL
ORTHOPEDICS WITH FUNCTIONAL
APPLIANCES,SECOND EDITION: PG 160-
214.
 T.M GRABER, REMOVABLE
ORTHODONTIC APPLIANCES, SECOND
EDITION: PG 198-234.

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